Merge pull request #44023 from Wavesonics/glb-import-crash-master

Update xatlas to upstream 5571fc7, fixes #44017

3 files changed, 2684 insertions, 3263 deletions

diff --git a/thirdparty/README.md b/thirdparty/README.md
index d011832210..e86d688ec1 100644
--- a/thirdparty/README.md
+++ b/thirdparty/README.md
@@ -671,7 +671,7 @@ File extracted from upstream release tarball:
 ## xatlas
 
 - Upstream: https://github.com/jpcy/xatlas
-- Version: git (470576d3516f7e6d8b4554e7c941194a935969fd, 2020)
+- Version: git (5571fc7ef0d06832947c0a935ccdcf083f7a9264, 2020)
 - License: MIT
 
 Files extracted from upstream source:
diff --git a/thirdparty/xatlas/xatlas.cpp b/thirdparty/xatlas/xatlas.cpp
index 43aec33a9f..9f66ae0067 100644
--- a/thirdparty/xatlas/xatlas.cpp
+++ b/thirdparty/xatlas/xatlas.cpp
@@ -33,19 +33,25 @@ https://github.com/brandonpelfrey/Fast-BVH
 MIT License
 Copyright (c) 2012 Brandon Pelfrey
 */
-#include <atomic>
-#include <condition_variable>
-#include <mutex>
-#include <thread>
+#include "xatlas.h"
+#ifndef XATLAS_C_API
+#define XATLAS_C_API 0
+#endif
+#if XATLAS_C_API
+#include "xatlas_c.h"
+#endif
 #include <assert.h>
 #include <float.h> // FLT_MAX
 #include <limits.h>
 #include <math.h>
+#include <atomic>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
 #define __STDC_LIMIT_MACROS
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
-#include "xatlas.h"
 
 #ifndef XA_DEBUG
 #ifdef NDEBUG
@@ -59,7 +65,7 @@ Copyright (c) 2012 Brandon Pelfrey
 #define XA_PROFILE 0
 #endif
 #if XA_PROFILE
-#include <time.h>
+#include <chrono>
 #endif
 
 #ifndef XA_MULTITHREADED
@@ -70,7 +76,10 @@ Copyright (c) 2012 Brandon Pelfrey
 #define XA_XSTR(x) XA_STR(x)
 
 #ifndef XA_ASSERT
-#define XA_ASSERT(exp) if (!(exp)) { XA_PRINT_WARNING("\rASSERT: %s %s %d\n", XA_XSTR(exp), __FILE__, __LINE__); }
+#define XA_ASSERT(exp)                                                              \
+	if (!(exp)) {                                                                   \
+		XA_PRINT_WARNING("\rASSERT: %s %s %d\n", XA_XSTR(exp), __FILE__, __LINE__); \
+	}
 #endif
 
 #ifndef XA_DEBUG_ASSERT
@@ -78,13 +87,13 @@ Copyright (c) 2012 Brandon Pelfrey
 #endif
 
 #ifndef XA_PRINT
-#define XA_PRINT(...) \
+#define XA_PRINT(...)                                                  \
 	if (xatlas::internal::s_print && xatlas::internal::s_printVerbose) \
 		xatlas::internal::s_print(__VA_ARGS__);
 #endif
 
 #ifndef XA_PRINT_WARNING
-#define XA_PRINT_WARNING(...) \
+#define XA_PRINT_WARNING(...)      \
 	if (xatlas::internal::s_print) \
 		xatlas::internal::s_print(__VA_ARGS__);
 #endif
@@ -116,9 +125,9 @@ Copyright (c) 2012 Brandon Pelfrey
 #define XA_MERGE_CHARTS 1
 #define XA_MERGE_CHARTS_MIN_NORMAL_DEVIATION 0.5f
 #define XA_RECOMPUTE_CHARTS 1
-#define XA_CLOSE_HOLES_CHECK_EDGE_INTERSECTION 0
-#define XA_FIX_INTERNAL_BOUNDARY_LOOPS 1
-#define XA_PRINT_CHART_WARNINGS 0
+#define XA_CHECK_PARAM_WINDING 0
+#define XA_CHECK_PIECEWISE_CHART_QUALITY 0
+#define XA_CHECK_T_JUNCTIONS 0
 
 #define XA_DEBUG_HEAP 0
 #define XA_DEBUG_SINGLE_CHART 0
@@ -131,25 +140,19 @@ Copyright (c) 2012 Brandon Pelfrey
 #define XA_DEBUG_EXPORT_OBJ_CHART_GROUPS 0
 #define XA_DEBUG_EXPORT_OBJ_PLANAR_REGIONS 0
 #define XA_DEBUG_EXPORT_OBJ_CHARTS 0
-#define XA_DEBUG_EXPORT_OBJ_BEFORE_FIX_TJUNCTION 0
-#define XA_DEBUG_EXPORT_OBJ_CLOSE_HOLES_ERROR 0
+#define XA_DEBUG_EXPORT_OBJ_TJUNCTION 0 // XA_CHECK_T_JUNCTIONS must also be set
 #define XA_DEBUG_EXPORT_OBJ_CHARTS_AFTER_PARAMETERIZATION 0
 #define XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION 0
 #define XA_DEBUG_EXPORT_OBJ_RECOMPUTED_CHARTS 0
 
-#define XA_DEBUG_EXPORT_OBJ (0 \
-	|| XA_DEBUG_EXPORT_OBJ_FACE_GROUPS \
-	|| XA_DEBUG_EXPORT_OBJ_CHART_GROUPS \
-	|| XA_DEBUG_EXPORT_OBJ_PLANAR_REGIONS \
-	|| XA_DEBUG_EXPORT_OBJ_CHARTS \
-	|| XA_DEBUG_EXPORT_OBJ_BEFORE_FIX_TJUNCTION \
-	|| XA_DEBUG_EXPORT_OBJ_CLOSE_HOLES_ERROR \
-	|| XA_DEBUG_EXPORT_OBJ_CHARTS_AFTER_PARAMETERIZATION \
-	|| XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION \
-	|| XA_DEBUG_EXPORT_OBJ_RECOMPUTED_CHARTS)
+#define XA_DEBUG_EXPORT_OBJ (0 || XA_DEBUG_EXPORT_OBJ_FACE_GROUPS || XA_DEBUG_EXPORT_OBJ_CHART_GROUPS || XA_DEBUG_EXPORT_OBJ_PLANAR_REGIONS || XA_DEBUG_EXPORT_OBJ_CHARTS || XA_DEBUG_EXPORT_OBJ_TJUNCTION || XA_DEBUG_EXPORT_OBJ_CHARTS_AFTER_PARAMETERIZATION || XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION || XA_DEBUG_EXPORT_OBJ_RECOMPUTED_CHARTS)
 
 #ifdef _MSC_VER
-#define XA_FOPEN(_file, _filename, _mode) { if (fopen_s(&_file, _filename, _mode) != 0) _file = NULL; }
+#define XA_FOPEN(_file, _filename, _mode)           \
+	{                                               \
+		if (fopen_s(&_file, _filename, _mode) != 0) \
+			_file = NULL;                           \
+	}
 #define XA_SPRINTF(_buffer, _size, _format, ...) sprintf_s(_buffer, _size, _format, __VA_ARGS__)
 #else
 #define XA_FOPEN(_file, _filename, _mode) _file = fopen(_filename, _mode)
@@ -165,74 +168,76 @@ static PrintFunc s_print = printf;
 static bool s_printVerbose = false;
 
 #if XA_PROFILE
-#define XA_PROFILE_START(var) const clock_t var##Start = clock();
-#define XA_PROFILE_END(var) internal::s_profile.var += clock() - var##Start;
-#define XA_PROFILE_PRINT_AND_RESET(label, var) XA_PRINT("%s%.2f seconds (%g ms)\n", label, internal::clockToSeconds(internal::s_profile.var), internal::clockToMs(internal::s_profile.var)); internal::s_profile.var = 0;
+typedef uint64_t Duration;
+
+#define XA_PROFILE_START(var) const std::chrono::time_point<std::chrono::high_resolution_clock> var##Start = std::chrono::high_resolution_clock::now();
+#define XA_PROFILE_END(var) internal::s_profile.var += uint64_t(std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - var##Start).count());
+#define XA_PROFILE_PRINT_AND_RESET(label, var)                                                                                                          \
+	XA_PRINT("%s%.2f seconds (%g ms)\n", label, internal::durationToSeconds(internal::s_profile.var), internal::durationToMs(internal::s_profile.var)); \
+	internal::s_profile.var = 0u;
 #define XA_PROFILE_ALLOC 0
 
-struct ProfileData
-{
+struct ProfileData {
 #if XA_PROFILE_ALLOC
-	std::atomic<clock_t> alloc;
+	std::atomic<Duration> alloc;
 #endif
-	clock_t addMeshReal;
-	clock_t addMeshCopyData;
-	std::atomic<clock_t> addMeshThread;
-	std::atomic<clock_t> addMeshCreateColocals;
-	clock_t computeChartsReal;
-	std::atomic<clock_t> computeChartsThread;
-	std::atomic<clock_t> createFaceGroups;
-	std::atomic<clock_t> extractInvalidMeshGeometry;
-	std::atomic<clock_t> chartGroupComputeChartsReal;
-	std::atomic<clock_t> chartGroupComputeChartsThread;
-	std::atomic<clock_t> createChartGroupMesh;
-	std::atomic<clock_t> createChartGroupMeshColocals;
-	std::atomic<clock_t> createChartGroupMeshBoundaries;
-	std::atomic<clock_t> buildAtlas;
-	std::atomic<clock_t> buildAtlasInit;
-	std::atomic<clock_t> planarCharts;
-	std::atomic<clock_t> clusteredCharts;
-	std::atomic<clock_t> clusteredChartsPlaceSeeds;
-	std::atomic<clock_t> clusteredChartsPlaceSeedsBoundaryIntersection;
-	std::atomic<clock_t> clusteredChartsRelocateSeeds;
-	std::atomic<clock_t> clusteredChartsReset;
-	std::atomic<clock_t> clusteredChartsGrow;
-	std::atomic<clock_t> clusteredChartsGrowBoundaryIntersection;
-	std::atomic<clock_t> clusteredChartsMerge;
-	std::atomic<clock_t> clusteredChartsFillHoles;
-	std::atomic<clock_t> copyChartFaces;
-	clock_t parameterizeChartsReal;
-	std::atomic<clock_t> parameterizeChartsThread;
-	std::atomic<clock_t> createChartMesh;
-	std::atomic<clock_t> fixChartMeshTJunctions;
-	std::atomic<clock_t> closeChartMeshHoles;
-	std::atomic<clock_t> parameterizeChartsOrthogonal;
-	std::atomic<clock_t> parameterizeChartsLSCM;
-	std::atomic<clock_t> parameterizeChartsRecompute;
-	std::atomic<clock_t> parameterizeChartsPiecewise;
-	std::atomic<clock_t> parameterizeChartsPiecewiseBoundaryIntersection;
-	std::atomic<clock_t> parameterizeChartsEvaluateQuality;
-	clock_t packCharts;
-	clock_t packChartsAddCharts;
-	std::atomic<clock_t> packChartsAddChartsThread;
-	std::atomic<clock_t> packChartsAddChartsRestoreTexcoords;
-	clock_t packChartsRasterize;
-	clock_t packChartsDilate;
-	clock_t packChartsFindLocation;
-	clock_t packChartsBlit;
-	clock_t buildOutputMeshes;
+	std::chrono::time_point<std::chrono::high_resolution_clock> addMeshRealStart;
+	Duration addMeshReal;
+	Duration addMeshCopyData;
+	std::atomic<Duration> addMeshThread;
+	std::atomic<Duration> addMeshCreateColocals;
+	Duration computeChartsReal;
+	std::atomic<Duration> computeChartsThread;
+	std::atomic<Duration> createFaceGroups;
+	std::atomic<Duration> extractInvalidMeshGeometry;
+	std::atomic<Duration> chartGroupComputeChartsReal;
+	std::atomic<Duration> chartGroupComputeChartsThread;
+	std::atomic<Duration> createChartGroupMesh;
+	std::atomic<Duration> createChartGroupMeshColocals;
+	std::atomic<Duration> createChartGroupMeshBoundaries;
+	std::atomic<Duration> buildAtlas;
+	std::atomic<Duration> buildAtlasInit;
+	std::atomic<Duration> planarCharts;
+	std::atomic<Duration> originalUvCharts;
+	std::atomic<Duration> clusteredCharts;
+	std::atomic<Duration> clusteredChartsPlaceSeeds;
+	std::atomic<Duration> clusteredChartsPlaceSeedsBoundaryIntersection;
+	std::atomic<Duration> clusteredChartsRelocateSeeds;
+	std::atomic<Duration> clusteredChartsReset;
+	std::atomic<Duration> clusteredChartsGrow;
+	std::atomic<Duration> clusteredChartsGrowBoundaryIntersection;
+	std::atomic<Duration> clusteredChartsMerge;
+	std::atomic<Duration> clusteredChartsFillHoles;
+	std::atomic<Duration> copyChartFaces;
+	std::atomic<Duration> createChartMeshAndParameterizeReal;
+	std::atomic<Duration> createChartMeshAndParameterizeThread;
+	std::atomic<Duration> createChartMesh;
+	std::atomic<Duration> parameterizeCharts;
+	std::atomic<Duration> parameterizeChartsOrthogonal;
+	std::atomic<Duration> parameterizeChartsLSCM;
+	std::atomic<Duration> parameterizeChartsRecompute;
+	std::atomic<Duration> parameterizeChartsPiecewise;
+	std::atomic<Duration> parameterizeChartsPiecewiseBoundaryIntersection;
+	std::atomic<Duration> parameterizeChartsEvaluateQuality;
+	Duration packCharts;
+	Duration packChartsAddCharts;
+	std::atomic<Duration> packChartsAddChartsThread;
+	std::atomic<Duration> packChartsAddChartsRestoreTexcoords;
+	Duration packChartsRasterize;
+	Duration packChartsDilate;
+	Duration packChartsFindLocation;
+	Duration packChartsBlit;
+	Duration buildOutputMeshes;
 };
 
 static ProfileData s_profile;
 
-static double clockToMs(clock_t c)
-{
-	return c * 1000.0 / CLOCKS_PER_SEC;
+static double durationToMs(Duration c) {
+	return (double)c * 0.001;
 }
 
-static double clockToSeconds(clock_t c)
-{
-	return c / (double)CLOCKS_PER_SEC;
+static double durationToSeconds(Duration c) {
+	return (double)c * 0.000001;
 }
 #else
 #define XA_PROFILE_START(var)
@@ -241,10 +246,8 @@ static double clockToSeconds(clock_t c)
 #define XA_PROFILE_ALLOC 0
 #endif
 
-struct MemTag
-{
-	enum
-	{
+struct MemTag {
+	enum {
 		Default,
 		BitImage,
 		BVH,
@@ -267,8 +270,7 @@ struct MemTag
 };
 
 #if XA_DEBUG_HEAP
-struct AllocHeader
-{
+struct AllocHeader {
 	size_t size;
 	const char *file;
 	int line;
@@ -281,11 +283,10 @@ struct AllocHeader
 static std::mutex s_allocMutex;
 static AllocHeader *s_allocRoot = nullptr;
 static size_t s_allocTotalCount = 0, s_allocTotalSize = 0, s_allocPeakSize = 0, s_allocCount[MemTag::Count] = { 0 }, s_allocTotalTagSize[MemTag::Count] = { 0 }, s_allocPeakTagSize[MemTag::Count] = { 0 };
-static uint32_t s_allocId =0 ;
+static uint32_t s_allocId = 0;
 static constexpr uint32_t kAllocRedzone = 0x12345678;
 
-static void *Realloc(void *ptr, size_t size, int tag, const char *file, int line)
-{
+static void *Realloc(void *ptr, size_t size, int tag, const char *file, int line) {
 	std::unique_lock<std::mutex> lock(s_allocMutex);
 	if (!size && !ptr)
 		return nullptr;
@@ -346,8 +347,7 @@ static void *Realloc(void *ptr, size_t size, int tag, const char *file, int line
 	return newPtr + sizeof(AllocHeader);
 }
 
-static void ReportLeaks()
-{
+static void ReportLeaks() {
 	printf("Checking for memory leaks...\n");
 	bool anyLeaks = false;
 	AllocHeader *header = s_allocRoot;
@@ -375,8 +375,7 @@ static void ReportLeaks()
 		s_allocTotalTagSize[i] = s_allocPeakTagSize[i] = 0;
 }
 
-static void PrintMemoryUsage()
-{
+static void PrintMemoryUsage() {
 	XA_PRINT("Total allocations: %zu\n", s_allocTotalCount);
 	XA_PRINT("Memory usage: %0.2fMB current, %0.2fMB peak\n", internal::s_allocTotalSize / 1024.0f / 1024.0f, internal::s_allocPeakSize / 1024.0f / 1024.0f);
 	static const char *labels[] = { // Sync with MemTag
@@ -405,8 +404,7 @@ static void PrintMemoryUsage()
 
 #define XA_PRINT_MEM_USAGE internal::PrintMemoryUsage();
 #else
-static void *Realloc(void *ptr, size_t size, int /*tag*/, const char * /*file*/, int /*line*/)
-{
+static void *Realloc(void *ptr, size_t size, int /*tag*/, const char * /*file*/, int /*line*/) {
 	if (size == 0 && !ptr)
 		return nullptr;
 	if (size == 0 && s_free) {
@@ -432,89 +430,75 @@ static constexpr float kEpsilon = 0.0001f;
 static constexpr float kAreaEpsilon = FLT_EPSILON;
 static constexpr float kNormalEpsilon = 0.001f;
 
-static int align(int x, int a)
-{
+static int align(int x, int a) {
 	return (x + a - 1) & ~(a - 1);
 }
 
 template <typename T>
-static T max(const T &a, const T &b)
-{
+static T max(const T &a, const T &b) {
 	return a > b ? a : b;
 }
 
 template <typename T>
-static T min(const T &a, const T &b)
-{
+static T min(const T &a, const T &b) {
 	return a < b ? a : b;
 }
 
 template <typename T>
-static T max3(const T &a, const T &b, const T &c)
-{
+static T max3(const T &a, const T &b, const T &c) {
 	return max(a, max(b, c));
 }
 
 /// Return the maximum of the three arguments.
 template <typename T>
-static T min3(const T &a, const T &b, const T &c)
-{
+static T min3(const T &a, const T &b, const T &c) {
 	return min(a, min(b, c));
 }
 
 /// Clamp between two values.
 template <typename T>
-static T clamp(const T &x, const T &a, const T &b)
-{
+static T clamp(const T &x, const T &a, const T &b) {
 	return min(max(x, a), b);
 }
 
 template <typename T>
-static void swap(T &a, T &b)
-{
+static void swap(T &a, T &b) {
 	T temp = a;
 	a = b;
 	b = temp;
 }
 
-union FloatUint32
-{
+union FloatUint32 {
 	float f;
 	uint32_t u;
 };
 
-static bool isFinite(float f)
-{
+static bool isFinite(float f) {
 	FloatUint32 fu;
 	fu.f = f;
 	return fu.u != 0x7F800000u && fu.u != 0x7F800001u;
 }
 
-static bool isNan(float f)
-{
+static bool isNan(float f) {
 	return f != f;
 }
 
 // Robust floating point comparisons:
 // http://realtimecollisiondetection.net/blog/?p=89
-static bool equal(const float f0, const float f1, const float epsilon)
-{
+static bool equal(const float f0, const float f1, const float epsilon) {
 	//return fabs(f0-f1) <= epsilon;
 	return fabs(f0 - f1) <= epsilon * max3(1.0f, fabsf(f0), fabsf(f1));
 }
 
-static int ftoi_ceil(float val)
-{
+static int ftoi_ceil(float val) {
 	return (int)ceilf(val);
 }
 
-static bool isZero(const float f, const float epsilon)
-{
+static bool isZero(const float f, const float epsilon) {
 	return fabs(f) <= epsilon;
 }
 
-static float square(float f)
-{
+static float square(float f) {
 	return f * f;
 }
 
@@ -524,9 +508,8 @@ static float square(float f)
 * @note isPowerOfTwo(x) == true -> nextPowerOfTwo(x) == x
 * @note nextPowerOfTwo(x) = 2 << log2(x-1)
 */
-static uint32_t nextPowerOfTwo(uint32_t x)
-{
-	XA_DEBUG_ASSERT( x != 0 );
+static uint32_t nextPowerOfTwo(uint32_t x) {
+	XA_DEBUG_ASSERT(x != 0);
 	// On modern CPUs this is supposed to be as fast as using the bsr instruction.
 	x--;
 	x |= x >> 1;
@@ -537,38 +520,34 @@ static uint32_t nextPowerOfTwo(uint32_t x)
 	return x + 1;
 }
 
-class Vector2
-{
+class Vector2 {
 public:
 	Vector2() {}
-	explicit Vector2(float f) : x(f), y(f) {}
-	Vector2(float x, float y): x(x), y(y) {}
+	explicit Vector2(float f) :
+			x(f), y(f) {}
+	Vector2(float _x, float _y) :
+			x(_x), y(_y) {}
 
-	Vector2 operator-() const
-	{
+	Vector2 operator-() const {
 		return Vector2(-x, -y);
 	}
 
-	void operator+=(const Vector2 &v)
-	{
+	void operator+=(const Vector2 &v) {
 		x += v.x;
 		y += v.y;
 	}
 
-	void operator-=(const Vector2 &v)
-	{
+	void operator-=(const Vector2 &v) {
 		x -= v.x;
 		y -= v.y;
 	}
 
-	void operator*=(float s)
-	{
+	void operator*=(float s) {
 		x *= s;
 		y *= s;
 	}
 
-	void operator*=(const Vector2 &v)
-	{
+	void operator*=(const Vector2 &v) {
 		x *= v.x;
 		y *= v.y;
 	}
@@ -576,13 +555,11 @@ public:
 	float x, y;
 };
 
-static bool operator==(const Vector2 &a, const Vector2 &b)
-{
+static bool operator==(const Vector2 &a, const Vector2 &b) {
 	return a.x == b.x && a.y == b.y;
 }
 
-static bool operator!=(const Vector2 &a, const Vector2 &b)
-{
+static bool operator!=(const Vector2 &a, const Vector2 &b) {
 	return a.x != b.x || a.y != b.y;
 }
 
@@ -591,78 +568,64 @@ static bool operator!=(const Vector2 &a, const Vector2 &b)
 	return Vector2(a.x + b.x, a.y + b.y);
 }*/
 
-static Vector2 operator-(const Vector2 &a, const Vector2 &b)
-{
+static Vector2 operator-(const Vector2 &a, const Vector2 &b) {
 	return Vector2(a.x - b.x, a.y - b.y);
 }
 
-static Vector2 operator*(const Vector2 &v, float s)
-{
+static Vector2 operator*(const Vector2 &v, float s) {
 	return Vector2(v.x * s, v.y * s);
 }
 
-static float dot(const Vector2 &a, const Vector2 &b)
-{
+static float dot(const Vector2 &a, const Vector2 &b) {
 	return a.x * b.x + a.y * b.y;
 }
 
-static float lengthSquared(const Vector2 &v)
-{
+static float lengthSquared(const Vector2 &v) {
 	return v.x * v.x + v.y * v.y;
 }
 
-static float length(const Vector2 &v)
-{
+static float length(const Vector2 &v) {
 	return sqrtf(lengthSquared(v));
 }
 
 #if XA_DEBUG
-static bool isNormalized(const Vector2 &v, float epsilon = kNormalEpsilon)
-{
+static bool isNormalized(const Vector2 &v, float epsilon = kNormalEpsilon) {
 	return equal(length(v), 1, epsilon);
 }
 #endif
 
-static Vector2 normalize(const Vector2 &v, float epsilon)
-{
-	float l = length(v);
-	XA_DEBUG_ASSERT(!isZero(l, epsilon));
-	XA_UNUSED(epsilon);
-	Vector2 n = v * (1.0f / l);
+static Vector2 normalize(const Vector2 &v) {
+	const float l = length(v);
+	XA_DEBUG_ASSERT(l > 0.0f); // Never negative.
+	const Vector2 n = v * (1.0f / l);
 	XA_DEBUG_ASSERT(isNormalized(n));
 	return n;
 }
 
-static Vector2 normalizeSafe(const Vector2 &v, const Vector2 &fallback, float epsilon)
-{
-	float l = length(v);
-	if (isZero(l, epsilon))
-		return fallback;
-	return v * (1.0f / l);
+static Vector2 normalizeSafe(const Vector2 &v, const Vector2 &fallback) {
+	const float l = length(v);
+	if (l > 0.0f) // Never negative.
+		return v * (1.0f / l);
+	return fallback;
 }
 
-static bool equal(const Vector2 &v1, const Vector2 &v2, float epsilon)
-{
+static bool equal(const Vector2 &v1, const Vector2 &v2, float epsilon) {
 	return equal(v1.x, v2.x, epsilon) && equal(v1.y, v2.y, epsilon);
 }
 
-static Vector2 min(const Vector2 &a, const Vector2 &b)
-{
+static Vector2 min(const Vector2 &a, const Vector2 &b) {
 	return Vector2(min(a.x, b.x), min(a.y, b.y));
 }
 
-static Vector2 max(const Vector2 &a, const Vector2 &b)
-{
+static Vector2 max(const Vector2 &a, const Vector2 &b) {
 	return Vector2(max(a.x, b.x), max(a.y, b.y));
 }
 
-static bool isFinite(const Vector2 &v)
-{
+static bool isFinite(const Vector2 &v) {
 	return isFinite(v.x) && isFinite(v.y);
 }
 
-static float triangleArea(const Vector2 &a, const Vector2 &b, const Vector2 &c)
-{
+static float triangleArea(const Vector2 &a, const Vector2 &b, const Vector2 &c) {
 	// IC: While it may be appealing to use the following expression:
 	//return (c.x * a.y + a.x * b.y + b.x * c.y - b.x * a.y - c.x * b.y - a.x * c.y) * 0.5f;
 	// That's actually a terrible idea. Small triangles far from the origin can end up producing fairly large floating point
@@ -676,8 +639,7 @@ static float triangleArea(const Vector2 &a, const Vector2 &b, const Vector2 &c)
 	return (v0.x * v1.y - v0.y * v1.x) * 0.5f;
 }
 
-static bool linesIntersect(const Vector2 &a1, const Vector2 &a2, const Vector2 &b1, const Vector2 &b2, float epsilon)
-{
+static bool linesIntersect(const Vector2 &a1, const Vector2 &a2, const Vector2 &b1, const Vector2 &b2, float epsilon) {
 	const Vector2 v0 = a2 - a1;
 	const Vector2 v1 = b2 - b1;
 	const float denom = -v1.x * v0.y + v0.x * v1.y;
@@ -685,76 +647,70 @@ static bool linesIntersect(const Vector2 &a1, const Vector2 &a2, const Vector2 &
 		return false;
 	const float s = (-v0.y * (a1.x - b1.x) + v0.x * (a1.y - b1.y)) / denom;
 	if (s > epsilon && s < 1.0f - epsilon) {
-		const float t = ( v1.x * (a1.y - b1.y) - v1.y * (a1.x - b1.x)) / denom;
+		const float t = (v1.x * (a1.y - b1.y) - v1.y * (a1.x - b1.x)) / denom;
 		return t > epsilon && t < 1.0f - epsilon;
 	}
 	return false;
 }
 
-struct Vector2i
-{
+struct Vector2i {
 	Vector2i() {}
-	Vector2i(int32_t x, int32_t y) : x(x), y(y) {}
+	Vector2i(int32_t _x, int32_t _y) :
+			x(_x), y(_y) {}
 
 	int32_t x, y;
 };
 
-class Vector3
-{
+class Vector3 {
 public:
 	Vector3() {}
-	explicit Vector3(float f) : x(f), y(f), z(f) {}
-	Vector3(float x, float y, float z) : x(x), y(y), z(z) {}
-	Vector3(const Vector2 &v, float z) : x(v.x), y(v.y), z(z) {}
-
-	Vector2 xy() const
-	{
+	explicit Vector3(float f) :
+			x(f), y(f), z(f) {}
+	Vector3(float _x, float _y, float _z) :
+			x(_x), y(_y), z(_z) {}
+	Vector3(const Vector2 &v, float _z) :
+			x(v.x), y(v.y), z(_z) {}
+
+	Vector2 xy() const {
 		return Vector2(x, y);
 	}
 
-	Vector3 operator-() const
-	{
+	Vector3 operator-() const {
 		return Vector3(-x, -y, -z);
 	}
 
-	void operator+=(const Vector3 &v)
-	{
+	void operator+=(const Vector3 &v) {
 		x += v.x;
 		y += v.y;
 		z += v.z;
 	}
 
-	void operator-=(const Vector3 &v)
-	{
+	void operator-=(const Vector3 &v) {
 		x -= v.x;
 		y -= v.y;
 		z -= v.z;
 	}
 
-	void operator*=(float s)
-	{
+	void operator*=(float s) {
 		x *= s;
 		y *= s;
 		z *= s;
 	}
 
-	void operator/=(float s)
-	{
+	void operator/=(float s) {
 		float is = 1.0f / s;
 		x *= is;
 		y *= is;
 		z *= is;
 	}
 
-	void operator*=(const Vector3 &v)
-	{
+	void operator*=(const Vector3 &v) {
 		x *= v.x;
 		y *= v.y;
 		z *= v.z;
 	}
 
-	void operator/=(const Vector3 &v)
-	{
+	void operator/=(const Vector3 &v) {
 		x /= v.x;
 		y /= v.y;
 		z /= v.z;
@@ -763,260 +719,151 @@ public:
 	float x, y, z;
 };
 
-static Vector3 operator+(const Vector3 &a, const Vector3 &b)
-{
+static Vector3 operator+(const Vector3 &a, const Vector3 &b) {
 	return Vector3(a.x + b.x, a.y + b.y, a.z + b.z);
 }
 
-static Vector3 operator-(const Vector3 &a, const Vector3 &b)
-{
+static Vector3 operator-(const Vector3 &a, const Vector3 &b) {
 	return Vector3(a.x - b.x, a.y - b.y, a.z - b.z);
 }
 
-static Vector3 cross(const Vector3 &a, const Vector3 &b)
-{
+static bool operator==(const Vector3 &a, const Vector3 &b) {
+	return a.x == b.x && a.y == b.y && a.z == b.z;
+}
+
+static Vector3 cross(const Vector3 &a, const Vector3 &b) {
 	return Vector3(a.y * b.z - a.z * b.y, a.z * b.x - a.x * b.z, a.x * b.y - a.y * b.x);
 }
 
-static Vector3 operator*(const Vector3 &v, float s)
-{
+static Vector3 operator*(const Vector3 &v, float s) {
 	return Vector3(v.x * s, v.y * s, v.z * s);
 }
 
-static Vector3 operator/(const Vector3 &v, float s)
-{
+static Vector3 operator/(const Vector3 &v, float s) {
 	return v * (1.0f / s);
 }
 
-static float dot(const Vector3 &a, const Vector3 &b)
-{
+static float dot(const Vector3 &a, const Vector3 &b) {
 	return a.x * b.x + a.y * b.y + a.z * b.z;
 }
 
-static float lengthSquared(const Vector3 &v)
-{
+static float lengthSquared(const Vector3 &v) {
 	return v.x * v.x + v.y * v.y + v.z * v.z;
 }
 
-static float length(const Vector3 &v)
-{
+static float length(const Vector3 &v) {
 	return sqrtf(lengthSquared(v));
 }
 
-static bool isNormalized(const Vector3 &v, float epsilon = kNormalEpsilon)
-{
-	return equal(length(v), 1, epsilon);
+static bool isNormalized(const Vector3 &v, float epsilon = kNormalEpsilon) {
+	return equal(length(v), 1.0f, epsilon);
 }
 
-static Vector3 normalize(const Vector3 &v, float epsilon)
-{
-	float l = length(v);
-	XA_DEBUG_ASSERT(!isZero(l, epsilon));
-	XA_UNUSED(epsilon);
-	Vector3 n = v * (1.0f / l);
+static Vector3 normalize(const Vector3 &v) {
+	const float l = length(v);
+	XA_DEBUG_ASSERT(l > 0.0f); // Never negative.
+	const Vector3 n = v * (1.0f / l);
 	XA_DEBUG_ASSERT(isNormalized(n));
 	return n;
 }
 
-static Vector3 normalizeSafe(const Vector3 &v, const Vector3 &fallback, float epsilon)
-{
-	float l = length(v);
-	if (isZero(l, epsilon)) {
-		return fallback;
-	}
-	return v * (1.0f / l);
+static Vector3 normalizeSafe(const Vector3 &v, const Vector3 &fallback) {
+	const float l = length(v);
+	if (l > 0.0f) // Never negative.
+		return v * (1.0f / l);
+	return fallback;
 }
 
-static bool equal(const Vector3 &v0, const Vector3 &v1, float epsilon)
-{
+static bool equal(const Vector3 &v0, const Vector3 &v1, float epsilon) {
 	return fabs(v0.x - v1.x) <= epsilon && fabs(v0.y - v1.y) <= epsilon && fabs(v0.z - v1.z) <= epsilon;
 }
 
-static Vector3 min(const Vector3 &a, const Vector3 &b)
-{
+static Vector3 min(const Vector3 &a, const Vector3 &b) {
 	return Vector3(min(a.x, b.x), min(a.y, b.y), min(a.z, b.z));
 }
 
-static Vector3 max(const Vector3 &a, const Vector3 &b)
-{
+static Vector3 max(const Vector3 &a, const Vector3 &b) {
 	return Vector3(max(a.x, b.x), max(a.y, b.y), max(a.z, b.z));
 }
 
 #if XA_DEBUG
-bool isFinite(const Vector3 &v)
-{
+bool isFinite(const Vector3 &v) {
 	return isFinite(v.x) && isFinite(v.y) && isFinite(v.z);
 }
 #endif
 
-struct Extents2
-{
+struct Extents2 {
 	Vector2 min, max;
 
 	Extents2() {}
-	
-	Extents2(Vector2 p1, Vector2 p2)
-	{
+
+	Extents2(Vector2 p1, Vector2 p2) {
 		min = xatlas::internal::min(p1, p2);
 		max = xatlas::internal::max(p1, p2);
 	}
 
-	void reset()
-	{
+	void reset() {
 		min.x = min.y = FLT_MAX;
 		max.x = max.y = -FLT_MAX;
 	}
 
-	void add(Vector2 p)
-	{
+	void add(Vector2 p) {
 		min = xatlas::internal::min(min, p);
 		max = xatlas::internal::max(max, p);
 	}
 
-	Vector2 midpoint() const
-	{
+	Vector2 midpoint() const {
 		return Vector2(min.x + (max.x - min.x) * 0.5f, min.y + (max.y - min.y) * 0.5f);
 	}
 
-	static bool intersect(const Extents2 &e1, const Extents2 &e2)
-	{
+	static bool intersect(const Extents2 &e1, const Extents2 &e2) {
 		return e1.min.x <= e2.max.x && e1.max.x >= e2.min.x && e1.min.y <= e2.max.y && e1.max.y >= e2.min.y;
 	}
 };
 
-struct Plane
-{
-	Plane() = default;
-	
-	Plane(const Vector3 &p1, const Vector3 &p2, const Vector3 &p3)
-	{
-		normal = cross(p2 - p1, p3 - p1);
-		dist = dot(normal, p1);
-	}
-
-	float distance(const Vector3 &p) const
-	{
-		return dot(normal, p) - dist;
-	}
-
-	void normalize()
-	{
-		const float len = length(normal);
-		if (len > 0.0f) {
-			const float il = 1.0f / len;
-			normal *= il;
-			dist *= il;
-		}
-	}
-
-	Vector3 normal;
-	float dist;
-};
-
-static bool lineIntersectsPoint(const Vector3 &point, const Vector3 &lineStart, const Vector3 &lineEnd, float *t, float epsilon)
-{
-	float tt;
-	if (!t)
-		t = &tt;
-	*t = 0.0f;
-	if (equal(lineStart, point, epsilon) || equal(lineEnd, point, epsilon))
-		return false; // Vertex lies on either line vertices.
-	const Vector3 v01 = point - lineStart;
-	const Vector3 v21 = lineEnd - lineStart;
-	const float l = length(v21);
-	const float d = length(cross(v01, v21)) / l;
-	if (!isZero(d, epsilon))
-		return false;
-	*t = dot(v01, v21) / (l * l);
-	return *t > kEpsilon && *t < 1.0f - kEpsilon;
-}
-
-static bool sameSide(const Vector3 &p1, const Vector3 &p2, const Vector3 &a, const Vector3 &b)
-{
-	const Vector3 &ab = b - a;
-	return dot(cross(ab, p1 - a), cross(ab, p2 - a)) >= 0.0f;
-}
-
-// http://blackpawn.com/texts/pointinpoly/default.html
-static bool pointInTriangle(const Vector3 &p, const Vector3 &a, const Vector3 &b, const Vector3 &c)
-{
-	return sameSide(p, a, b, c) && sameSide(p, b, a, c) && sameSide(p, c, a, b);
-}
-
-#if XA_CLOSE_HOLES_CHECK_EDGE_INTERSECTION
-// https://en.wikipedia.org/wiki/M%C3%B6ller%E2%80%93Trumbore_intersection_algorithm
-static bool rayIntersectsTriangle(const Vector3 &rayOrigin, const Vector3 &rayDir, const Vector3 *tri, float *t)
-{
-	*t = 0.0f;
-	const Vector3 &edge1 = tri[1] - tri[0];
-	const Vector3 &edge2 = tri[2] - tri[0];
-	const Vector3 h = cross(rayDir, edge2);
-	const float a = dot(edge1, h);
-	if (a > -kEpsilon && a < kEpsilon)
-		return false; // This ray is parallel to this triangle.
-	const float f = 1.0f / a;
-	const Vector3 s = rayOrigin - tri[0];
-	const float u = f * dot(s, h);
-	if (u < 0.0f || u > 1.0f)
-		return false;
-	const Vector3 q = cross(s, edge1);
-	const float v = f * dot(rayDir, q);
-	if (v < 0.0f || u + v > 1.0f)
-		return false;
-	// At this stage we can compute t to find out where the intersection point is on the line.
-	*t = f * dot(edge2, q);
-	if (*t > kEpsilon && *t < 1.0f - kEpsilon)
-		return true;
-	// This means that there is a line intersection but not a ray intersection.
-	return false;
-}
-#endif
-
 // From Fast-BVH
-struct AABB
-{
-	AABB() : min(FLT_MAX, FLT_MAX, FLT_MAX), max(-FLT_MAX, -FLT_MAX, -FLT_MAX) {}
-	AABB(const Vector3 &min, const Vector3 &max) : min(min), max(max) { }
-	AABB(const Vector3 &p, float radius = 0.0f) : min(p), max(p) { if (radius > 0.0f) expand(radius); }
-
-	bool intersect(const AABB &other) const
-	{
+struct AABB {
+	AABB() :
+			min(FLT_MAX, FLT_MAX, FLT_MAX), max(-FLT_MAX, -FLT_MAX, -FLT_MAX) {}
+	AABB(const Vector3 &_min, const Vector3 &_max) :
+			min(_min), max(_max) {}
+	AABB(const Vector3 &p, float radius = 0.0f) :
+			min(p), max(p) {
+		if (radius > 0.0f)
+			expand(radius);
+	}
+
+	bool intersect(const AABB &other) const {
 		return min.x <= other.max.x && max.x >= other.min.x && min.y <= other.max.y && max.y >= other.min.y && min.z <= other.max.z && max.z >= other.min.z;
 	}
 
-	void expandToInclude(const Vector3 &p)
-	{
+	void expandToInclude(const Vector3 &p) {
 		min = internal::min(min, p);
 		max = internal::max(max, p);
 	}
 
-	void expandToInclude(const AABB &aabb)
-	{
+	void expandToInclude(const AABB &aabb) {
 		min = internal::min(min, aabb.min);
 		max = internal::max(max, aabb.max);
 	}
 
-	void expand(float amount)
-	{
+	void expand(float amount) {
 		min -= Vector3(amount);
 		max += Vector3(amount);
 	}
 
-	Vector3 centroid() const
-	{
+	Vector3 centroid() const {
 		return min + (max - min) * 0.5f;
 	}
 
-	uint32_t maxDimension() const
-	{
+	uint32_t maxDimension() const {
 		const Vector3 extent = max - min;
 		uint32_t result = 0;
 		if (extent.y > extent.x) {
 			result = 1;
 			if (extent.z > extent.y)
 				result = 2;
-		}
-		else if(extent.z > extent.x)
+		} else if (extent.z > extent.x)
 			result = 2;
 		return result;
 	}
@@ -1024,10 +871,9 @@ struct AABB
 	Vector3 min, max;
 };
 
-struct ArrayBase
-{
-	ArrayBase(uint32_t elementSize, int memTag = MemTag::Default) : buffer(nullptr), elementSize(elementSize), size(0), capacity(0)
-	{
+struct ArrayBase {
+	ArrayBase(uint32_t _elementSize, int memTag = MemTag::Default) :
+			buffer(nullptr), elementSize(_elementSize), size(0), capacity(0) {
 #if XA_DEBUG_HEAP
 		this->memTag = memTag;
 #else
@@ -1035,31 +881,31 @@ struct ArrayBase
 #endif
 	}
 
-	~ArrayBase()
-	{
+	~ArrayBase() {
 		XA_FREE(buffer);
 	}
 
-	XA_INLINE void clear()
-	{
+	XA_INLINE void clear() {
 		size = 0;
 	}
 
-	void copyFrom(const uint8_t *data, uint32_t length)
-	{
+	void copyFrom(const uint8_t *data, uint32_t length) {
+		XA_DEBUG_ASSERT(data);
+		XA_DEBUG_ASSERT(length > 0);
 		resize(length, true);
-		memcpy(buffer, data, length * elementSize);
+		if (buffer && data && length > 0)
+			memcpy(buffer, data, length * elementSize);
 	}
 
-	void copyTo(ArrayBase &other) const
-	{
+	void copyTo(ArrayBase &other) const {
 		XA_DEBUG_ASSERT(elementSize == other.elementSize);
+		XA_DEBUG_ASSERT(size > 0);
 		other.resize(size, true);
-		memcpy(other.buffer, buffer, size * elementSize);
+		if (other.buffer && buffer && size > 0)
+			memcpy(other.buffer, buffer, size * elementSize);
 	}
 
-	void destroy()
-	{
+	void destroy() {
 		size = 0;
 		XA_FREE(buffer);
 		buffer = nullptr;
@@ -1068,17 +914,18 @@ struct ArrayBase
 	}
 
 	// Insert the given element at the given index shifting all the elements up.
-	void insertAt(uint32_t index, const uint8_t *value)
-	{
+	void insertAt(uint32_t index, const uint8_t *value) {
 		XA_DEBUG_ASSERT(index >= 0 && index <= size);
+		XA_DEBUG_ASSERT(value);
 		resize(size + 1, false);
-		if (index < size - 1)
+		XA_DEBUG_ASSERT(buffer);
+		if (buffer && index < size - 1)
 			memmove(buffer + elementSize * (index + 1), buffer + elementSize * index, elementSize * (size - 1 - index));
-		memcpy(&buffer[index * elementSize], value, elementSize);
+		if (buffer && value)
+			memcpy(&buffer[index * elementSize], value, elementSize);
 	}
 
-	void moveTo(ArrayBase &other)
-	{
+	void moveTo(ArrayBase &other) {
 		XA_DEBUG_ASSERT(elementSize == other.elementSize);
 		other.destroy();
 		other.buffer = buffer;
@@ -1092,55 +939,61 @@ struct ArrayBase
 		elementSize = size = capacity = 0;
 	}
 
-	void pop_back()
-	{
+	void pop_back() {
 		XA_DEBUG_ASSERT(size > 0);
 		resize(size - 1, false);
 	}
 
-	void push_back(const uint8_t *value)
-	{
+	void push_back(const uint8_t *value) {
 		XA_DEBUG_ASSERT(value < buffer || value >= buffer + size);
+		XA_DEBUG_ASSERT(value);
 		resize(size + 1, false);
-		memcpy(&buffer[(size - 1) * elementSize], value, elementSize);
+		XA_DEBUG_ASSERT(buffer);
+		if (buffer && value)
+			memcpy(&buffer[(size - 1) * elementSize], value, elementSize);
 	}
 
-	void push_back(const ArrayBase &other)
-	{
+	void push_back(const ArrayBase &other) {
 		XA_DEBUG_ASSERT(elementSize == other.elementSize);
-		if (other.size == 0)
-			return;
-		const uint32_t oldSize = size;
-		resize(size + other.size, false);
-		memcpy(buffer + oldSize * elementSize, other.buffer, other.size * other.elementSize);
+		if (other.size > 0) {
+			const uint32_t oldSize = size;
+			resize(size + other.size, false);
+			XA_DEBUG_ASSERT(buffer);
+			if (buffer)
+				memcpy(buffer + oldSize * elementSize, other.buffer, other.size * other.elementSize);
+		}
 	}
 
 	// Remove the element at the given index. This is an expensive operation!
-	void removeAt(uint32_t index)
-	{
+	void removeAt(uint32_t index) {
 		XA_DEBUG_ASSERT(index >= 0 && index < size);
-		if (size != 1)
-			memmove(buffer + elementSize * index, buffer + elementSize * (index + 1), elementSize * (size - 1 - index));
-		size--;
+		XA_DEBUG_ASSERT(buffer);
+		if (buffer) {
+			if (size > 1)
+				memmove(buffer + elementSize * index, buffer + elementSize * (index + 1), elementSize * (size - 1 - index));
+			if (size > 0)
+				size--;
+		}
 	}
 
 	// Element at index is swapped with the last element, then the array length is decremented.
-	void removeAtFast(uint32_t index)
-	{
+	void removeAtFast(uint32_t index) {
 		XA_DEBUG_ASSERT(index >= 0 && index < size);
-		if (size != 1 && index != size - 1)
-			memcpy(buffer + elementSize * index, buffer + elementSize * (size - 1), elementSize);
-		size--;
+		XA_DEBUG_ASSERT(buffer);
+		if (buffer) {
+			if (size > 1 && index != size - 1)
+				memcpy(buffer + elementSize * index, buffer + elementSize * (size - 1), elementSize);
+			if (size > 0)
+				size--;
+		}
 	}
 
-	void reserve(uint32_t desiredSize)
-	{
+	void reserve(uint32_t desiredSize) {
 		if (desiredSize > capacity)
 			setArrayCapacity(desiredSize);
 	}
 
-	void resize(uint32_t newSize, bool exact)
-	{
+	void resize(uint32_t newSize, bool exact) {
 		size = newSize;
 		if (size > capacity) {
 			// First allocation is always exact. Otherwise, following allocations grow array to 150% of desired size.
@@ -1153,8 +1006,7 @@ struct ArrayBase
 		}
 	}
 
-	void setArrayCapacity(uint32_t newCapacity)
-	{
+	void setArrayCapacity(uint32_t newCapacity) {
 		XA_DEBUG_ASSERT(newCapacity >= size);
 		if (newCapacity == 0) {
 			// free the buffer.
@@ -1174,8 +1026,7 @@ struct ArrayBase
 	}
 
 #if XA_DEBUG_HEAP
-	void setMemTag(int _memTag)
-	{
+	void setMemTag(int _memTag) {
 		this->memTag = _memTag;
 	}
 #endif
@@ -1189,28 +1040,27 @@ struct ArrayBase
 #endif
 };
 
-template<typename T>
-class Array
-{
+template <typename T>
+class Array {
 public:
-	Array(int memTag = MemTag::Default) : m_base(sizeof(T), memTag) {}
-	Array(const Array&) = delete;
+	Array(int memTag = MemTag::Default) :
+			m_base(sizeof(T), memTag) {}
+	Array(const Array &) = delete;
 	Array &operator=(const Array &) = delete;
 
-	XA_INLINE const T &operator[](uint32_t index) const
-	{
+	XA_INLINE const T &operator[](uint32_t index) const {
 		XA_DEBUG_ASSERT(index < m_base.size);
+		XA_DEBUG_ASSERT(m_base.buffer);
 		return ((const T *)m_base.buffer)[index];
 	}
 
-	XA_INLINE T &operator[](uint32_t index)
-	{
+	XA_INLINE T &operator[](uint32_t index) {
 		XA_DEBUG_ASSERT(index < m_base.size);
+		XA_DEBUG_ASSERT(m_base.buffer);
 		return ((T *)m_base.buffer)[index];
 	}
 
-	XA_INLINE const T &back() const
-	{
+	XA_INLINE const T &back() const {
 		XA_DEBUG_ASSERT(!isEmpty());
 		return ((const T *)m_base.buffer)[m_base.size - 1];
 	}
@@ -1218,8 +1068,7 @@ public:
 	XA_INLINE T *begin() { return (T *)m_base.buffer; }
 	XA_INLINE void clear() { m_base.clear(); }
 
-	bool contains(const T &value) const
-	{
+	bool contains(const T &value) const {
 		for (uint32_t i = 0; i < m_base.size; i++) {
 			if (((const T *)m_base.buffer)[i] == value)
 				return true;
@@ -1244,28 +1093,25 @@ public:
 	void reserve(uint32_t desiredSize) { m_base.reserve(desiredSize); }
 	void resize(uint32_t newSize) { m_base.resize(newSize, true); }
 
-	void runCtors()
-	{
+	void runCtors() {
 		for (uint32_t i = 0; i < m_base.size; i++)
 			new (&((T *)m_base.buffer)[i]) T;
 	}
 
-	void runDtors()
-	{
+	void runDtors() {
 		for (uint32_t i = 0; i < m_base.size; i++)
 			((T *)m_base.buffer)[i].~T();
 	}
 
-	void fill(const T &value)
-	{
+	void fill(const T &value) {
 		auto buffer = (T *)m_base.buffer;
 		for (uint32_t i = 0; i < m_base.size; i++)
 			buffer[i] = value;
 	}
 
-	void fillBytes(uint8_t value)
-	{
-		memset(m_base.buffer, (int)value, m_base.size * m_base.elementSize);
+	void fillBytes(uint8_t value) {
+		if (m_base.buffer && m_base.size > 0)
+			memset(m_base.buffer, (int)value, m_base.size * m_base.elementSize);
 	}
 
 #if XA_DEBUG_HEAP
@@ -1273,41 +1119,67 @@ public:
 #endif
 
 	XA_INLINE uint32_t size() const { return m_base.size; }
-	XA_INLINE void zeroOutMemory() { memset(m_base.buffer, 0, m_base.elementSize * m_base.size); }
+
+	XA_INLINE void zeroOutMemory() {
+		if (m_base.buffer && m_base.size > 0)
+			memset(m_base.buffer, 0, m_base.elementSize * m_base.size);
+	}
 
 private:
 	ArrayBase m_base;
 };
 
-template<typename T>
-struct ArrayView
-{
-	ArrayView() : data(nullptr), length(0) {}
-	ArrayView(Array<T> &a) : data(a.data()), length(a.size()) {}
-	ArrayView(T *data, uint32_t length) : data(data), length(length) {}
-	ArrayView &operator=(Array<T> &a) { data = a.data(); length = a.size(); return *this; }
-	XA_INLINE const T &operator[](uint32_t index) const { XA_DEBUG_ASSERT(index < length); return data[index]; }
+template <typename T>
+struct ArrayView {
+	ArrayView() :
+			data(nullptr), length(0) {}
+	ArrayView(Array<T> &a) :
+			data(a.data()), length(a.size()) {}
+	ArrayView(T *_data, uint32_t _length) :
+			data(_data), length(_length) {}
+	ArrayView &operator=(Array<T> &a) {
+		data = a.data();
+		length = a.size();
+		return *this;
+	}
+	XA_INLINE const T &operator[](uint32_t index) const {
+		XA_DEBUG_ASSERT(index < length);
+		return data[index];
+	}
+	XA_INLINE T &operator[](uint32_t index) {
+		XA_DEBUG_ASSERT(index < length);
+		return data[index];
+	}
 	T *data;
 	uint32_t length;
 };
 
-template<typename T>
-struct ConstArrayView
-{
-	ConstArrayView() : data(nullptr), length(0) {}
-	ConstArrayView(const Array<T> &a) : data(a.data()), length(a.size()) {}
-	ConstArrayView(const T *data, uint32_t length) : data(data), length(length) {}
-	ConstArrayView &operator=(const Array<T> &a) { data = a.data(); length = a.size(); return *this; }
-	XA_INLINE const T &operator[](uint32_t index) const { XA_DEBUG_ASSERT(index < length); return data[index]; }
+template <typename T>
+struct ConstArrayView {
+	ConstArrayView() :
+			data(nullptr), length(0) {}
+	ConstArrayView(const Array<T> &a) :
+			data(a.data()), length(a.size()) {}
+	ConstArrayView(ArrayView<T> av) :
+			data(av.data), length(av.length) {}
+	ConstArrayView(const T *_data, uint32_t _length) :
+			data(_data), length(_length) {}
+	ConstArrayView &operator=(const Array<T> &a) {
+		data = a.data();
+		length = a.size();
+		return *this;
+	}
+	XA_INLINE const T &operator[](uint32_t index) const {
+		XA_DEBUG_ASSERT(index < length);
+		return data[index];
+	}
 	const T *data;
 	uint32_t length;
 };
 
 /// Basis class to compute tangent space basis, ortogonalizations and to transform vectors from one space to another.
-struct Basis
-{
-	XA_NODISCARD static Vector3 computeTangent(const Vector3 &normal)
-	{
+struct Basis {
+	XA_NODISCARD static Vector3 computeTangent(const Vector3 &normal) {
 		XA_ASSERT(isNormalized(normal));
 		// Choose minimum axis.
 		Vector3 tangent;
@@ -1319,12 +1191,11 @@ struct Basis
 			tangent = Vector3(0, 0, 1);
 		// Ortogonalize
 		tangent -= normal * dot(normal, tangent);
-		tangent = normalize(tangent, kEpsilon);
+		tangent = normalize(tangent);
 		return tangent;
 	}
 
-	XA_NODISCARD static Vector3 computeBitangent(const Vector3 &normal, const Vector3 &tangent)
-	{
+	XA_NODISCARD static Vector3 computeBitangent(const Vector3 &normal, const Vector3 &tangent) {
 		return cross(normal, tangent);
 	}
 
@@ -1334,42 +1205,36 @@ struct Basis
 };
 
 // Simple bit array.
-class BitArray
-{
+class BitArray {
 public:
-	BitArray() : m_size(0) {}
+	BitArray() :
+			m_size(0) {}
 
-	BitArray(uint32_t sz)
-	{
+	BitArray(uint32_t sz) {
 		resize(sz);
 	}
 
-	void resize(uint32_t new_size)
-	{
+	void resize(uint32_t new_size) {
 		m_size = new_size;
 		m_wordArray.resize((m_size + 31) >> 5);
 	}
 
-	bool get(uint32_t index) const
-	{
+	bool get(uint32_t index) const {
 		XA_DEBUG_ASSERT(index < m_size);
 		return (m_wordArray[index >> 5] & (1 << (index & 31))) != 0;
 	}
 
-	void set(uint32_t index)
-	{
+	void set(uint32_t index) {
 		XA_DEBUG_ASSERT(index < m_size);
 		m_wordArray[index >> 5] |= (1 << (index & 31));
 	}
 
-	void unset(uint32_t index)
-	{
+	void unset(uint32_t index) {
 		XA_DEBUG_ASSERT(index < m_size);
 		m_wordArray[index >> 5] &= ~(1 << (index & 31));
 	}
 
-	void zeroOutMemory()
-	{
+	void zeroOutMemory() {
 		m_wordArray.zeroOutMemory();
 	}
 
@@ -1378,13 +1243,13 @@ private:
 	Array<uint32_t> m_wordArray;
 };
 
-class BitImage
-{
+class BitImage {
 public:
-	BitImage() : m_width(0), m_height(0), m_rowStride(0), m_data(MemTag::BitImage) {}
+	BitImage() :
+			m_width(0), m_height(0), m_rowStride(0), m_data(MemTag::BitImage) {}
 
-	BitImage(uint32_t w, uint32_t h) : m_width(w), m_height(h), m_data(MemTag::BitImage)
-	{
+	BitImage(uint32_t w, uint32_t h) :
+			m_width(w), m_height(h), m_data(MemTag::BitImage) {
 		m_rowStride = (m_width + 63) >> 6;
 		m_data.resize(m_rowStride * m_height);
 		m_data.zeroOutMemory();
@@ -1395,16 +1260,14 @@ public:
 	uint32_t width() const { return m_width; }
 	uint32_t height() const { return m_height; }
 
-	void copyTo(BitImage &other)
-	{
+	void copyTo(BitImage &other) {
 		other.m_width = m_width;
 		other.m_height = m_height;
 		other.m_rowStride = m_rowStride;
 		m_data.copyTo(other.m_data);
 	}
 
-	void resize(uint32_t w, uint32_t h, bool discard)
-	{
+	void resize(uint32_t w, uint32_t h, bool discard) {
 		const uint32_t rowStride = (w + 63) >> 6;
 		if (discard) {
 			m_data.resize(rowStride * h);
@@ -1428,28 +1291,24 @@ public:
 		m_rowStride = rowStride;
 	}
 
-	bool get(uint32_t x, uint32_t y) const
-	{
+	bool get(uint32_t x, uint32_t y) const {
 		XA_DEBUG_ASSERT(x < m_width && y < m_height);
 		const uint32_t index = (x >> 6) + y * m_rowStride;
 		return (m_data[index] & (UINT64_C(1) << (uint64_t(x) & UINT64_C(63)))) != 0;
 	}
 
-	void set(uint32_t x, uint32_t y)
-	{
+	void set(uint32_t x, uint32_t y) {
 		XA_DEBUG_ASSERT(x < m_width && y < m_height);
 		const uint32_t index = (x >> 6) + y * m_rowStride;
 		m_data[index] |= UINT64_C(1) << (uint64_t(x) & UINT64_C(63));
 		XA_DEBUG_ASSERT(get(x, y));
 	}
 
-	void zeroOutMemory()
-	{
+	void zeroOutMemory() {
 		m_data.zeroOutMemory();
 	}
 
-	bool canBlit(const BitImage &image, uint32_t offsetX, uint32_t offsetY) const
-	{
+	bool canBlit(const BitImage &image, uint32_t offsetX, uint32_t offsetY) const {
 		for (uint32_t y = 0; y < image.m_height; y++) {
 			const uint32_t thisY = y + offsetY;
 			if (thisY >= m_height)
@@ -1473,8 +1332,7 @@ public:
 		return true;
 	}
 
-	void dilate(uint32_t padding)
-	{
+	void dilate(uint32_t padding) {
 		BitImage tmp(m_width, m_height);
 		for (uint32_t p = 0; p < padding; p++) {
 			tmp.zeroOutMemory();
@@ -1484,15 +1342,21 @@ public:
 					if (!b) {
 						if (x > 0) {
 							b |= get(x - 1, y);
-							if (y > 0) b |= get(x - 1, y - 1);
-							if (y < m_height - 1) b |= get(x - 1, y + 1);
+							if (y > 0)
+								b |= get(x - 1, y - 1);
+							if (y < m_height - 1)
+								b |= get(x - 1, y + 1);
 						}
-						if (y > 0) b |= get(x, y - 1);
-						if (y < m_height - 1) b |= get(x, y + 1);
+						if (y > 0)
+							b |= get(x, y - 1);
+						if (y < m_height - 1)
+							b |= get(x, y + 1);
 						if (x < m_width - 1) {
 							b |= get(x + 1, y);
-							if (y > 0) b |= get(x + 1, y - 1);
-							if (y < m_height - 1) b |= get(x + 1, y + 1);
+							if (y > 0)
+								b |= get(x + 1, y - 1);
+							if (y < m_height - 1)
+								b |= get(x + 1, y + 1);
 						}
 					}
 					if (b)
@@ -1511,11 +1375,10 @@ private:
 };
 
 // From Fast-BVH
-class BVH
-{
+class BVH {
 public:
-	BVH(const Array<AABB> &objectAabbs, uint32_t leafSize = 4) : m_objectIds(MemTag::BVH), m_nodes(MemTag::BVH)
-	{
+	BVH(const Array<AABB> &objectAabbs, uint32_t leafSize = 4) :
+			m_objectIds(MemTag::BVH), m_nodes(MemTag::BVH) {
 		m_objectAabbs = &objectAabbs;
 		if (m_objectAabbs->isEmpty())
 			return;
@@ -1535,7 +1398,7 @@ public:
 		Node node;
 		m_nodes.reserve(objectAabbs.size() * 2);
 		uint32_t nNodes = 0;
-		while(stackptr > 0) {
+		while (stackptr > 0) {
 			// Pop the next item off of the stack
 			const BuildEntry &bnode = todo[--stackptr];
 			const uint32_t start = bnode.start;
@@ -1548,7 +1411,7 @@ public:
 			// Calculate the bounding box for this node
 			AABB bb(objectAabbs[m_objectIds[start]]);
 			AABB bc(objectAabbs[m_objectIds[start]].centroid());
-			for(uint32_t p = start + 1; p < end; ++p) {
+			for (uint32_t p = start + 1; p < end; ++p) {
 				bb.expandToInclude(objectAabbs[m_objectIds[p]]);
 				bc.expandToInclude(objectAabbs[m_objectIds[p]].centroid());
 			}
@@ -1564,7 +1427,7 @@ public:
 				m_nodes[bnode.parent].rightOffset--;
 				// When this is the second touch, this is the right child.
 				// The right child sets up the offset for the flat tree.
-				if (m_nodes[bnode.parent].rightOffset == kTouchedTwice )
+				if (m_nodes[bnode.parent].rightOffset == kTouchedTwice)
 					m_nodes[bnode.parent].rightOffset = nNodes - 1 - bnode.parent;
 			}
 			// If this is a leaf, no need to subdivide.
@@ -1599,21 +1462,20 @@ public:
 		}
 	}
 
-	void query(const AABB &queryAabb, Array<uint32_t> &result) const
-	{
+	void query(const AABB &queryAabb, Array<uint32_t> &result) const {
 		result.clear();
 		// Working set
 		uint32_t todo[64];
 		int32_t stackptr = 0;
 		// "Push" on the root node to the working set
 		todo[stackptr] = 0;
-		while(stackptr >= 0) {
+		while (stackptr >= 0) {
 			// Pop off the next node to work on.
 			const int ni = todo[stackptr--];
 			const Node &node = m_nodes[ni];
 			// Is leaf -> Intersect
 			if (node.rightOffset == 0) {
-				for(uint32_t o = 0; o < node.nPrims; ++o) {
+				for (uint32_t o = 0; o < node.nPrims; ++o) {
 					const uint32_t obj = node.start + o;
 					if (queryAabb.intersect((*m_objectAabbs)[m_objectIds[obj]]))
 						result.push_back(m_objectIds[obj]);
@@ -1630,14 +1492,12 @@ public:
 	}
 
 private:
-	struct BuildEntry
-	{
+	struct BuildEntry {
 		uint32_t parent; // If non-zero then this is the index of the parent. (used in offsets)
 		uint32_t start, end; // The range of objects in the object list covered by this node.
 	};
 
-	struct Node
-	{
+	struct Node {
 		AABB aabb;
 		uint32_t start, nPrims, rightOffset;
 	};
@@ -1647,16 +1507,14 @@ private:
 	Array<Node> m_nodes;
 };
 
-struct Fit
-{
-	static bool computeBasis(const Vector3 *points, uint32_t pointsCount, Basis *basis)
-	{
-		if (computeLeastSquaresNormal(points, pointsCount, &basis->normal)) {
+struct Fit {
+	static bool computeBasis(ConstArrayView<Vector3> points, Basis *basis) {
+		if (computeLeastSquaresNormal(points, &basis->normal)) {
 			basis->tangent = Basis::computeTangent(basis->normal);
 			basis->bitangent = Basis::computeBitangent(basis->normal, basis->tangent);
 			return true;
 		}
-		return computeEigen(points, pointsCount, basis);
+		return computeEigen(points, basis);
 	}
 
 private:
@@ -1664,21 +1522,20 @@ private:
 	// Fast, and accurate to within a few degrees.
 	// Returns None if the points do not span a plane.
 	// https://www.ilikebigbits.com/2015_03_04_plane_from_points.html
-	static bool computeLeastSquaresNormal(const Vector3 *points, uint32_t pointsCount, Vector3 *normal)
-	{
-		XA_DEBUG_ASSERT(pointsCount >= 3);
-		if (pointsCount == 3) {
-			*normal = normalize(cross(points[2] - points[0], points[1] - points[0]), kEpsilon);
+	static bool computeLeastSquaresNormal(ConstArrayView<Vector3> points, Vector3 *normal) {
+		XA_DEBUG_ASSERT(points.length >= 3);
+		if (points.length == 3) {
+			*normal = normalize(cross(points[2] - points[0], points[1] - points[0]));
 			return true;
 		}
-		const float invN = 1.0f / float(pointsCount);
+		const float invN = 1.0f / float(points.length);
 		Vector3 centroid(0.0f);
-		for (uint32_t i = 0; i < pointsCount; i++)
+		for (uint32_t i = 0; i < points.length; i++)
 			centroid += points[i];
 		centroid *= invN;
 		// Calculate full 3x3 covariance matrix, excluding symmetries:
 		float xx = 0.0f, xy = 0.0f, xz = 0.0f, yy = 0.0f, yz = 0.0f, zz = 0.0f;
-		for (uint32_t i = 0; i < pointsCount; i++) {
+		for (uint32_t i = 0; i < points.length; i++) {
 			Vector3 r = points[i] - centroid;
 			xx += r.x * r.x;
 			xy += r.x * r.y;
@@ -1730,7 +1587,7 @@ private:
 		// Pick path with best conditioning:
 		Vector3 dir(0.0f);
 		if (det_max == det_x)
-			dir = Vector3(det_x,xz * yz - xy * zz,xy * yz - xz * yy);
+			dir = Vector3(det_x, xz * yz - xy * zz, xy * yz - xz * yy);
 		else if (det_max == det_y)
 			dir = Vector3(xz * yz - xy * zz, det_y, xy * xz - yz * xx);
 		else if (det_max == det_z)
@@ -1743,41 +1600,37 @@ private:
 		return isNormalized(*normal);
 	}
 
-	static bool computeEigen(const Vector3 *points, uint32_t pointsCount, Basis *basis)
-	{
+	static bool computeEigen(ConstArrayView<Vector3> points, Basis *basis) {
 		float matrix[6];
-		computeCovariance(pointsCount, points, matrix);
+		computeCovariance(points, matrix);
 		if (matrix[0] == 0 && matrix[3] == 0 && matrix[5] == 0)
 			return false;
 		float eigenValues[3];
 		Vector3 eigenVectors[3];
 		if (!eigenSolveSymmetric3(matrix, eigenValues, eigenVectors))
 			return false;
-		basis->normal = normalize(eigenVectors[2], kEpsilon);
-		basis->tangent = normalize(eigenVectors[0], kEpsilon);
-		basis->bitangent = normalize(eigenVectors[1], kEpsilon);
+		basis->normal = normalize(eigenVectors[2]);
+		basis->tangent = normalize(eigenVectors[0]);
+		basis->bitangent = normalize(eigenVectors[1]);
 		return true;
 	}
 
-	static Vector3 computeCentroid(int n, const Vector3 * points)
-	{
+	static Vector3 computeCentroid(ConstArrayView<Vector3> points) {
 		Vector3 centroid(0.0f);
-		for (int i = 0; i < n; i++) {
+		for (uint32_t i = 0; i < points.length; i++)
 			centroid += points[i];
-		}
-		centroid /= float(n);
+		centroid /= float(points.length);
 		return centroid;
 	}
 
-	static Vector3 computeCovariance(int n, const Vector3 * points, float * covariance)
-	{
+	static Vector3 computeCovariance(ConstArrayView<Vector3> points, float *covariance) {
 		// compute the centroid
-		Vector3 centroid = computeCentroid(n, points);
+		Vector3 centroid = computeCentroid(points);
 		// compute covariance matrix
 		for (int i = 0; i < 6; i++) {
 			covariance[i] = 0.0f;
 		}
-		for (int i = 0; i < n; i++) {
+		for (uint32_t i = 0; i < points.length; i++) {
 			Vector3 v = points[i] - centroid;
 			covariance[0] += v.x * v.x;
 			covariance[1] += v.x * v.y;
@@ -1792,8 +1645,7 @@ private:
 	// Tridiagonal solver from Charles Bloom.
 	// Householder transforms followed by QL decomposition.
 	// Seems to be based on the code from Numerical Recipes in C.
-	static bool eigenSolveSymmetric3(const float matrix[6], float eigenValues[3], Vector3 eigenVectors[3])
-	{
+	static bool eigenSolveSymmetric3(const float matrix[6], float eigenValues[3], Vector3 eigenVectors[3]) {
 		XA_DEBUG_ASSERT(matrix != nullptr && eigenValues != nullptr && eigenVectors != nullptr);
 		float subd[3];
 		float diag[3];
@@ -1818,7 +1670,7 @@ private:
 		// eigenvectors are the columns; make them the rows :
 		for (int i = 0; i < 3; i++) {
 			for (int j = 0; j < 3; j++) {
-				(&eigenVectors[j].x)[i] = (float) work[i][j];
+				(&eigenVectors[j].x)[i] = (float)work[i][j];
 			}
 		}
 		// shuffle to sort by singular value :
@@ -1840,8 +1692,7 @@ private:
 	}
 
 private:
-	static void EigenSolver3_Tridiagonal(float mat[3][3], float *diag, float *subd)
-	{
+	static void EigenSolver3_Tridiagonal(float mat[3][3], float *diag, float *subd) {
 		// Householder reduction T = Q^t M Q
 		//   Input:
 		//     mat, symmetric 3x3 matrix M
@@ -1893,8 +1744,7 @@ private:
 		}
 	}
 
-	static bool EigenSolver3_QLAlgorithm(float mat[3][3], float *diag, float *subd)
-	{
+	static bool EigenSolver3_QLAlgorithm(float mat[3][3], float *diag, float *subd) {
 		// QL iteration with implicit shifting to reduce matrix from tridiagonal
 		// to diagonal
 		const int maxiter = 32;
@@ -1904,21 +1754,21 @@ private:
 				int m;
 				for (m = ell; m <= 1; m++) {
 					float dd = fabsf(diag[m]) + fabsf(diag[m + 1]);
-					if ( fabsf(subd[m]) + dd == dd )
+					if (fabsf(subd[m]) + dd == dd)
 						break;
 				}
-				if ( m == ell )
+				if (m == ell)
 					break;
 				float g = (diag[ell + 1] - diag[ell]) / (2 * subd[ell]);
 				float r = sqrtf(g * g + 1);
-				if ( g < 0 )
+				if (g < 0)
 					g = diag[m] - diag[ell] + subd[ell] / (g - r);
 				else
 					g = diag[m] - diag[ell] + subd[ell] / (g + r);
 				float s = 1, c = 1, p = 0;
 				for (int i = m - 1; i >= ell; i--) {
 					float f = s * subd[i], b = c * subd[i];
-					if ( fabsf(f) >= fabsf(g) ) {
+					if (fabsf(f) >= fabsf(g)) {
 						c = g / f;
 						r = sqrtf(c * c + 1);
 						subd[i + 1] = f * r;
@@ -1944,7 +1794,7 @@ private:
 				subd[ell] = g;
 				subd[m] = 0;
 			}
-			if ( iter == maxiter )
+			if (iter == maxiter)
 				// should not get here under normal circumstances
 				return false;
 		}
@@ -1952,56 +1802,48 @@ private:
 	}
 };
 
-static uint32_t sdbmHash(const void *data_in, uint32_t size, uint32_t h = 5381)
-{
-	const uint8_t *data = (const uint8_t *) data_in;
+static uint32_t sdbmHash(const void *data_in, uint32_t size, uint32_t h = 5381) {
+	const uint8_t *data = (const uint8_t *)data_in;
 	uint32_t i = 0;
 	while (i < size) {
-		h = (h << 16) + (h << 6) - h + (uint32_t ) data[i++];
+		h = (h << 16) + (h << 6) - h + (uint32_t)data[i++];
 	}
 	return h;
 }
 
 template <typename T>
-static uint32_t hash(const T &t, uint32_t h = 5381)
-{
+static uint32_t hash(const T &t, uint32_t h = 5381) {
 	return sdbmHash(&t, sizeof(T), h);
 }
 
 template <typename Key>
-struct Hash
-{
+struct Hash {
 	uint32_t operator()(const Key &k) const { return hash(k); }
 };
 
 template <typename Key>
-struct PassthroughHash
-{
+struct PassthroughHash {
 	uint32_t operator()(const Key &k) const { return (uint32_t)k; }
 };
 
 template <typename Key>
-struct Equal
-{
+struct Equal {
 	bool operator()(const Key &k0, const Key &k1) const { return k0 == k1; }
 };
 
-template<typename Key, typename H = Hash<Key>, typename E = Equal<Key> >
-class HashMap
-{
+template <typename Key, typename H = Hash<Key>, typename E = Equal<Key>>
+class HashMap {
 public:
-	HashMap(int memTag, uint32_t size) : m_memTag(memTag), m_size(size), m_numSlots(0), m_slots(nullptr), m_keys(memTag), m_next(memTag)
-	{
+	HashMap(int memTag, uint32_t size) :
+			m_memTag(memTag), m_size(size), m_numSlots(0), m_slots(nullptr), m_keys(memTag), m_next(memTag) {
 	}
 
-	~HashMap()
-	{
+	~HashMap() {
 		if (m_slots)
 			XA_FREE(m_slots);
 	}
 
-	void destroy()
-	{
+	void destroy() {
 		if (m_slots) {
 			XA_FREE(m_slots);
 			m_slots = nullptr;
@@ -2010,8 +1852,7 @@ public:
 		m_next.destroy();
 	}
 
-	uint32_t add(const Key &key)
-	{
+	uint32_t add(const Key &key) {
 		if (!m_slots)
 			alloc();
 		const uint32_t hash = computeHash(key);
@@ -2021,36 +1862,18 @@ public:
 		return m_keys.size() - 1;
 	}
 
-	uint32_t get(const Key &key) const
-	{
+	uint32_t get(const Key &key) const {
 		if (!m_slots)
 			return UINT32_MAX;
-		const uint32_t hash = computeHash(key);
-		uint32_t i = m_slots[hash];
-		E equal;
-		while (i != UINT32_MAX) {
-			if (equal(m_keys[i], key))
-				return i;
-			i = m_next[i];
-		}
-		return UINT32_MAX;
+		return find(key, m_slots[computeHash(key)]);
 	}
 
-	uint32_t getNext(uint32_t current) const
-	{
-		uint32_t i = m_next[current];
-		E equal;
-		while (i != UINT32_MAX) {
-			if (equal(m_keys[i], m_keys[current]))
-				return i;
-			i = m_next[i];
-		}
-		return UINT32_MAX;
+	uint32_t getNext(const Key &key, uint32_t current) const {
+		return find(key, m_next[current]);
 	}
 
 private:
-	void alloc()
-	{
+	void alloc() {
 		XA_DEBUG_ASSERT(m_size > 0);
 		m_numSlots = nextPowerOfTwo(m_size);
 		auto minNumSlots = uint32_t(m_size * 1.3);
@@ -2063,12 +1886,21 @@ private:
 		m_next.reserve(m_size);
 	}
 
-	uint32_t computeHash(const Key &key) const
-	{
+	uint32_t computeHash(const Key &key) const {
 		H hash;
 		return hash(key) & (m_numSlots - 1);
 	}
 
+	uint32_t find(const Key &key, uint32_t current) const {
+		E equal;
+		while (current != UINT32_MAX) {
+			if (equal(m_keys[current], key))
+				return current;
+			current = m_next[current];
+		}
+		return current;
+	}
+
 	int m_memTag;
 	uint32_t m_size;
 	uint32_t m_numSlots;
@@ -2077,9 +1909,8 @@ private:
 	Array<uint32_t> m_next;
 };
 
-template<typename T>
-static void insertionSort(T *data, uint32_t length)
-{
+template <typename T>
+static void insertionSort(T *data, uint32_t length) {
 	for (int32_t i = 1; i < (int32_t)length; i++) {
 		T x = data[i];
 		int32_t j = i - 1;
@@ -2091,21 +1922,18 @@ static void insertionSort(T *data, uint32_t length)
 	}
 }
 
-class KISSRng
-{
+class KISSRng {
 public:
 	KISSRng() { reset(); }
 
-	void reset()
-	{
+	void reset() {
 		x = 123456789;
 		y = 362436000;
 		z = 521288629;
 		c = 7654321;
 	}
 
-	uint32_t getRange(uint32_t range)
-	{
+	uint32_t getRange(uint32_t range) {
 		if (range == 0)
 			return 0;
 		x = 69069 * x + 12345;
@@ -2124,12 +1952,10 @@ private:
 // Based on Pierre Terdiman's and Michael Herf's source code.
 // http://www.codercorner.com/RadixSortRevisited.htm
 // http://www.stereopsis.com/radix.html
-class RadixSort
-{
+class RadixSort {
 public:
-	void sort(const float *input, uint32_t count)
-	{
-		if (input == nullptr || count == 0) {
+	void sort(ConstArrayView<float> input) {
+		if (input.length == 0) {
 			m_buffer1.clear();
 			m_buffer2.clear();
 			m_ranks = m_buffer1.data();
@@ -2137,33 +1963,27 @@ public:
 			return;
 		}
 		// Resize lists if needed
-		m_buffer1.resize(count);
-		m_buffer2.resize(count);
+		m_buffer1.resize(input.length);
+		m_buffer2.resize(input.length);
 		m_ranks = m_buffer1.data();
 		m_ranks2 = m_buffer2.data();
 		m_validRanks = false;
-		if (count < 32)
-			insertionSort(input, count);
+		if (input.length < 32)
+			insertionSort(input);
 		else {
 			// @@ Avoid touching the input multiple times.
-			for (uint32_t i = 0; i < count; i++) {
+			for (uint32_t i = 0; i < input.length; i++) {
 				floatFlip((uint32_t &)input[i]);
 			}
-			radixSort<uint32_t>((const uint32_t *)input, count);
-			for (uint32_t i = 0; i < count; i++) {
+			radixSort(ConstArrayView<uint32_t>((const uint32_t *)input.data, input.length));
+			for (uint32_t i = 0; i < input.length; i++) {
 				ifloatFlip((uint32_t &)input[i]);
 			}
 		}
 	}
 
-	void sort(const Array<float> &input)
-	{
-		sort(input.data(), input.size());
-	}
-
 	// Access to results. m_ranks is a list of indices in sorted order, i.e. in the order you may further process your data
-	const uint32_t *ranks() const
-	{
+	const uint32_t *ranks() const {
 		XA_DEBUG_ASSERT(m_validRanks);
 		return m_ranks;
 	}
@@ -2171,54 +1991,40 @@ public:
 private:
 	uint32_t *m_ranks, *m_ranks2;
 	Array<uint32_t> m_buffer1, m_buffer2;
-	bool m_validRanks;
+	bool m_validRanks = false;
 
-	void floatFlip(uint32_t &f)
-	{
+	void floatFlip(uint32_t &f) {
 		int32_t mask = (int32_t(f) >> 31) | 0x80000000; // Warren Hunt, Manchor Ko.
 		f ^= mask;
 	}
 
-	void ifloatFlip(uint32_t &f)
-	{
+	void ifloatFlip(uint32_t &f) {
 		uint32_t mask = ((f >> 31) - 1) | 0x80000000; // Michael Herf.
 		f ^= mask;
 	}
 
-	template<typename T>
-	void createHistograms(const T *buffer, uint32_t count, uint32_t *histogram)
-	{
-		const uint32_t bucketCount = sizeof(T); // (8 * sizeof(T)) / log2(radix)
+	void createHistograms(ConstArrayView<uint32_t> input, uint32_t *histogram) {
+		const uint32_t bucketCount = sizeof(uint32_t);
 		// Init bucket pointers.
 		uint32_t *h[bucketCount];
 		for (uint32_t i = 0; i < bucketCount; i++) {
 			h[i] = histogram + 256 * i;
 		}
 		// Clear histograms.
-		memset(histogram, 0, 256 * bucketCount * sizeof(uint32_t ));
+		memset(histogram, 0, 256 * bucketCount * sizeof(uint32_t));
 		// @@ Add support for signed integers.
 		// Build histograms.
-		const uint8_t *p = (const uint8_t *)buffer;  // @@ Does this break aliasing rules?
-		const uint8_t *pe = p + count * sizeof(T);
+		const uint8_t *p = (const uint8_t *)input.data; // @@ Does this break aliasing rules?
+		const uint8_t *pe = p + input.length * sizeof(uint32_t);
 		while (p != pe) {
 			h[0][*p++]++, h[1][*p++]++, h[2][*p++]++, h[3][*p++]++;
-#ifdef _MSC_VER
-#pragma warning(push)
-#pragma warning(disable : 4127)
-#endif
-			if (bucketCount == 8) h[4][*p++]++, h[5][*p++]++, h[6][*p++]++, h[7][*p++]++;
-#ifdef _MSC_VER
-#pragma warning(pop)
-#endif
 		}
 	}
 
-	template <typename T>
-	void insertionSort(const T *input, uint32_t count)
-	{
+	void insertionSort(ConstArrayView<float> input) {
 		if (!m_validRanks) {
 			m_ranks[0] = 0;
-			for (uint32_t i = 1; i != count; ++i) {
+			for (uint32_t i = 1; i != input.length; ++i) {
 				int rank = m_ranks[i] = i;
 				uint32_t j = i;
 				while (j != 0 && input[rank] < input[m_ranks[j - 1]]) {
@@ -2231,7 +2037,7 @@ private:
 			}
 			m_validRanks = true;
 		} else {
-			for (uint32_t i = 1; i != count; ++i) {
+			for (uint32_t i = 1; i != input.length; ++i) {
 				int rank = m_ranks[i];
 				uint32_t j = i;
 				while (j != 0 && input[rank] < input[m_ranks[j - 1]]) {
@@ -2245,35 +2051,34 @@ private:
 		}
 	}
 
-	template <typename T>
-	void radixSort(const T *input, uint32_t count)
-	{
-		const uint32_t P = sizeof(T); // pass count
+	void radixSort(ConstArrayView<uint32_t> input) {
+		const uint32_t P = sizeof(uint32_t); // pass count
 		// Allocate histograms & offsets on the stack
 		uint32_t histogram[256 * P];
 		uint32_t *link[256];
-		createHistograms(input, count, histogram);
+		createHistograms(input, histogram);
 		// Radix sort, j is the pass number (0=LSB, P=MSB)
 		for (uint32_t j = 0; j < P; j++) {
 			// Pointer to this bucket.
 			const uint32_t *h = &histogram[j * 256];
-			const uint8_t *inputBytes = (const uint8_t *)input; // @@ Is this aliasing legal?
+			auto inputBytes = (const uint8_t *)input.data; // @@ Is this aliasing legal?
 			inputBytes += j;
-			if (h[inputBytes[0]] == count) {
+			if (h[inputBytes[0]] == input.length) {
 				// Skip this pass, all values are the same.
 				continue;
 			}
 			// Create offsets
 			link[0] = m_ranks2;
-			for (uint32_t i = 1; i < 256; i++) link[i] = link[i - 1] + h[i - 1];
+			for (uint32_t i = 1; i < 256; i++)
+				link[i] = link[i - 1] + h[i - 1];
 			// Perform Radix Sort
 			if (!m_validRanks) {
-				for (uint32_t i = 0; i < count; i++) {
+				for (uint32_t i = 0; i < input.length; i++) {
 					*link[inputBytes[i * P]]++ = i;
 				}
 				m_validRanks = true;
 			} else {
-				for (uint32_t i = 0; i < count; i++) {
+				for (uint32_t i = 0; i < input.length; i++) {
 					const uint32_t idx = m_ranks[i];
 					*link[inputBytes[idx * P]]++ = idx;
 				}
@@ -2283,7 +2088,7 @@ private:
 		}
 		// All values were equal, generate linear ranks.
 		if (!m_validRanks) {
-			for (uint32_t i = 0; i < count; i++)
+			for (uint32_t i = 0; i < input.length; i++)
 				m_ranks[i] = i;
 			m_validRanks = true;
 		}
@@ -2291,30 +2096,25 @@ private:
 };
 
 // Wrapping this in a class allows temporary arrays to be re-used.
-class BoundingBox2D
-{
+class BoundingBox2D {
 public:
 	Vector2 majorAxis, minorAxis, minCorner, maxCorner;
 
-	void clear()
-	{
+	void clear() {
 		m_boundaryVertices.clear();
 	}
 
-	void appendBoundaryVertex(Vector2 v)
-	{
+	void appendBoundaryVertex(Vector2 v) {
 		m_boundaryVertices.push_back(v);
 	}
 
 	// This should compute convex hull and use rotating calipers to find the best box. Currently it uses a brute force method.
-	// If vertices is null or vertexCount is 0, the boundary vertices are used.
-	void compute(const Vector2 *vertices = nullptr, uint32_t vertexCount = 0)
-	{
-		if (!vertices || vertexCount == 0) {
-			vertices = m_boundaryVertices.data();
-			vertexCount = m_boundaryVertices.size();
-		}
-		convexHull(m_boundaryVertices.data(), m_boundaryVertices.size(), m_hull, 0.00001f);
+	// If vertices are empty, the boundary vertices are used.
+	void compute(ConstArrayView<Vector2> vertices = ConstArrayView<Vector2>()) {
+		XA_DEBUG_ASSERT(!m_boundaryVertices.isEmpty());
+		if (vertices.length == 0)
+			vertices = m_boundaryVertices;
+		convexHull(m_boundaryVertices, m_hull, 0.00001f);
 		// @@ Ideally I should use rotating calipers to find the best box. Using brute force for now.
 		float best_area = FLT_MAX;
 		Vector2 best_min(0);
@@ -2324,13 +2124,13 @@ public:
 		for (uint32_t i = 0, j = hullCount - 1; i < hullCount; j = i, i++) {
 			if (equal(m_hull[i], m_hull[j], kEpsilon))
 				continue;
-			Vector2 axis = normalize(m_hull[i] - m_hull[j], 0.0f);
+			Vector2 axis = normalize(m_hull[i] - m_hull[j]);
 			XA_DEBUG_ASSERT(isFinite(axis));
 			// Compute bounding box.
 			Vector2 box_min(FLT_MAX, FLT_MAX);
 			Vector2 box_max(-FLT_MAX, -FLT_MAX);
 			// Consider all points, not only boundary points, in case the input chart is malformed.
-			for (uint32_t v = 0; v < vertexCount; v++) {
+			for (uint32_t v = 0; v < vertices.length; v++) {
 				const Vector2 &point = vertices[v];
 				const float x = dot(axis, point);
 				const float y = dot(Vector2(-axis.y, axis.x), point);
@@ -2357,28 +2157,27 @@ public:
 
 private:
 	// Compute the convex hull using Graham Scan.
-	void convexHull(const Vector2 *input, uint32_t inputCount, Array<Vector2> &output, float epsilon)
-	{
-		m_coords.resize(inputCount);
-		for (uint32_t i = 0; i < inputCount; i++)
+	void convexHull(ConstArrayView<Vector2> input, Array<Vector2> &output, float epsilon) {
+		m_coords.resize(input.length);
+		for (uint32_t i = 0; i < input.length; i++)
 			m_coords[i] = input[i].x;
 		m_radix.sort(m_coords);
 		const uint32_t *ranks = m_radix.ranks();
 		m_top.clear();
 		m_bottom.clear();
-		m_top.reserve(inputCount);
-		m_bottom.reserve(inputCount);
+		m_top.reserve(input.length);
+		m_bottom.reserve(input.length);
 		Vector2 P = input[ranks[0]];
-		Vector2 Q = input[ranks[inputCount - 1]];
+		Vector2 Q = input[ranks[input.length - 1]];
 		float topy = max(P.y, Q.y);
 		float boty = min(P.y, Q.y);
-		for (uint32_t i = 0; i < inputCount; i++) {
+		for (uint32_t i = 0; i < input.length; i++) {
 			Vector2 p = input[ranks[i]];
 			if (p.y >= boty)
 				m_top.push_back(p);
 		}
-		for (uint32_t i = 0; i < inputCount; i++) {
-			Vector2 p = input[ranks[inputCount - 1 - i]];
+		for (uint32_t i = 0; i < input.length; i++) {
+			Vector2 p = input[ranks[input.length - 1 - i]];
 			if (p.y <= topy)
 				m_bottom.push_back(p);
 		}
@@ -2387,7 +2186,7 @@ private:
 		XA_DEBUG_ASSERT(m_top.size() >= 2);
 		output.push_back(m_top[0]);
 		output.push_back(m_top[1]);
-		for (uint32_t i = 2; i < m_top.size(); ) {
+		for (uint32_t i = 2; i < m_top.size();) {
 			Vector2 a = output[output.size() - 2];
 			Vector2 b = output[output.size() - 1];
 			Vector2 c = m_top[i];
@@ -2403,7 +2202,7 @@ private:
 		XA_DEBUG_ASSERT(m_bottom.size() >= 2);
 		output.push_back(m_bottom[1]);
 		// Filter bottom list.
-		for (uint32_t i = 2; i < m_bottom.size(); ) {
+		for (uint32_t i = 2; i < m_bottom.size();) {
 			Vector2 a = output[output.size() - 2];
 			Vector2 b = output[output.size() - 1];
 			Vector2 c = m_bottom[i];
@@ -2426,32 +2225,45 @@ private:
 	RadixSort m_radix;
 };
 
-static uint32_t meshEdgeFace(uint32_t edge) { return edge / 3; }
-static uint32_t meshEdgeIndex0(uint32_t edge) { return edge; }
+struct EdgeKey {
+	EdgeKey(const EdgeKey &k) :
+			v0(k.v0), v1(k.v1) {}
+	EdgeKey(uint32_t _v0, uint32_t _v1) :
+			v0(_v0), v1(_v1) {}
+	bool operator==(const EdgeKey &k) const { return v0 == k.v0 && v1 == k.v1; }
 
-static uint32_t meshEdgeIndex1(uint32_t edge)
-{
+	uint32_t v0;
+	uint32_t v1;
+};
+
+struct EdgeHash {
+	uint32_t operator()(const EdgeKey &k) const { return k.v0 * 32768u + k.v1; }
+};
+
+static uint32_t meshEdgeFace(uint32_t edge) {
+	return edge / 3;
+}
+static uint32_t meshEdgeIndex0(uint32_t edge) {
+	return edge;
+}
+
+static uint32_t meshEdgeIndex1(uint32_t edge) {
 	const uint32_t faceFirstEdge = edge / 3 * 3;
 	return faceFirstEdge + (edge - faceFirstEdge + 1) % 3;
 }
 
-struct MeshFlags
-{
-	enum
-	{
-		HasIgnoredFaces = 1<<0,
-		HasNormals = 1<<1
+struct MeshFlags {
+	enum {
+		HasIgnoredFaces = 1 << 0,
+		HasNormals = 1 << 1,
+		HasMaterials = 1 << 2
 	};
 };
 
-class Mesh;
-static void meshGetBoundaryLoops(const Mesh &mesh, Array<uint32_t> &boundaryLoops);
-
-class Mesh
-{
+class Mesh {
 public:
-	Mesh(float epsilon, uint32_t approxVertexCount, uint32_t approxFaceCount, uint32_t flags = 0, uint32_t id = UINT32_MAX) : m_epsilon(epsilon), m_flags(flags), m_id(id), m_faceIgnore(MemTag::Mesh), m_indices(MemTag::MeshIndices), m_positions(MemTag::MeshPositions), m_normals(MemTag::MeshNormals), m_texcoords(MemTag::MeshTexcoords), m_nextColocalVertex(MemTag::MeshColocals), m_boundaryEdges(MemTag::MeshBoundaries), m_oppositeEdges(MemTag::MeshBoundaries), m_nextBoundaryEdges(MemTag::MeshBoundaries), m_edgeMap(MemTag::MeshEdgeMap, approxFaceCount * 3)
-	{
+	Mesh(float epsilon, uint32_t approxVertexCount, uint32_t approxFaceCount, uint32_t flags = 0, uint32_t id = UINT32_MAX) :
+			m_epsilon(epsilon), m_flags(flags), m_id(id), m_faceIgnore(MemTag::Mesh), m_faceMaterials(MemTag::Mesh), m_indices(MemTag::MeshIndices), m_positions(MemTag::MeshPositions), m_normals(MemTag::MeshNormals), m_texcoords(MemTag::MeshTexcoords), m_nextColocalVertex(MemTag::MeshColocals), m_firstColocalVertex(MemTag::MeshColocals), m_boundaryEdges(MemTag::MeshBoundaries), m_oppositeEdges(MemTag::MeshBoundaries), m_edgeMap(MemTag::MeshEdgeMap, approxFaceCount * 3) {
 		m_indices.reserve(approxFaceCount * 3);
 		m_positions.reserve(approxVertexCount);
 		m_texcoords.reserve(approxVertexCount);
@@ -2459,13 +2271,14 @@ public:
 			m_faceIgnore.reserve(approxFaceCount);
 		if (m_flags & MeshFlags::HasNormals)
 			m_normals.reserve(approxVertexCount);
+		if (m_flags & MeshFlags::HasMaterials)
+			m_faceMaterials.reserve(approxFaceCount);
 	}
 
 	uint32_t flags() const { return m_flags; }
 	uint32_t id() const { return m_id; }
 
-	void addVertex(const Vector3 &pos, const Vector3 &normal = Vector3(0.0f), const Vector2 &texcoord = Vector2(0.0f))
-	{
+	void addVertex(const Vector3 &pos, const Vector3 &normal = Vector3(0.0f), const Vector2 &texcoord = Vector2(0.0f)) {
 		XA_DEBUG_ASSERT(isFinite(pos));
 		m_positions.push_back(pos);
 		if (m_flags & MeshFlags::HasNormals)
@@ -2473,45 +2286,22 @@ public:
 		m_texcoords.push_back(texcoord);
 	}
 
-	struct AddFaceResult
-	{
-		enum Enum
-		{
-			OK,
-			DuplicateEdge = 1
-		};
-	};
-
-	AddFaceResult::Enum addFace(uint32_t v0, uint32_t v1, uint32_t v2, bool ignore = false)
-	{
-		uint32_t indexArray[3];
-		indexArray[0] = v0;
-		indexArray[1] = v1;
-		indexArray[2] = v2;
-		return addFace(indexArray, ignore);
-	}
-
-	AddFaceResult::Enum addFace(const uint32_t *indices, bool ignore = false)
-	{
-		AddFaceResult::Enum result = AddFaceResult::OK;
+	void addFace(const uint32_t *indices, bool ignore = false, uint32_t material = UINT32_MAX) {
 		if (m_flags & MeshFlags::HasIgnoredFaces)
 			m_faceIgnore.push_back(ignore);
+		if (m_flags & MeshFlags::HasMaterials)
+			m_faceMaterials.push_back(material);
 		const uint32_t firstIndex = m_indices.size();
 		for (uint32_t i = 0; i < 3; i++)
 			m_indices.push_back(indices[i]);
 		for (uint32_t i = 0; i < 3; i++) {
 			const uint32_t vertex0 = m_indices[firstIndex + i];
 			const uint32_t vertex1 = m_indices[firstIndex + (i + 1) % 3];
-			const EdgeKey key(vertex0, vertex1);
-			if (m_edgeMap.get(key) != UINT32_MAX)
-				result = AddFaceResult::DuplicateEdge;
-			m_edgeMap.add(key);
+			m_edgeMap.add(EdgeKey(vertex0, vertex1));
 		}
-		return result;
 	}
 
-	void createColocals()
-	{
+	void createColocalsBVH() {
 		const uint32_t vertexCount = m_positions.size();
 		Array<AABB> aabbs(MemTag::BVH);
 		aabbs.resize(vertexCount);
@@ -2522,6 +2312,8 @@ public:
 		Array<uint32_t> potential(MemTag::MeshColocals);
 		m_nextColocalVertex.resize(vertexCount);
 		m_nextColocalVertex.fillBytes(0xff);
+		m_firstColocalVertex.resize(vertexCount);
+		m_firstColocalVertex.fillBytes(0xff);
 		for (uint32_t i = 0; i < vertexCount; i++) {
 			if (m_nextColocalVertex[i] != UINT32_MAX)
 				continue; // Already linked.
@@ -2537,18 +2329,65 @@ public:
 			if (colocals.size() == 1) {
 				// No colocals for this vertex.
 				m_nextColocalVertex[i] = i;
-				continue; 
+				m_firstColocalVertex[i] = i;
+				continue;
 			}
 			// Link in ascending order.
 			insertionSort(colocals.data(), colocals.size());
-			for (uint32_t j = 0; j < colocals.size(); j++)
+			for (uint32_t j = 0; j < colocals.size(); j++) {
 				m_nextColocalVertex[colocals[j]] = colocals[(j + 1) % colocals.size()];
+				m_firstColocalVertex[colocals[j]] = colocals[0];
+			}
 			XA_DEBUG_ASSERT(m_nextColocalVertex[i] != UINT32_MAX);
 		}
 	}
 
-	void createBoundaries()
-	{
+	void createColocalsHash() {
+		const uint32_t vertexCount = m_positions.size();
+		HashMap<Vector3> positionToVertexMap(MemTag::Default, vertexCount);
+		for (uint32_t i = 0; i < vertexCount; i++)
+			positionToVertexMap.add(m_positions[i]);
+		Array<uint32_t> colocals(MemTag::MeshColocals);
+		m_nextColocalVertex.resize(vertexCount);
+		m_nextColocalVertex.fillBytes(0xff);
+		m_firstColocalVertex.resize(vertexCount);
+		m_firstColocalVertex.fillBytes(0xff);
+		for (uint32_t i = 0; i < vertexCount; i++) {
+			if (m_nextColocalVertex[i] != UINT32_MAX)
+				continue; // Already linked.
+			// Find other vertices colocal to this one.
+			colocals.clear();
+			colocals.push_back(i); // Always add this vertex.
+			uint32_t otherVertex = positionToVertexMap.get(m_positions[i]);
+			while (otherVertex != UINT32_MAX) {
+				if (otherVertex != i && equal(m_positions[i], m_positions[otherVertex], m_epsilon) && m_nextColocalVertex[otherVertex] == UINT32_MAX)
+					colocals.push_back(otherVertex);
+				otherVertex = positionToVertexMap.getNext(m_positions[i], otherVertex);
+			}
+			if (colocals.size() == 1) {
+				// No colocals for this vertex.
+				m_nextColocalVertex[i] = i;
+				m_firstColocalVertex[i] = i;
+				continue;
+			}
+			// Link in ascending order.
+			insertionSort(colocals.data(), colocals.size());
+			for (uint32_t j = 0; j < colocals.size(); j++) {
+				m_nextColocalVertex[colocals[j]] = colocals[(j + 1) % colocals.size()];
+				m_firstColocalVertex[colocals[j]] = colocals[0];
+			}
+			XA_DEBUG_ASSERT(m_nextColocalVertex[i] != UINT32_MAX);
+		}
+	}
+
+	void createColocals() {
+		if (m_epsilon <= FLT_EPSILON)
+			createColocalsHash();
+		else
+			createColocalsBVH();
+	}
+
+	void createBoundaries() {
 		const uint32_t edgeCount = m_indices.size();
 		const uint32_t vertexCount = m_positions.size();
 		m_oppositeEdges.resize(edgeCount);
@@ -2578,151 +2417,54 @@ public:
 		}
 	}
 
-	void linkBoundaries()
-	{
-		const uint32_t edgeCount = m_indices.size();
-		HashMap<uint32_t> vertexToEdgeMap(MemTag::Mesh, edgeCount); // Edge is index / 2
-		for (uint32_t i = 0; i < edgeCount; i++) {
-			vertexToEdgeMap.add(m_indices[meshEdgeIndex0(i)]);
-			vertexToEdgeMap.add(m_indices[meshEdgeIndex1(i)]);
-		}
-		m_nextBoundaryEdges.resize(edgeCount);
-		for (uint32_t i = 0; i < edgeCount; i++)
-			m_nextBoundaryEdges[i] = UINT32_MAX;
-		uint32_t numBoundaryLoops = 0, numUnclosedBoundaries = 0;
-		BitArray linkedEdges(edgeCount);
-		linkedEdges.zeroOutMemory();
-		for (;;) {
-			// Find the first boundary edge that hasn't been linked yet.
-			uint32_t firstEdge = UINT32_MAX;
-			for (uint32_t i = 0; i < edgeCount; i++) {
-				if (m_oppositeEdges[i] == UINT32_MAX && !linkedEdges.get(i)) {
-					firstEdge = i;
-					break;
-				}
-			}
-			if (firstEdge == UINT32_MAX)
-				break;
-			uint32_t currentEdge = firstEdge;
-			for (;;) {
-				// Find the next boundary edge. The first vertex will be the same as (or colocal to) the current edge second vertex.
-				const uint32_t startVertex = m_indices[meshEdgeIndex1(currentEdge)];
-				uint32_t bestNextEdge = UINT32_MAX;
-				for (ColocalVertexIterator it(this, startVertex); !it.isDone(); it.advance()) {
-					uint32_t mapIndex = vertexToEdgeMap.get(it.vertex());
-					while (mapIndex != UINT32_MAX) {
-						const uint32_t otherEdge = mapIndex / 2; // Two vertices added per edge.
-						if (m_oppositeEdges[otherEdge] != UINT32_MAX)
-							goto next; // Not a boundary edge.
-						if (linkedEdges.get(otherEdge))
-							goto next; // Already linked.
-						if (m_indices[meshEdgeIndex0(otherEdge)] != it.vertex())
-							goto next; // Edge contains the vertex, but it's the wrong one.
-						// First edge (closing the boundary loop) has the highest priority.
-						// Non-colocal vertex has the next highest.
-						if (bestNextEdge != firstEdge && (bestNextEdge == UINT32_MAX || it.vertex() == startVertex))
-							bestNextEdge = otherEdge;
-					next:
-						mapIndex = vertexToEdgeMap.getNext(mapIndex);
-					}
-				}
-				if (bestNextEdge == UINT32_MAX) {
-					numUnclosedBoundaries++;
-					if (currentEdge == firstEdge)
-						linkedEdges.set(firstEdge); // Only 1 edge in this boundary "loop".
-					break; // Can't find a next edge.
-				}
-				m_nextBoundaryEdges[currentEdge] = bestNextEdge;
-				linkedEdges.set(bestNextEdge);
-				currentEdge = bestNextEdge;
-				if (currentEdge == firstEdge) {
-					numBoundaryLoops++;
-					break; // Closed the boundary loop.
-				}
-			}
-		}
-#if XA_FIX_INTERNAL_BOUNDARY_LOOPS
-		// Find internal boundary loops and separate them.
-		// Detect by finding two edges in a boundary loop that have a colocal end vertex.
-		// Fix by swapping their next boundary edge.
-		// Need to start over after every fix since known boundary loops have changed.
-		Array<uint32_t> boundaryLoops;
-	fixInternalBoundary:
-		meshGetBoundaryLoops(*this, boundaryLoops);
-		for (uint32_t loop = 0; loop < boundaryLoops.size(); loop++) {
-			linkedEdges.zeroOutMemory();
-			for (Mesh::BoundaryLoopEdgeIterator it1(this, boundaryLoops[loop]); !it1.isDone(); it1.advance()) {
-				const uint32_t e1 = it1.edge();
-				if (linkedEdges.get(e1))
-					continue;
-				for (Mesh::BoundaryLoopEdgeIterator it2(this, boundaryLoops[loop]); !it2.isDone(); it2.advance()) {
-					const uint32_t e2 = it2.edge();
-					if (e1 == e2 || !isBoundaryEdge(e2) || linkedEdges.get(e2))
-						continue;
-					if (!areColocal(m_indices[meshEdgeIndex1(e1)], m_indices[meshEdgeIndex1(e2)]))
-						continue;
-					swap(m_nextBoundaryEdges[e1], m_nextBoundaryEdges[e2]);
-					linkedEdges.set(e1);
-					linkedEdges.set(e2);
-					goto fixInternalBoundary; // start over
-				}
-			}
-		}
-#endif
-	}
-
 	/// Find edge, test all colocals.
-	uint32_t findEdge(uint32_t vertex0, uint32_t vertex1) const
-	{
-		uint32_t result = UINT32_MAX;
-		if (m_nextColocalVertex.isEmpty()) {
+	uint32_t findEdge(uint32_t vertex0, uint32_t vertex1) const {
+		// Try to find exact vertex match first.
+		{
 			EdgeKey key(vertex0, vertex1);
 			uint32_t edge = m_edgeMap.get(key);
 			while (edge != UINT32_MAX) {
 				// Don't find edges of ignored faces.
-				if (!isFaceIgnored(meshEdgeFace(edge))) {
-					//XA_DEBUG_ASSERT(m_id != UINT32_MAX || (m_id == UINT32_MAX && result == UINT32_MAX)); // duplicate edge - ignore on initial meshes
-					result = edge;
-#if !XA_DEBUG
-					return result;
-#endif
-				}
-				edge = m_edgeMap.getNext(edge);
+				if (!isFaceIgnored(meshEdgeFace(edge)))
+					return edge;
+				edge = m_edgeMap.getNext(key, edge);
 			}
-		} else {
-			for (ColocalVertexIterator it0(this, vertex0); !it0.isDone(); it0.advance()) {
-				for (ColocalVertexIterator it1(this, vertex1); !it1.isDone(); it1.advance()) {
-					EdgeKey key(it0.vertex(), it1.vertex());
+		}
+		// If colocals were created, try every permutation.
+		if (!m_nextColocalVertex.isEmpty()) {
+			uint32_t colocalVertex0 = vertex0;
+			for (;;) {
+				uint32_t colocalVertex1 = vertex1;
+				for (;;) {
+					EdgeKey key(colocalVertex0, colocalVertex1);
 					uint32_t edge = m_edgeMap.get(key);
 					while (edge != UINT32_MAX) {
 						// Don't find edges of ignored faces.
-						if (!isFaceIgnored(meshEdgeFace(edge))) {
-							XA_DEBUG_ASSERT(m_id != UINT32_MAX || (m_id == UINT32_MAX && result == UINT32_MAX)); // duplicate edge - ignore on initial meshes
-							result = edge;
-#if !XA_DEBUG
-							return result;
-#endif
-						}
-						edge = m_edgeMap.getNext(edge);
+						if (!isFaceIgnored(meshEdgeFace(edge)))
+							return edge;
+						edge = m_edgeMap.getNext(key, edge);
 					}
+					colocalVertex1 = m_nextColocalVertex[colocalVertex1];
+					if (colocalVertex1 == vertex1)
+						break; // Back to start.
 				}
+				colocalVertex0 = m_nextColocalVertex[colocalVertex0];
+				if (colocalVertex0 == vertex0)
+					break; // Back to start.
 			}
 		}
-		return result;
+		return UINT32_MAX;
 	}
 
 	// Edge map can be destroyed when no longer used to reduce memory usage. It's used by:
 	//   * Mesh::createBoundaries()
-	//   * Mesh::ColocalEdgeIterator (used by MeshFaceGroups)
-	//   * meshCloseHole()
-	void destroyEdgeMap()
-	{
+	//   * Mesh::edgeMap() (used by MeshFaceGroups)
+	void destroyEdgeMap() {
 		m_edgeMap.destroy();
 	}
 
 #if XA_DEBUG_EXPORT_OBJ
-	void writeObjVertices(FILE *file) const
-	{
+	void writeObjVertices(FILE *file) const {
 		for (uint32_t i = 0; i < m_positions.size(); i++)
 			fprintf(file, "v %g %g %g\n", m_positions[i].x, m_positions[i].y, m_positions[i].z);
 		if (m_flags & MeshFlags::HasNormals) {
@@ -2733,8 +2475,7 @@ public:
 			fprintf(file, "vt %g %g\n", m_texcoords[i].x, m_texcoords[i].y);
 	}
 
-	void writeObjFace(FILE *file, uint32_t face, uint32_t offset = 0) const
-	{
+	void writeObjFace(FILE *file, uint32_t face, uint32_t offset = 0) const {
 		fprintf(file, "f ");
 		for (uint32_t j = 0; j < 3; j++) {
 			const uint32_t index = m_indices[face * 3 + j] + 1 + offset; // 1-indexed
@@ -2742,8 +2483,7 @@ public:
 		}
 	}
 
-	void writeObjBoundaryEges(FILE *file) const
-	{
+	void writeObjBoundaryEges(FILE *file) const {
 		if (m_oppositeEdges.isEmpty())
 			return; // Boundaries haven't been created.
 		fprintf(file, "o boundary_edges\n");
@@ -2754,31 +2494,7 @@ public:
 		}
 	}
 
-	void writeObjLinkedBoundaries(FILE *file) const
-	{
-		if (m_oppositeEdges.isEmpty() || m_nextBoundaryEdges.isEmpty())
-			return; // Boundaries haven't been created and/or linked.
-		Array<uint32_t> boundaryLoops;
-		meshGetBoundaryLoops(*this, boundaryLoops);
-		for (uint32_t i = 0; i < boundaryLoops.size(); i++) {
-			uint32_t edge = boundaryLoops[i];
-			fprintf(file, "o boundary_%04d\n", i);
-			fprintf(file, "l");
-			for (;;) {
-				const uint32_t vertex0 = m_indices[meshEdgeIndex0(edge)];
-				const uint32_t vertex1 = m_indices[meshEdgeIndex1(edge)];
-				fprintf(file, " %d", vertex0 + 1); // 1-indexed
-				edge = m_nextBoundaryEdges[edge];
-				if (edge == boundaryLoops[i] || edge == UINT32_MAX) {
-					fprintf(file, " %d\n", vertex1 + 1); // 1-indexed
-					break;
-				}
-			}
-		}
-	}
-
-	void writeObjFile(const char *filename) const
-	{
+	void writeObjFile(const char *filename) const {
 		FILE *file;
 		XA_FOPEN(file, filename, "w");
 		if (!file)
@@ -2789,13 +2505,11 @@ public:
 		for (uint32_t i = 0; i < faceCount(); i++)
 			writeObjFace(file, i);
 		writeObjBoundaryEges(file);
-		writeObjLinkedBoundaries(file);
 		fclose(file);
 	}
 #endif
 
-	float computeSurfaceArea() const
-	{
+	float computeSurfaceArea() const {
 		float area = 0;
 		for (uint32_t f = 0; f < faceCount(); f++)
 			area += computeFaceArea(f);
@@ -2804,24 +2518,21 @@ public:
 	}
 
 	// Returned value is always positive, even if some triangles are flipped.
-	float computeParametricArea() const
-	{
+	float computeParametricArea() const {
 		float area = 0;
 		for (uint32_t f = 0; f < faceCount(); f++)
 			area += fabsf(computeFaceParametricArea(f)); // May be negative, depends on texcoord winding.
-		return area; 
+		return area;
 	}
 
-	float computeFaceArea(uint32_t face) const
-	{
+	float computeFaceArea(uint32_t face) const {
 		const Vector3 &p0 = m_positions[m_indices[face * 3 + 0]];
 		const Vector3 &p1 = m_positions[m_indices[face * 3 + 1]];
 		const Vector3 &p2 = m_positions[m_indices[face * 3 + 2]];
 		return length(cross(p1 - p0, p2 - p0)) * 0.5f;
 	}
 
-	Vector3 computeFaceCentroid(uint32_t face) const
-	{
+	Vector3 computeFaceCentroid(uint32_t face) const {
 		Vector3 sum(0.0f);
 		for (uint32_t i = 0; i < 3; i++)
 			sum += m_positions[m_indices[face * 3 + i]];
@@ -2830,8 +2541,7 @@ public:
 
 	// Average of the edge midpoints weighted by the edge length.
 	// I want a point inside the triangle, but closer to the cirumcenter.
-	Vector3 computeFaceCenter(uint32_t face) const
-	{
+	Vector3 computeFaceCenter(uint32_t face) const {
 		const Vector3 &p0 = m_positions[m_indices[face * 3 + 0]];
 		const Vector3 &p1 = m_positions[m_indices[face * 3 + 1]];
 		const Vector3 &p2 = m_positions[m_indices[face * 3 + 2]];
@@ -2844,28 +2554,25 @@ public:
 		return m0 + m1 + m2;
 	}
 
-	Vector3 computeFaceNormal(uint32_t face) const
-	{
+	Vector3 computeFaceNormal(uint32_t face) const {
 		const Vector3 &p0 = m_positions[m_indices[face * 3 + 0]];
 		const Vector3 &p1 = m_positions[m_indices[face * 3 + 1]];
 		const Vector3 &p2 = m_positions[m_indices[face * 3 + 2]];
 		const Vector3 e0 = p2 - p0;
 		const Vector3 e1 = p1 - p0;
 		const Vector3 normalAreaScaled = cross(e0, e1);
-		return normalizeSafe(normalAreaScaled, Vector3(0, 0, 1), 0.0f);
+		return normalizeSafe(normalAreaScaled, Vector3(0, 0, 1));
 	}
 
-	float computeFaceParametricArea(uint32_t face) const
-	{
+	float computeFaceParametricArea(uint32_t face) const {
 		const Vector2 &t0 = m_texcoords[m_indices[face * 3 + 0]];
 		const Vector2 &t1 = m_texcoords[m_indices[face * 3 + 1]];
 		const Vector2 &t2 = m_texcoords[m_indices[face * 3 + 2]];
 		return triangleArea(t0, t1, t2);
 	}
-	
+
 	// @@ This is not exactly accurate, we should compare the texture coordinates...
-	bool isSeam(uint32_t edge) const
-	{
+	bool isSeam(uint32_t edge) const {
 		const uint32_t oppositeEdge = m_oppositeEdges[edge];
 		if (oppositeEdge == UINT32_MAX)
 			return false; // boundary edge
@@ -2876,8 +2583,7 @@ public:
 		return m_indices[e0] != m_indices[oe1] || m_indices[e1] != m_indices[oe0];
 	}
 
-	bool isTextureSeam(uint32_t edge) const
-	{
+	bool isTextureSeam(uint32_t edge) const {
 		const uint32_t oppositeEdge = m_oppositeEdges[edge];
 		if (oppositeEdge == UINT32_MAX)
 			return false; // boundary edge
@@ -2888,26 +2594,9 @@ public:
 		return m_texcoords[m_indices[e0]] != m_texcoords[m_indices[oe1]] || m_texcoords[m_indices[e1]] != m_texcoords[m_indices[oe0]];
 	}
 
-	uint32_t firstColocal(uint32_t vertex) const
-	{
-		for (ColocalVertexIterator it(this, vertex); !it.isDone(); it.advance()) {
-			if (it.vertex() < vertex)
-				vertex = it.vertex();
-		}
-		return vertex;
-	}
-
-	bool areColocal(uint32_t vertex0, uint32_t vertex1) const
-	{
-		if (vertex0 == vertex1)
-			return true;
-		if (m_nextColocalVertex.isEmpty())
-			return false;
-		for (ColocalVertexIterator it(this, vertex0); !it.isDone(); it.advance()) {
-			if (it.vertex() == vertex1)
-				return true;
-		}
-		return false;
+	uint32_t firstColocalVertex(uint32_t vertex) const {
+		XA_DEBUG_ASSERT(m_firstColocalVertex.size() == m_positions.size());
+		return m_firstColocalVertex[vertex];
 	}
 
 	XA_INLINE float epsilon() const { return m_epsilon; }
@@ -2919,23 +2608,28 @@ public:
 	XA_INLINE uint32_t vertexCount() const { return m_positions.size(); }
 	XA_INLINE uint32_t vertexAt(uint32_t i) const { return m_indices[i]; }
 	XA_INLINE const Vector3 &position(uint32_t vertex) const { return m_positions[vertex]; }
-	XA_INLINE const Vector3 *positions() const { return m_positions.data(); }
-	XA_INLINE const Vector3 &normal(uint32_t vertex) const { XA_DEBUG_ASSERT(m_flags & MeshFlags::HasNormals); return m_normals[vertex]; }
+	XA_INLINE ConstArrayView<Vector3> positions() const { return m_positions; }
+	XA_INLINE const Vector3 &normal(uint32_t vertex) const {
+		XA_DEBUG_ASSERT(m_flags & MeshFlags::HasNormals);
+		return m_normals[vertex];
+	}
 	XA_INLINE const Vector2 &texcoord(uint32_t vertex) const { return m_texcoords[vertex]; }
 	XA_INLINE Vector2 &texcoord(uint32_t vertex) { return m_texcoords[vertex]; }
-	XA_INLINE const Vector2 *texcoords() const { return m_texcoords.data(); }
-	XA_INLINE Vector2 *texcoords() { return m_texcoords.data(); }
+	XA_INLINE const ConstArrayView<Vector2> texcoords() const { return m_texcoords; }
+	XA_INLINE ArrayView<Vector2> texcoords() { return m_texcoords; }
 	XA_INLINE uint32_t faceCount() const { return m_indices.size() / 3; }
-	XA_INLINE const uint32_t *indices() const { return m_indices.data(); }
+	XA_INLINE ConstArrayView<uint32_t> indices() const { return m_indices; }
 	XA_INLINE uint32_t indexCount() const { return m_indices.size(); }
 	XA_INLINE bool isFaceIgnored(uint32_t face) const { return (m_flags & MeshFlags::HasIgnoredFaces) && m_faceIgnore[face]; }
+	XA_INLINE uint32_t faceMaterial(uint32_t face) const { return (m_flags & MeshFlags::HasMaterials) ? m_faceMaterials[face] : UINT32_MAX; }
+	XA_INLINE const HashMap<EdgeKey, EdgeHash> &edgeMap() const { return m_edgeMap; }
 
 private:
-
 	float m_epsilon;
 	uint32_t m_flags;
 	uint32_t m_id;
 	Array<bool> m_faceIgnore;
+	Array<uint32_t> m_faceMaterials;
 	Array<uint32_t> m_indices;
 	Array<Vector3> m_positions;
 	Array<Vector3> m_normals;
@@ -2943,205 +2637,31 @@ private:
 
 	// Populated by createColocals
 	Array<uint32_t> m_nextColocalVertex; // In: vertex index. Out: the vertex index of the next colocal position.
+	Array<uint32_t> m_firstColocalVertex;
 
 	// Populated by createBoundaries
 	BitArray m_isBoundaryVertex;
 	Array<uint32_t> m_boundaryEdges;
 	Array<uint32_t> m_oppositeEdges; // In: edge index. Out: the index of the opposite edge (i.e. wound the opposite direction). UINT32_MAX if the input edge is a boundary edge.
 
-	// Populated by linkBoundaries
-	Array<uint32_t> m_nextBoundaryEdges; // The index of the next boundary edge. UINT32_MAX if the edge is not a boundary edge.
-
-	struct EdgeKey
-	{
-		EdgeKey(const EdgeKey &k) : v0(k.v0), v1(k.v1) {}
-		EdgeKey(uint32_t v0, uint32_t v1) : v0(v0), v1(v1) {}
-		bool operator==(const EdgeKey &k) const { return v0 == k.v0 && v1 == k.v1; }
-
-		uint32_t v0;
-		uint32_t v1;
-	};
-
-	struct EdgeHash
-	{
-		uint32_t operator()(const EdgeKey &k) const { return k.v0 * 32768u + k.v1; }
-	};
-
 	HashMap<EdgeKey, EdgeHash> m_edgeMap;
 
 public:
-	class BoundaryLoopEdgeIterator
-	{
+	class FaceEdgeIterator {
 	public:
-		BoundaryLoopEdgeIterator(const Mesh *mesh, uint32_t edge) : m_mesh(mesh), m_first(UINT32_MAX), m_current(edge) {}
-
-		void advance()
-		{
-			if (m_first == UINT32_MAX)
-				m_first = m_current;
-			m_current = m_mesh->m_nextBoundaryEdges[m_current];
-		}
-
-		bool isDone() const
-		{
-			return m_first == m_current || m_current == UINT32_MAX;
-		}
-
-		uint32_t edge() const
-		{
-			return m_current;
-		}
-
-		uint32_t nextEdge() const
-		{
-			return m_mesh->m_nextBoundaryEdges[m_current];
-		}
-
-	private:
-		const Mesh *m_mesh;
-		uint32_t m_first;
-		uint32_t m_current;
-	};
-
-	class ColocalVertexIterator
-	{
-	public:
-		ColocalVertexIterator(const Mesh *mesh, uint32_t v) : m_mesh(mesh), m_first(UINT32_MAX), m_current(v) {}
-
-		void advance()
-		{
-			if (m_first == UINT32_MAX)
-				m_first = m_current;
-			if (!m_mesh->m_nextColocalVertex.isEmpty())
-				m_current = m_mesh->m_nextColocalVertex[m_current];
-		}
-
-		bool isDone() const
-		{
-			return m_first == m_current;
-		}
-
-		uint32_t vertex() const
-		{
-			return m_current;
-		}
-
-		const Vector3 *pos() const
-		{
-			return &m_mesh->m_positions[m_current];
-		}
-
-	private:
-		const Mesh *m_mesh;
-		uint32_t m_first;
-		uint32_t m_current;
-	};
-
-	class ColocalEdgeIterator
-	{
-	public:
-		ColocalEdgeIterator(const Mesh *mesh, uint32_t vertex0, uint32_t vertex1) : m_mesh(mesh), m_vertex0It(mesh, vertex0), m_vertex1It(mesh, vertex1), m_vertex1(vertex1)
-		{
-			do {
-				if (!resetElement()) {
-					advanceVertex1();
-				}
-				else {
-					break;
-				}
-			} while (!isDone());
-		}
-
-		void advance()
-		{
-			advanceElement();
-		}
-
-		bool isDone() const
-		{
-			return m_vertex0It.isDone() && m_vertex1It.isDone() && m_edge == UINT32_MAX;
-		}
-
-		uint32_t edge() const
-		{
-			return m_edge;
-		}
-
-	private:
-		bool resetElement()
-		{
-			m_edge = m_mesh->m_edgeMap.get(Mesh::EdgeKey(m_vertex0It.vertex(), m_vertex1It.vertex()));
-			while (m_edge != UINT32_MAX) {
-				if (!isIgnoredFace())
-					break;
-				m_edge = m_mesh->m_edgeMap.getNext(m_edge);
-			}
-			if (m_edge == UINT32_MAX) {
-				return false;
-			}
-			return true;
-		}
-
-		void advanceElement()
-		{
-			for (;;) {
-				m_edge = m_mesh->m_edgeMap.getNext(m_edge);
-				if (m_edge == UINT32_MAX)
-					break;
-				if (!isIgnoredFace())
-					break;
-			}
-			if (m_edge == UINT32_MAX)
-				advanceVertex1();
-		}
-
-		void advanceVertex1()
-		{
-			auto successful = false;
-			while (!successful)	{
-				m_vertex1It.advance();
-				if (m_vertex1It.isDone()) {
-					if (!m_vertex0It.isDone()) {
-						m_vertex0It.advance();
-						m_vertex1It = ColocalVertexIterator(m_mesh, m_vertex1);
-					}
-					else {
-						return;
-					}
-				}
-				successful = resetElement();
-			}
-		}
-
-		bool isIgnoredFace() const
-		{
-			return m_mesh->m_faceIgnore[meshEdgeFace(m_edge)];
-		}
-
-		const Mesh *m_mesh;
-		ColocalVertexIterator m_vertex0It, m_vertex1It;
-		const uint32_t m_vertex1;
-		uint32_t m_edge;
-	};
-
-	class FaceEdgeIterator 
-	{
-	public:
-		FaceEdgeIterator (const Mesh *mesh, uint32_t face) : m_mesh(mesh), m_face(face), m_relativeEdge(0)
-		{
+		FaceEdgeIterator(const Mesh *mesh, uint32_t face) :
+				m_mesh(mesh), m_face(face), m_relativeEdge(0) {
 			m_edge = m_face * 3;
 		}
 
-		void advance()
-		{
+		void advance() {
 			if (m_relativeEdge < 3) {
 				m_edge++;
 				m_relativeEdge++;
 			}
 		}
 
-		bool isDone() const
-		{
+		bool isDone() const {
 			return m_relativeEdge == 3;
 		}
 
@@ -3152,9 +2672,8 @@ public:
 		uint32_t relativeEdge() const { return m_relativeEdge; }
 		uint32_t face() const { return m_face; }
 		uint32_t oppositeEdge() const { return m_mesh->m_oppositeEdges[m_edge]; }
-		
-		uint32_t oppositeFace() const
-		{
+
+		uint32_t oppositeFace() const {
 			const uint32_t oedge = m_mesh->m_oppositeEdges[m_edge];
 			if (oedge == UINT32_MAX)
 				return UINT32_MAX;
@@ -3178,19 +2697,18 @@ public:
 	};
 };
 
-struct MeshFaceGroups
-{
+struct MeshFaceGroups {
 	typedef uint32_t Handle;
 	static constexpr Handle kInvalid = UINT32_MAX;
 
-	MeshFaceGroups(const Mesh *mesh) : m_mesh(mesh), m_groups(MemTag::Mesh), m_firstFace(MemTag::Mesh), m_nextFace(MemTag::Mesh), m_faceCount(MemTag::Mesh) {}
+	MeshFaceGroups(const Mesh *mesh) :
+			m_mesh(mesh), m_groups(MemTag::Mesh), m_firstFace(MemTag::Mesh), m_nextFace(MemTag::Mesh), m_faceCount(MemTag::Mesh) {}
 	XA_INLINE Handle groupAt(uint32_t face) const { return m_groups[face]; }
 	XA_INLINE uint32_t groupCount() const { return m_faceCount.size(); }
 	XA_INLINE uint32_t nextFace(uint32_t face) const { return m_nextFace[face]; }
 	XA_INLINE uint32_t faceCount(uint32_t group) const { return m_faceCount[group]; }
 
-	void compute()
-	{
+	void compute() {
 		m_groups.resize(m_mesh->faceCount());
 		m_groups.fillBytes(0xff); // Set all faces to kInvalid
 		uint32_t firstUnassignedFace = 0;
@@ -3222,57 +2740,25 @@ struct MeshFaceGroups
 					break;
 				const uint32_t f = growFaces.back();
 				growFaces.pop_back();
+				const uint32_t material = m_mesh->faceMaterial(f);
 				for (Mesh::FaceEdgeIterator edgeIt(m_mesh, f); !edgeIt.isDone(); edgeIt.advance()) {
-					// Iterate opposite edges. There may be more than one - non-manifold geometry can have duplicate edges.
-					// Prioritize the one with exact vertex match, not just colocal.
-					// If *any* of the opposite edges are already assigned to this group, don't do anything.
-					bool alreadyAssignedToThisGroup = false;
-					uint32_t bestConnectedFace = UINT32_MAX;
-					for (Mesh::ColocalEdgeIterator oppositeEdgeIt(m_mesh, edgeIt.vertex1(), edgeIt.vertex0()); !oppositeEdgeIt.isDone(); oppositeEdgeIt.advance()) {
-						const uint32_t oppositeEdge = oppositeEdgeIt.edge();
-						const uint32_t oppositeFace = meshEdgeFace(oppositeEdge);
-#if 0
-						// Reject opposite face if dihedral angle >= 90 degrees.
-						{
-							Vector3 a = m_mesh->computeFaceNormal(f);
-							Vector3 b = m_mesh->computeFaceNormal(oppositeFace);
-							if (dot(a, b) <= 0.0f)
-								continue;
-						}
-#endif
-						if (m_mesh->isFaceIgnored(oppositeFace))
-							continue; // Don't add ignored faces to group.
-						if (m_groups[oppositeFace] == group) {
-							alreadyAssignedToThisGroup = true;
-							break;
-						}
-						if (m_groups[oppositeFace] != kInvalid)
-							continue; // Connected face is already assigned to another group.
-						if (faceDuplicatesGroupEdge(group, oppositeFace))
-							continue; // Don't want duplicate edges in a group.
-						const uint32_t oppositeVertex0 = m_mesh->vertexAt(meshEdgeIndex0(oppositeEdge));
-						const uint32_t oppositeVertex1 = m_mesh->vertexAt(meshEdgeIndex1(oppositeEdge));
-						if (bestConnectedFace == UINT32_MAX || (oppositeVertex0 == edgeIt.vertex1() && oppositeVertex1 == edgeIt.vertex0()))
-							bestConnectedFace = oppositeFace;
-#if 0
-						else {
-							// Choose the opposite face with the smallest dihedral angle.
-							const float d1 = 1.0f - dot(computeFaceNormal(f), computeFaceNormal(bestConnectedFace));
-							const float d2 = 1.0f - dot(computeFaceNormal(f), computeFaceNormal(oppositeFace));
-							if (d2 < d1)
-								bestConnectedFace = oppositeFace;
-						}
-#endif
-					}
-					if (!alreadyAssignedToThisGroup && bestConnectedFace != UINT32_MAX) {
-						m_groups[bestConnectedFace] = group;
-						m_nextFace[bestConnectedFace] = UINT32_MAX;
-						if (prevFace != UINT32_MAX)
-							m_nextFace[prevFace] = bestConnectedFace;
-						prevFace = bestConnectedFace;
-						groupFaceCount++;
-						growFaces.push_back(bestConnectedFace);
-					}
+					const uint32_t oppositeEdge = m_mesh->findEdge(edgeIt.vertex1(), edgeIt.vertex0());
+					if (oppositeEdge == UINT32_MAX)
+						continue; // Boundary edge.
+					const uint32_t oppositeFace = meshEdgeFace(oppositeEdge);
+					if (m_mesh->isFaceIgnored(oppositeFace))
+						continue; // Don't add ignored faces to group.
+					if (m_mesh->faceMaterial(oppositeFace) != material)
+						continue; // Different material.
+					if (m_groups[oppositeFace] != kInvalid)
+						continue; // Connected face is already assigned to another group.
+					m_groups[oppositeFace] = group;
+					m_nextFace[oppositeFace] = UINT32_MAX;
+					if (prevFace != UINT32_MAX)
+						m_nextFace[prevFace] = oppositeFace;
+					prevFace = oppositeFace;
+					groupFaceCount++;
+					growFaces.push_back(oppositeFace);
 				}
 			}
 			m_faceCount.push_back(groupFaceCount);
@@ -3281,27 +2767,23 @@ struct MeshFaceGroups
 		}
 	}
 
-	class Iterator
-	{
+	class Iterator {
 	public:
-		Iterator(const MeshFaceGroups *meshFaceGroups, Handle group) : m_meshFaceGroups(meshFaceGroups)
-		{
+		Iterator(const MeshFaceGroups *meshFaceGroups, Handle group) :
+				m_meshFaceGroups(meshFaceGroups) {
 			XA_DEBUG_ASSERT(group != kInvalid);
 			m_current = m_meshFaceGroups->m_firstFace[group];
 		}
 
-		void advance()
-		{
+		void advance() {
 			m_current = m_meshFaceGroups->m_nextFace[m_current];
 		}
 
-		bool isDone() const
-		{
+		bool isDone() const {
 			return m_current == UINT32_MAX;
 		}
 
-		uint32_t face() const
-		{
+		uint32_t face() const {
 			return m_current;
 		}
 
@@ -3311,18 +2793,6 @@ struct MeshFaceGroups
 	};
 
 private:
-	// Check if the face duplicates any edges of any face already in the group.
-	bool faceDuplicatesGroupEdge(Handle group, uint32_t face) const
-	{
-		for (Mesh::FaceEdgeIterator edgeIt(m_mesh, face); !edgeIt.isDone(); edgeIt.advance()) {
-			for (Mesh::ColocalEdgeIterator colocalEdgeIt(m_mesh, edgeIt.vertex0(), edgeIt.vertex1()); !colocalEdgeIt.isDone(); colocalEdgeIt.advance()) {
-				if (m_groups[meshEdgeFace(colocalEdgeIt.edge())] == group)
-					return true;
-			}
-		}
-		return false;
-	}
-
 	const Mesh *m_mesh;
 	Array<Handle> m_groups;
 	Array<uint32_t> m_firstFace;
@@ -3332,243 +2802,27 @@ private:
 
 constexpr MeshFaceGroups::Handle MeshFaceGroups::kInvalid;
 
-static bool meshCloseHole(Mesh *mesh, const Array<uint32_t> &holeVertices, const Vector3 &normal)
-{
-#if XA_CLOSE_HOLES_CHECK_EDGE_INTERSECTION
-	const uint32_t faceCount = mesh->faceCount();
-#endif
-	const bool compareNormal = equal(normal, Vector3(0.0f), FLT_EPSILON);
-	uint32_t frontCount = holeVertices.size();
-	Array<uint32_t> frontVertices;
-	Array<Vector3> frontPoints;
-	Array<float> frontAngles;
-	frontVertices.resize(frontCount);
-	frontPoints.resize(frontCount);
-	for (uint32_t i = 0; i < frontCount; i++) {
-		frontVertices[i] = holeVertices[i];
-		frontPoints[i] = mesh->position(frontVertices[i]);
-	}
-	while (frontCount >= 3) {
-		frontAngles.resize(frontCount);
-		float smallestAngle = kPi2, smallestAngleIgnoringNormal = kPi2;
-		uint32_t smallestAngleIndex = UINT32_MAX, smallestAngleIndexIgnoringNormal = UINT32_MAX;
-		for (uint32_t i = 0; i < frontCount; i++) {
-			const uint32_t i1 = i == 0 ? frontCount - 1 : i - 1;
-			const uint32_t i2 = i;
-			const uint32_t i3 = (i + 1) % frontCount;
-			const Vector3 edge1 = frontPoints[i1] - frontPoints[i2];
-			const Vector3 edge2 = frontPoints[i3] - frontPoints[i2];
-			frontAngles[i] = atan2f(length(cross(edge1, edge2)), dot(edge1, edge2));
-			if (frontAngles[i] >= smallestAngle || isNan(frontAngles[i]))
-				continue;
-			// Don't duplicate edges.
-			if (mesh->findEdge(frontVertices[i1], frontVertices[i2]) != UINT32_MAX)
-				continue;
-			if (mesh->findEdge(frontVertices[i2], frontVertices[i3]) != UINT32_MAX)
-				continue;
-			if (mesh->findEdge(frontVertices[i3], frontVertices[i1]) != UINT32_MAX)
-				continue;
-			/*
-			Make sure he new edge that would be formed by (i3, i1) doesn't intersect any vertices. This often happens when fixing t-junctions.
-
-			       i2
-			       *
-			      / \
-			     /   \
-			 i1 *--*--* i3
-			     \ | /
-				  \|/
-				   *
-			*/
-			bool intersection = false;
-			for (uint32_t j = 0; j < frontCount; j++) {
-				if (j == i1 || j == i2 || j == i3)
-					continue;
-				if (lineIntersectsPoint(frontPoints[j], frontPoints[i3], frontPoints[i1], nullptr, mesh->epsilon())) {
-					intersection = true;
-					break;
-				}
-			}
-			if (intersection)
-				continue;
-			// Don't add the triangle if a boundary point lies on the same plane as the triangle, and is inside it.
-			intersection = false;
-			const Plane plane(frontPoints[i1], frontPoints[i2], frontPoints[i3]);
-			for (uint32_t j = 0; j < frontCount; j++) {
-				if (j == i1 || j == i2 || j == i3)
-					continue;
-				if (!isZero(plane.distance(frontPoints[j]), mesh->epsilon()))
-					continue;
-				if (pointInTriangle(frontPoints[j], frontPoints[i1], frontPoints[i2], frontPoints[i3])) {
-					intersection = true;
-					break;
-				}
-			}
-			if (intersection)
-				continue;
-#if XA_CLOSE_HOLES_CHECK_EDGE_INTERSECTION
-			// Don't add the triangle if the new edge (i3, i1), intersects any other triangle that isn't part of the filled hole.
-			intersection = false;
-			const Vector3 newEdgeVector = frontPoints[i1] - frontPoints[i3];
-			for (uint32_t f = 0; f < faceCount; f++) {
-				Vector3 tri[3];
-				for (uint32_t j = 0; j < 3; j++)
-					tri[j] = mesh->position(mesh->vertexAt(f * 3 + j));
-				float t;
-				if (rayIntersectsTriangle(frontPoints[i3], newEdgeVector, tri, &t)) {
-					intersection = true;
-					break;
-				}
-			}
-			if (intersection)
-				continue;
-#endif
-			// Skip backwards facing triangles.
-			if (compareNormal) {
-				if (frontAngles[i] < smallestAngleIgnoringNormal) {
-					smallestAngleIgnoringNormal = frontAngles[i];
-					smallestAngleIndexIgnoringNormal = i;
-				}
-				const Vector3 e0 = frontPoints[i3] - frontPoints[i1];
-				const Vector3 e1 = frontPoints[i2] - frontPoints[i1];
-				const Vector3 triNormal = normalizeSafe(cross(e0, e1), Vector3(0.0f), mesh->epsilon());
-				if (dot(normal, triNormal) <= 0.0f)
-					continue;
-			}
-			smallestAngle = smallestAngleIgnoringNormal = frontAngles[i];
-			smallestAngleIndex = smallestAngleIndexIgnoringNormal = i;
-		}
-		// Closing holes failed if we don't have a smallest angle.
-		// Fallback to ignoring the backwards facing normal test if possible.
-		if (smallestAngleIndex == UINT32_MAX || smallestAngle <= 0.0f || smallestAngle >= kPi) {
-			if (smallestAngleIgnoringNormal == UINT32_MAX || smallestAngleIgnoringNormal <= 0.0f || smallestAngleIgnoringNormal >= kPi)
-				return false;
-			else
-				smallestAngleIndex = smallestAngleIndexIgnoringNormal;
-		}
-		const uint32_t i1 = smallestAngleIndex == 0 ? frontCount - 1 : smallestAngleIndex - 1;
-		const uint32_t i2 = smallestAngleIndex;
-		const uint32_t i3 = (smallestAngleIndex + 1) % frontCount;
-		const Mesh::AddFaceResult::Enum result = mesh->addFace(frontVertices[i1], frontVertices[i2], frontVertices[i3]);
-		XA_DEBUG_ASSERT(result == Mesh::AddFaceResult::OK); // Shouldn't happen due to the findEdge calls above.
-		XA_UNUSED(result);
-		frontVertices.removeAt(i2);
-		frontPoints.removeAt(i2);
-		frontCount = frontVertices.size();
-	}
-	return true;
-}
-
-static bool meshCloseHoles(Mesh *mesh, const Array<uint32_t> &boundaryLoops, const Vector3 &normal, uint32_t *holeCount, Array<uint32_t> *holeFaceCounts)
-{
-	if (holeFaceCounts)
-		holeFaceCounts->clear();
-	// Compute lengths.
-	const uint32_t boundaryCount = boundaryLoops.size();
-	Array<float> boundaryLengths;
-	Array<uint32_t> boundaryEdgeCounts;
-	boundaryEdgeCounts.resize(boundaryCount);
-	for (uint32_t i = 0; i < boundaryCount; i++) {
-		float boundaryLength = 0.0f;
-		boundaryEdgeCounts[i] = 0;
-		for (Mesh::BoundaryLoopEdgeIterator it(mesh, boundaryLoops[i]); !it.isDone(); it.advance()) {
-			const Vector3 &t0 = mesh->position(mesh->vertexAt(meshEdgeIndex0(it.edge())));
-			const Vector3 &t1 = mesh->position(mesh->vertexAt(meshEdgeIndex1(it.edge())));
-			boundaryLength += length(t1 - t0);
-			boundaryEdgeCounts[i]++;
-		}
-		boundaryLengths.push_back(boundaryLength);
-	}
-	// Find disk boundary.
-	uint32_t diskBoundary = 0;
-	float maxLength = boundaryLengths[0];
-	for (uint32_t i = 1; i < boundaryCount; i++) {
-		if (boundaryLengths[i] > maxLength) {
-			maxLength = boundaryLengths[i];
-			diskBoundary = i;
-		}
-	}
-	// Close holes.
-	Array<uint32_t> holeVertices;
-	Array<Vector3> holePoints;
-	bool result = true;
-	for (uint32_t i = 0; i < boundaryCount; i++) {
-		if (diskBoundary == i)
-			continue; // Skip disk boundary.
-		holeVertices.resize(boundaryEdgeCounts[i]);
-		holePoints.resize(boundaryEdgeCounts[i]);
-		// Winding is backwards for internal boundaries.
-		uint32_t e = 0;
-		for (Mesh::BoundaryLoopEdgeIterator it(mesh, boundaryLoops[i]); !it.isDone(); it.advance()) {
-			const uint32_t vertex = mesh->vertexAt(meshEdgeIndex0(it.edge()));
-			holeVertices[boundaryEdgeCounts[i] - 1 - e] = vertex;
-			holePoints[boundaryEdgeCounts[i] - 1 - e] = mesh->position(vertex);
-			e++;
-		}
-		const uint32_t oldFaceCount = mesh->faceCount();
-		if (!meshCloseHole(mesh, holeVertices, normal))
-			result = false; // Return false if any hole failed to close, but keep trying to close other holes.
-		if (holeCount)
-			(*holeCount)++;
-		if (holeFaceCounts)
-			holeFaceCounts->push_back(mesh->faceCount() - oldFaceCount);
-	}
-	return result;
-}
-
-static bool meshIsPlanar(const Mesh &mesh)
-{
-	const Vector3 p1 = mesh.position(mesh.vertexAt(0));
-	const Vector3 p2 = mesh.position(mesh.vertexAt(1));
-	const Vector3 p3 = mesh.position(mesh.vertexAt(2));
-	const Plane plane(p1, p2, p3);
-	const uint32_t vertexCount = mesh.vertexCount();
-	for (uint32_t v = 0; v < vertexCount; v++) {
-		const float d = plane.distance(mesh.position(v));
-		if (!isZero(d, mesh.epsilon()))
-			return false;
-	}
-	return true;
-}
-
-/*
-Fixing T-junctions.
-
-- Find T-junctions. Find  vertices that are on an edge.
-- This test is approximate.
-- Insert edges on a spatial index to speedup queries.
-- Consider only open edges, that is edges that have no pairs.
-- Consider only vertices on boundaries.
-- Close T-junction.
-- Split edge.
-
-*/
-struct SplitEdge
-{
-	uint32_t edge;
-	float t;
-	uint32_t vertex;
-
-	bool operator<(const SplitEdge &other) const
-	{
-		if (edge < other.edge)
-			return true;
-		else if (edge == other.edge) {
-			if (t < other.t)
-				return true;
-		}
+#if XA_CHECK_T_JUNCTIONS
+static bool lineIntersectsPoint(const Vector3 &point, const Vector3 &lineStart, const Vector3 &lineEnd, float *t, float epsilon) {
+	float tt;
+	if (!t)
+		t = &tt;
+	*t = 0.0f;
+	if (equal(lineStart, point, epsilon) || equal(lineEnd, point, epsilon))
+		return false; // Vertex lies on either line vertices.
+	const Vector3 v01 = point - lineStart;
+	const Vector3 v21 = lineEnd - lineStart;
+	const float l = length(v21);
+	const float d = length(cross(v01, v21)) / l;
+	if (!isZero(d, epsilon))
 		return false;
-	}
-};
+	*t = dot(v01, v21) / (l * l);
+	return *t > kEpsilon && *t < 1.0f - kEpsilon;
+}
 
-// Returns nullptr if there were no t-junctions to fix.
-static Mesh *meshFixTJunctions(const Mesh &inputMesh, bool *duplicatedEdge, bool *failed, uint32_t *fixedTJunctionsCount)
-{
-	if (duplicatedEdge)
-		*duplicatedEdge = false;
-	if (failed)
-		*failed = false;
-	Array<SplitEdge> splitEdges;
+// Returns the number of T-junctions found.
+static int meshCheckTJunctions(const Mesh &inputMesh) {
+	int count = 0;
 	const uint32_t vertexCount = inputMesh.vertexCount();
 	const uint32_t edgeCount = inputMesh.edgeCount();
 	for (uint32_t v = 0; v < vertexCount; v++) {
@@ -3582,155 +2836,130 @@ static Mesh *meshFixTJunctions(const Mesh &inputMesh, bool *duplicatedEdge, bool
 			const Vector3 &edgePos1 = inputMesh.position(inputMesh.vertexAt(meshEdgeIndex0(e)));
 			const Vector3 &edgePos2 = inputMesh.position(inputMesh.vertexAt(meshEdgeIndex1(e)));
 			float t;
-			if (!lineIntersectsPoint(pos, edgePos1, edgePos2, &t, inputMesh.epsilon()))
-				continue;
-			SplitEdge splitEdge;
-			splitEdge.edge = e;
-			splitEdge.t = t;
-			splitEdge.vertex = v;
-			splitEdges.push_back(splitEdge);
+			if (lineIntersectsPoint(pos, edgePos1, edgePos2, &t, inputMesh.epsilon()))
+				count++;
 		}
 	}
-	if (splitEdges.isEmpty())
-		return nullptr;
-	const uint32_t faceCount = inputMesh.faceCount();
-	Mesh *mesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, inputMesh.epsilon(), vertexCount + splitEdges.size(), faceCount);
-	for (uint32_t v = 0; v < vertexCount; v++)
-		mesh->addVertex(inputMesh.position(v));
-	Array<uint32_t> indexArray;
-	indexArray.reserve(4);
-	Array<SplitEdge> faceSplitEdges;
-	faceSplitEdges.reserve(4);
-	for (uint32_t f = 0; f < faceCount; f++) {
-		// Find t-junctions in this face.
-		faceSplitEdges.clear();
-		for (uint32_t i = 0; i < splitEdges.size(); i++) {
-			if (meshEdgeFace(splitEdges[i].edge) == f)
-				faceSplitEdges.push_back(splitEdges[i]);
-		}
-		if (!faceSplitEdges.isEmpty()) {
-			// Need to split edges in winding order when a single edge has multiple t-junctions.
-			insertionSort(faceSplitEdges.data(), faceSplitEdges.size());
-			indexArray.clear();
-			for (Mesh::FaceEdgeIterator it(&inputMesh, f); !it.isDone(); it.advance()) {
-				indexArray.push_back(it.vertex0());
-				for (uint32_t se = 0; se < faceSplitEdges.size(); se++) {
-					const SplitEdge &splitEdge = faceSplitEdges[se];
-					if (splitEdge.edge == it.edge())
-						indexArray.push_back(splitEdge.vertex);
+	return count;
+}
+#endif
+
+// References invalid faces and vertices in a mesh.
+struct InvalidMeshGeometry {
+	// If meshFaceGroups is not null, invalid faces have the face group MeshFaceGroups::kInvalid.
+	// If meshFaceGroups is null, invalid faces are Mesh::isFaceIgnored.
+	void extract(const Mesh *mesh, const MeshFaceGroups *meshFaceGroups) {
+		// Copy invalid faces.
+		m_faces.clear();
+		const uint32_t meshFaceCount = mesh->faceCount();
+		for (uint32_t f = 0; f < meshFaceCount; f++) {
+			if ((meshFaceGroups && meshFaceGroups->groupAt(f) == MeshFaceGroups::kInvalid) || (!meshFaceGroups && mesh->isFaceIgnored(f)))
+				m_faces.push_back(f);
+		}
+		// Create *unique* list of vertices of invalid faces.
+		const uint32_t faceCount = m_faces.size();
+		m_indices.resize(faceCount * 3);
+		const uint32_t approxVertexCount = min(faceCount * 3, mesh->vertexCount());
+		m_vertexToSourceVertexMap.clear();
+		m_vertexToSourceVertexMap.reserve(approxVertexCount);
+		HashMap<uint32_t, PassthroughHash<uint32_t>> sourceVertexToVertexMap(MemTag::Mesh, approxVertexCount);
+		for (uint32_t f = 0; f < faceCount; f++) {
+			const uint32_t face = m_faces[f];
+			for (uint32_t i = 0; i < 3; i++) {
+				const uint32_t vertex = mesh->vertexAt(face * 3 + i);
+				uint32_t newVertex = sourceVertexToVertexMap.get(vertex);
+				if (newVertex == UINT32_MAX) {
+					newVertex = sourceVertexToVertexMap.add(vertex);
+					m_vertexToSourceVertexMap.push_back(vertex);
 				}
-			}
-			if (!meshCloseHole(mesh, indexArray, Vector3(0.0f))) {
-				if (failed)
-					*failed = true;
-			}
-		} else {
-			// No t-junctions in this face. Copy from input mesh.
-			if (mesh->addFace(&inputMesh.indices()[f * 3]) == Mesh::AddFaceResult::DuplicateEdge) {
-				if (duplicatedEdge)
-					*duplicatedEdge = true;
+				m_indices[f * 3 + i] = newVertex;
 			}
 		}
 	}
-	if (fixedTJunctionsCount)
-		*fixedTJunctionsCount = splitEdges.size();
-	return mesh;
-}
 
-// boundaryLoops are the first edges for each boundary loop.
-static void meshGetBoundaryLoops(const Mesh &mesh, Array<uint32_t> &boundaryLoops)
-{
-	const uint32_t edgeCount = mesh.edgeCount();
-	BitArray bitFlags(edgeCount);
-	bitFlags.zeroOutMemory();
-	boundaryLoops.clear();
-	// Search for boundary edges. Mark all the edges that belong to the same boundary.
-	for (uint32_t e = 0; e < edgeCount; e++) {
-		if (bitFlags.get(e) || !mesh.isBoundaryEdge(e))
-			continue;
-		for (Mesh::BoundaryLoopEdgeIterator it(&mesh, e); !it.isDone(); it.advance())
-			bitFlags.set(it.edge());
-		boundaryLoops.push_back(e);
-	}
-}
+	ConstArrayView<uint32_t> faces() const { return m_faces; }
+	ConstArrayView<uint32_t> indices() const { return m_indices; }
+	ConstArrayView<uint32_t> vertices() const { return m_vertexToSourceVertexMap; }
 
-struct Progress
-{
-	Progress(ProgressCategory::Enum category, ProgressFunc func, void *userData, uint32_t maxValue) : value(0), cancel(false), m_category(category), m_func(func), m_userData(userData), m_maxValue(maxValue), m_progress(0)
-	{
+private:
+	Array<uint32_t> m_faces, m_indices;
+	Array<uint32_t> m_vertexToSourceVertexMap; // Map face vertices to vertices of the source mesh.
+};
+
+struct Progress {
+	Progress(ProgressCategory category, ProgressFunc func, void *userData, uint32_t maxValue) :
+			cancel(false), m_category(category), m_func(func), m_userData(userData), m_value(0), m_maxValue(maxValue), m_percent(0) {
 		if (m_func) {
 			if (!m_func(category, 0, userData))
 				cancel = true;
 		}
 	}
 
-	~Progress()
-	{
+	~Progress() {
 		if (m_func) {
 			if (!m_func(m_category, 100, m_userData))
 				cancel = true;
 		}
 	}
 
-	void update()
-	{
-		if (!m_func)
-			return;
-		m_mutex.lock();
-		const uint32_t newProgress = uint32_t(ceilf(value.load() / (float)m_maxValue * 100.0f));
-		if (newProgress != m_progress && newProgress < 100) {
-			m_progress = newProgress;
-			if (!m_func(m_category, m_progress, m_userData))
-				cancel = true;
-		}
-		m_mutex.unlock();
+	void increment(uint32_t value) {
+		m_value += value;
+		update();
 	}
 
-	void setMaxValue(uint32_t maxValue)
-	{
-		m_mutex.lock();
+	void setMaxValue(uint32_t maxValue) {
 		m_maxValue = maxValue;
-		m_mutex.unlock();
+		update();
 	}
 
-	std::atomic<uint32_t> value;
 	std::atomic<bool> cancel;
 
 private:
-	ProgressCategory::Enum m_category;
+	void update() {
+		if (!m_func)
+			return;
+		const uint32_t newPercent = uint32_t(ceilf(m_value.load() / (float)m_maxValue.load() * 100.0f));
+		if (newPercent != m_percent) {
+			// Atomic max.
+			uint32_t oldPercent = m_percent;
+			while (oldPercent < newPercent && !m_percent.compare_exchange_weak(oldPercent, newPercent)) {
+			}
+			if (!m_func(m_category, m_percent, m_userData))
+				cancel = true;
+		}
+	}
+
+	ProgressCategory m_category;
 	ProgressFunc m_func;
 	void *m_userData;
-	uint32_t m_maxValue;
-	uint32_t m_progress;
-	std::mutex m_mutex;
+	std::atomic<uint32_t> m_value, m_maxValue, m_percent;
 };
 
-struct Spinlock
-{
-	void lock() { while(m_lock.test_and_set(std::memory_order_acquire)) {} }
+struct Spinlock {
+	void lock() {
+		while (m_lock.test_and_set(std::memory_order_acquire)) {
+		}
+	}
 	void unlock() { m_lock.clear(std::memory_order_release); }
 
 private:
 	std::atomic_flag m_lock = ATOMIC_FLAG_INIT;
 };
 
-struct TaskGroupHandle
-{
+struct TaskGroupHandle {
 	uint32_t value = UINT32_MAX;
 };
 
-struct Task
-{
-	void (*func)(void *userData);
-	void *userData;
+struct Task {
+	void (*func)(void *groupUserData, void *taskUserData);
+	void *userData; // Passed to func as taskUserData.
 };
 
 #if XA_MULTITHREADED
-class TaskScheduler
-{
+class TaskScheduler {
 public:
-	TaskScheduler() : m_shutdown(false)
-	{
+	TaskScheduler() :
+			m_shutdown(false) {
 		m_threadIndex = 0;
 		// Max with current task scheduler usage is 1 per thread + 1 deep nesting, but allow for some slop.
 		m_maxGroups = std::thread::hardware_concurrency() * 4;
@@ -3739,6 +2968,7 @@ public:
 			new (&m_groups[i]) TaskGroup();
 			m_groups[i].free = true;
 			m_groups[i].ref = 0;
+			m_groups[i].userData = nullptr;
 		}
 		m_workers.resize(std::thread::hardware_concurrency() <= 1 ? 1 : std::thread::hardware_concurrency() - 1);
 		for (uint32_t i = 0; i < m_workers.size(); i++) {
@@ -3748,8 +2978,7 @@ public:
 		}
 	}
 
-	~TaskScheduler()
-	{
+	~TaskScheduler() {
 		m_shutdown = true;
 		for (uint32_t i = 0; i < m_workers.size(); i++) {
 			Worker &worker = m_workers[i];
@@ -3767,13 +2996,12 @@ public:
 		XA_FREE(m_groups);
 	}
 
-	uint32_t threadCount() const
-	{
+	uint32_t threadCount() const {
 		return max(1u, std::thread::hardware_concurrency()); // Including the main thread.
 	}
 
-	TaskGroupHandle createTaskGroup(uint32_t reserveSize = 0)
-	{
+	// userData is passed to Task::func as groupUserData.
+	TaskGroupHandle createTaskGroup(void *userData = nullptr, uint32_t reserveSize = 0) {
 		// Claim the first free group.
 		for (uint32_t i = 0; i < m_maxGroups; i++) {
 			TaskGroup &group = m_groups[i];
@@ -3785,6 +3013,8 @@ public:
 			group.queue.clear();
 			group.queue.reserve(reserveSize);
 			group.queueLock.unlock();
+			group.userData = userData;
+			group.ref = 0;
 			TaskGroupHandle handle;
 			handle.value = i;
 			return handle;
@@ -3795,8 +3025,7 @@ public:
 		return handle;
 	}
 
-	void run(TaskGroupHandle handle, const Task &task)
-	{
+	void run(TaskGroupHandle handle, const Task &task) {
 		XA_DEBUG_ASSERT(handle.value != UINT32_MAX);
 		TaskGroup &group = m_groups[handle.value];
 		group.queueLock.lock();
@@ -3810,8 +3039,7 @@ public:
 		}
 	}
 
-	void wait(TaskGroupHandle *handle)
-	{
+	void wait(TaskGroupHandle *handle) {
 		if (handle->value == UINT32_MAX) {
 			XA_DEBUG_ASSERT(false);
 			return;
@@ -3826,7 +3054,7 @@ public:
 			group.queueLock.unlock();
 			if (!task)
 				break;
-			task->func(task->userData);
+			task->func(group.userData, task->userData);
 			group.ref--;
 		}
 		// Even though the task queue is empty, workers can still be running tasks.
@@ -3839,17 +3067,16 @@ public:
 	static uint32_t currentThreadIndex() { return m_threadIndex; }
 
 private:
-	struct TaskGroup
-	{
+	struct TaskGroup {
 		std::atomic<bool> free;
 		Array<Task> queue; // Items are never removed. queueHead is incremented to pop items.
 		uint32_t queueHead = 0;
 		Spinlock queueLock;
 		std::atomic<uint32_t> ref; // Increment when a task is enqueued, decrement when a task finishes.
+		void *userData;
 	};
 
-	struct Worker
-	{
+	struct Worker {
 		std::thread *thread = nullptr;
 		std::mutex mutex;
 		std::condition_variable cv;
@@ -3862,12 +3089,11 @@ private:
 	uint32_t m_maxGroups;
 	static thread_local uint32_t m_threadIndex;
 
-	static void workerThread(TaskScheduler *scheduler, Worker *worker, uint32_t threadIndex)
-	{
+	static void workerThread(TaskScheduler *scheduler, Worker *worker, uint32_t threadIndex) {
 		m_threadIndex = threadIndex;
 		std::unique_lock<std::mutex> lock(worker->mutex);
 		for (;;) {
-			worker->cv.wait(lock, [=]{ return worker->wakeup.load(); });
+			worker->cv.wait(lock, [=] { return worker->wakeup.load(); });
 			worker->wakeup = false;
 			for (;;) {
 				if (scheduler->m_shutdown)
@@ -3889,7 +3115,7 @@ private:
 				}
 				if (!task)
 					break;
-				task->func(task->userData);
+				task->func(group->userData, task->userData);
 				group->ref--;
 			}
 		}
@@ -3898,44 +3124,39 @@ private:
 
 thread_local uint32_t TaskScheduler::m_threadIndex;
 #else
-class TaskScheduler
-{
+class TaskScheduler {
 public:
-	~TaskScheduler()
-	{
+	~TaskScheduler() {
 		for (uint32_t i = 0; i < m_groups.size(); i++)
 			destroyGroup({ i });
 	}
 
-	uint32_t threadCount() const
-	{
+	uint32_t threadCount() const {
 		return 1;
 	}
 
-	TaskGroupHandle createTaskGroup(uint32_t reserveSize = 0)
-	{
+	TaskGroupHandle createTaskGroup(void *userData = nullptr, uint32_t reserveSize = 0) {
 		TaskGroup *group = XA_NEW(MemTag::Default, TaskGroup);
 		group->queue.reserve(reserveSize);
+		group->userData = userData;
 		m_groups.push_back(group);
 		TaskGroupHandle handle;
 		handle.value = m_groups.size() - 1;
 		return handle;
 	}
 
-	void run(TaskGroupHandle handle, Task task)
-	{
+	void run(TaskGroupHandle handle, Task task) {
 		m_groups[handle.value]->queue.push_back(task);
 	}
 
-	void wait(TaskGroupHandle *handle)
-	{
+	void wait(TaskGroupHandle *handle) {
 		if (handle->value == UINT32_MAX) {
 			XA_DEBUG_ASSERT(false);
 			return;
 		}
 		TaskGroup *group = m_groups[handle->value];
 		for (uint32_t i = 0; i < group->queue.size(); i++)
-			group->queue[i].func(group->queue[i].userData);
+			group->queue[i].func(group->userData, group->queue[i].userData);
 		group->queue.clear();
 		destroyGroup(*handle);
 		handle->value = UINT32_MAX;
@@ -3944,8 +3165,7 @@ public:
 	static uint32_t currentThreadIndex() { return 0; }
 
 private:
-	void destroyGroup(TaskGroupHandle handle)
-	{
+	void destroyGroup(TaskGroupHandle handle) {
 		TaskGroup *group = m_groups[handle.value];
 		if (group) {
 			group->~TaskGroup();
@@ -3954,9 +3174,9 @@ private:
 		}
 	}
 
-	struct TaskGroup
-	{
+	struct TaskGroup {
 		Array<Task> queue;
+		void *userData;
 	};
 
 	Array<TaskGroup *> m_groups;
@@ -3968,8 +3188,7 @@ const uint8_t TGA_TYPE_RGB = 2;
 const uint8_t TGA_ORIGIN_UPPER = 0x20;
 
 #pragma pack(push, 1)
-struct TgaHeader
-{
+struct TgaHeader {
 	uint8_t id_length;
 	uint8_t colormap_type;
 	uint8_t image_type;
@@ -3986,8 +3205,7 @@ struct TgaHeader
 };
 #pragma pack(pop)
 
-static void WriteTga(const char *filename, const uint8_t *data, uint32_t width, uint32_t height)
-{
+static void WriteTga(const char *filename, const uint8_t *data, uint32_t width, uint32_t height) {
 	XA_DEBUG_ASSERT(sizeof(TgaHeader) == TgaHeader::Size);
 	FILE *f;
 	XA_FOPEN(f, filename, "wb");
@@ -4012,12 +3230,10 @@ static void WriteTga(const char *filename, const uint8_t *data, uint32_t width,
 }
 #endif
 
-template<typename T>
-class ThreadLocal
-{
+template <typename T>
+class ThreadLocal {
 public:
-	ThreadLocal()
-	{
+	ThreadLocal() {
 #if XA_MULTITHREADED
 		const uint32_t n = std::thread::hardware_concurrency();
 #else
@@ -4028,8 +3244,7 @@ public:
 			new (&m_array[i]) T;
 	}
 
-	~ThreadLocal()
-	{
+	~ThreadLocal() {
 #if XA_MULTITHREADED
 		const uint32_t n = std::thread::hardware_concurrency();
 #else
@@ -4040,8 +3255,7 @@ public:
 		XA_FREE(m_array);
 	}
 
-	T &get() const
-	{
+	T &get() const {
 		return m_array[TaskScheduler::currentThreadIndex()];
 	}
 
@@ -4049,11 +3263,104 @@ private:
 	T *m_array;
 };
 
-class UniformGrid2
-{
+// Implemented as a struct so the temporary arrays can be reused.
+struct Triangulator {
+	// This is doing a simple ear-clipping algorithm that skips invalid triangles. Ideally, we should
+	// also sort the ears by angle, start with the ones that have the smallest angle and proceed in order.
+	void triangulatePolygon(ConstArrayView<Vector3> vertices, ConstArrayView<uint32_t> inputIndices, Array<uint32_t> &outputIndices) {
+		m_polygonVertices.clear();
+		m_polygonVertices.reserve(inputIndices.length);
+		outputIndices.clear();
+		if (inputIndices.length == 3) {
+			// Simple case for triangles.
+			outputIndices.push_back(inputIndices[0]);
+			outputIndices.push_back(inputIndices[1]);
+			outputIndices.push_back(inputIndices[2]);
+		} else {
+			// Build 2D polygon projecting vertices onto normal plane.
+			// Faces are not necesarily planar, this is for example the case, when the face comes from filling a hole. In such cases
+			// it's much better to use the best fit plane.
+			Basis basis;
+			basis.normal = normalize(cross(vertices[inputIndices[1]] - vertices[inputIndices[0]], vertices[inputIndices[2]] - vertices[inputIndices[1]]));
+			basis.tangent = basis.computeTangent(basis.normal);
+			basis.bitangent = basis.computeBitangent(basis.normal, basis.tangent);
+			const uint32_t edgeCount = inputIndices.length;
+			m_polygonPoints.clear();
+			m_polygonPoints.reserve(edgeCount);
+			m_polygonAngles.clear();
+			m_polygonAngles.reserve(edgeCount);
+			for (uint32_t i = 0; i < inputIndices.length; i++) {
+				m_polygonVertices.push_back(inputIndices[i]);
+				const Vector3 &pos = vertices[inputIndices[i]];
+				m_polygonPoints.push_back(Vector2(dot(basis.tangent, pos), dot(basis.bitangent, pos)));
+			}
+			m_polygonAngles.resize(edgeCount);
+			while (m_polygonVertices.size() > 2) {
+				const uint32_t size = m_polygonVertices.size();
+				// Update polygon angles. @@ Update only those that have changed.
+				float minAngle = kPi2;
+				uint32_t bestEar = 0; // Use first one if none of them is valid.
+				bool bestIsValid = false;
+				for (uint32_t i = 0; i < size; i++) {
+					uint32_t i0 = i;
+					uint32_t i1 = (i + 1) % size; // Use Sean's polygon interation trick.
+					uint32_t i2 = (i + 2) % size;
+					Vector2 p0 = m_polygonPoints[i0];
+					Vector2 p1 = m_polygonPoints[i1];
+					Vector2 p2 = m_polygonPoints[i2];
+					float d = clamp(dot(p0 - p1, p2 - p1) / (length(p0 - p1) * length(p2 - p1)), -1.0f, 1.0f);
+					float angle = acosf(d);
+					float area = triangleArea(p0, p1, p2);
+					if (area < 0.0f)
+						angle = kPi2 - angle;
+					m_polygonAngles[i1] = angle;
+					if (angle < minAngle || !bestIsValid) {
+						// Make sure this is a valid ear, if not, skip this point.
+						bool valid = true;
+						for (uint32_t j = 0; j < size; j++) {
+							if (j == i0 || j == i1 || j == i2)
+								continue;
+							Vector2 p = m_polygonPoints[j];
+							if (pointInTriangle(p, p0, p1, p2)) {
+								valid = false;
+								break;
+							}
+						}
+						if (valid || !bestIsValid) {
+							minAngle = angle;
+							bestEar = i1;
+							bestIsValid = valid;
+						}
+					}
+				}
+				// Clip best ear:
+				const uint32_t i0 = (bestEar + size - 1) % size;
+				const uint32_t i1 = (bestEar + 0) % size;
+				const uint32_t i2 = (bestEar + 1) % size;
+				outputIndices.push_back(m_polygonVertices[i0]);
+				outputIndices.push_back(m_polygonVertices[i1]);
+				outputIndices.push_back(m_polygonVertices[i2]);
+				m_polygonVertices.removeAt(i1);
+				m_polygonPoints.removeAt(i1);
+				m_polygonAngles.removeAt(i1);
+			}
+		}
+	}
+
+private:
+	static bool pointInTriangle(const Vector2 &p, const Vector2 &a, const Vector2 &b, const Vector2 &c) {
+		return triangleArea(a, b, p) >= kAreaEpsilon && triangleArea(b, c, p) >= kAreaEpsilon && triangleArea(c, a, p) >= kAreaEpsilon;
+	}
+
+	Array<int> m_polygonVertices;
+	Array<float> m_polygonAngles;
+	Array<Vector2> m_polygonPoints;
+};
+
+class UniformGrid2 {
 public:
-	void reset(const Vector2 *positions, const uint32_t *indices = nullptr, uint32_t reserveEdgeCount = 0)
-	{
+	// indices are optional.
+	void reset(ConstArrayView<Vector2> positions, ConstArrayView<uint32_t> indices = ConstArrayView<uint32_t>(), uint32_t reserveEdgeCount = 0) {
 		m_edges.clear();
 		if (reserveEdgeCount > 0)
 			m_edges.reserve(reserveEdgeCount);
@@ -4062,14 +3369,12 @@ public:
 		m_cellDataOffsets.clear();
 	}
 
-	void append(uint32_t edge)
-	{
+	void append(uint32_t edge) {
 		XA_DEBUG_ASSERT(m_cellDataOffsets.isEmpty());
 		m_edges.push_back(edge);
 	}
 
-	bool intersect(Vector2 v1, Vector2 v2, float epsilon)
-	{
+	bool intersect(Vector2 v1, Vector2 v2, float epsilon) {
 		const uint32_t edgeCount = m_edges.size();
 		bool bruteForce = edgeCount <= 20;
 		if (!bruteForce && m_cellDataOffsets.isEmpty())
@@ -4096,8 +3401,7 @@ public:
 	}
 
 	// If edges is empty, checks for intersection with all edges in the grid.
-	bool intersect(float epsilon, ConstArrayView<uint32_t> edges = ConstArrayView<uint32_t>(), ConstArrayView<uint32_t> ignoreEdges = ConstArrayView<uint32_t>())
-	{
+	bool intersect(float epsilon, ConstArrayView<uint32_t> edges = ConstArrayView<uint32_t>(), ConstArrayView<uint32_t> ignoreEdges = ConstArrayView<uint32_t>()) {
 		bool bruteForce = m_edges.size() <= 20;
 		if (!bruteForce && m_cellDataOffsets.isEmpty())
 			bruteForce = !createGrid();
@@ -4167,8 +3471,7 @@ public:
 	}
 
 #if XA_DEBUG_EXPORT_BOUNDARY_GRID
-	void debugExport(const char *filename)
-	{
+	void debugExport(const char *filename) {
 		Array<uint8_t> image;
 		image.resize(m_gridWidth * m_gridHeight * 3);
 		for (uint32_t y = 0; y < m_gridHeight; y++) {
@@ -4190,8 +3493,7 @@ public:
 #endif
 
 private:
-	bool createGrid()
-	{
+	bool createGrid() {
 		// Compute edge extents. Min will be the grid origin.
 		const uint32_t edgeCount = m_edges.size();
 		Extents2 edgeExtents;
@@ -4202,14 +3504,14 @@ private:
 			edgeExtents.add(edgePosition1(edge));
 		}
 		m_gridOrigin = edgeExtents.min;
-		// Size grid to approximately one edge per cell.
+		// Size grid to approximately one edge per cell in the largest dimension.
 		const Vector2 extentsSize(edgeExtents.max - edgeExtents.min);
-		m_cellSize = min(extentsSize.x, extentsSize.y) / sqrtf((float)edgeCount);
+		m_cellSize = max(extentsSize.x, extentsSize.y) / (float)clamp(edgeCount, 32u, 512u);
 		if (m_cellSize <= 0.0f)
 			return false;
 		m_gridWidth = uint32_t(ceilf(extentsSize.x / m_cellSize));
 		m_gridHeight = uint32_t(ceilf(extentsSize.y / m_cellSize));
-		if (m_gridWidth == 0 || m_gridHeight == 0)
+		if (m_gridWidth <= 1 || m_gridHeight <= 1)
 			return false;
 		// Insert edges into cells.
 		m_cellDataOffsets.resize(m_gridWidth * m_gridHeight);
@@ -4243,8 +3545,7 @@ private:
 		return true;
 	}
 
-	void computePotentialEdges(Vector2 p1, Vector2 p2)
-	{
+	void computePotentialEdges(Vector2 p1, Vector2 p2) {
 		m_potentialEdges.clear();
 		traverse(p1, p2);
 		for (uint32_t j = 0; j < m_traversedCellOffsets.size(); j++) {
@@ -4262,10 +3563,9 @@ private:
 	}
 
 	// "A Fast Voxel Traversal Algorithm for Ray Tracing"
-	void traverse(Vector2 p1, Vector2 p2)
-	{
+	void traverse(Vector2 p1, Vector2 p2) {
 		const Vector2 dir = p2 - p1;
-		const Vector2 normal = normalizeSafe(dir, Vector2(0.0f), kEpsilon);
+		const Vector2 normal = normalizeSafe(dir, Vector2(0.0f));
 		const int stepX = dir.x >= 0 ? 1 : -1;
 		const int stepY = dir.y >= 0 ? 1 : -1;
 		const uint32_t firstCell[2] = { cellX(p1.x), cellY(p1.y) };
@@ -4284,14 +3584,12 @@ private:
 		if (normal.x > kEpsilon || normal.x < -kEpsilon) {
 			tMaxX = (distToNextCellX * stepX) / normal.x;
 			tDeltaX = (m_cellSize * stepX) / normal.x;
-		}
-		else
+		} else
 			tMaxX = tDeltaX = FLT_MAX;
 		if (normal.y > kEpsilon || normal.y < -kEpsilon) {
 			tMaxY = (distToNextCellY * stepY) / normal.y;
 			tDeltaY = (m_cellSize * stepY) / normal.y;
-		}
-		else
+		} else
 			tMaxY = tDeltaY = FLT_MAX;
 		m_traversedCellOffsets.clear();
 		m_traversedCellOffsets.push_back(firstCell[0] + firstCell[1] * m_gridWidth);
@@ -4318,34 +3616,29 @@ private:
 		}
 	}
 
-	uint32_t cellX(float x) const
-	{
+	uint32_t cellX(float x) const {
 		return min((uint32_t)max(0.0f, (x - m_gridOrigin.x) / m_cellSize), m_gridWidth - 1u);
 	}
 
-	uint32_t cellY(float y) const
-	{
+	uint32_t cellY(float y) const {
 		return min((uint32_t)max(0.0f, (y - m_gridOrigin.y) / m_cellSize), m_gridHeight - 1u);
 	}
 
-	Vector2 edgePosition0(uint32_t edge) const
-	{
+	Vector2 edgePosition0(uint32_t edge) const {
 		return m_positions[vertexAt(meshEdgeIndex0(edge))];
 	}
 
-	Vector2 edgePosition1(uint32_t edge) const
-	{
+	Vector2 edgePosition1(uint32_t edge) const {
 		return m_positions[vertexAt(meshEdgeIndex1(edge))];
 	}
 
-	uint32_t vertexAt(uint32_t index) const
-	{
-		return m_indices ? m_indices[index] : index;
+	uint32_t vertexAt(uint32_t index) const {
+		return m_indices.length > 0 ? m_indices[index] : index;
 	}
 
 	Array<uint32_t> m_edges;
-	const Vector2 *m_positions;
-	const uint32_t *m_indices; // Optional
+	ConstArrayView<Vector2> m_positions;
+	ConstArrayView<uint32_t> m_indices; // Optional. Empty if unused.
 	float m_cellSize;
 	Vector2 m_gridOrigin;
 	uint32_t m_gridWidth, m_gridHeight; // in cells
@@ -4355,26 +3648,25 @@ private:
 	Array<uint32_t> m_traversedCellOffsets;
 };
 
-struct UvMeshChart
-{
+struct UvMeshChart {
 	Array<uint32_t> faces;
 	Array<uint32_t> indices;
 	uint32_t material;
 };
 
-struct UvMesh
-{
+struct UvMesh {
 	UvMeshDecl decl;
+	BitArray faceIgnore;
+	Array<uint32_t> faceMaterials;
 	Array<uint32_t> indices;
+	Array<Vector2> texcoords; // Copied from input and never modified, UvMeshInstance::texcoords are. Used to restore UvMeshInstance::texcoords so packing can be run multiple times.
 	Array<UvMeshChart *> charts;
 	Array<uint32_t> vertexToChartMap;
 };
 
-struct UvMeshInstance
-{
+struct UvMeshInstance {
 	UvMesh *mesh;
 	Array<Vector2> texcoords;
-	bool rotateCharts;
 };
 
 /*
@@ -4420,27 +3712,30 @@ struct UvMeshInstance
  *     FRANCE
  */
 namespace opennl {
-#define NL_NEW(T)              XA_ALLOC(MemTag::OpenNL, T)
-#define NL_NEW_ARRAY(T,NB)     XA_ALLOC_ARRAY(MemTag::OpenNL, T, NB)
-#define NL_RENEW_ARRAY(T,x,NB) XA_REALLOC(MemTag::OpenNL, x, T, NB)
-#define NL_DELETE(x)           XA_FREE(x); x = nullptr 
-#define NL_DELETE_ARRAY(x)     XA_FREE(x); x = nullptr
-#define NL_CLEAR(x, T)         memset(x, 0, sizeof(T));
-#define NL_CLEAR_ARRAY(T,x,NB) memset(x, 0, (size_t)(NB)*sizeof(T)) 
-#define NL_NEW_VECTOR(dim)     XA_ALLOC_ARRAY(MemTag::OpenNL, double, dim)
-#define NL_DELETE_VECTOR(ptr)  XA_FREE(ptr)
+#define NL_NEW(T) XA_ALLOC(MemTag::OpenNL, T)
+#define NL_NEW_ARRAY(T, NB) XA_ALLOC_ARRAY(MemTag::OpenNL, T, NB)
+#define NL_RENEW_ARRAY(T, x, NB) XA_REALLOC(MemTag::OpenNL, x, T, NB)
+#define NL_DELETE(x) \
+	XA_FREE(x);      \
+	x = nullptr
+#define NL_DELETE_ARRAY(x) \
+	XA_FREE(x);            \
+	x = nullptr
+#define NL_CLEAR(x, T) memset(x, 0, sizeof(T));
+#define NL_CLEAR_ARRAY(T, x, NB) memset(x, 0, (size_t)(NB) * sizeof(T))
+#define NL_NEW_VECTOR(dim) XA_ALLOC_ARRAY(MemTag::OpenNL, double, dim)
+#define NL_DELETE_VECTOR(ptr) XA_FREE(ptr)
 
 struct NLMatrixStruct;
-typedef NLMatrixStruct * NLMatrix;
+typedef NLMatrixStruct *NLMatrix;
 typedef void (*NLDestroyMatrixFunc)(NLMatrix M);
-typedef void (*NLMultMatrixVectorFunc)(NLMatrix M, const double* x, double* y);
+typedef void (*NLMultMatrixVectorFunc)(NLMatrix M, const double *x, double *y);
 
 #define NL_MATRIX_SPARSE_DYNAMIC 0x1001
-#define NL_MATRIX_CRS            0x1002
-#define NL_MATRIX_OTHER          0x1006
+#define NL_MATRIX_CRS 0x1002
+#define NL_MATRIX_OTHER 0x1006
 
-struct NLMatrixStruct
-{
+struct NLMatrixStruct {
 	uint32_t m;
 	uint32_t n;
 	uint32_t type;
@@ -4450,39 +3745,35 @@ struct NLMatrixStruct
 
 /* Dynamic arrays for sparse row/columns */
 
-struct NLCoeff
-{
+struct NLCoeff {
 	uint32_t index;
 	double value;
 };
 
-struct NLRowColumn
-{
+struct NLRowColumn {
 	uint32_t size;
 	uint32_t capacity;
-	NLCoeff* coeff;
+	NLCoeff *coeff;
 };
 
 /* Compressed Row Storage */
 
-struct NLCRSMatrix
-{
+struct NLCRSMatrix {
 	uint32_t m;
 	uint32_t n;
 	uint32_t type;
 	NLDestroyMatrixFunc destroy_func;
 	NLMultMatrixVectorFunc mult_func;
-	double* val;
-	uint32_t* rowptr;
-	uint32_t* colind;
+	double *val;
+	uint32_t *rowptr;
+	uint32_t *colind;
 	uint32_t nslices;
-	uint32_t* sliceptr;
+	uint32_t *sliceptr;
 };
 
 /* SparseMatrix data structure */
 
-struct NLSparseMatrix
-{
+struct NLSparseMatrix {
 	uint32_t m;
 	uint32_t n;
 	uint32_t type;
@@ -4490,25 +3781,23 @@ struct NLSparseMatrix
 	NLMultMatrixVectorFunc mult_func;
 	uint32_t diag_size;
 	uint32_t diag_capacity;
-	NLRowColumn* row;
-	NLRowColumn* column;
-	double*    diag;
+	NLRowColumn *row;
+	NLRowColumn *column;
+	double *diag;
 	uint32_t row_capacity;
 	uint32_t column_capacity;
 };
 
 /* NLContext data structure */
 
-struct NLBufferBinding
-{
-	void* base_address;
+struct NLBufferBinding {
+	void *base_address;
 	uint32_t stride;
 };
 
-#define NL_BUFFER_ITEM(B,i) *(double*)((void*)((char*)((B).base_address)+((i)*(B).stride)))
+#define NL_BUFFER_ITEM(B, i) *(double *)((void *)((char *)((B).base_address) + ((i) * (B).stride)))
 
-struct NLContext
-{
+struct NLContext {
 	NLBufferBinding *variable_buffer;
 	double *variable_value;
 	bool *variable_is_locked;
@@ -4532,35 +3821,30 @@ struct NLContext
 	double error;
 };
 
-static void nlDeleteMatrix(NLMatrix M)
-{
+static void nlDeleteMatrix(NLMatrix M) {
 	if (!M)
 		return;
 	M->destroy_func(M);
 	NL_DELETE(M);
 }
 
-static void nlMultMatrixVector(NLMatrix M, const double* x, double* y)
-{
+static void nlMultMatrixVector(NLMatrix M, const double *x, double *y) {
 	M->mult_func(M, x, y);
 }
 
-static void nlRowColumnConstruct(NLRowColumn* c)
-{
+static void nlRowColumnConstruct(NLRowColumn *c) {
 	c->size = 0;
 	c->capacity = 0;
 	c->coeff = nullptr;
 }
 
-static void nlRowColumnDestroy(NLRowColumn* c)
-{
+static void nlRowColumnDestroy(NLRowColumn *c) {
 	NL_DELETE_ARRAY(c->coeff);
 	c->size = 0;
 	c->capacity = 0;
 }
 
-static void nlRowColumnGrow(NLRowColumn* c)
-{
+static void nlRowColumnGrow(NLRowColumn *c) {
 	if (c->capacity != 0) {
 		c->capacity = 2 * c->capacity;
 		c->coeff = NL_RENEW_ARRAY(NLCoeff, c->coeff, c->capacity);
@@ -4571,8 +3855,7 @@ static void nlRowColumnGrow(NLRowColumn* c)
 	}
 }
 
-static void nlRowColumnAdd(NLRowColumn* c, uint32_t index, double value)
-{
+static void nlRowColumnAdd(NLRowColumn *c, uint32_t index, double value) {
 	for (uint32_t i = 0; i < c->size; i++) {
 		if (c->coeff[i].index == index) {
 			c->coeff[i].value += value;
@@ -4587,8 +3870,7 @@ static void nlRowColumnAdd(NLRowColumn* c, uint32_t index, double value)
 }
 
 /* Does not check whether the index already exists */
-static void nlRowColumnAppend(NLRowColumn* c, uint32_t index, double value)
-{
+static void nlRowColumnAppend(NLRowColumn *c, uint32_t index, double value) {
 	if (c->size == c->capacity)
 		nlRowColumnGrow(c);
 	c->coeff[c->size].index = index;
@@ -4596,32 +3878,27 @@ static void nlRowColumnAppend(NLRowColumn* c, uint32_t index, double value)
 	c->size++;
 }
 
-static void nlRowColumnZero(NLRowColumn* c)
-{
+static void nlRowColumnZero(NLRowColumn *c) {
 	c->size = 0;
 }
 
-static void nlRowColumnClear(NLRowColumn* c)
-{
+static void nlRowColumnClear(NLRowColumn *c) {
 	c->size = 0;
 	c->capacity = 0;
 	NL_DELETE_ARRAY(c->coeff);
 }
 
-static int nlCoeffCompare(const void* p1, const void* p2)
-{
-	return (((NLCoeff*)(p2))->index < ((NLCoeff*)(p1))->index);
+static int nlCoeffCompare(const void *p1, const void *p2) {
+	return (((NLCoeff *)(p2))->index < ((NLCoeff *)(p1))->index);
 }
 
-static void nlRowColumnSort(NLRowColumn* c)
-{
+static void nlRowColumnSort(NLRowColumn *c) {
 	qsort(c->coeff, c->size, sizeof(NLCoeff), nlCoeffCompare);
 }
 
 /* CRSMatrix data structure */
 
-static void nlCRSMatrixDestroy(NLCRSMatrix* M)
-{
+static void nlCRSMatrixDestroy(NLCRSMatrix *M) {
 	NL_DELETE_ARRAY(M->val);
 	NL_DELETE_ARRAY(M->rowptr);
 	NL_DELETE_ARRAY(M->colind);
@@ -4631,8 +3908,7 @@ static void nlCRSMatrixDestroy(NLCRSMatrix* M)
 	M->nslices = 0;
 }
 
-static void nlCRSMatrixMultSlice(NLCRSMatrix* M, const double* x, double* y, uint32_t Ibegin, uint32_t Iend)
-{
+static void nlCRSMatrixMultSlice(NLCRSMatrix *M, const double *x, double *y, uint32_t Ibegin, uint32_t Iend) {
 	for (uint32_t i = Ibegin; i < Iend; ++i) {
 		double sum = 0.0;
 		for (uint32_t j = M->rowptr[i]; j < M->rowptr[i + 1]; ++j)
@@ -4641,15 +3917,13 @@ static void nlCRSMatrixMultSlice(NLCRSMatrix* M, const double* x, double* y, uin
 	}
 }
 
-static void nlCRSMatrixMult(NLCRSMatrix* M, const double* x, double* y)
-{
+static void nlCRSMatrixMult(NLCRSMatrix *M, const double *x, double *y) {
 	int nslices = (int)(M->nslices);
 	for (int slice = 0; slice < nslices; ++slice)
 		nlCRSMatrixMultSlice(M, x, y, M->sliceptr[slice], M->sliceptr[slice + 1]);
 }
 
-static void nlCRSMatrixConstruct(NLCRSMatrix* M, uint32_t m, uint32_t n, uint32_t nnz, uint32_t nslices)
-{
+static void nlCRSMatrixConstruct(NLCRSMatrix *M, uint32_t m, uint32_t n, uint32_t nnz, uint32_t nslices) {
 	M->m = m;
 	M->n = n;
 	M->type = NL_MATRIX_CRS;
@@ -4668,22 +3942,19 @@ static void nlCRSMatrixConstruct(NLCRSMatrix* M, uint32_t m, uint32_t n, uint32_
 
 /* SparseMatrix data structure */
 
-static void nlSparseMatrixDestroyRowColumns(NLSparseMatrix* M)
-{
+static void nlSparseMatrixDestroyRowColumns(NLSparseMatrix *M) {
 	for (uint32_t i = 0; i < M->m; i++)
 		nlRowColumnDestroy(&(M->row[i]));
 	NL_DELETE_ARRAY(M->row);
 }
 
-static void nlSparseMatrixDestroy(NLSparseMatrix* M)
-{
+static void nlSparseMatrixDestroy(NLSparseMatrix *M) {
 	XA_DEBUG_ASSERT(M->type == NL_MATRIX_SPARSE_DYNAMIC);
 	nlSparseMatrixDestroyRowColumns(M);
 	NL_DELETE_ARRAY(M->diag);
 }
 
-static void nlSparseMatrixAdd(NLSparseMatrix* M, uint32_t i, uint32_t j, double value)
-{
+static void nlSparseMatrixAdd(NLSparseMatrix *M, uint32_t i, uint32_t j, double value) {
 	XA_DEBUG_ASSERT(i >= 0 && i <= M->m - 1);
 	XA_DEBUG_ASSERT(j >= 0 && j <= M->n - 1);
 	if (i == j)
@@ -4692,24 +3963,21 @@ static void nlSparseMatrixAdd(NLSparseMatrix* M, uint32_t i, uint32_t j, double
 }
 
 /* Returns the number of non-zero coefficients */
-static uint32_t nlSparseMatrixNNZ(NLSparseMatrix* M)
-{
+static uint32_t nlSparseMatrixNNZ(NLSparseMatrix *M) {
 	uint32_t nnz = 0;
 	for (uint32_t i = 0; i < M->m; i++)
 		nnz += M->row[i].size;
 	return nnz;
 }
 
-static void nlSparseMatrixSort(NLSparseMatrix* M)
-{
+static void nlSparseMatrixSort(NLSparseMatrix *M) {
 	for (uint32_t i = 0; i < M->m; i++)
 		nlRowColumnSort(&(M->row[i]));
 }
 
 /* SparseMatrix x Vector routines, internal helper routines */
 
-static void nlSparseMatrix_mult_rows(NLSparseMatrix* A,	const double* x, double* y)
-{
+static void nlSparseMatrix_mult_rows(NLSparseMatrix *A, const double *x, double *y) {
 	/*
 	 * Note: OpenMP does not like unsigned ints
 	 * (causes some floating point exceptions),
@@ -4717,8 +3985,8 @@ static void nlSparseMatrix_mult_rows(NLSparseMatrix* A,	const double* x, double*
 	 * indices.
 	 */
 	int m = (int)(A->m);
-	NLCoeff* c = nullptr;
-	NLRowColumn* Ri = nullptr;
+	NLCoeff *c = nullptr;
+	NLRowColumn *Ri = nullptr;
 	for (int i = 0; i < m; i++) {
 		Ri = &(A->row[i]);
 		y[i] = 0;
@@ -4729,14 +3997,12 @@ static void nlSparseMatrix_mult_rows(NLSparseMatrix* A,	const double* x, double*
 	}
 }
 
-static void nlSparseMatrixMult(NLSparseMatrix* A, const double* x, double* y)
-{
+static void nlSparseMatrixMult(NLSparseMatrix *A, const double *x, double *y) {
 	XA_DEBUG_ASSERT(A->type == NL_MATRIX_SPARSE_DYNAMIC);
 	nlSparseMatrix_mult_rows(A, x, y);
 }
 
-static void nlSparseMatrixConstruct(NLSparseMatrix* M, uint32_t m, uint32_t n)
-{
+static void nlSparseMatrixConstruct(NLSparseMatrix *M, uint32_t m, uint32_t n) {
 	M->m = m;
 	M->n = n;
 	M->type = NL_MATRIX_SPARSE_DYNAMIC;
@@ -4756,24 +4022,23 @@ static void nlSparseMatrixConstruct(NLSparseMatrix* M, uint32_t m, uint32_t n)
 	NL_CLEAR_ARRAY(double, M->diag, M->diag_size);
 }
 
-static NLMatrix nlCRSMatrixNewFromSparseMatrix(NLSparseMatrix* M)
-{
+static NLMatrix nlCRSMatrixNewFromSparseMatrix(NLSparseMatrix *M) {
 	uint32_t nnz = nlSparseMatrixNNZ(M);
 	uint32_t nslices = 8; /* TODO: get number of cores */
 	uint32_t slice, cur_bound, cur_NNZ, cur_row;
 	uint32_t k;
 	uint32_t slice_size = nnz / nslices;
-	NLCRSMatrix* CRS = NL_NEW(NLCRSMatrix);
+	NLCRSMatrix *CRS = NL_NEW(NLCRSMatrix);
 	NL_CLEAR(CRS, NLCRSMatrix);
 	nlCRSMatrixConstruct(CRS, M->m, M->n, nnz, nslices);
 	nlSparseMatrixSort(M);
 	/* Convert matrix to CRS format */
 	k = 0;
 	for (uint32_t i = 0; i < M->m; ++i) {
-		NLRowColumn* Ri = &(M->row[i]);
+		NLRowColumn *Ri = &(M->row[i]);
 		CRS->rowptr[i] = k;
 		for (uint32_t ij = 0; ij < Ri->size; ij++) {
-			NLCoeff* c = &(Ri->coeff[ij]);
+			NLCoeff *c = &(Ri->coeff[ij]);
 			CRS->val[k] = c->value;
 			CRS->colind[k] = c->index;
 			++k;
@@ -4799,19 +4064,17 @@ static NLMatrix nlCRSMatrixNewFromSparseMatrix(NLSparseMatrix* M)
 	return (NLMatrix)CRS;
 }
 
-static void nlMatrixCompress(NLMatrix* M)
-{
+static void nlMatrixCompress(NLMatrix *M) {
 	NLMatrix CRS = nullptr;
 	if ((*M)->type != NL_MATRIX_SPARSE_DYNAMIC)
 		return;
-	CRS = nlCRSMatrixNewFromSparseMatrix((NLSparseMatrix*)*M);
+	CRS = nlCRSMatrixNewFromSparseMatrix((NLSparseMatrix *)*M);
 	nlDeleteMatrix(*M);
 	*M = CRS;
 }
 
-static NLContext *nlNewContext()
-{
-	NLContext* result = NL_NEW(NLContext);
+static NLContext *nlNewContext() {
+	NLContext *result = NL_NEW(NLContext);
 	NL_CLEAR(result, NLContext);
 	result->max_iterations = 100;
 	result->threshold = 1e-6;
@@ -4820,8 +4083,7 @@ static NLContext *nlNewContext()
 	return result;
 }
 
-static void nlDeleteContext(NLContext *context)
-{
+static void nlDeleteContext(NLContext *context) {
 	nlDeleteMatrix(context->M);
 	context->M = nullptr;
 	nlDeleteMatrix(context->P);
@@ -4839,22 +4101,19 @@ static void nlDeleteContext(NLContext *context)
 	NL_DELETE(context);
 }
 
-static double ddot(int n, const double *x, const double *y)
-{
+static double ddot(int n, const double *x, const double *y) {
 	double sum = 0.0;
 	for (int i = 0; i < n; i++)
 		sum += x[i] * y[i];
 	return sum;
 }
 
-static void daxpy(int n, double a, const double *x, double *y)
-{
+static void daxpy(int n, double a, const double *x, double *y) {
 	for (int i = 0; i < n; i++)
 		y[i] = a * x[i] + y[i];
 }
 
-static void dscal(int n, double a, double *x)
-{
+static void dscal(int n, double a, double *x) {
 	for (int i = 0; i < n; i++)
 		x[i] *= a;
 }
@@ -4877,17 +4136,16 @@ static void dscal(int n, double a, double *x)
  *     versions of matrix x vector product (CPU/GPU, sparse/dense ...)
  */
 
-static uint32_t nlSolveSystem_PRE_CG(NLMatrix M, NLMatrix P, double* b, double* x, double eps, uint32_t max_iter, double *sq_bnorm, double *sq_rnorm)
-{
-	int     N = (int)M->n;
-	double* r = NL_NEW_VECTOR(N);
-	double* d = NL_NEW_VECTOR(N);
-	double* h = NL_NEW_VECTOR(N);
+static uint32_t nlSolveSystem_PRE_CG(NLMatrix M, NLMatrix P, double *b, double *x, double eps, uint32_t max_iter, double *sq_bnorm, double *sq_rnorm) {
+	int N = (int)M->n;
+	double *r = NL_NEW_VECTOR(N);
+	double *d = NL_NEW_VECTOR(N);
+	double *h = NL_NEW_VECTOR(N);
 	double *Ad = h;
 	uint32_t its = 0;
 	double rh, alpha, beta;
 	double b_square = ddot(N, b, b);
-	double err = eps * eps*b_square;
+	double err = eps * eps * b_square;
 	double curr_err;
 	nlMultMatrixVector(M, x, r);
 	daxpy(N, -1., b, r);
@@ -4917,13 +4175,12 @@ static uint32_t nlSolveSystem_PRE_CG(NLMatrix M, NLMatrix P, double* b, double*
 	return its;
 }
 
-static uint32_t nlSolveSystemIterative(NLContext *context, NLMatrix M, NLMatrix P, double* b_in, double* x_in, double eps, uint32_t max_iter)
-{
+static uint32_t nlSolveSystemIterative(NLContext *context, NLMatrix M, NLMatrix P, double *b_in, double *x_in, double eps, uint32_t max_iter) {
 	uint32_t result = 0;
 	double rnorm = 0.0;
 	double bnorm = 0.0;
-	double* b = b_in;
-	double* x = x_in;
+	double *b = b_in;
+	double *x = x_in;
 	XA_DEBUG_ASSERT(M->m == M->n);
 	double sq_bnorm, sq_rnorm;
 	result = nlSolveSystem_PRE_CG(M, P, b, x, eps, max_iter, &sq_bnorm, &sq_rnorm);
@@ -4938,10 +4195,9 @@ static uint32_t nlSolveSystemIterative(NLContext *context, NLMatrix M, NLMatrix
 	return result;
 }
 
-static bool nlSolveIterative(NLContext *context)
-{
-	double* b = context->b;
-	double* x = context->x;
+static bool nlSolveIterative(NLContext *context) {
+	double *b = context->b;
+	double *x = context->x;
 	uint32_t n = context->n;
 	NLMatrix M = context->M;
 	NLMatrix P = context->P;
@@ -4953,34 +4209,30 @@ static bool nlSolveIterative(NLContext *context)
 	return true;
 }
 
-struct NLJacobiPreconditioner
-{
+struct NLJacobiPreconditioner {
 	uint32_t m;
 	uint32_t n;
 	uint32_t type;
 	NLDestroyMatrixFunc destroy_func;
 	NLMultMatrixVectorFunc mult_func;
-	double* diag_inv;
+	double *diag_inv;
 };
 
-static void nlJacobiPreconditionerDestroy(NLJacobiPreconditioner* M)
-{
+static void nlJacobiPreconditionerDestroy(NLJacobiPreconditioner *M) {
 	NL_DELETE_ARRAY(M->diag_inv);
 }
 
-static void nlJacobiPreconditionerMult(NLJacobiPreconditioner* M, const double* x, double* y)
-{
+static void nlJacobiPreconditionerMult(NLJacobiPreconditioner *M, const double *x, double *y) {
 	for (uint32_t i = 0; i < M->n; ++i)
 		y[i] = x[i] * M->diag_inv[i];
 }
 
-static NLMatrix nlNewJacobiPreconditioner(NLMatrix M_in)
-{
-	NLSparseMatrix* M = nullptr;
-	NLJacobiPreconditioner* result = nullptr;
+static NLMatrix nlNewJacobiPreconditioner(NLMatrix M_in) {
+	NLSparseMatrix *M = nullptr;
+	NLJacobiPreconditioner *result = nullptr;
 	XA_DEBUG_ASSERT(M_in->type == NL_MATRIX_SPARSE_DYNAMIC);
 	XA_DEBUG_ASSERT(M_in->m == M_in->n);
-	M = (NLSparseMatrix*)M_in;
+	M = (NLSparseMatrix *)M_in;
 	result = NL_NEW(NLJacobiPreconditioner);
 	NL_CLEAR(result, NLJacobiPreconditioner);
 	result->m = M->m;
@@ -4998,8 +4250,7 @@ static NLMatrix nlNewJacobiPreconditioner(NLMatrix M_in)
 #define NL_NB_VARIABLES 0x101
 #define NL_MAX_ITERATIONS 0x103
 
-static void nlSolverParameteri(NLContext *context, uint32_t pname, int param)
-{
+static void nlSolverParameteri(NLContext *context, uint32_t pname, int param) {
 	if (pname == NL_NB_VARIABLES) {
 		XA_DEBUG_ASSERT(param > 0);
 		context->nb_variables = (uint32_t)param;
@@ -5010,26 +4261,22 @@ static void nlSolverParameteri(NLContext *context, uint32_t pname, int param)
 	}
 }
 
-static void nlSetVariable(NLContext *context, uint32_t index, double value)
-{
+static void nlSetVariable(NLContext *context, uint32_t index, double value) {
 	XA_DEBUG_ASSERT(index >= 0 && index <= context->nb_variables - 1);
 	NL_BUFFER_ITEM(context->variable_buffer[0], index) = value;
 }
 
-static double nlGetVariable(NLContext *context, uint32_t index)
-{
+static double nlGetVariable(NLContext *context, uint32_t index) {
 	XA_DEBUG_ASSERT(index >= 0 && index <= context->nb_variables - 1);
 	return NL_BUFFER_ITEM(context->variable_buffer[0], index);
 }
 
-static void nlLockVariable(NLContext *context, uint32_t index)
-{
+static void nlLockVariable(NLContext *context, uint32_t index) {
 	XA_DEBUG_ASSERT(index >= 0 && index <= context->nb_variables - 1);
 	context->variable_is_locked[index] = true;
 }
 
-static void nlVariablesToVector(NLContext *context)
-{
+static void nlVariablesToVector(NLContext *context) {
 	uint32_t n = context->n;
 	XA_DEBUG_ASSERT(context->x);
 	for (uint32_t k = 0; k < context->nb_systems; ++k) {
@@ -5044,8 +4291,7 @@ static void nlVariablesToVector(NLContext *context)
 	}
 }
 
-static void nlVectorToVariables(NLContext *context)
-{
+static void nlVectorToVariables(NLContext *context) {
 	uint32_t n = context->n;
 	XA_DEBUG_ASSERT(context->x);
 	for (uint32_t k = 0; k < context->nb_systems; ++k) {
@@ -5060,8 +4306,7 @@ static void nlVectorToVariables(NLContext *context)
 	}
 }
 
-static void nlCoefficient(NLContext *context, uint32_t index, double value)
-{
+static void nlCoefficient(NLContext *context, uint32_t index, double value) {
 	XA_DEBUG_ASSERT(index >= 0 && index <= context->nb_variables - 1);
 	if (context->variable_is_locked[index]) {
 		/*
@@ -5078,12 +4323,11 @@ static void nlCoefficient(NLContext *context, uint32_t index, double value)
 	}
 }
 
-#define NL_SYSTEM  0x0
-#define NL_MATRIX  0x1
-#define NL_ROW     0x2
+#define NL_SYSTEM 0x0
+#define NL_MATRIX 0x1
+#define NL_ROW 0x2
 
-static void nlBegin(NLContext *context, uint32_t prim)
-{
+static void nlBegin(NLContext *context, uint32_t prim) {
 	if (prim == NL_SYSTEM) {
 		XA_DEBUG_ASSERT(context->nb_variables > 0);
 		context->variable_buffer = NL_NEW_ARRAY(NLBufferBinding, context->nb_systems);
@@ -5092,8 +4336,8 @@ static void nlBegin(NLContext *context, uint32_t prim)
 		NL_CLEAR_ARRAY(double, context->variable_value, context->nb_variables * context->nb_systems);
 		for (uint32_t k = 0; k < context->nb_systems; ++k) {
 			context->variable_buffer[k].base_address =
-				context->variable_value +
-				k * context->nb_variables;
+					context->variable_value +
+					k * context->nb_variables;
 			context->variable_buffer[k].stride = sizeof(double);
 		}
 		context->variable_is_locked = NL_NEW_ARRAY(bool, context->nb_variables);
@@ -5116,11 +4360,11 @@ static void nlBegin(NLContext *context, uint32_t prim)
 			context->max_iterations = n * 5;
 		context->M = (NLMatrix)(NL_NEW(NLSparseMatrix));
 		NL_CLEAR(context->M, NLSparseMatrix);
-		nlSparseMatrixConstruct((NLSparseMatrix*)(context->M), n, n);
-		context->x = NL_NEW_ARRAY(double, n*context->nb_systems);
-		NL_CLEAR_ARRAY(double, context->x, n*context->nb_systems);
-		context->b = NL_NEW_ARRAY(double, n*context->nb_systems);
-		NL_CLEAR_ARRAY(double, context->b, n*context->nb_systems);
+		nlSparseMatrixConstruct((NLSparseMatrix *)(context->M), n, n);
+		context->x = NL_NEW_ARRAY(double, n * context->nb_systems);
+		NL_CLEAR_ARRAY(double, context->x, n * context->nb_systems);
+		context->b = NL_NEW_ARRAY(double, n * context->nb_systems);
+		NL_CLEAR_ARRAY(double, context->b, n * context->nb_systems);
 		nlVariablesToVector(context);
 		nlRowColumnConstruct(&context->af);
 		nlRowColumnConstruct(&context->al);
@@ -5131,16 +4375,15 @@ static void nlBegin(NLContext *context, uint32_t prim)
 	}
 }
 
-static void nlEnd(NLContext *context, uint32_t prim)
-{
+static void nlEnd(NLContext *context, uint32_t prim) {
 	if (prim == NL_MATRIX) {
 		nlRowColumnClear(&context->af);
 		nlRowColumnClear(&context->al);
 	} else if (prim == NL_ROW) {
-		NLRowColumn*    af = &context->af;
-		NLRowColumn*    al = &context->al;
-		NLSparseMatrix* M = (NLSparseMatrix*)context->M;
-		double* b = context->b;
+		NLRowColumn *af = &context->af;
+		NLRowColumn *al = &context->al;
+		NLSparseMatrix *M = (NLSparseMatrix *)context->M;
+		double *b = context->b;
 		uint32_t nf = af->size;
 		uint32_t nl = al->size;
 		uint32_t n = context->n;
@@ -5161,14 +4404,13 @@ static void nlEnd(NLContext *context, uint32_t prim)
 				S += al->coeff[jj].value * NL_BUFFER_ITEM(context->variable_buffer[k], j);
 			}
 			for (uint32_t jj = 0; jj < nf; jj++)
-				b[k*n + af->coeff[jj].index] -= af->coeff[jj].value * S;
+				b[k * n + af->coeff[jj].index] -= af->coeff[jj].value * S;
 		}
 		context->current_row++;
 	}
 }
 
-static bool nlSolve(NLContext *context)
-{
+static bool nlSolve(NLContext *context) {
 	nlDeleteMatrix(context->P);
 	context->P = nlNewJacobiPreconditioner(context->M);
 	nlMatrixCompress(&context->M);
@@ -5179,11 +4421,9 @@ static bool nlSolve(NLContext *context)
 } // namespace opennl
 
 namespace raster {
-class ClippedTriangle
-{
+class ClippedTriangle {
 public:
-	ClippedTriangle(const Vector2 &a, const Vector2 &b, const Vector2 &c)
-	{
+	ClippedTriangle(const Vector2 &a, const Vector2 &b, const Vector2 &c) {
 		m_numVertices = 3;
 		m_activeVertexBuffer = 0;
 		m_verticesA[0] = a;
@@ -5194,20 +4434,20 @@ public:
 		m_area = 0;
 	}
 
-	void clipHorizontalPlane(float offset, float clipdirection)
-	{
-		Vector2 *v  = m_vertexBuffers[m_activeVertexBuffer];
+	void clipHorizontalPlane(float offset, float clipdirection) {
+		Vector2 *v = m_vertexBuffers[m_activeVertexBuffer];
 		m_activeVertexBuffer ^= 1;
 		Vector2 *v2 = m_vertexBuffers[m_activeVertexBuffer];
 		v[m_numVertices] = v[0];
-		float dy2,   dy1 = offset - v[0].y;
-		int   dy2in, dy1in = clipdirection * dy1 >= 0;
-		uint32_t  p = 0;
+		float dy2, dy1 = offset - v[0].y;
+		int dy2in, dy1in = clipdirection * dy1 >= 0;
+		uint32_t p = 0;
 		for (uint32_t k = 0; k < m_numVertices; k++) {
-			dy2   = offset - v[k + 1].y;
+			dy2 = offset - v[k + 1].y;
 			dy2in = clipdirection * dy2 >= 0;
-			if (dy1in) v2[p++] = v[k];
-			if ( dy1in + dy2in == 1 ) { // not both in/out
+			if (dy1in)
+				v2[p++] = v[k];
+			if (dy1in + dy2in == 1) { // not both in/out
 				float dx = v[k + 1].x - v[k].x;
 				float dy = v[k + 1].y - v[k].y;
 				v2[p++] = Vector2(v[k].x + dy1 * (dx / dy), offset);
@@ -5218,20 +4458,20 @@ public:
 		m_numVertices = p;
 	}
 
-	void clipVerticalPlane(float offset, float clipdirection)
-	{
-		Vector2 *v  = m_vertexBuffers[m_activeVertexBuffer];
+	void clipVerticalPlane(float offset, float clipdirection) {
+		Vector2 *v = m_vertexBuffers[m_activeVertexBuffer];
 		m_activeVertexBuffer ^= 1;
 		Vector2 *v2 = m_vertexBuffers[m_activeVertexBuffer];
 		v[m_numVertices] = v[0];
-		float dx2,   dx1   = offset - v[0].x;
-		int   dx2in, dx1in = clipdirection * dx1 >= 0;
-		uint32_t  p = 0;
+		float dx2, dx1 = offset - v[0].x;
+		int dx2in, dx1in = clipdirection * dx1 >= 0;
+		uint32_t p = 0;
 		for (uint32_t k = 0; k < m_numVertices; k++) {
 			dx2 = offset - v[k + 1].x;
 			dx2in = clipdirection * dx2 >= 0;
-			if (dx1in) v2[p++] = v[k];
-			if ( dx1in + dx2in == 1 ) { // not both in/out
+			if (dx1in)
+				v2[p++] = v[k];
+			if (dx1in + dx2in == 1) { // not both in/out
 				float dx = v[k + 1].x - v[k].x;
 				float dy = v[k + 1].y - v[k].y;
 				v2[p++] = Vector2(offset, v[k].y + dx1 * (dy / dx));
@@ -5242,9 +4482,8 @@ public:
 		m_numVertices = p;
 	}
 
-	void computeArea()
-	{
-		Vector2 *v  = m_vertexBuffers[m_activeVertexBuffer];
+	void computeArea() {
+		Vector2 *v = m_vertexBuffers[m_activeVertexBuffer];
 		v[m_numVertices] = v[0];
 		m_area = 0;
 		float centroidx = 0, centroidy = 0;
@@ -5258,8 +4497,7 @@ public:
 		m_area = 0.5f * fabsf(m_area);
 	}
 
-	void clipAABox(float x0, float y0, float x1, float y1)
-	{
+	void clipAABox(float x0, float y0, float x1, float y1) {
 		clipVerticalPlane(x0, -1);
 		clipHorizontalPlane(y0, -1);
 		clipVerticalPlane(x1, 1);
@@ -5267,8 +4505,7 @@ public:
 		computeArea();
 	}
 
-	float area() const
-	{
+	float area() const {
 		return m_area;
 	}
 
@@ -5285,10 +4522,9 @@ private:
 typedef bool (*SamplingCallback)(void *param, int x, int y);
 
 /// A triangle for rasterization.
-struct Triangle
-{
-	Triangle(const Vector2 &_v0, const Vector2 &_v1, const Vector2 &_v2) : v1(_v0), v2(_v2), v3(_v1)
-	{
+struct Triangle {
+	Triangle(const Vector2 &_v0, const Vector2 &_v1, const Vector2 &_v2) :
+			v1(_v0), v2(_v2), v3(_v1), n1(0.0f), n2(0.0f), n3(0.0f) {
 		// make sure every triangle is front facing.
 		flipBackface();
 		// Compute deltas.
@@ -5296,8 +4532,7 @@ struct Triangle
 			computeUnitInwardNormals();
 	}
 
-	bool isValid()
-	{
+	bool isValid() {
 		const Vector2 e0 = v3 - v1;
 		const Vector2 e1 = v2 - v1;
 		const float area = e0.y * e1.x - e1.y * e0.x;
@@ -5305,18 +4540,17 @@ struct Triangle
 	}
 
 	// extents has to be multiple of BK_SIZE!!
-	bool drawAA(const Vector2 &extents, SamplingCallback cb, void *param)
-	{
-		const float PX_INSIDE = 1.0f/sqrtf(2.0f);
-		const float PX_OUTSIDE = -1.0f/sqrtf(2.0f);
+	bool drawAA(const Vector2 &extents, SamplingCallback cb, void *param) {
+		const float PX_INSIDE = 1.0f / sqrtf(2.0f);
+		const float PX_OUTSIDE = -1.0f / sqrtf(2.0f);
 		const float BK_SIZE = 8;
-		const float BK_INSIDE = sqrtf(BK_SIZE*BK_SIZE/2.0f);
-		const float BK_OUTSIDE = -sqrtf(BK_SIZE*BK_SIZE/2.0f);
+		const float BK_INSIDE = sqrtf(BK_SIZE * BK_SIZE / 2.0f);
+		const float BK_OUTSIDE = -sqrtf(BK_SIZE * BK_SIZE / 2.0f);
 		// Bounding rectangle
 		float minx = floorf(max(min3(v1.x, v2.x, v3.x), 0.0f));
 		float miny = floorf(max(min3(v1.y, v2.y, v3.y), 0.0f));
-		float maxx = ceilf( min(max3(v1.x, v2.x, v3.x), extents.x - 1.0f));
-		float maxy = ceilf( min(max3(v1.y, v2.y, v3.y), extents.y - 1.0f));
+		float maxx = ceilf(min(max3(v1.x, v2.x, v3.x), extents.x - 1.0f));
+		float maxy = ceilf(min(max3(v1.y, v2.y, v3.y), extents.y - 1.0f));
 		// There's no reason to align the blocks to the viewport, instead we align them to the origin of the triangle bounds.
 		minx = floorf(minx);
 		miny = floorf(miny);
@@ -5341,9 +4575,10 @@ struct Triangle
 				float bC = C2 + n2.x * xc + n2.y * yc;
 				float cC = C3 + n3.x * xc + n3.y * yc;
 				// Skip block when outside an edge
-				if ( (aC <= BK_OUTSIDE) || (bC <= BK_OUTSIDE) || (cC <= BK_OUTSIDE) ) continue;
+				if ((aC <= BK_OUTSIDE) || (bC <= BK_OUTSIDE) || (cC <= BK_OUTSIDE))
+					continue;
 				// Accept whole block when totally covered
-				if ( (aC >= BK_INSIDE) && (bC >= BK_INSIDE) && (cC >= BK_INSIDE) ) {
+				if ((aC >= BK_INSIDE) && (bC >= BK_INSIDE) && (cC >= BK_INSIDE)) {
 					for (float y = y0; y < y0 + BK_SIZE; y++) {
 						for (float x = x0; x < x0 + BK_SIZE; x++) {
 							if (!cb(param, (int)x, (int)y))
@@ -5386,10 +4621,9 @@ struct Triangle
 	}
 
 private:
-	void flipBackface()
-	{
+	void flipBackface() {
 		// check if triangle is backfacing, if so, swap two vertices
-		if ( ((v3.x - v1.x) * (v2.y - v1.y) - (v3.y - v1.y) * (v2.x - v1.x)) < 0 ) {
+		if (((v3.x - v1.x) * (v2.y - v1.y) - (v3.y - v1.y) * (v2.x - v1.x)) < 0) {
 			Vector2 hv = v1;
 			v1 = v2;
 			v2 = hv; // swap pos
@@ -5397,8 +4631,7 @@ private:
 	}
 
 	// compute unit inward normals for each edge.
-	void computeUnitInwardNormals()
-	{
+	void computeUnitInwardNormals() {
 		n1 = v1 - v2;
 		n1 = Vector2(-n1.y, n1.x);
 		n1 = n1 * (1.0f / sqrtf(dot(n1, n1)));
@@ -5416,8 +4649,7 @@ private:
 };
 
 // Process the given triangle. Returns false if rasterization was interrupted by the callback.
-static bool drawTriangle(const Vector2 &extents, const Vector2 v[3], SamplingCallback cb, void *param)
-{
+static bool drawTriangle(const Vector2 &extents, const Vector2 v[3], SamplingCallback cb, void *param) {
 	Triangle tri(v[0], v[1], v[2]);
 	// @@ It would be nice to have a conservative drawing mode that enlarges the triangle extents by one texel and is able to handle degenerate triangles.
 	// @@ Maybe the simplest thing to do would be raster triangle edges.
@@ -5432,22 +4664,19 @@ namespace segment {
 
 // - Insertion is o(n)
 // - Smallest element goes at the end, so that popping it is o(1).
-struct CostQueue
-{
-	CostQueue(uint32_t size = UINT32_MAX) : m_maxSize(size), m_pairs(MemTag::SegmentAtlasChartCandidates) {}
+struct CostQueue {
+	CostQueue(uint32_t size = UINT32_MAX) :
+			m_maxSize(size), m_pairs(MemTag::SegmentAtlasChartCandidates) {}
 
-	float peekCost() const
-	{
+	float peekCost() const {
 		return m_pairs.back().cost;
 	}
 
-	uint32_t peekFace() const
-	{
+	uint32_t peekFace() const {
 		return m_pairs.back().face;
 	}
 
-	void push(float cost, uint32_t face)
-	{
+	void push(float cost, uint32_t face) {
 		const Pair p = { cost, face };
 		if (m_pairs.isEmpty() || cost < peekCost())
 			m_pairs.push_back(p);
@@ -5464,29 +4693,25 @@ struct CostQueue
 		}
 	}
 
-	uint32_t pop()
-	{
+	uint32_t pop() {
 		XA_DEBUG_ASSERT(!m_pairs.isEmpty());
 		uint32_t f = m_pairs.back().face;
 		m_pairs.pop_back();
 		return f;
 	}
 
-	XA_INLINE void clear()
-	{
+	XA_INLINE void clear() {
 		m_pairs.clear();
 	}
 
-	XA_INLINE uint32_t count() const
-	{
+	XA_INLINE uint32_t count() const {
 		return m_pairs.size();
 	}
 
 private:
 	const uint32_t m_maxSize;
 
-	struct Pair
-	{
+	struct Pair {
 		float cost;
 		uint32_t face;
 	};
@@ -5494,25 +4719,27 @@ private:
 	Array<Pair> m_pairs;
 };
 
-struct AtlasData
-{
+struct AtlasData {
 	ChartOptions options;
 	const Mesh *mesh = nullptr;
 	Array<float> edgeDihedralAngles;
 	Array<float> edgeLengths;
 	Array<float> faceAreas;
+	Array<float> faceUvAreas; // Can be negative.
 	Array<Vector3> faceNormals;
 	BitArray isFaceInChart;
 
-	AtlasData() : edgeDihedralAngles(MemTag::SegmentAtlasMeshData), edgeLengths(MemTag::SegmentAtlasMeshData), faceAreas(MemTag::SegmentAtlasMeshData), faceNormals(MemTag::SegmentAtlasMeshData) {}
+	AtlasData() :
+			edgeDihedralAngles(MemTag::SegmentAtlasMeshData), edgeLengths(MemTag::SegmentAtlasMeshData), faceAreas(MemTag::SegmentAtlasMeshData), faceNormals(MemTag::SegmentAtlasMeshData) {}
 
-	void compute()
-	{
+	void compute() {
 		const uint32_t faceCount = mesh->faceCount();
 		const uint32_t edgeCount = mesh->edgeCount();
 		edgeDihedralAngles.resize(edgeCount);
 		edgeLengths.resize(edgeCount);
 		faceAreas.resize(faceCount);
+		if (options.useInputMeshUvs)
+			faceUvAreas.resize(faceCount);
 		faceNormals.resize(faceCount);
 		isFaceInChart.resize(faceCount);
 		isFaceInChart.zeroOutMemory();
@@ -5526,6 +4753,8 @@ struct AtlasData
 			}
 			faceAreas[f] = mesh->computeFaceArea(f);
 			XA_DEBUG_ASSERT(faceAreas[f] > 0.0f);
+			if (options.useInputMeshUvs)
+				faceUvAreas[f] = mesh->computeFaceParametricArea(f);
 			faceNormals[f] = mesh->computeFaceNormal(f);
 		}
 		for (uint32_t face = 0; face < faceCount; face++) {
@@ -5543,19 +4772,109 @@ struct AtlasData
 	}
 };
 
+// If MeshDecl::vertexUvData is set on input meshes, find charts by floodfilling faces in world/model space without crossing UV seams.
+struct OriginalUvCharts {
+	OriginalUvCharts(AtlasData &data) :
+			m_data(data) {}
+	uint32_t chartCount() const { return m_charts.size(); }
+	const Basis &chartBasis(uint32_t chartIndex) const { return m_chartBasis[chartIndex]; }
+
+	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const {
+		const Chart &chart = m_charts[chartIndex];
+		return ConstArrayView<uint32_t>(&m_chartFaces[chart.firstFace], chart.faceCount);
+	}
+
+	void compute() {
+		m_charts.clear();
+		m_chartFaces.clear();
+		const Mesh *mesh = m_data.mesh;
+		const uint32_t faceCount = mesh->faceCount();
+		for (uint32_t f = 0; f < faceCount; f++) {
+			if (m_data.isFaceInChart.get(f))
+				continue;
+			if (isZero(m_data.faceUvAreas[f], kAreaEpsilon))
+				continue; // Face must have valid UVs.
+			// Found an unassigned face, create a new chart.
+			Chart chart;
+			chart.firstFace = m_chartFaces.size();
+			chart.faceCount = 1;
+			m_chartFaces.push_back(f);
+			m_data.isFaceInChart.set(f);
+			floodfillFaces(chart);
+			m_charts.push_back(chart);
+		}
+		// Compute basis for each chart.
+		m_chartBasis.resize(m_charts.size());
+		for (uint32_t c = 0; c < m_charts.size(); c++) {
+			const Chart &chart = m_charts[c];
+			m_tempPoints.resize(chart.faceCount * 3);
+			for (uint32_t f = 0; f < chart.faceCount; f++) {
+				const uint32_t face = m_chartFaces[chart.firstFace + f];
+				for (uint32_t i = 0; i < 3; i++)
+					m_tempPoints[f * 3 + i] = m_data.mesh->position(m_data.mesh->vertexAt(face * 3 + i));
+			}
+			Fit::computeBasis(m_tempPoints, &m_chartBasis[c]);
+		}
+	}
+
+private:
+	struct Chart {
+		uint32_t firstFace, faceCount;
+	};
+
+	void floodfillFaces(Chart &chart) {
+		const bool isFaceAreaNegative = m_data.faceUvAreas[m_chartFaces[chart.firstFace]] < 0.0f;
+		for (;;) {
+			bool newFaceAdded = false;
+			const uint32_t faceCount = chart.faceCount;
+			for (uint32_t f = 0; f < faceCount; f++) {
+				const uint32_t sourceFace = m_chartFaces[chart.firstFace + f];
+				for (Mesh::FaceEdgeIterator edgeIt(m_data.mesh, sourceFace); !edgeIt.isDone(); edgeIt.advance()) {
+					const uint32_t face = edgeIt.oppositeFace();
+					if (face == UINT32_MAX)
+						continue; // Boundary edge.
+					if (m_data.isFaceInChart.get(face))
+						continue; // Already assigned to a chart.
+					if (isZero(m_data.faceUvAreas[face], kAreaEpsilon))
+						continue; // Face must have valid UVs.
+					if ((m_data.faceUvAreas[face] < 0.0f) != isFaceAreaNegative)
+						continue; // Face winding is opposite of the first chart face.
+					const Vector2 &uv0 = m_data.mesh->texcoord(edgeIt.vertex0());
+					const Vector2 &uv1 = m_data.mesh->texcoord(edgeIt.vertex1());
+					const Vector2 &ouv0 = m_data.mesh->texcoord(m_data.mesh->vertexAt(meshEdgeIndex0(edgeIt.oppositeEdge())));
+					const Vector2 &ouv1 = m_data.mesh->texcoord(m_data.mesh->vertexAt(meshEdgeIndex1(edgeIt.oppositeEdge())));
+					if (!equal(uv0, ouv1, m_data.mesh->epsilon()) || !equal(uv1, ouv0, m_data.mesh->epsilon()))
+						continue; // UVs must match exactly.
+					m_chartFaces.push_back(face);
+					chart.faceCount++;
+					m_data.isFaceInChart.set(face);
+					newFaceAdded = true;
+				}
+			}
+			if (!newFaceAdded)
+				break;
+		}
+	}
+
+	AtlasData &m_data;
+	Array<Chart> m_charts;
+	Array<Basis> m_chartBasis;
+	Array<uint32_t> m_chartFaces;
+	Array<Vector3> m_tempPoints;
+};
+
 #if XA_DEBUG_EXPORT_OBJ_PLANAR_REGIONS
 static uint32_t s_planarRegionsCurrentRegion;
 static uint32_t s_planarRegionsCurrentVertex;
 #endif
 
-struct PlanarCharts
-{
-	PlanarCharts(AtlasData &data) : m_data(data), m_nextRegionFace(MemTag::SegmentAtlasPlanarRegions), m_faceToRegionId(MemTag::SegmentAtlasPlanarRegions) {}
+struct PlanarCharts {
+	PlanarCharts(AtlasData &data) :
+			m_data(data), m_nextRegionFace(MemTag::SegmentAtlasPlanarRegions), m_faceToRegionId(MemTag::SegmentAtlasPlanarRegions) {}
 	const Basis &chartBasis(uint32_t chartIndex) const { return m_chartBasis[chartIndex]; }
 	uint32_t chartCount() const { return m_charts.size(); }
-	
-	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const
-	{
+
+	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const {
 		const Chart &chart = m_charts[chartIndex];
 		return ConstArrayView<uint32_t>(&m_chartFaces[chart.firstFace], chart.faceCount);
 	}
@@ -5564,8 +4883,7 @@ struct PlanarCharts
 	uint32_t nextRegionFace(uint32_t face) const { return m_nextRegionFace[face]; }
 	float regionArea(uint32_t region) const { return m_regionAreas[region]; }
 
-	void compute()
-	{
+	void compute() {
 		const uint32_t faceCount = m_data.mesh->faceCount();
 		// Precompute regions of coplanar incident faces.
 		m_regionFirstFace.clear();
@@ -5581,6 +4899,8 @@ struct PlanarCharts
 		for (uint32_t f = 0; f < faceCount; f++) {
 			if (m_nextRegionFace[f] != f)
 				continue; // Already assigned.
+			if (m_data.isFaceInChart.get(f))
+				continue; // Already in a chart.
 			faceStack.clear();
 			faceStack.push_back(f);
 			for (;;) {
@@ -5595,6 +4915,8 @@ struct PlanarCharts
 						continue;
 					if (m_nextRegionFace[oface] != oface)
 						continue; // Already assigned.
+					if (m_data.isFaceInChart.get(oface))
+						continue; // Already in a chart.
 					if (!equal(dot(m_data.faceNormals[face], m_data.faceNormals[oface]), 1.0f, kEpsilon))
 						continue; // Not coplanar.
 					const uint32_t next = m_nextRegionFace[face];
@@ -5632,8 +4954,11 @@ struct PlanarCharts
 		// Precompute planar region areas.
 		m_regionAreas.resize(regionCount);
 		m_regionAreas.zeroOutMemory();
-		for (uint32_t f = 0; f < faceCount; f++)
+		for (uint32_t f = 0; f < faceCount; f++) {
+			if (m_faceToRegionId[f] == UINT32_MAX)
+				continue;
 			m_regionAreas[m_faceToRegionId[f]] += m_data.faceAreas[f];
+		}
 		// Create charts from suitable planar regions.
 		// The dihedral angle of all boundary edges must be >= 90 degrees.
 		m_charts.clear();
@@ -5658,8 +4983,7 @@ struct PlanarCharts
 				if (!createChart)
 					break;
 				face = m_nextRegionFace[face];
-			}
-			while (face != firstRegionFace);
+			} while (face != firstRegionFace);
 			// Create a chart.
 			if (createChart) {
 				Chart chart;
@@ -5671,15 +4995,13 @@ struct PlanarCharts
 					m_chartFaces.push_back(face);
 					chart.faceCount++;
 					face = m_nextRegionFace[face];
-				}
-				while (face != firstRegionFace);
+				} while (face != firstRegionFace);
 				m_charts.push_back(chart);
 			}
 		}
 		// Compute basis for each chart using the first face normal (all faces have the same normal).
 		m_chartBasis.resize(m_charts.size());
-		for (uint32_t c = 0; c < m_charts.size(); c++)
-		{
+		for (uint32_t c = 0; c < m_charts.size(); c++) {
 			const uint32_t face = m_chartFaces[m_charts[c].firstFace];
 			Basis &basis = m_chartBasis[c];
 			basis.normal = m_data.faceNormals[face];
@@ -5689,8 +5011,7 @@ struct PlanarCharts
 	}
 
 private:
-	struct Chart
-	{
+	struct Chart {
 		uint32_t firstFace, faceCount;
 	};
 
@@ -5704,12 +5025,11 @@ private:
 	Array<Basis> m_chartBasis;
 };
 
-struct ClusteredCharts
-{
-	ClusteredCharts(AtlasData &data, const PlanarCharts &planarCharts) : m_data(data), m_planarCharts(planarCharts), m_texcoords(MemTag::SegmentAtlasMeshData), m_bestTriangles(10), m_placingSeeds(false) {}
+struct ClusteredCharts {
+	ClusteredCharts(AtlasData &data, const PlanarCharts &planarCharts) :
+			m_data(data), m_planarCharts(planarCharts), m_texcoords(MemTag::SegmentAtlasMeshData), m_bestTriangles(10), m_placingSeeds(false) {}
 
-	~ClusteredCharts()
-	{
+	~ClusteredCharts() {
 		const uint32_t chartCount = m_charts.size();
 		for (uint32_t i = 0; i < chartCount; i++) {
 			m_charts[i]->~Chart();
@@ -5721,8 +5041,7 @@ struct ClusteredCharts
 	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const { return m_charts[chartIndex]->faces; }
 	const Basis &chartBasis(uint32_t chartIndex) const { return m_charts[chartIndex]->basis; }
 
-	void compute()
-	{
+	void compute() {
 		const uint32_t faceCount = m_data.mesh->faceCount();
 		m_facesLeft = 0;
 		for (uint32_t i = 0; i < faceCount; i++) {
@@ -5768,9 +5087,9 @@ struct ClusteredCharts
 	}
 
 private:
-	struct Chart
-	{
-		Chart() : faces(MemTag::SegmentAtlasChartFaces) {}
+	struct Chart {
+		Chart() :
+				faces(MemTag::SegmentAtlasChartFaces) {}
 
 		int id = -1;
 		Basis basis; // Best fit normal.
@@ -5784,8 +5103,7 @@ private:
 		uint32_t seed;
 	};
 
-	void placeSeeds(float threshold)
-	{
+	void placeSeeds(float threshold) {
 		XA_PROFILE_START(clusteredChartsPlaceSeeds)
 		m_placingSeeds = true;
 		// Instead of using a predefiened number of seeds:
@@ -5801,8 +5119,7 @@ private:
 	}
 
 	// Returns true if any of the charts can grow more.
-	void growCharts(float threshold)
-	{
+	void growCharts(float threshold) {
 		XA_PROFILE_START(clusteredChartsGrow)
 		for (;;) {
 			if (m_facesLeft == 0)
@@ -5848,8 +5165,7 @@ private:
 		XA_PROFILE_END(clusteredChartsGrow)
 	}
 
-	void resetCharts()
-	{
+	void resetCharts() {
 		XA_PROFILE_START(clusteredChartsReset)
 		const uint32_t faceCount = m_data.mesh->faceCount();
 		for (uint32_t i = 0; i < faceCount; i++) {
@@ -5880,8 +5196,7 @@ private:
 		XA_PROFILE_END(clusteredChartsReset)
 	}
 
-	bool relocateSeeds()
-	{
+	bool relocateSeeds() {
 		XA_PROFILE_START(clusteredChartsRelocateSeeds)
 		bool anySeedChanged = false;
 		const uint32_t chartCount = m_charts.size();
@@ -5894,8 +5209,7 @@ private:
 		return anySeedChanged;
 	}
 
-	void fillHoles(float threshold)
-	{
+	void fillHoles(float threshold) {
 		XA_PROFILE_START(clusteredChartsFillHoles)
 		while (m_facesLeft > 0)
 			createChart(threshold);
@@ -5903,8 +5217,7 @@ private:
 	}
 
 #if XA_MERGE_CHARTS
-	void mergeCharts()
-	{
+	void mergeCharts() {
 		XA_PROFILE_START(clusteredChartsMerge)
 		const uint32_t chartCount = m_charts.size();
 		// Merge charts progressively until there's none left to merge.
@@ -5964,7 +5277,7 @@ private:
 					// Merge if chart2 has a single face.
 					// chart1 must have more than 1 face.
 					// chart2 area must be <= 10% of chart1 area.
-					if (m_sharedBoundaryLengthsNoSeams[cc] > 0.0f && chart->faces.size() > 1 && chart2->faces.size() == 1 && chart2->area <= chart->area * 0.1f) 
+					if (m_sharedBoundaryLengthsNoSeams[cc] > 0.0f && chart->faces.size() > 1 && chart2->faces.size() == 1 && chart2->area <= chart->area * 0.1f)
 						goto merge;
 					// Merge if chart2 has two faces (probably a quad), and chart1 bounds at least 2 of its edges.
 					if (chart2->faces.size() == 2 && m_sharedBoundaryEdgeCountNoSeams[cc] >= 2)
@@ -5972,8 +5285,8 @@ private:
 					// Merge if chart2 is wholely inside chart1, ignoring seams.
 					if (m_sharedBoundaryLengthsNoSeams[cc] > 0.0f && equal(m_sharedBoundaryLengthsNoSeams[cc], chart2->boundaryLength, kEpsilon))
 						goto merge;
-					if (m_sharedBoundaryLengths[cc] > 0.2f * max(0.0f, chart->boundaryLength - externalBoundaryLength) || 
-						m_sharedBoundaryLengths[cc] > 0.75f * chart2->boundaryLength)
+					if (m_sharedBoundaryLengths[cc] > 0.2f * max(0.0f, chart->boundaryLength - externalBoundaryLength) ||
+							m_sharedBoundaryLengths[cc] > 0.75f * chart2->boundaryLength)
 						goto merge;
 					continue;
 				merge:
@@ -6011,8 +5324,7 @@ private:
 #endif
 
 private:
-	void createChart(float threshold)
-	{
+	void createChart(float threshold) {
 		Chart *chart = XA_NEW(MemTag::Default, Chart);
 		chart->id = (int)m_charts.size();
 		m_charts.push_back(chart);
@@ -6043,15 +5355,13 @@ private:
 		}
 	}
 
-	bool isChartBoundaryEdge(const Chart *chart, uint32_t edge) const
-	{
+	bool isChartBoundaryEdge(const Chart *chart, uint32_t edge) const {
 		const uint32_t oppositeEdge = m_data.mesh->oppositeEdge(edge);
 		const uint32_t oppositeFace = meshEdgeFace(oppositeEdge);
 		return oppositeEdge == UINT32_MAX || m_faceCharts[oppositeFace] != chart->id;
 	}
 
-	bool computeChartBasis(Chart *chart, Basis *basis)
-	{
+	bool computeChartBasis(Chart *chart, Basis *basis) {
 		const uint32_t faceCount = chart->faces.size();
 		m_tempPoints.resize(chart->faces.size() * 3);
 		for (uint32_t i = 0; i < faceCount; i++) {
@@ -6059,11 +5369,10 @@ private:
 			for (uint32_t j = 0; j < 3; j++)
 				m_tempPoints[i * 3 + j] = m_data.mesh->position(m_data.mesh->vertexAt(f * 3 + j));
 		}
-		return Fit::computeBasis(m_tempPoints.data(), m_tempPoints.size(), basis);
+		return Fit::computeBasis(m_tempPoints, basis);
 	}
 
-	bool isFaceFlipped(uint32_t face) const
-	{
+	bool isFaceFlipped(uint32_t face) const {
 		const Vector2 &v1 = m_texcoords[face * 3 + 0];
 		const Vector2 &v2 = m_texcoords[face * 3 + 1];
 		const Vector2 &v3 = m_texcoords[face * 3 + 2];
@@ -6071,8 +5380,7 @@ private:
 		return parametricArea < 0.0f;
 	}
 
-	void parameterizeChart(const Chart *chart)
-	{
+	void parameterizeChart(const Chart *chart) {
 		const uint32_t faceCount = chart->faces.size();
 		for (uint32_t i = 0; i < faceCount; i++) {
 			const uint32_t face = chart->faces[i];
@@ -6085,8 +5393,7 @@ private:
 	}
 
 	// m_faceCharts for the chart faces must be set to the chart ID. Needed to compute boundary edges.
-	bool isChartParameterizationValid(const Chart *chart)
-	{
+	bool isChartParameterizationValid(const Chart *chart) {
 		const uint32_t faceCount = chart->faces.size();
 		// Check for flipped faces in the parameterization. OK if all are flipped.
 		uint32_t flippedFaceCount = 0;
@@ -6099,7 +5406,7 @@ private:
 		// Check for boundary intersection in the parameterization.
 		XA_PROFILE_START(clusteredChartsPlaceSeedsBoundaryIntersection)
 		XA_PROFILE_START(clusteredChartsGrowBoundaryIntersection)
-		m_boundaryGrid.reset(m_texcoords.data());
+		m_boundaryGrid.reset(m_texcoords);
 		for (uint32_t i = 0; i < faceCount; i++) {
 			const uint32_t f = chart->faces[i];
 			for (uint32_t j = 0; j < 3; j++) {
@@ -6120,15 +5427,14 @@ private:
 		return true;
 	}
 
-	bool addFaceToChart(Chart *chart, uint32_t face)
-	{
+	bool addFaceToChart(Chart *chart, uint32_t face) {
 		XA_DEBUG_ASSERT(!m_data.isFaceInChart.get(face));
 		const uint32_t oldFaceCount = chart->faces.size();
 		const bool firstFace = oldFaceCount == 0;
 		// Append the face and any coplanar connected faces to the chart faces array.
 		chart->faces.push_back(face);
 		uint32_t coplanarFace = m_planarCharts.nextRegionFace(face);
-		while (coplanarFace != face) { 
+		while (coplanarFace != face) {
 			XA_DEBUG_ASSERT(!m_data.isFaceInChart.get(coplanarFace));
 			chart->faces.push_back(coplanarFace);
 			coplanarFace = m_planarCharts.nextRegionFace(coplanarFace);
@@ -6140,7 +5446,7 @@ private:
 			// Use the first face normal.
 			// Use any edge as the tangent vector.
 			basis.normal = m_data.faceNormals[face];
-			basis.tangent = normalize(m_data.mesh->position(m_data.mesh->vertexAt(face * 3 + 0)) - m_data.mesh->position(m_data.mesh->vertexAt(face * 3 + 1)), kEpsilon);
+			basis.tangent = normalize(m_data.mesh->position(m_data.mesh->vertexAt(face * 3 + 0)) - m_data.mesh->position(m_data.mesh->vertexAt(face * 3 + 1)));
 			basis.bitangent = cross(basis.normal, basis.tangent);
 		} else {
 			// Use best fit normal.
@@ -6199,8 +5505,7 @@ private:
 	}
 
 	// Returns true if the seed has changed.
-	bool relocateSeed(Chart *chart)
-	{
+	bool relocateSeed(Chart *chart) {
 		// Find the first N triangles that fit the proxy best.
 		const uint32_t faceCount = chart->faces.size();
 		m_bestTriangles.clear();
@@ -6230,8 +5535,7 @@ private:
 	}
 
 	// Cost is combined metrics * weights.
-	float computeCost(Chart *chart, uint32_t face) const
-	{
+	float computeCost(Chart *chart, uint32_t face) const {
 		// Estimate boundary length and area:
 		const float newChartArea = computeArea(chart, face);
 		const float newBoundaryLength = computeBoundaryLength(chart, face);
@@ -6267,28 +5571,25 @@ private:
 	// Returns a value in [0-1].
 	// 0 if face normal is coplanar to the chart's best fit normal.
 	// 1 if face normal is perpendicular.
-	float computeNormalDeviationMetric(Chart *chart, uint32_t face) const
-	{
+	float computeNormalDeviationMetric(Chart *chart, uint32_t face) const {
 		// All faces in coplanar regions have the same normal, can use any face.
 		const Vector3 faceNormal = m_data.faceNormals[face];
 		// Use plane fitting metric for now:
 		return min(1.0f - dot(faceNormal, chart->basis.normal), 1.0f); // @@ normal deviations should be weighted by face area
 	}
 
-	float computeRoundnessMetric(Chart *chart, float newBoundaryLength, float newChartArea) const
-	{
+	float computeRoundnessMetric(Chart *chart, float newBoundaryLength, float newChartArea) const {
 		const float oldRoundness = square(chart->boundaryLength) / chart->area;
 		const float newRoundness = square(newBoundaryLength) / newChartArea;
 		return 1.0f - oldRoundness / newRoundness;
 	}
 
-	float computeStraightnessMetric(Chart *chart, uint32_t firstFace) const
-	{
+	float computeStraightnessMetric(Chart *chart, uint32_t firstFace) const {
 		float l_out = 0.0f; // Length of firstFace planar region boundary that doesn't border the chart.
 		float l_in = 0.0f; // Length that does border the chart.
 		const uint32_t planarRegionId = m_planarCharts.regionIdFromFace(firstFace);
 		uint32_t face = firstFace;
-		for (;;) { 
+		for (;;) {
 			for (Mesh::FaceEdgeIterator it(m_data.mesh, face); !it.isDone(); it.advance()) {
 				const float l = m_data.edgeLengths[it.edge()];
 				if (it.isBoundary()) {
@@ -6305,7 +5606,6 @@ private:
 				break;
 		}
 #if 1
-		XA_DEBUG_ASSERT(l_in != 0.0f); // Candidate face must be adjacent to chart. @@ This is not true if the input mesh has zero-length edges.
 		float ratio = (l_out - l_in) / (l_out + l_in);
 		return min(ratio, 0.0f); // Only use the straightness metric to close gaps.
 #else
@@ -6313,8 +5613,7 @@ private:
 #endif
 	}
 
-	bool isNormalSeam(uint32_t edge) const
-	{
+	bool isNormalSeam(uint32_t edge) const {
 		const uint32_t oppositeEdge = m_data.mesh->oppositeEdge(edge);
 		if (oppositeEdge == UINT32_MAX)
 			return false; // boundary edge
@@ -6334,11 +5633,10 @@ private:
 		return !equal(m_data.faceNormals[f0], m_data.faceNormals[f1], kNormalEpsilon);
 	}
 
-	float computeNormalSeamMetric(Chart *chart, uint32_t firstFace) const
-	{
+	float computeNormalSeamMetric(Chart *chart, uint32_t firstFace) const {
 		float seamFactor = 0.0f, totalLength = 0.0f;
 		uint32_t face = firstFace;
-		for (;;) { 
+		for (;;) {
 			for (Mesh::FaceEdgeIterator it(m_data.mesh, face); !it.isDone(); it.advance()) {
 				if (it.isBoundary())
 					continue;
@@ -6375,11 +5673,10 @@ private:
 		return seamFactor / totalLength;
 	}
 
-	float computeTextureSeamMetric(Chart *chart, uint32_t firstFace) const
-	{
+	float computeTextureSeamMetric(Chart *chart, uint32_t firstFace) const {
 		float seamLength = 0.0f, totalLength = 0.0f;
 		uint32_t face = firstFace;
-		for (;;) { 
+		for (;;) {
 			for (Mesh::FaceEdgeIterator it(m_data.mesh, face); !it.isDone(); it.advance()) {
 				if (it.isBoundary())
 					continue;
@@ -6402,11 +5699,10 @@ private:
 		return seamLength / totalLength;
 	}
 
-	float computeArea(Chart *chart, uint32_t firstFace) const
-	{
+	float computeArea(Chart *chart, uint32_t firstFace) const {
 		float area = chart->area;
 		uint32_t face = firstFace;
-		for (;;) { 
+		for (;;) {
 			area += m_data.faceAreas[face];
 			face = m_planarCharts.nextRegionFace(face);
 			if (face == firstFace)
@@ -6415,13 +5711,12 @@ private:
 		return area;
 	}
 
-	float computeBoundaryLength(Chart *chart, uint32_t firstFace) const
-	{
+	float computeBoundaryLength(Chart *chart, uint32_t firstFace) const {
 		float boundaryLength = chart->boundaryLength;
 		// Add new edges, subtract edges shared with the chart.
 		const uint32_t planarRegionId = m_planarCharts.regionIdFromFace(firstFace);
 		uint32_t face = firstFace;
-		for (;;) { 
+		for (;;) {
 			for (Mesh::FaceEdgeIterator it(m_data.mesh, face); !it.isDone(); it.advance()) {
 				const float edgeLength = m_data.edgeLengths[it.edge()];
 				if (it.isBoundary()) {
@@ -6437,11 +5732,10 @@ private:
 			if (face == firstFace)
 				break;
 		}
-		return max(0.0f, boundaryLength);  // @@ Hack!
+		return max(0.0f, boundaryLength); // @@ Hack!
 	}
 
-	bool mergeChart(Chart *owner, Chart *chart, float sharedBoundaryLength)
-	{
+	bool mergeChart(Chart *owner, Chart *chart, float sharedBoundaryLength) {
 		const uint32_t oldOwnerFaceCount = owner->faces.size();
 		const uint32_t chartFaceCount = chart->faces.size();
 		owner->faces.push_back(chart->faces);
@@ -6499,33 +5793,53 @@ private:
 	bool m_placingSeeds;
 };
 
-struct Atlas
-{
-	Atlas() : m_planarCharts(m_data), m_clusteredCharts(m_data, m_planarCharts) {}
+struct ChartGeneratorType {
+	enum Enum {
+		OriginalUv,
+		Planar,
+		Clustered,
+		Piecewise
+	};
+};
 
-	uint32_t chartCount() const
-	{
-		return m_planarCharts.chartCount() + m_clusteredCharts.chartCount();
+struct Atlas {
+	Atlas() :
+			m_originalUvCharts(m_data), m_planarCharts(m_data), m_clusteredCharts(m_data, m_planarCharts) {}
+
+	uint32_t chartCount() const {
+		return m_originalUvCharts.chartCount() + m_planarCharts.chartCount() + m_clusteredCharts.chartCount();
 	}
 
-	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const
-	{
+	ConstArrayView<uint32_t> chartFaces(uint32_t chartIndex) const {
+		if (chartIndex < m_originalUvCharts.chartCount())
+			return m_originalUvCharts.chartFaces(chartIndex);
+		chartIndex -= m_originalUvCharts.chartCount();
 		if (chartIndex < m_planarCharts.chartCount())
 			return m_planarCharts.chartFaces(chartIndex);
 		chartIndex -= m_planarCharts.chartCount();
 		return m_clusteredCharts.chartFaces(chartIndex);
 	}
 
-	const Basis &chartBasis(uint32_t chartIndex) const
-	{
+	const Basis &chartBasis(uint32_t chartIndex) const {
+		if (chartIndex < m_originalUvCharts.chartCount())
+			return m_originalUvCharts.chartBasis(chartIndex);
+		chartIndex -= m_originalUvCharts.chartCount();
 		if (chartIndex < m_planarCharts.chartCount())
 			return m_planarCharts.chartBasis(chartIndex);
 		chartIndex -= m_planarCharts.chartCount();
 		return m_clusteredCharts.chartBasis(chartIndex);
 	}
 
-	void reset(const Mesh *mesh, const ChartOptions &options)
-	{
+	ChartGeneratorType::Enum chartGeneratorType(uint32_t chartIndex) const {
+		if (chartIndex < m_originalUvCharts.chartCount())
+			return ChartGeneratorType::OriginalUv;
+		chartIndex -= m_originalUvCharts.chartCount();
+		if (chartIndex < m_planarCharts.chartCount())
+			return ChartGeneratorType::Planar;
+		return ChartGeneratorType::Clustered;
+	}
+
+	void reset(const Mesh *mesh, const ChartOptions &options) {
 		XA_PROFILE_START(buildAtlasInit)
 		m_data.options = options;
 		m_data.mesh = mesh;
@@ -6533,8 +5847,12 @@ struct Atlas
 		XA_PROFILE_END(buildAtlasInit)
 	}
 
-	void compute()
-	{
+	void compute() {
+		if (m_data.options.useInputMeshUvs) {
+			XA_PROFILE_START(originalUvCharts)
+			m_originalUvCharts.compute();
+			XA_PROFILE_END(originalUvCharts)
+		}
 		XA_PROFILE_START(planarCharts)
 		m_planarCharts.compute();
 		XA_PROFILE_END(planarCharts)
@@ -6545,17 +5863,143 @@ struct Atlas
 
 private:
 	AtlasData m_data;
+	OriginalUvCharts m_originalUvCharts;
 	PlanarCharts m_planarCharts;
 	ClusteredCharts m_clusteredCharts;
 };
 
+struct ComputeUvMeshChartsTaskArgs {
+	UvMesh *mesh;
+	Progress *progress;
+};
+
+// Charts are found by floodfilling faces without crossing UV seams.
+struct ComputeUvMeshChartsTask {
+	ComputeUvMeshChartsTask(ComputeUvMeshChartsTaskArgs *args) :
+			m_mesh(args->mesh), m_progress(args->progress), m_uvToEdgeMap(MemTag::Default, m_mesh->indices.size()), m_faceAssigned(m_mesh->indices.size() / 3) {}
+
+	void run() {
+		const uint32_t vertexCount = m_mesh->texcoords.size();
+		const uint32_t indexCount = m_mesh->indices.size();
+		const uint32_t faceCount = indexCount / 3;
+		// A vertex can only be assigned to one chart.
+		m_mesh->vertexToChartMap.resize(vertexCount);
+		m_mesh->vertexToChartMap.fill(UINT32_MAX);
+		// Map vertex UV to edge. Face is then edge / 3.
+		for (uint32_t i = 0; i < indexCount; i++)
+			m_uvToEdgeMap.add(m_mesh->texcoords[m_mesh->indices[i]]);
+		// Find charts.
+		m_faceAssigned.zeroOutMemory();
+		for (uint32_t f = 0; f < faceCount; f++) {
+			if (m_progress->cancel)
+				return;
+			m_progress->increment(1);
+			// Found an unassigned face, see if it can be added.
+			const uint32_t chartIndex = m_mesh->charts.size();
+			if (!canAddFaceToChart(chartIndex, f))
+				continue;
+			// Face is OK, create a new chart with the face.
+			UvMeshChart *chart = XA_NEW(MemTag::Default, UvMeshChart);
+			m_mesh->charts.push_back(chart);
+			chart->material = m_mesh->faceMaterials.isEmpty() ? 0 : m_mesh->faceMaterials[f];
+			addFaceToChart(chartIndex, f);
+			// Walk incident faces and assign them to the chart.
+			uint32_t f2 = 0;
+			for (;;) {
+				bool newFaceAssigned = false;
+				const uint32_t faceCount2 = chart->faces.size();
+				for (; f2 < faceCount2; f2++) {
+					const uint32_t face = chart->faces[f2];
+					for (uint32_t i = 0; i < 3; i++) {
+						// Add any valid faces with colocal UVs to the chart.
+						const Vector2 &uv = m_mesh->texcoords[m_mesh->indices[face * 3 + i]];
+						uint32_t edge = m_uvToEdgeMap.get(uv);
+						while (edge != UINT32_MAX) {
+							const uint32_t newFace = edge / 3;
+							if (canAddFaceToChart(chartIndex, newFace)) {
+								addFaceToChart(chartIndex, newFace);
+								newFaceAssigned = true;
+							}
+							edge = m_uvToEdgeMap.getNext(uv, edge);
+						}
+					}
+				}
+				if (!newFaceAssigned)
+					break;
+			}
+		}
+	}
+
+private:
+	// The chart at chartIndex doesn't have to exist yet.
+	bool canAddFaceToChart(uint32_t chartIndex, uint32_t face) const {
+		if (m_faceAssigned.get(face))
+			return false; // Already assigned to a chart.
+		if (m_mesh->faceIgnore.get(face))
+			return false; // Face is ignored (zero area or nan UVs).
+		if (!m_mesh->faceMaterials.isEmpty() && chartIndex < m_mesh->charts.size()) {
+			if (m_mesh->faceMaterials[face] != m_mesh->charts[chartIndex]->material)
+				return false; // Materials don't match.
+		}
+		for (uint32_t i = 0; i < 3; i++) {
+			const uint32_t vertex = m_mesh->indices[face * 3 + i];
+			if (m_mesh->vertexToChartMap[vertex] != UINT32_MAX && m_mesh->vertexToChartMap[vertex] != chartIndex)
+				return false; // Vertex already assigned to another chart.
+		}
+		return true;
+	}
+
+	void addFaceToChart(uint32_t chartIndex, uint32_t face) {
+		UvMeshChart *chart = m_mesh->charts[chartIndex];
+		m_faceAssigned.set(face);
+		chart->faces.push_back(face);
+		for (uint32_t i = 0; i < 3; i++) {
+			const uint32_t vertex = m_mesh->indices[face * 3 + i];
+			m_mesh->vertexToChartMap[vertex] = chartIndex;
+			chart->indices.push_back(vertex);
+		}
+	}
+
+	UvMesh *const m_mesh;
+	Progress *const m_progress;
+	HashMap<Vector2> m_uvToEdgeMap; // Face is edge / 3.
+	BitArray m_faceAssigned;
+};
+
+static void runComputeUvMeshChartsTask(void * /*groupUserData*/, void *taskUserData) {
+	XA_PROFILE_START(computeChartsThread)
+	ComputeUvMeshChartsTask task((ComputeUvMeshChartsTaskArgs *)taskUserData);
+	task.run();
+	XA_PROFILE_END(computeChartsThread)
+}
+
+static bool computeUvMeshCharts(TaskScheduler *taskScheduler, ArrayView<UvMesh *> meshes, ProgressFunc progressFunc, void *progressUserData) {
+	uint32_t totalFaceCount = 0;
+	for (uint32_t i = 0; i < meshes.length; i++)
+		totalFaceCount += meshes[i]->indices.size() / 3;
+	Progress progress(ProgressCategory::ComputeCharts, progressFunc, progressUserData, totalFaceCount);
+	TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(nullptr, meshes.length);
+	Array<ComputeUvMeshChartsTaskArgs> taskArgs;
+	taskArgs.resize(meshes.length);
+	for (uint32_t i = 0; i < meshes.length; i++) {
+		ComputeUvMeshChartsTaskArgs &args = taskArgs[i];
+		args.mesh = meshes[i];
+		args.progress = &progress;
+		Task task;
+		task.userData = &args;
+		task.func = runComputeUvMeshChartsTask;
+		taskScheduler->run(taskGroup, task);
+	}
+	taskScheduler->wait(&taskGroup);
+	return !progress.cancel;
+}
+
 } // namespace segment
 
 namespace param {
 
 // Fast sweep in 3 directions
-static bool findApproximateDiameterVertices(Mesh *mesh, uint32_t *a, uint32_t *b)
-{
+static bool findApproximateDiameterVertices(Mesh *mesh, uint32_t *a, uint32_t *b) {
 	XA_DEBUG_ASSERT(a != nullptr);
 	XA_DEBUG_ASSERT(b != nullptr);
 	const uint32_t vertexCount = mesh->vertexCount();
@@ -6612,10 +6056,9 @@ static bool findApproximateDiameterVertices(Mesh *mesh, uint32_t *a, uint32_t *b
 
 // From OpenNL LSCM example.
 // Computes the coordinates of the vertices of a triangle in a local 2D orthonormal basis of the triangle's plane.
-static void projectTriangle(Vector3 p0, Vector3 p1, Vector3 p2, Vector2 *z0, Vector2 *z1, Vector2 *z2, float epsilon)
-{
-	Vector3 X = normalize(p1 - p0, epsilon);
-	Vector3 Z = normalize(cross(X, p2 - p0), epsilon);
+static void projectTriangle(Vector3 p0, Vector3 p1, Vector3 p2, Vector2 *z0, Vector2 *z1, Vector2 *z2) {
+	Vector3 X = normalize(p1 - p0);
+	Vector3 Z = normalize(cross(X, p2 - p0));
 	Vector3 Y = cross(Z, X);
 	Vector3 &O = p0;
 	*z0 = Vector2(0, 0);
@@ -6623,8 +6066,83 @@ static void projectTriangle(Vector3 p0, Vector3 p1, Vector3 p2, Vector2 *z0, Vec
 	*z2 = Vector2(dot(p2 - O, X), dot(p2 - O, Y));
 }
 
-static bool computeLeastSquaresConformalMap(Mesh *mesh)
-{
+// Conformal relations from Brecht Van Lommel (based on ABF):
+
+static float vec_angle_cos(const Vector3 &v1, const Vector3 &v2, const Vector3 &v3) {
+	Vector3 d1 = v1 - v2;
+	Vector3 d2 = v3 - v2;
+	return clamp(dot(d1, d2) / (length(d1) * length(d2)), -1.0f, 1.0f);
+}
+
+static float vec_angle(const Vector3 &v1, const Vector3 &v2, const Vector3 &v3) {
+	float dot = vec_angle_cos(v1, v2, v3);
+	return acosf(dot);
+}
+
+static void triangle_angles(const Vector3 &v1, const Vector3 &v2, const Vector3 &v3, float *a1, float *a2, float *a3) {
+	*a1 = vec_angle(v3, v1, v2);
+	*a2 = vec_angle(v1, v2, v3);
+	*a3 = kPi - *a2 - *a1;
+}
+
+static bool setup_abf_relations(opennl::NLContext *context, int id0, int id1, int id2, const Vector3 &p0, const Vector3 &p1, const Vector3 &p2) {
+	// @@ IC: Wouldn't it be more accurate to return cos and compute 1-cos^2?
+	// It does indeed seem to be a little bit more robust.
+	// @@ Need to revisit this more carefully!
+	float a0, a1, a2;
+	triangle_angles(p0, p1, p2, &a0, &a1, &a2);
+	if (a0 == 0.0f || a1 == 0.0f || a2 == 0.0f)
+		return false;
+	float s0 = sinf(a0);
+	float s1 = sinf(a1);
+	float s2 = sinf(a2);
+	if (s1 > s0 && s1 > s2) {
+		swap(s1, s2);
+		swap(s0, s1);
+		swap(a1, a2);
+		swap(a0, a1);
+		swap(id1, id2);
+		swap(id0, id1);
+	} else if (s0 > s1 && s0 > s2) {
+		swap(s0, s2);
+		swap(s0, s1);
+		swap(a0, a2);
+		swap(a0, a1);
+		swap(id0, id2);
+		swap(id0, id1);
+	}
+	float c0 = cosf(a0);
+	float ratio = (s2 == 0.0f) ? 1.0f : s1 / s2;
+	float cosine = c0 * ratio;
+	float sine = s0 * ratio;
+	// Note  : 2*id + 0 --> u
+	//         2*id + 1 --> v
+	int u0_id = 2 * id0 + 0;
+	int v0_id = 2 * id0 + 1;
+	int u1_id = 2 * id1 + 0;
+	int v1_id = 2 * id1 + 1;
+	int u2_id = 2 * id2 + 0;
+	int v2_id = 2 * id2 + 1;
+	// Real part
+	opennl::nlBegin(context, NL_ROW);
+	opennl::nlCoefficient(context, u0_id, cosine - 1.0f);
+	opennl::nlCoefficient(context, v0_id, -sine);
+	opennl::nlCoefficient(context, u1_id, -cosine);
+	opennl::nlCoefficient(context, v1_id, sine);
+	opennl::nlCoefficient(context, u2_id, 1);
+	opennl::nlEnd(context, NL_ROW);
+	// Imaginary part
+	opennl::nlBegin(context, NL_ROW);
+	opennl::nlCoefficient(context, u0_id, sine);
+	opennl::nlCoefficient(context, v0_id, cosine - 1.0f);
+	opennl::nlCoefficient(context, u1_id, -sine);
+	opennl::nlCoefficient(context, v1_id, -cosine);
+	opennl::nlCoefficient(context, v2_id, 1);
+	opennl::nlEnd(context, NL_ROW);
+	return true;
+}
+
+static bool computeLeastSquaresConformalMap(Mesh *mesh) {
 	uint32_t lockedVertex0, lockedVertex1;
 	if (!findApproximateDiameterVertices(mesh, &lockedVertex0, &lockedVertex1)) {
 		// Mesh has no boundaries.
@@ -6635,55 +6153,57 @@ static bool computeLeastSquaresConformalMap(Mesh *mesh)
 	opennl::nlSolverParameteri(context, NL_NB_VARIABLES, int(2 * vertexCount));
 	opennl::nlSolverParameteri(context, NL_MAX_ITERATIONS, int(5 * vertexCount));
 	opennl::nlBegin(context, NL_SYSTEM);
-	const Vector2 *texcoords = mesh->texcoords();
+	ArrayView<Vector2> texcoords = mesh->texcoords();
 	for (uint32_t i = 0; i < vertexCount; i++) {
 		opennl::nlSetVariable(context, 2 * i, texcoords[i].x);
 		opennl::nlSetVariable(context, 2 * i + 1, texcoords[i].y);
 		if (i == lockedVertex0 || i == lockedVertex1) {
 			opennl::nlLockVariable(context, 2 * i);
 			opennl::nlLockVariable(context, 2 * i + 1);
-		} 
+		}
 	}
 	opennl::nlBegin(context, NL_MATRIX);
 	const uint32_t faceCount = mesh->faceCount();
-	const Vector3 *positions = mesh->positions();
-	const uint32_t *indices = mesh->indices();
+	ConstArrayView<Vector3> positions = mesh->positions();
+	ConstArrayView<uint32_t> indices = mesh->indices();
 	for (uint32_t f = 0; f < faceCount; f++) {
 		const uint32_t v0 = indices[f * 3 + 0];
 		const uint32_t v1 = indices[f * 3 + 1];
 		const uint32_t v2 = indices[f * 3 + 2];
-		Vector2 z0, z1, z2;
-		projectTriangle(positions[v0], positions[v1], positions[v2], &z0, &z1, &z2, mesh->epsilon());
-		double a = z1.x - z0.x;
-		double b = z1.y - z0.y;
-		double c = z2.x - z0.x;
-		double d = z2.y - z0.y;
-		XA_DEBUG_ASSERT(b == 0.0);
-		// Note  : 2*id + 0 --> u
-		//         2*id + 1 --> v
-		uint32_t u0_id = 2 * v0;
-		uint32_t v0_id = 2 * v0 + 1;
-		uint32_t u1_id = 2 * v1;
-		uint32_t v1_id = 2 * v1 + 1;
-		uint32_t u2_id = 2 * v2;
-		uint32_t v2_id = 2 * v2 + 1;
-		// Note : b = 0
-		// Real part
-		opennl::nlBegin(context, NL_ROW);
-		opennl::nlCoefficient(context, u0_id, -a+c) ;
-		opennl::nlCoefficient(context, v0_id, b-d) ;
-		opennl::nlCoefficient(context, u1_id, -c) ;
-		opennl::nlCoefficient(context, v1_id, d) ;
-		opennl::nlCoefficient(context, u2_id, a);
-		opennl::nlEnd(context, NL_ROW);
-		// Imaginary part
-		opennl::nlBegin(context, NL_ROW);
-		opennl::nlCoefficient(context, u0_id, -b+d);
-		opennl::nlCoefficient(context, v0_id, -a+c);
-		opennl::nlCoefficient(context, u1_id, -d);
-		opennl::nlCoefficient(context, v1_id, -c);
-		opennl::nlCoefficient(context, v2_id, a);
-		opennl::nlEnd(context, NL_ROW);
+		if (!setup_abf_relations(context, v0, v1, v2, positions[v0], positions[v1], positions[v2])) {
+			Vector2 z0, z1, z2;
+			projectTriangle(positions[v0], positions[v1], positions[v2], &z0, &z1, &z2);
+			double a = z1.x - z0.x;
+			double b = z1.y - z0.y;
+			double c = z2.x - z0.x;
+			double d = z2.y - z0.y;
+			XA_DEBUG_ASSERT(b == 0.0);
+			// Note  : 2*id + 0 --> u
+			//         2*id + 1 --> v
+			uint32_t u0_id = 2 * v0;
+			uint32_t v0_id = 2 * v0 + 1;
+			uint32_t u1_id = 2 * v1;
+			uint32_t v1_id = 2 * v1 + 1;
+			uint32_t u2_id = 2 * v2;
+			uint32_t v2_id = 2 * v2 + 1;
+			// Note : b = 0
+			// Real part
+			opennl::nlBegin(context, NL_ROW);
+			opennl::nlCoefficient(context, u0_id, -a + c);
+			opennl::nlCoefficient(context, v0_id, b - d);
+			opennl::nlCoefficient(context, u1_id, -c);
+			opennl::nlCoefficient(context, v1_id, d);
+			opennl::nlCoefficient(context, u2_id, a);
+			opennl::nlEnd(context, NL_ROW);
+			// Imaginary part
+			opennl::nlBegin(context, NL_ROW);
+			opennl::nlCoefficient(context, u0_id, -b + d);
+			opennl::nlCoefficient(context, v0_id, -a + c);
+			opennl::nlCoefficient(context, u1_id, -d);
+			opennl::nlCoefficient(context, v1_id, -c);
+			opennl::nlCoefficient(context, v2_id, a);
+			opennl::nlEnd(context, NL_ROW);
+		}
 	}
 	opennl::nlEnd(context, NL_MATRIX);
 	opennl::nlEnd(context, NL_SYSTEM);
@@ -6694,7 +6214,7 @@ static bool computeLeastSquaresConformalMap(Mesh *mesh)
 	for (uint32_t i = 0; i < vertexCount; i++) {
 		const double u = opennl::nlGetVariable(context, 2 * i);
 		const double v = opennl::nlGetVariable(context, 2 * i + 1);
-		mesh->texcoord(i) = Vector2((float)u, (float)v);
+		texcoords[i] = Vector2((float)u, (float)v);
 		XA_DEBUG_ASSERT(!isNan(mesh->texcoord(i).x));
 		XA_DEBUG_ASSERT(!isNan(mesh->texcoord(i).y));
 	}
@@ -6702,30 +6222,26 @@ static bool computeLeastSquaresConformalMap(Mesh *mesh)
 	return true;
 }
 
-#if XA_RECOMPUTE_CHARTS
-struct PiecewiseParam
-{
-	void reset(const Mesh *mesh, uint32_t faceCount)
-	{
+struct PiecewiseParam {
+	void reset(const Mesh *mesh) {
 		m_mesh = mesh;
-		m_faceCount = faceCount;
+		const uint32_t faceCount = m_mesh->faceCount();
 		const uint32_t vertexCount = m_mesh->vertexCount();
 		m_texcoords.resize(vertexCount);
-		m_patch.reserve(m_faceCount);
-		m_candidates.reserve(m_faceCount);
-		m_faceInAnyPatch.resize(m_faceCount);
+		m_patch.reserve(faceCount);
+		m_candidates.reserve(faceCount);
+		m_faceInAnyPatch.resize(faceCount);
 		m_faceInAnyPatch.zeroOutMemory();
-		m_faceInvalid.resize(m_faceCount);
-		m_faceInPatch.resize(m_faceCount);
+		m_faceInvalid.resize(faceCount);
+		m_faceInPatch.resize(faceCount);
 		m_vertexInPatch.resize(vertexCount);
-		m_faceToCandidate.resize(m_faceCount);
+		m_faceToCandidate.resize(faceCount);
 	}
 
 	ConstArrayView<uint32_t> chartFaces() const { return m_patch; }
-	const Vector2 *texcoords() const { return m_texcoords.data(); }
+	ConstArrayView<Vector2> texcoords() const { return m_texcoords; }
 
-	bool computeChart()
-	{
+	bool computeChart() {
 		// Clear per-patch state.
 		m_patch.clear();
 		m_candidates.clear();
@@ -6734,8 +6250,9 @@ struct PiecewiseParam
 		m_faceInPatch.zeroOutMemory();
 		m_vertexInPatch.zeroOutMemory();
 		// Add the seed face (first unassigned face) to the patch.
+		const uint32_t faceCount = m_mesh->faceCount();
 		uint32_t seed = UINT32_MAX;
-		for (uint32_t f = 0; f < m_faceCount; f++) {
+		for (uint32_t f = 0; f < faceCount; f++) {
 			if (m_faceInAnyPatch.get(f))
 				continue;
 			seed = f;
@@ -6749,7 +6266,7 @@ struct PiecewiseParam
 			}
 			addFaceToPatch(seed);
 			// Initialize the boundary grid.
-			m_boundaryGrid.reset(m_texcoords.data(), m_mesh->indices());
+			m_boundaryGrid.reset(m_texcoords, m_mesh->indices());
 			for (Mesh::FaceEdgeIterator it(m_mesh, seed); !it.isDone(); it.advance())
 				m_boundaryGrid.append(it.edge());
 			break;
@@ -6793,22 +6310,34 @@ struct PiecewiseParam
 					break;
 				}
 			}
+			// Check for zero area and flipped faces (using area).
+			for (CandidateIterator it(bestCandidate); !it.isDone(); it.advance()) {
+				const Vector2 a = m_texcoords[m_mesh->vertexAt(it.current()->face * 3 + 0)];
+				const Vector2 b = m_texcoords[m_mesh->vertexAt(it.current()->face * 3 + 1)];
+				const Vector2 c = m_texcoords[m_mesh->vertexAt(it.current()->face * 3 + 2)];
+				const float area = triangleArea(a, b, c);
+				if (area <= 0.0f) {
+					invalid = true;
+					break;
+				}
+			}
 			// Check for boundary intersection.
 			if (!invalid) {
 				XA_PROFILE_START(parameterizeChartsPiecewiseBoundaryIntersection)
 				// Test candidate edges that would form part of the new patch boundary.
 				// Ignore boundary edges that would become internal if the candidate faces were added to the patch.
-				Array<uint32_t> newBoundaryEdges, ignoreEdges;
+				m_newBoundaryEdges.clear();
+				m_ignoreBoundaryEdges.clear();
 				for (CandidateIterator candidateIt(bestCandidate); !candidateIt.isDone(); candidateIt.advance()) {
 					for (Mesh::FaceEdgeIterator it(m_mesh, candidateIt.current()->face); !it.isDone(); it.advance()) {
 						const uint32_t oface = it.oppositeFace();
-						if (oface == UINT32_MAX || oface >= m_faceCount || !m_faceInPatch.get(oface))
-							newBoundaryEdges.push_back(it.edge());
-						if (oface != UINT32_MAX && oface < m_faceCount && m_faceInPatch.get(oface))
-							ignoreEdges.push_back(it.oppositeEdge());
+						if (oface == UINT32_MAX || !m_faceInPatch.get(oface))
+							m_newBoundaryEdges.push_back(it.edge());
+						if (oface != UINT32_MAX && m_faceInPatch.get(oface))
+							m_ignoreBoundaryEdges.push_back(it.oppositeEdge());
 					}
 				}
-				invalid = m_boundaryGrid.intersect(m_mesh->epsilon(), newBoundaryEdges, ignoreEdges);
+				invalid = m_boundaryGrid.intersect(m_mesh->epsilon(), m_newBoundaryEdges, m_ignoreBoundaryEdges);
 				XA_PROFILE_END(parameterizeChartsPiecewiseBoundaryIntersection)
 			}
 			if (invalid) {
@@ -6826,11 +6355,11 @@ struct PiecewiseParam
 				removeLinkedCandidates(bestCandidate);
 				// Reset the grid with all edges on the patch boundary.
 				XA_PROFILE_START(parameterizeChartsPiecewiseBoundaryIntersection)
-				m_boundaryGrid.reset(m_texcoords.data(), m_mesh->indices());
+				m_boundaryGrid.reset(m_texcoords, m_mesh->indices());
 				for (uint32_t i = 0; i < m_patch.size(); i++) {
 					for (Mesh::FaceEdgeIterator it(m_mesh, m_patch[i]); !it.isDone(); it.advance()) {
 						const uint32_t oface = it.oppositeFace();
-						if (oface == UINT32_MAX || oface >= m_faceCount || !m_faceInPatch.get(oface))
+						if (oface == UINT32_MAX || !m_faceInPatch.get(oface))
 							m_boundaryGrid.append(it.edge());
 					}
 				}
@@ -6841,8 +6370,7 @@ struct PiecewiseParam
 	}
 
 private:
-	struct Candidate
-	{
+	struct Candidate {
 		uint32_t face, vertex;
 		Candidate *prev, *next; // The previous/next candidate with the same vertex.
 		Vector2 position;
@@ -6852,10 +6380,14 @@ private:
 		float patchVertexOrient;
 	};
 
-	struct CandidateIterator
-	{
-		CandidateIterator(Candidate *head) : m_current(head) { XA_DEBUG_ASSERT(!head->prev); }
-		void advance() { if (m_current != nullptr) { m_current = m_current->next; } }
+	struct CandidateIterator {
+		CandidateIterator(Candidate *head) :
+				m_current(head) { XA_DEBUG_ASSERT(!head->prev); }
+		void advance() {
+			if (m_current != nullptr) {
+				m_current = m_current->next;
+			}
+		}
 		bool isDone() const { return !m_current; }
 		Candidate *current() { return m_current; }
 
@@ -6864,7 +6396,6 @@ private:
 	};
 
 	const Mesh *m_mesh;
-	uint32_t m_faceCount;
 	Array<Vector2> m_texcoords;
 	BitArray m_faceInAnyPatch; // Face is in a previous chart patch or the current patch.
 	Array<Candidate *> m_candidates; // Incident faces to the patch.
@@ -6873,9 +6404,9 @@ private:
 	BitArray m_faceInPatch, m_vertexInPatch; // Face/vertex is in the current patch.
 	BitArray m_faceInvalid; // Face cannot be added to the patch - flipped, cost too high or causes boundary intersection.
 	UniformGrid2 m_boundaryGrid;
+	Array<uint32_t> m_newBoundaryEdges, m_ignoreBoundaryEdges; // Temp arrays used when testing for boundary intersection.
 
-	void addFaceToPatch(uint32_t face)
-	{
+	void addFaceToPatch(uint32_t face) {
 		XA_DEBUG_ASSERT(!m_faceInPatch.get(face));
 		XA_DEBUG_ASSERT(!m_faceInAnyPatch.get(face));
 		m_patch.push_back(face);
@@ -6884,7 +6415,7 @@ private:
 		// Find new candidate faces on the patch incident to the newly added face.
 		for (Mesh::FaceEdgeIterator it(m_mesh, face); !it.isDone(); it.advance()) {
 			const uint32_t oface = it.oppositeFace();
-			if (oface == UINT32_MAX || oface >= m_faceCount || m_faceInAnyPatch.get(oface) || m_faceToCandidate[oface])
+			if (oface == UINT32_MAX || m_faceInAnyPatch.get(oface) || m_faceToCandidate[oface])
 				continue;
 			// Found an active edge on the patch front.
 			// Find the free vertex (the vertex that isn't on the active edge).
@@ -6900,12 +6431,14 @@ private:
 				}
 			}
 			XA_DEBUG_ASSERT(freeVertex != UINT32_MAX);
-			// If the free vertex is already in the patch, the face is enclosed by the patch. Add the face to the patch - don't need to assign texcoords.
-			/*if (m_vertexInPatch.get(freeVertex)) {
+			if (m_vertexInPatch.get(freeVertex)) {
+#if 0
+				// If the free vertex is already in the patch, the face is enclosed by the patch. Add the face to the patch - don't need to assign texcoords.
 				freeVertex = UINT32_MAX;
-				addFaceToPatch(oface, false);
+				addFaceToPatch(oface);
+#endif
 				continue;
-			}*/
+			}
 			// Check this here rather than above so faces enclosed by the patch are always added.
 			if (m_faceInvalid.get(oface))
 				continue;
@@ -6913,8 +6446,7 @@ private:
 		}
 	}
 
-	void addCandidateFace(uint32_t patchEdge, float patchVertexOrient, uint32_t face, uint32_t edge, uint32_t freeVertex)
-	{
+	void addCandidateFace(uint32_t patchEdge, float patchVertexOrient, uint32_t face, uint32_t edge, uint32_t freeVertex) {
 		XA_DEBUG_ASSERT(!m_faceToCandidate[face]);
 		Vector2 texcoords[3];
 		orthoProjectFace(face, texcoords);
@@ -6960,8 +6492,10 @@ private:
 			uv.x = x + texcoords[localVertex0].x;
 			uv.y = y + texcoords[localVertex0].y;
 		}
-		if (isNan(texcoords[localFreeVertex].x) || isNan(texcoords[localFreeVertex].y))
+		if (isNan(texcoords[localFreeVertex].x) || isNan(texcoords[localFreeVertex].y)) {
+			m_faceInvalid.set(face);
 			return;
+		}
 		// Check for local overlap (flipped triangle).
 		// The patch face vertex that isn't on the active edge and the free vertex should be oriented on opposite sides to the active edge.
 		const float freeVertexOrient = orientToEdge(m_texcoords[vertex0], m_texcoords[vertex1], texcoords[localFreeVertex]);
@@ -6975,12 +6509,10 @@ private:
 			return;
 		}
 		const float cost = fabsf(stretch - 1.0f);
-#if 0
-		if (cost > 0.25f) {
+		if (cost > 0.5f) {
 			m_faceInvalid.set(face);
 			return;
 		}
-#endif
 		// Add the candidate.
 		Candidate *candidate = XA_ALLOC(MemTag::Default, Candidate);
 		candidate->face = face;
@@ -7017,8 +6549,7 @@ private:
 			it.current()->maxCost = maxCost;
 	}
 
-	Candidate *linkedCandidateHead(Candidate *candidate)
-	{
+	Candidate *linkedCandidateHead(Candidate *candidate) {
 		Candidate *current = candidate;
 		for (;;) {
 			if (!current->prev)
@@ -7028,8 +6559,7 @@ private:
 		return current;
 	}
 
-	void removeLinkedCandidates(Candidate *head)
-	{
+	void removeLinkedCandidates(Candidate *head) {
 		XA_DEBUG_ASSERT(!head->prev);
 		Candidate *current = head;
 		while (current) {
@@ -7046,10 +6576,9 @@ private:
 		}
 	}
 
-	void orthoProjectFace(uint32_t face, Vector2 *texcoords) const
-	{
-		const Vector3 normal = m_mesh->computeFaceNormal(face);
-		const Vector3 tangent = normalize(m_mesh->position(m_mesh->vertexAt(face * 3 + 1)) - m_mesh->position(m_mesh->vertexAt(face * 3 + 0)), kEpsilon);
+	void orthoProjectFace(uint32_t face, Vector2 *texcoords) const {
+		const Vector3 normal = -m_mesh->computeFaceNormal(face);
+		const Vector3 tangent = normalize(m_mesh->position(m_mesh->vertexAt(face * 3 + 1)) - m_mesh->position(m_mesh->vertexAt(face * 3 + 0)));
 		const Vector3 bitangent = cross(normal, tangent);
 		for (uint32_t i = 0; i < 3; i++) {
 			const Vector3 &pos = m_mesh->position(m_mesh->vertexAt(face * 3 + i));
@@ -7057,16 +6586,14 @@ private:
 		}
 	}
 
-	float parametricArea(const Vector2 *texcoords) const
-	{
+	float parametricArea(const Vector2 *texcoords) const {
 		const Vector2 &v1 = texcoords[0];
 		const Vector2 &v2 = texcoords[1];
 		const Vector2 &v3 = texcoords[2];
 		return ((v2.x - v1.x) * (v3.y - v1.y) - (v3.x - v1.x) * (v2.y - v1.y)) * 0.5f;
 	}
 
-	float computeStretch(Vector3 p1, Vector3 p2, Vector3 p3, Vector2 t1, Vector2 t2, Vector2 t3) const
-	{
+	float computeStretch(Vector3 p1, Vector3 p2, Vector3 p3, Vector2 t1, Vector2 t2, Vector2 t3) const {
 		float parametricArea = ((t2.y - t1.y) * (t3.x - t1.x) - (t3.y - t1.y) * (t2.x - t1.x)) * 0.5f;
 		if (isZero(parametricArea, kAreaEpsilon))
 			return FLT_MAX;
@@ -7080,16 +6607,13 @@ private:
 	}
 
 	// Return value is positive if the point is one side of the edge, negative if on the other side.
-	float orientToEdge(Vector2 edgeVertex0, Vector2 edgeVertex1, Vector2 point) const
-	{
+	float orientToEdge(Vector2 edgeVertex0, Vector2 edgeVertex1, Vector2 point) const {
 		return (edgeVertex0.x - point.x) * (edgeVertex1.y - point.y) - (edgeVertex0.y - point.y) * (edgeVertex1.x - point.x);
 	}
 };
-#endif
 
 // Estimate quality of existing parameterization.
-struct Quality
-{
+struct Quality {
 	// computeBoundaryIntersection
 	bool boundaryIntersection = false;
 
@@ -7106,8 +6630,7 @@ struct Quality
 	float conformalMetric = 0.0f;
 	float authalicMetric = 0.0f;
 
-	void computeBoundaryIntersection(const Mesh *mesh, UniformGrid2 &boundaryGrid)
-	{
+	void computeBoundaryIntersection(const Mesh *mesh, UniformGrid2 &boundaryGrid) {
 		const Array<uint32_t> &boundaryEdges = mesh->boundaryEdges();
 		const uint32_t boundaryEdgeCount = boundaryEdges.size();
 		boundaryGrid.reset(mesh->texcoords(), mesh->indices(), boundaryEdgeCount);
@@ -7123,11 +6646,11 @@ struct Quality
 #endif
 	}
 
-	void computeFlippedFaces(const Mesh *mesh, uint32_t faceCount, Array<uint32_t> *flippedFaces)
-	{
+	void computeFlippedFaces(const Mesh *mesh, Array<uint32_t> *flippedFaces) {
 		totalTriangleCount = flippedTriangleCount = zeroAreaTriangleCount = 0;
 		if (flippedFaces)
 			flippedFaces->clear();
+		const uint32_t faceCount = mesh->faceCount();
 		for (uint32_t f = 0; f < faceCount; f++) {
 			Vector2 texcoord[3];
 			for (int i = 0; i < 3; i++) {
@@ -7159,8 +6682,7 @@ struct Quality
 				flippedFaces->clear();
 			flippedTriangleCount = 0;
 		}
-		if (flippedTriangleCount > totalTriangleCount / 2)
-		{
+		if (flippedTriangleCount > totalTriangleCount / 2) {
 			// If more than half the triangles are flipped, reverse the flipped / not flipped classification.
 			flippedTriangleCount = totalTriangleCount - flippedTriangleCount;
 			if (flippedFaces) {
@@ -7182,10 +6704,10 @@ struct Quality
 		}
 	}
 
-	void computeMetrics(const Mesh *mesh, uint32_t faceCount)
-	{
+	void computeMetrics(const Mesh *mesh) {
 		totalGeometricArea = totalParametricArea = 0.0f;
 		stretchMetric = maxStretchMetric = conformalMetric = authalicMetric = 0.0f;
+		const uint32_t faceCount = mesh->faceCount();
 		for (uint32_t f = 0; f < faceCount; f++) {
 			Vector3 pos[3];
 			Vector2 texcoord[3];
@@ -7214,7 +6736,7 @@ struct Quality
 			const float a = dot(Ss, Ss); // E
 			const float b = dot(Ss, St); // F
 			const float c = dot(St, St); // G
-										 // Compute eigen-values of the first fundamental form:
+					// Compute eigen-values of the first fundamental form:
 			const float sigma1 = sqrtf(0.5f * max(0.0f, a + c - sqrtf(square(a - c) + 4 * square(b)))); // gamma uppercase, min eigenvalue.
 			const float sigma2 = sqrtf(0.5f * max(0.0f, a + c + sqrtf(square(a - c) + 4 * square(b)))); // gamma lowercase, max eigenvalue.
 			XA_ASSERT(sigma2 > sigma1 || equal(sigma1, sigma2, kEpsilon));
@@ -7245,347 +6767,261 @@ struct Quality
 		if (totalGeometricArea > 0.0f) {
 			const float normFactor = sqrtf(totalParametricArea / totalGeometricArea);
 			stretchMetric = sqrtf(stretchMetric / totalGeometricArea) * normFactor;
-			maxStretchMetric  *= normFactor;
+			maxStretchMetric *= normFactor;
 			conformalMetric = sqrtf(conformalMetric / totalGeometricArea);
 			authalicMetric = sqrtf(authalicMetric / totalGeometricArea);
 		}
 	}
 };
 
-struct ChartWarningFlags
-{
-	enum Enum
-	{
-		CloseHolesFailed = 1<<1,
-		FixTJunctionsDuplicatedEdge = 1<<2,
-		FixTJunctionsFailed = 1<<3,
-		TriangulateDuplicatedEdge = 1<<4,
-	};
-};
-
-struct ChartCtorBuffers
-{
+struct ChartCtorBuffers {
 	Array<uint32_t> chartMeshIndices;
 	Array<uint32_t> unifiedMeshIndices;
-	Array<uint32_t> boundaryLoops;
 };
 
-class Chart
-{
+class Chart {
 public:
-	Chart(ChartCtorBuffers &buffers, const ParameterizeOptions &options, const Basis &basis, ConstArrayView<uint32_t> faces, const Mesh *sourceMesh, uint32_t chartGroupId, uint32_t chartId) : m_basis(basis), m_mesh(nullptr), m_unifiedMesh(nullptr), m_unmodifiedUnifiedMesh(nullptr), m_type(ChartType::LSCM), m_warningFlags(0), m_closedHolesCount(0), m_fixedTJunctionsCount(0), m_isInvalid(false)
-	{
+	Chart(const Basis &basis, segment::ChartGeneratorType::Enum generatorType, ConstArrayView<uint32_t> faces, const Mesh *sourceMesh, uint32_t chartGroupId, uint32_t chartId) :
+			m_basis(basis), m_unifiedMesh(nullptr), m_type(ChartType::LSCM), m_generatorType(generatorType), m_tjunctionCount(0), m_originalVertexCount(0), m_isInvalid(false) {
 		XA_UNUSED(chartGroupId);
 		XA_UNUSED(chartId);
 		m_faceToSourceFaceMap.copyFrom(faces.data, faces.length);
 		const uint32_t approxVertexCount = min(faces.length * 3, sourceMesh->vertexCount());
-		m_mesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, sourceMesh->epsilon(), approxVertexCount, faces.length);
 		m_unifiedMesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, sourceMesh->epsilon(), approxVertexCount, faces.length);
 		HashMap<uint32_t, PassthroughHash<uint32_t>> sourceVertexToUnifiedVertexMap(MemTag::Mesh, approxVertexCount), sourceVertexToChartVertexMap(MemTag::Mesh, approxVertexCount);
-		// Add vertices.
-		const uint32_t faceCount = m_initialFaceCount = faces.length;
+		m_originalIndices.resize(faces.length * 3);
+		// Add geometry.
+		const uint32_t faceCount = faces.length;
 		for (uint32_t f = 0; f < faceCount; f++) {
+			uint32_t unifiedIndices[3];
 			for (uint32_t i = 0; i < 3; i++) {
 				const uint32_t sourceVertex = sourceMesh->vertexAt(m_faceToSourceFaceMap[f] * 3 + i);
-				const uint32_t sourceUnifiedVertex = sourceMesh->firstColocal(sourceVertex);
+				uint32_t sourceUnifiedVertex = sourceMesh->firstColocalVertex(sourceVertex);
+				if (m_generatorType == segment::ChartGeneratorType::OriginalUv && sourceVertex != sourceUnifiedVertex) {
+					// Original UVs: don't unify vertices with different UVs; we want to preserve UVs.
+					if (!equal(sourceMesh->texcoord(sourceVertex), sourceMesh->texcoord(sourceUnifiedVertex), sourceMesh->epsilon()))
+						sourceUnifiedVertex = sourceVertex;
+				}
 				uint32_t unifiedVertex = sourceVertexToUnifiedVertexMap.get(sourceUnifiedVertex);
 				if (unifiedVertex == UINT32_MAX) {
 					unifiedVertex = sourceVertexToUnifiedVertexMap.add(sourceUnifiedVertex);
-					m_unifiedMesh->addVertex(sourceMesh->position(sourceVertex));
+					m_unifiedMesh->addVertex(sourceMesh->position(sourceVertex), Vector3(0.0f), sourceMesh->texcoord(sourceVertex));
 				}
 				if (sourceVertexToChartVertexMap.get(sourceVertex) == UINT32_MAX) {
 					sourceVertexToChartVertexMap.add(sourceVertex);
 					m_vertexToSourceVertexMap.push_back(sourceVertex);
 					m_chartVertexToUnifiedVertexMap.push_back(unifiedVertex);
-					m_mesh->addVertex(sourceMesh->position(sourceVertex), Vector3(0.0f), sourceMesh->texcoord(sourceVertex));
+					m_originalVertexCount++;
 				}
-			}
-		}
-		// Add faces.
-		for (uint32_t f = 0; f < faceCount; f++) {
-			uint32_t indices[3], unifiedIndices[3];
-			for (uint32_t i = 0; i < 3; i++) {
-				const uint32_t sourceVertex = sourceMesh->vertexAt(m_faceToSourceFaceMap[f] * 3 + i);
-				const uint32_t sourceUnifiedVertex = sourceMesh->firstColocal(sourceVertex);
-				indices[i] = sourceVertexToChartVertexMap.get(sourceVertex);
-				XA_DEBUG_ASSERT(indices[i] != UINT32_MAX);
+				m_originalIndices[f * 3 + i] = sourceVertexToChartVertexMap.get(sourceVertex);
+				;
+				XA_DEBUG_ASSERT(m_originalIndices[f * 3 + i] != UINT32_MAX);
 				unifiedIndices[i] = sourceVertexToUnifiedVertexMap.get(sourceUnifiedVertex);
 				XA_DEBUG_ASSERT(unifiedIndices[i] != UINT32_MAX);
 			}
-			Mesh::AddFaceResult::Enum result = m_mesh->addFace(indices);
-			XA_UNUSED(result);
-			XA_DEBUG_ASSERT(result == Mesh::AddFaceResult::OK);
-#if XA_DEBUG
-			// Unifying colocals may create degenerate edges. e.g. if two triangle vertices are colocal.
-			for (int i = 0; i < 3; i++) {
-				const uint32_t index1 = unifiedIndices[i];
-				const uint32_t index2 = unifiedIndices[(i + 1) % 3];
-				XA_DEBUG_ASSERT(index1 != index2);
-			}
-#endif
-			result = m_unifiedMesh->addFace(unifiedIndices);
-			XA_UNUSED(result);
-			XA_DEBUG_ASSERT(result == Mesh::AddFaceResult::OK);
+			m_unifiedMesh->addFace(unifiedIndices);
 		}
-		m_mesh->createBoundaries(); // For AtlasPacker::computeBoundingBox
-		m_mesh->destroyEdgeMap(); // Only needed it for createBoundaries.
 		m_unifiedMesh->createBoundaries();
-		if (meshIsPlanar(*m_unifiedMesh)) {
+		if (m_generatorType == segment::ChartGeneratorType::Planar) {
 			m_type = ChartType::Planar;
 			return;
 		}
-		m_unifiedMesh->linkBoundaries();
-#if XA_DEBUG_EXPORT_OBJ_BEFORE_FIX_TJUNCTION
-		m_unifiedMesh->writeObjFile("debug_before_fix_tjunction.obj");
-#endif
-		bool duplicatedEdge = false, failed = false;
-		if (options.fixTJunctions) {
-			XA_PROFILE_START(fixChartMeshTJunctions)
-			Mesh *fixedUnifiedMesh = meshFixTJunctions(*m_unifiedMesh, &duplicatedEdge, &failed, &m_fixedTJunctionsCount);
-			XA_PROFILE_END(fixChartMeshTJunctions)
-			if (fixedUnifiedMesh) {
-				if (duplicatedEdge)
-					m_warningFlags |= ChartWarningFlags::FixTJunctionsDuplicatedEdge;
-				if (failed)
-					m_warningFlags |= ChartWarningFlags::FixTJunctionsFailed;
-				m_unmodifiedUnifiedMesh = m_unifiedMesh;
-				m_unifiedMesh = fixedUnifiedMesh;
-				m_unifiedMesh->createBoundaries();
-				m_unifiedMesh->linkBoundaries();
-				m_initialFaceCount = m_unifiedMesh->faceCount(); // Fixing t-junctions rewrites faces.
-			}
-		}
-		if (options.closeHoles) {
-			// See if there are any holes that need closing.
-			Array<uint32_t> &boundaryLoops = buffers.boundaryLoops;
-			meshGetBoundaryLoops(*m_unifiedMesh, boundaryLoops);
-			if (boundaryLoops.size() > 1) {
-#if XA_DEBUG_EXPORT_OBJ_CLOSE_HOLES_ERROR
-				const uint32_t faceCountBeforeHolesClosed = m_unifiedMesh->faceCount();
+#if XA_CHECK_T_JUNCTIONS
+		m_tjunctionCount = meshCheckTJunctions(*m_unifiedMesh);
+#if XA_DEBUG_EXPORT_OBJ_TJUNCTION
+		if (m_tjunctionCount > 0) {
+			char filename[256];
+			XA_SPRINTF(filename, sizeof(filename), "debug_mesh_%03u_chartgroup_%03u_chart_%03u_tjunction.obj", sourceMesh->id(), chartGroupId, chartId);
+			m_unifiedMesh->writeObjFile(filename);
+		}
 #endif
-				// Closing the holes is not always the best solution and does not fix all the problems.
-				// We need to do some analysis of the holes and the genus to:
-				// - Find cuts that reduce genus.
-				// - Find cuts to connect holes.
-				// - Use minimal spanning trees or seamster.
-				XA_PROFILE_START(closeChartMeshHoles)
-				uint32_t holeCount = 0;
-#if XA_DEBUG_EXPORT_OBJ_CLOSE_HOLES_ERROR
-				Array<uint32_t> holeFaceCounts;
-				failed = !meshCloseHoles(m_unifiedMesh, boundaryLoops, m_basis.normal, &holeFaceCounts);
-#else
-				failed = !meshCloseHoles(m_unifiedMesh, boundaryLoops, m_basis.normal, &holeCount, nullptr);
 #endif
-				XA_PROFILE_END(closeChartMeshHoles)
-				m_unifiedMesh->createBoundaries();
-				m_unifiedMesh->linkBoundaries();
-				meshGetBoundaryLoops(*m_unifiedMesh, boundaryLoops);
-				if (failed || boundaryLoops.size() > 1)
-					m_warningFlags |= ChartWarningFlags::CloseHolesFailed;
-				m_closedHolesCount = holeCount;
-#if XA_DEBUG_EXPORT_OBJ_CLOSE_HOLES_ERROR
-				if (m_warningFlags & ChartWarningFlags::CloseHolesFailed) {
-					char filename[256];
-					XA_SPRINTF(filename, sizeof(filename), "debug_mesh_%03u_chartgroup_%03u_chart_%03u_close_holes_error.obj", sourceMesh->id(), chartGroupId, chartId);
-					FILE *file;
-					XA_FOPEN(file, filename, "w");
-					if (file) {
-						m_unifiedMesh->writeObjVertices(file);
-						fprintf(file, "s off\n");
-						fprintf(file, "o object\n");
-						for (uint32_t i = 0; i < faceCountBeforeHolesClosed; i++)
-							m_unifiedMesh->writeObjFace(file, i);
-						uint32_t face = faceCountBeforeHolesClosed;
-						for (uint32_t i = 0; i < holeFaceCounts.size(); i++) {
-							fprintf(file, "s off\n");
-							fprintf(file, "o hole%u\n", i);
-							for (uint32_t j = 0; j < holeFaceCounts[i]; j++) {
-								m_unifiedMesh->writeObjFace(file, face);
-								face++;
-							}
-						}
-						m_unifiedMesh->writeObjBoundaryEges(file);
-						m_unifiedMesh->writeObjLinkedBoundaries(file);
-						fclose(file);
-					}
-				}
-#endif
-			}
-		}
 	}
 
-#if XA_RECOMPUTE_CHARTS
-	Chart(ChartCtorBuffers &buffers, const Chart *parent, const Mesh *parentMesh, ConstArrayView<uint32_t> faces, const Vector2 *texcoords, const Mesh *sourceMesh) : m_mesh(nullptr), m_unifiedMesh(nullptr), m_unmodifiedUnifiedMesh(nullptr), m_type(ChartType::Piecewise), m_warningFlags(0), m_closedHolesCount(0), m_fixedTJunctionsCount(0), m_isInvalid(false)
-	{
-		const uint32_t faceCount = m_initialFaceCount = faces.length;
+	Chart(ChartCtorBuffers &buffers, const Chart *parent, const Mesh *parentMesh, ConstArrayView<uint32_t> faces, ConstArrayView<Vector2> texcoords, const Mesh *sourceMesh) :
+			m_unifiedMesh(nullptr), m_type(ChartType::Piecewise), m_generatorType(segment::ChartGeneratorType::Piecewise), m_tjunctionCount(0), m_originalVertexCount(0), m_isInvalid(false) {
+		const uint32_t faceCount = faces.length;
 		m_faceToSourceFaceMap.resize(faceCount);
 		for (uint32_t i = 0; i < faceCount; i++)
 			m_faceToSourceFaceMap[i] = parent->m_faceToSourceFaceMap[faces[i]]; // Map faces to parent chart source mesh.
 		// Copy face indices.
-		m_mesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, sourceMesh->epsilon(), m_faceToSourceFaceMap.size() * 3, m_faceToSourceFaceMap.size());
 		Array<uint32_t> &chartMeshIndices = buffers.chartMeshIndices;
 		chartMeshIndices.resize(sourceMesh->vertexCount());
 		chartMeshIndices.fillBytes(0xff);
+		m_unifiedMesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, sourceMesh->epsilon(), m_faceToSourceFaceMap.size() * 3, m_faceToSourceFaceMap.size());
+		HashMap<uint32_t, PassthroughHash<uint32_t>> sourceVertexToUnifiedVertexMap(MemTag::Mesh, m_faceToSourceFaceMap.size() * 3);
 		// Add vertices.
 		for (uint32_t f = 0; f < faceCount; f++) {
 			for (uint32_t i = 0; i < 3; i++) {
 				const uint32_t vertex = sourceMesh->vertexAt(m_faceToSourceFaceMap[f] * 3 + i);
+				const uint32_t sourceUnifiedVertex = sourceMesh->firstColocalVertex(vertex);
 				const uint32_t parentVertex = parentMesh->vertexAt(faces[f] * 3 + i);
-				if (chartMeshIndices[vertex] == (uint32_t)~0) {
-					chartMeshIndices[vertex] = m_mesh->vertexCount();
+				uint32_t unifiedVertex = sourceVertexToUnifiedVertexMap.get(sourceUnifiedVertex);
+				if (unifiedVertex == UINT32_MAX) {
+					unifiedVertex = sourceVertexToUnifiedVertexMap.add(sourceUnifiedVertex);
+					m_unifiedMesh->addVertex(sourceMesh->position(vertex), Vector3(0.0f), texcoords[parentVertex]);
+				}
+				if (chartMeshIndices[vertex] == UINT32_MAX) {
+					chartMeshIndices[vertex] = m_originalVertexCount;
+					m_originalVertexCount++;
 					m_vertexToSourceVertexMap.push_back(vertex);
-					m_mesh->addVertex(sourceMesh->position(vertex), Vector3(0.0f), texcoords[parentVertex]);
+					m_chartVertexToUnifiedVertexMap.push_back(unifiedVertex);
 				}
 			}
 		}
 		// Add faces.
+		m_originalIndices.resize(faceCount * 3);
 		for (uint32_t f = 0; f < faceCount; f++) {
-			uint32_t indices[3];
+			uint32_t unifiedIndices[3];
 			for (uint32_t i = 0; i < 3; i++) {
 				const uint32_t vertex = sourceMesh->vertexAt(m_faceToSourceFaceMap[f] * 3 + i);
-				indices[i] = chartMeshIndices[vertex];
+				m_originalIndices[f * 3 + i] = chartMeshIndices[vertex];
+				const uint32_t unifiedVertex = sourceMesh->firstColocalVertex(vertex);
+				unifiedIndices[i] = sourceVertexToUnifiedVertexMap.get(unifiedVertex);
 			}
-			Mesh::AddFaceResult::Enum result = m_mesh->addFace(indices);
-			XA_UNUSED(result);
-			XA_DEBUG_ASSERT(result == Mesh::AddFaceResult::OK);
+			m_unifiedMesh->addFace(unifiedIndices);
 		}
-		m_mesh->createBoundaries(); // For AtlasPacker::computeBoundingBox
-		m_mesh->destroyEdgeMap(); // Only needed it for createBoundaries.
+		m_unifiedMesh->createBoundaries();
 		// Need to store texcoords for backup/restore so packing can be run multiple times.
 		backupTexcoords();
 	}
-#endif
 
-	~Chart()
-	{
-		if (m_mesh) {
-			m_mesh->~Mesh();
-			XA_FREE(m_mesh);
+	~Chart() {
+		if (m_unifiedMesh) {
+			m_unifiedMesh->~Mesh();
+			XA_FREE(m_unifiedMesh);
+			m_unifiedMesh = nullptr;
 		}
-		destroyUnifiedMesh();
 	}
 
 	bool isInvalid() const { return m_isInvalid; }
-	ChartType::Enum type() const { return m_type; }
-	uint32_t warningFlags() const { return m_warningFlags; }
-	uint32_t closedHolesCount() const { return m_closedHolesCount; }
-	uint32_t fixedTJunctionsCount() const { return m_fixedTJunctionsCount; }
+	ChartType type() const { return m_type; }
+	segment::ChartGeneratorType::Enum generatorType() const { return m_generatorType; }
+	uint32_t tjunctionCount() const { return m_tjunctionCount; }
 	const Quality &quality() const { return m_quality; }
-	uint32_t initialFaceCount() const { return m_initialFaceCount; }
 #if XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION
 	const Array<uint32_t> &paramFlippedFaces() const { return m_paramFlippedFaces; }
 #endif
 	uint32_t mapFaceToSourceFace(uint32_t i) const { return m_faceToSourceFaceMap[i]; }
 	uint32_t mapChartVertexToSourceVertex(uint32_t i) const { return m_vertexToSourceVertexMap[i]; }
-	const Mesh *mesh() const { return m_mesh; }
-	Mesh *mesh() { return m_mesh; }
 	const Mesh *unifiedMesh() const { return m_unifiedMesh; }
-	const Mesh *unmodifiedUnifiedMesh() const { return m_unmodifiedUnifiedMesh; }
+	Mesh *unifiedMesh() { return m_unifiedMesh; }
 
-	void parameterize(const ParameterizeOptions &options, UniformGrid2 &boundaryGrid)
-	{
-		XA_PROFILE_START(parameterizeChartsOrthogonal)
-		{
+	// Vertex count of the chart mesh before unifying vertices.
+	uint32_t originalVertexCount() const { return m_originalVertexCount; }
+
+	uint32_t originalVertexToUnifiedVertex(uint32_t v) const { return m_chartVertexToUnifiedVertexMap[v]; }
+
+	ConstArrayView<uint32_t> originalVertices() const { return m_originalIndices; }
+
+	void parameterize(const ChartOptions &options, UniformGrid2 &boundaryGrid) {
+		const uint32_t unifiedVertexCount = m_unifiedMesh->vertexCount();
+		if (m_generatorType == segment::ChartGeneratorType::OriginalUv) {
+		} else {
 			// Project vertices to plane.
-			const uint32_t vertexCount = m_unifiedMesh->vertexCount();
-			for (uint32_t i = 0; i < vertexCount; i++)
+			XA_PROFILE_START(parameterizeChartsOrthogonal)
+			for (uint32_t i = 0; i < unifiedVertexCount; i++)
 				m_unifiedMesh->texcoord(i) = Vector2(dot(m_basis.tangent, m_unifiedMesh->position(i)), dot(m_basis.bitangent, m_unifiedMesh->position(i)));
-		}
-		XA_PROFILE_END(parameterizeChartsOrthogonal)
-		// Computing charts checks for flipped triangles and boundary intersection. Don't need to do that again here if chart is planar.
-		if (m_type != ChartType::Planar) {
-			XA_PROFILE_START(parameterizeChartsEvaluateQuality)
-			m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
-			m_quality.computeFlippedFaces(m_unifiedMesh, m_initialFaceCount, nullptr);
-			m_quality.computeMetrics(m_unifiedMesh, m_initialFaceCount);
-			XA_PROFILE_END(parameterizeChartsEvaluateQuality)
-			// Use orthogonal parameterization if quality is acceptable.
-			if (!m_quality.boundaryIntersection && m_quality.flippedTriangleCount == 0 && m_quality.totalGeometricArea > 0.0f && m_quality.stretchMetric <= 1.1f && m_quality.maxStretchMetric <= 1.25f)
-				m_type = ChartType::Ortho;
-		}
-		if (m_type == ChartType::LSCM) {
-			XA_PROFILE_START(parameterizeChartsLSCM)
-			if (options.func) {
-				options.func(&m_unifiedMesh->position(0).x, &m_unifiedMesh->texcoord(0).x, m_unifiedMesh->vertexCount(), m_unifiedMesh->indices(), m_unifiedMesh->indexCount());
-			}
-			else
-				computeLeastSquaresConformalMap(m_unifiedMesh);
-			XA_PROFILE_END(parameterizeChartsLSCM)
-			XA_PROFILE_START(parameterizeChartsEvaluateQuality)
-			m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
+			XA_PROFILE_END(parameterizeChartsOrthogonal)
+			// Computing charts checks for flipped triangles and boundary intersection. Don't need to do that again here if chart is planar.
+			if (m_type != ChartType::Planar && m_generatorType != segment::ChartGeneratorType::OriginalUv) {
+				XA_PROFILE_START(parameterizeChartsEvaluateQuality)
+				m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
+				m_quality.computeFlippedFaces(m_unifiedMesh, nullptr);
+				m_quality.computeMetrics(m_unifiedMesh);
+				XA_PROFILE_END(parameterizeChartsEvaluateQuality)
+				// Use orthogonal parameterization if quality is acceptable.
+				if (!m_quality.boundaryIntersection && m_quality.flippedTriangleCount == 0 && m_quality.zeroAreaTriangleCount == 0 && m_quality.totalGeometricArea > 0.0f && m_quality.stretchMetric <= 1.1f && m_quality.maxStretchMetric <= 1.25f)
+					m_type = ChartType::Ortho;
+			}
+			if (m_type == ChartType::LSCM) {
+				XA_PROFILE_START(parameterizeChartsLSCM)
+				if (options.paramFunc) {
+					options.paramFunc(&m_unifiedMesh->position(0).x, &m_unifiedMesh->texcoord(0).x, m_unifiedMesh->vertexCount(), m_unifiedMesh->indices().data, m_unifiedMesh->indexCount());
+				} else
+					computeLeastSquaresConformalMap(m_unifiedMesh);
+				XA_PROFILE_END(parameterizeChartsLSCM)
+				XA_PROFILE_START(parameterizeChartsEvaluateQuality)
+				m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
 #if XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION
-			m_quality.computeFlippedFaces(m_unifiedMesh, m_initialFaceCount, &m_paramFlippedFaces);
+				m_quality.computeFlippedFaces(m_unifiedMesh, &m_paramFlippedFaces);
 #else
-			m_quality.computeFlippedFaces(m_unifiedMesh, m_initialFaceCount, nullptr);
+				m_quality.computeFlippedFaces(m_unifiedMesh, nullptr);
 #endif
-			// Don't need to call computeMetrics here, that's only used in evaluateOrthoQuality to determine if quality is acceptable enough to use ortho projection.
-			if (m_quality.boundaryIntersection || m_quality.flippedTriangleCount > 0)
-				m_isInvalid = true;
-			XA_PROFILE_END(parameterizeChartsEvaluateQuality)
+				// Don't need to call computeMetrics here, that's only used in evaluateOrthoQuality to determine if quality is acceptable enough to use ortho projection.
+				if (m_quality.boundaryIntersection || m_quality.flippedTriangleCount > 0 || m_quality.zeroAreaTriangleCount > 0)
+					m_isInvalid = true;
+				XA_PROFILE_END(parameterizeChartsEvaluateQuality)
+			}
 		}
+		if (options.fixWinding && m_unifiedMesh->computeFaceParametricArea(0) < 0.0f) {
+			for (uint32_t i = 0; i < unifiedVertexCount; i++)
+				m_unifiedMesh->texcoord(i).x *= -1.0f;
+		}
+#if XA_CHECK_PARAM_WINDING
+		const uint32_t faceCount = m_unifiedMesh->faceCount();
+		uint32_t flippedCount = 0;
+		for (uint32_t i = 0; i < faceCount; i++) {
+			const float area = m_unifiedMesh->computeFaceParametricArea(i);
+			if (area < 0.0f)
+				flippedCount++;
+		}
+		if (flippedCount == faceCount) {
+			XA_PRINT_WARNING("param: all faces flipped\n");
+		} else if (flippedCount > 0) {
+			XA_PRINT_WARNING("param: %u / %u faces flipped\n", flippedCount, faceCount);
+		}
+#endif
+
 #if XA_DEBUG_ALL_CHARTS_INVALID
 		m_isInvalid = true;
 #endif
-		// Transfer parameterization from unified mesh to chart mesh.
-		const uint32_t vertexCount = m_mesh->vertexCount();
-		for (uint32_t v = 0; v < vertexCount; v++)
-			m_mesh->texcoord(v) = m_unifiedMesh->texcoord(m_chartVertexToUnifiedVertexMap[v]);
-		// Can destroy unified mesh now.
-		// But not if the parameterization is invalid, the unified mesh will be needed for PiecewiseParameterization.
-		if (!m_isInvalid)
-			destroyUnifiedMesh();
 		// Need to store texcoords for backup/restore so packing can be run multiple times.
 		backupTexcoords();
 	}
 
-	Vector2 computeParametricBounds() const
-	{
+	Vector2 computeParametricBounds() const {
 		Vector2 minCorner(FLT_MAX, FLT_MAX);
 		Vector2 maxCorner(-FLT_MAX, -FLT_MAX);
-		const uint32_t vertexCount = m_mesh->vertexCount();
+		const uint32_t vertexCount = m_unifiedMesh->vertexCount();
 		for (uint32_t v = 0; v < vertexCount; v++) {
-			minCorner = min(minCorner, m_mesh->texcoord(v));
-			maxCorner = max(maxCorner, m_mesh->texcoord(v));
+			minCorner = min(minCorner, m_unifiedMesh->texcoord(v));
+			maxCorner = max(maxCorner, m_unifiedMesh->texcoord(v));
 		}
 		return (maxCorner - minCorner) * 0.5f;
 	}
 
-	void restoreTexcoords()
-	{
-		memcpy(m_mesh->texcoords(), m_backupTexcoords.data(), m_mesh->vertexCount() * sizeof(Vector2));
+#if XA_CHECK_PIECEWISE_CHART_QUALITY
+	void evaluateQuality(UniformGrid2 &boundaryGrid) {
+		m_quality.computeBoundaryIntersection(m_unifiedMesh, boundaryGrid);
+#if XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION
+		m_quality.computeFlippedFaces(m_unifiedMesh, &m_paramFlippedFaces);
+#else
+		m_quality.computeFlippedFaces(m_unifiedMesh, nullptr);
+#endif
+		if (m_quality.boundaryIntersection || m_quality.flippedTriangleCount > 0 || m_quality.zeroAreaTriangleCount > 0)
+			m_isInvalid = true;
 	}
+#endif
 
-private:
-	void backupTexcoords()
-	{
-		m_backupTexcoords.resize(m_mesh->vertexCount());
-		memcpy(m_backupTexcoords.data(), m_mesh->texcoords(), m_mesh->vertexCount() * sizeof(Vector2));
+	void restoreTexcoords() {
+		memcpy(m_unifiedMesh->texcoords().data, m_backupTexcoords.data(), m_unifiedMesh->vertexCount() * sizeof(Vector2));
 	}
 
-	void destroyUnifiedMesh()
-	{
-		if (m_unifiedMesh) {
-			m_unifiedMesh->~Mesh();
-			XA_FREE(m_unifiedMesh);
-			m_unifiedMesh = nullptr;
-		}
-		if (m_unmodifiedUnifiedMesh) {
-			m_unmodifiedUnifiedMesh->~Mesh();
-			XA_FREE(m_unmodifiedUnifiedMesh);
-			m_unmodifiedUnifiedMesh = nullptr;
-		}
-		// Don't need this when unified meshes are destroyed.
-		m_chartVertexToUnifiedVertexMap.destroy();
+private:
+	void backupTexcoords() {
+		m_backupTexcoords.resize(m_unifiedMesh->vertexCount());
+		memcpy(m_backupTexcoords.data(), m_unifiedMesh->texcoords().data, m_unifiedMesh->vertexCount() * sizeof(Vector2));
 	}
 
 	Basis m_basis;
-	Mesh *m_mesh;
 	Mesh *m_unifiedMesh;
-	Mesh *m_unmodifiedUnifiedMesh; // Unified mesh before fixing t-junctions. Null if no t-junctions were fixed
-	ChartType::Enum m_type;
-	uint32_t m_warningFlags;
-	uint32_t m_initialFaceCount; // Before fixing T-junctions and/or closing holes.
-	uint32_t m_closedHolesCount, m_fixedTJunctionsCount;
+	ChartType m_type;
+	segment::ChartGeneratorType::Enum m_generatorType;
+	uint32_t m_tjunctionCount;
+
+	uint32_t m_originalVertexCount;
+	Array<uint32_t> m_originalIndices;
 
 	// List of faces of the source mesh that belong to this chart.
 	Array<uint32_t> m_faceToSourceFaceMap;
@@ -7604,47 +7040,46 @@ private:
 	bool m_isInvalid;
 };
 
-struct CreateAndParameterizeChartTaskArgs
-{
-	const Basis *basis;
+struct CreateAndParameterizeChartTaskGroupArgs {
+	Progress *progress;
 	ThreadLocal<UniformGrid2> *boundaryGrid;
+	ThreadLocal<ChartCtorBuffers> *chartBuffers;
+	const ChartOptions *options;
+	ThreadLocal<PiecewiseParam> *pp;
+};
+
+struct CreateAndParameterizeChartTaskArgs {
+	const Basis *basis;
 	Chart *chart; // output
 	Array<Chart *> charts; // output (if more than one chart)
-	ThreadLocal<ChartCtorBuffers> *chartBuffers;
+	segment::ChartGeneratorType::Enum chartGeneratorType;
 	const Mesh *mesh;
-	const ParameterizeOptions *options;
-#if XA_RECOMPUTE_CHARTS
-	ThreadLocal<PiecewiseParam> *pp;
-#endif
 	ConstArrayView<uint32_t> faces;
 	uint32_t chartGroupId;
 	uint32_t chartId;
 };
 
-static void runCreateAndParameterizeChartTask(void *userData)
-{
-	auto args = (CreateAndParameterizeChartTaskArgs *)userData;
+static void runCreateAndParameterizeChartTask(void *groupUserData, void *taskUserData) {
+	XA_PROFILE_START(createChartMeshAndParameterizeThread)
+	auto groupArgs = (CreateAndParameterizeChartTaskGroupArgs *)groupUserData;
+	auto args = (CreateAndParameterizeChartTaskArgs *)taskUserData;
 	XA_PROFILE_START(createChartMesh)
-	args->chart = XA_NEW_ARGS(MemTag::Default, Chart, args->chartBuffers->get(), *args->options, *args->basis, args->faces, args->mesh, args->chartGroupId, args->chartId);
+	args->chart = XA_NEW_ARGS(MemTag::Default, Chart, *args->basis, args->chartGeneratorType, args->faces, args->mesh, args->chartGroupId, args->chartId);
 	XA_PROFILE_END(createChartMesh)
-	args->chart->parameterize(*args->options, args->boundaryGrid->get());
+	XA_PROFILE_START(parameterizeCharts)
+	args->chart->parameterize(*groupArgs->options, groupArgs->boundaryGrid->get());
+	XA_PROFILE_END(parameterizeCharts)
 #if XA_RECOMPUTE_CHARTS
-	if (!args->chart->isInvalid())
+	if (!args->chart->isInvalid()) {
+		XA_PROFILE_END(createChartMeshAndParameterizeThread)
 		return;
+	}
 	// Recompute charts with invalid parameterizations.
 	XA_PROFILE_START(parameterizeChartsRecompute)
 	Chart *invalidChart = args->chart;
-	// Fixing t-junctions rewrites unified mesh faces, and we need to map faces back to input mesh. So use the unmodified unified mesh.
-	const Mesh *invalidMesh = invalidChart->unmodifiedUnifiedMesh();
-	uint32_t faceCount = 0;
-	if (invalidMesh) {
-		faceCount = invalidMesh->faceCount();
-	} else {
-		invalidMesh = invalidChart->unifiedMesh();
-		faceCount = invalidChart->initialFaceCount(); // Not invalidMesh->faceCount(). Don't want faces added by hole closing.
-	}
-	PiecewiseParam &pp = args->pp->get();
-	pp.reset(invalidMesh, faceCount);
+	const Mesh *invalidMesh = invalidChart->unifiedMesh();
+	PiecewiseParam &pp = groupArgs->pp->get();
+	pp.reset(invalidMesh);
 #if XA_DEBUG_EXPORT_OBJ_RECOMPUTED_CHARTS
 	char filename[256];
 	XA_SPRINTF(filename, sizeof(filename), "debug_mesh_%03u_chartgroup_%03u_chart_%03u_recomputed.obj", args->mesh->id(), args->chartGroupId, args->chartId);
@@ -7658,7 +7093,10 @@ static void runCreateAndParameterizeChartTask(void *userData)
 		XA_PROFILE_END(parameterizeChartsPiecewise)
 		if (!facesRemaining)
 			break;
-		Chart *chart = XA_NEW_ARGS(MemTag::Default, Chart, args->chartBuffers->get(), invalidChart, invalidMesh, pp.chartFaces(), pp.texcoords(), args->mesh);
+		Chart *chart = XA_NEW_ARGS(MemTag::Default, Chart, groupArgs->chartBuffers->get(), invalidChart, invalidMesh, pp.chartFaces(), pp.texcoords(), args->mesh);
+#if XA_CHECK_PIECEWISE_CHART_QUALITY
+		chart->evaluateQuality(args->boundaryGrid->get());
+#endif
 		args->charts.push_back(chart);
 #if XA_DEBUG_EXPORT_OBJ_RECOMPUTED_CHARTS
 		if (file) {
@@ -7686,50 +7124,63 @@ static void runCreateAndParameterizeChartTask(void *userData)
 #endif
 	XA_PROFILE_END(parameterizeChartsRecompute)
 #endif // XA_RECOMPUTE_CHARTS
+	XA_PROFILE_END(createChartMeshAndParameterizeThread)
+	// Update progress.
+	groupArgs->progress->increment(args->faces.length);
 }
 
 // Set of charts corresponding to mesh faces in the same face group.
-class ChartGroup
-{
+class ChartGroup {
 public:
-	ChartGroup(uint32_t id, const Mesh *sourceMesh, const MeshFaceGroups *sourceMeshFaceGroups, MeshFaceGroups::Handle faceGroup) : m_id(id), m_sourceMesh(sourceMesh), m_sourceMeshFaceGroups(sourceMeshFaceGroups), m_faceGroup(faceGroup), m_faceCount(0), m_paramAddedChartsCount(0), m_paramDeletedChartsCount(0)
-	{
+	ChartGroup(uint32_t id, const Mesh *sourceMesh, const MeshFaceGroups *sourceMeshFaceGroups, MeshFaceGroups::Handle faceGroup) :
+			m_id(id), m_sourceMesh(sourceMesh), m_sourceMeshFaceGroups(sourceMeshFaceGroups), m_faceGroup(faceGroup) {
 	}
 
-	~ChartGroup()
-	{
+	~ChartGroup() {
 		for (uint32_t i = 0; i < m_charts.size(); i++) {
 			m_charts[i]->~Chart();
 			XA_FREE(m_charts[i]);
 		}
 	}
 
-	uint32_t segmentChartCount() const { return m_chartBasis.size(); }
 	uint32_t chartCount() const { return m_charts.size(); }
 	Chart *chartAt(uint32_t i) const { return m_charts[i]; }
-	uint32_t faceCount() const { return m_faceCount; }
-	uint32_t paramAddedChartsCount() const { return m_paramAddedChartsCount; }
-	uint32_t paramDeletedChartsCount() const { return m_paramDeletedChartsCount; }
+	uint32_t faceCount() const { return m_sourceMeshFaceGroups->faceCount(m_faceGroup); }
 
-	void computeChartFaces(const ChartOptions &options, segment::Atlas &atlas)
-	{
+	void computeCharts(TaskScheduler *taskScheduler, const ChartOptions &options, Progress *progress, segment::Atlas &atlas, ThreadLocal<UniformGrid2> *boundaryGrid, ThreadLocal<ChartCtorBuffers> *chartBuffers, ThreadLocal<PiecewiseParam> *piecewiseParam) {
+		// This function may be called multiple times, so destroy existing charts.
+		for (uint32_t i = 0; i < m_charts.size(); i++) {
+			m_charts[i]->~Chart();
+			XA_FREE(m_charts[i]);
+		}
 		// Create mesh from source mesh, using only the faces in this face group.
 		XA_PROFILE_START(createChartGroupMesh)
 		Mesh *mesh = createMesh();
 		XA_PROFILE_END(createChartGroupMesh)
 		// Segment mesh into charts (arrays of faces).
 #if XA_DEBUG_SINGLE_CHART
-		m_chartBasis.resize(1);
-		Fit::computeBasis(&mesh->position(0), mesh->vertexCount(), &m_chartBasis[0]);
-		m_chartFaces.resize(1 + mesh->faceCount());
-		m_chartFaces[0] = mesh->faceCount();
-		for (uint32_t i = 0; i < m_chartFaces.size(); i++)
-			m_chartFaces[i + 1] = i;
+		XA_UNUSED(options);
+		XA_UNUSED(atlas);
+		const uint32_t chartCount = 1;
+		uint32_t offset;
+		Basis chartBasis;
+		Fit::computeBasis(&mesh->position(0), mesh->vertexCount(), &chartBasis);
+		Array<uint32_t> chartFaces;
+		chartFaces.resize(1 + mesh->faceCount());
+		chartFaces[0] = mesh->faceCount();
+		for (uint32_t i = 0; i < chartFaces.size() - 1; i++)
+			chartFaces[i + 1] = m_faceToSourceFaceMap[i];
+		// Destroy mesh.
+		const uint32_t faceCount = mesh->faceCount();
+		mesh->~Mesh();
+		XA_FREE(mesh);
 #else
 		XA_PROFILE_START(buildAtlas)
 		atlas.reset(mesh, options);
 		atlas.compute();
 		XA_PROFILE_END(buildAtlas)
+		// Update progress.
+		progress->increment(faceCount());
 #if XA_DEBUG_EXPORT_OBJ_CHARTS
 		char filename[256];
 		XA_SPRINTF(filename, sizeof(filename), "debug_mesh_%03u_chartgroup_%03u_charts.obj", m_sourceMesh->id(), m_id);
@@ -7745,7 +7196,6 @@ public:
 					mesh->writeObjFace(file, faces[f]);
 			}
 			mesh->writeObjBoundaryEges(file);
-			mesh->writeObjLinkedBoundaries(file);
 			fclose(file);
 		}
 #endif
@@ -7754,65 +7204,57 @@ public:
 		mesh->~Mesh();
 		XA_FREE(mesh);
 		XA_PROFILE_START(copyChartFaces)
-		// Copy basis.
-		const uint32_t chartCount = atlas.chartCount();
-		m_chartBasis.resize(chartCount);
-		for (uint32_t i = 0; i < chartCount; i++)
-			m_chartBasis[i] = atlas.chartBasis(i);
+		if (progress->cancel)
+			return;
 		// Copy faces from segment::Atlas to m_chartFaces array with <chart 0 face count> <face 0> <face n> <chart 1 face count> etc. encoding.
 		// segment::Atlas faces refer to the chart group mesh. Map them to the input mesh instead.
-		m_chartFaces.resize(chartCount + faceCount);
+		const uint32_t chartCount = atlas.chartCount();
+		Array<uint32_t> chartFaces;
+		chartFaces.resize(chartCount + faceCount);
 		uint32_t offset = 0;
 		for (uint32_t i = 0; i < chartCount; i++) {
 			ConstArrayView<uint32_t> faces = atlas.chartFaces(i);
-			m_chartFaces[offset++] = faces.length;
+			chartFaces[offset++] = faces.length;
 			for (uint32_t j = 0; j < faces.length; j++)
-				m_chartFaces[offset++] = m_faceToSourceFaceMap[faces[j]];
+				chartFaces[offset++] = m_faceToSourceFaceMap[faces[j]];
 		}
 		XA_PROFILE_END(copyChartFaces)
 #endif
-	}
-
-#if XA_RECOMPUTE_CHARTS
-	void parameterizeCharts(TaskScheduler *taskScheduler, const ParameterizeOptions &options, ThreadLocal<UniformGrid2> *boundaryGrid, ThreadLocal<ChartCtorBuffers> *chartBuffers, ThreadLocal<PiecewiseParam> *piecewiseParam)
-#else
-	void parameterizeCharts(TaskScheduler* taskScheduler, const ParameterizeOptions &options, ThreadLocal<UniformGrid2>* boundaryGrid, ThreadLocal<ChartCtorBuffers>* chartBuffers)
-#endif
-	{
-		// This function may be called multiple times, so destroy existing charts.
-		for (uint32_t i = 0; i < m_charts.size(); i++) {
-			m_charts[i]->~Chart();
-			XA_FREE(m_charts[i]);
-		}
-		m_paramAddedChartsCount = 0;
-		const uint32_t chartCount = m_chartBasis.size();
+		XA_PROFILE_START(createChartMeshAndParameterizeReal)
+		CreateAndParameterizeChartTaskGroupArgs groupArgs;
+		groupArgs.progress = progress;
+		groupArgs.boundaryGrid = boundaryGrid;
+		groupArgs.chartBuffers = chartBuffers;
+		groupArgs.options = &options;
+		groupArgs.pp = piecewiseParam;
+		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(&groupArgs, chartCount);
 		Array<CreateAndParameterizeChartTaskArgs> taskArgs;
 		taskArgs.resize(chartCount);
 		taskArgs.runCtors(); // Has Array member.
-		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(chartCount);
-		uint32_t offset = 0;
+		offset = 0;
 		for (uint32_t i = 0; i < chartCount; i++) {
 			CreateAndParameterizeChartTaskArgs &args = taskArgs[i];
-			args.basis = &m_chartBasis[i];
-			args.boundaryGrid = boundaryGrid;
+#if XA_DEBUG_SINGLE_CHART
+			args.basis = &chartBasis;
+			args.isPlanar = false;
+#else
+			args.basis = &atlas.chartBasis(i);
+			args.chartGeneratorType = atlas.chartGeneratorType(i);
+#endif
 			args.chart = nullptr;
 			args.chartGroupId = m_id;
 			args.chartId = i;
-			args.chartBuffers = chartBuffers;
-			const uint32_t faceCount = m_chartFaces[offset++];
-			args.faces = ConstArrayView<uint32_t>(&m_chartFaces[offset], faceCount);
-			offset += faceCount;
+			const uint32_t chartFaceCount = chartFaces[offset++];
+			args.faces = ConstArrayView<uint32_t>(&chartFaces[offset], chartFaceCount);
+			offset += chartFaceCount;
 			args.mesh = m_sourceMesh;
-			args.options = &options;
-#if XA_RECOMPUTE_CHARTS
-			args.pp = piecewiseParam;
-#endif
 			Task task;
 			task.userData = &args;
 			task.func = runCreateAndParameterizeChartTask;
 			taskScheduler->run(taskGroup, task);
 		}
 		taskScheduler->wait(&taskGroup);
+		XA_PROFILE_END(createChartMeshAndParameterizeReal)
 #if XA_RECOMPUTE_CHARTS
 		// Count charts. Skip invalid ones and include new ones added by recomputing.
 		uint32_t newChartCount = 0;
@@ -7830,7 +7272,6 @@ public:
 			if (chart->isInvalid()) {
 				chart->~Chart();
 				XA_FREE(chart);
-				m_paramDeletedChartsCount++;
 				continue;
 			}
 			m_charts[current++] = chart;
@@ -7838,10 +7279,8 @@ public:
 		// Now add new charts.
 		for (uint32_t i = 0; i < chartCount; i++) {
 			CreateAndParameterizeChartTaskArgs &args = taskArgs[i];
-			for (uint32_t j = 0; j < args.charts.size(); j++) {
+			for (uint32_t j = 0; j < args.charts.size(); j++)
 				m_charts[current++] = args.charts[j];
-				m_paramAddedChartsCount++;
-			}
 		}
 #else // XA_RECOMPUTE_CHARTS
 		m_charts.resize(chartCount);
@@ -7852,15 +7291,14 @@ public:
 	}
 
 private:
-	Mesh *createMesh()
-	{
+	Mesh *createMesh() {
 		XA_DEBUG_ASSERT(m_faceGroup != MeshFaceGroups::kInvalid);
 		// Create new mesh from the source mesh, using faces that belong to this group.
 		m_faceToSourceFaceMap.reserve(m_sourceMeshFaceGroups->faceCount(m_faceGroup));
 		for (MeshFaceGroups::Iterator it(m_sourceMeshFaceGroups, m_faceGroup); !it.isDone(); it.advance())
 			m_faceToSourceFaceMap.push_back(it.face());
 		// Only initial meshes has ignored faces. The only flag we care about is HasNormals.
-		const uint32_t faceCount = m_faceCount = m_faceToSourceFaceMap.size();
+		const uint32_t faceCount = m_faceToSourceFaceMap.size();
 		XA_DEBUG_ASSERT(faceCount > 0);
 		const uint32_t approxVertexCount = min(faceCount * 3, m_sourceMesh->vertexCount());
 		Mesh *mesh = XA_NEW_ARGS(MemTag::Mesh, Mesh, m_sourceMesh->epsilon(), approxVertexCount, faceCount, m_sourceMesh->flags() & MeshFlags::HasNormals);
@@ -7889,9 +7327,7 @@ private:
 				XA_DEBUG_ASSERT(indices[i] != UINT32_MAX);
 			}
 			// Don't copy flags - ignored faces aren't used by chart groups, they are handled by InvalidMeshGeometry.
-			Mesh::AddFaceResult::Enum result = mesh->addFace(indices);
-			XA_UNUSED(result);
-			XA_DEBUG_ASSERT(result == Mesh::AddFaceResult::OK);
+			mesh->addFace(indices);
 		}
 		XA_PROFILE_START(createChartGroupMeshColocals)
 		mesh->createColocals();
@@ -7909,98 +7345,57 @@ private:
 	}
 
 	const uint32_t m_id;
-	const Mesh * const m_sourceMesh;
-	const MeshFaceGroups * const m_sourceMeshFaceGroups;
+	const Mesh *const m_sourceMesh;
+	const MeshFaceGroups *const m_sourceMeshFaceGroups;
 	const MeshFaceGroups::Handle m_faceGroup;
 	Array<uint32_t> m_faceToSourceFaceMap; // List of faces of the source mesh that belong to this chart group.
-	Array<Basis> m_chartBasis; // Copied from segment::Atlas.
-	Array<uint32_t> m_chartFaces; // Copied from segment::Atlas. Encoding: <chart 0 face count> <face 0> <face n> <chart 1 face count> etc.
 	Array<Chart *> m_charts;
-	uint32_t m_faceCount; // Set by createMesh(). Used for sorting.
-	uint32_t m_paramAddedChartsCount; // Number of new charts added by recomputing charts with invalid parameterizations.
-	uint32_t m_paramDeletedChartsCount; // Number of charts with invalid parameterizations that were deleted, after charts were recomputed.
-};
-
-// References invalid faces and vertices in a mesh.
-struct InvalidMeshGeometry
-{
-	// Invalid faces have the face groups MeshFaceGroups::kInvalid.
-	void extract(const Mesh *mesh, const MeshFaceGroups *meshFaceGroups)
-	{
-		// Copy invalid faces.
-		m_faces.clear();
-		const uint32_t meshFaceCount = mesh->faceCount();
-		for (uint32_t f = 0; f < meshFaceCount; f++) {
-			if (meshFaceGroups->groupAt(f) == MeshFaceGroups::kInvalid)
-				m_faces.push_back(f);
-		}
-		// Create *unique* list of vertices of invalid faces.
-		const uint32_t faceCount = m_faces.size();
-		m_indices.resize(faceCount * 3);
-		const uint32_t approxVertexCount = min(faceCount * 3, mesh->vertexCount());
-		m_vertexToSourceVertexMap.clear();
-		m_vertexToSourceVertexMap.reserve(approxVertexCount);
-		HashMap<uint32_t, PassthroughHash<uint32_t>> sourceVertexToVertexMap(MemTag::Mesh, approxVertexCount);
-		for (uint32_t f = 0; f < faceCount; f++) {
-			const uint32_t face = m_faces[f];
-			for (uint32_t i = 0; i < 3; i++) {
-				const uint32_t vertex = mesh->vertexAt(face * 3 + i);
-				uint32_t newVertex = sourceVertexToVertexMap.get(vertex);
-				if (newVertex == UINT32_MAX) {
-					newVertex = sourceVertexToVertexMap.add(vertex);
-					m_vertexToSourceVertexMap.push_back(vertex);
-				}
-				m_indices[f * 3 + i] = newVertex;
-			}
-		}
-	}
-
-	ConstArrayView<uint32_t> faces() const { return m_faces; }
-	ConstArrayView<uint32_t> indices() const { return m_indices; }
-	ConstArrayView<uint32_t> vertices() const { return m_vertexToSourceVertexMap; }
-
-private:
-	Array<uint32_t> m_faces, m_indices;
-	Array<uint32_t> m_vertexToSourceVertexMap; // Map face vertices to vertices of the source mesh.
 };
 
-struct ChartGroupComputeChartFacesTaskArgs
-{
+struct ChartGroupComputeChartsTaskGroupArgs {
 	ThreadLocal<segment::Atlas> *atlas;
-	ChartGroup *chartGroup;
 	const ChartOptions *options;
 	Progress *progress;
+	TaskScheduler *taskScheduler;
+	ThreadLocal<UniformGrid2> *boundaryGrid;
+	ThreadLocal<ChartCtorBuffers> *chartBuffers;
+	ThreadLocal<PiecewiseParam> *piecewiseParam;
 };
 
-static void runChartGroupComputeChartFacesJob(void *userData)
-{
-	auto args = (ChartGroupComputeChartFacesTaskArgs *)userData;
+static void runChartGroupComputeChartsTask(void *groupUserData, void *taskUserData) {
+	auto args = (ChartGroupComputeChartsTaskGroupArgs *)groupUserData;
+	auto chartGroup = (ChartGroup *)taskUserData;
 	if (args->progress->cancel)
 		return;
 	XA_PROFILE_START(chartGroupComputeChartsThread)
-	args->chartGroup->computeChartFaces(*args->options, args->atlas->get());
+	chartGroup->computeCharts(args->taskScheduler, *args->options, args->progress, args->atlas->get(), args->boundaryGrid, args->chartBuffers, args->piecewiseParam);
 	XA_PROFILE_END(chartGroupComputeChartsThread)
 }
 
-struct MeshComputeChartFacesTaskArgs
-{
-	Array<ChartGroup *> *chartGroups; // output
-	InvalidMeshGeometry *invalidMeshGeometry; // output
+struct MeshComputeChartsTaskGroupArgs {
 	ThreadLocal<segment::Atlas> *atlas;
 	const ChartOptions *options;
 	Progress *progress;
-	const Mesh *sourceMesh;
 	TaskScheduler *taskScheduler;
+	ThreadLocal<UniformGrid2> *boundaryGrid;
+	ThreadLocal<ChartCtorBuffers> *chartBuffers;
+	ThreadLocal<PiecewiseParam> *piecewiseParam;
+};
+
+struct MeshComputeChartsTaskArgs {
+	const Mesh *sourceMesh;
+	Array<ChartGroup *> *chartGroups; // output
+	InvalidMeshGeometry *invalidMeshGeometry; // output
 };
 
 #if XA_DEBUG_EXPORT_OBJ_FACE_GROUPS
 static uint32_t s_faceGroupsCurrentVertex = 0;
 #endif
 
-static void runMeshComputeChartFacesJob(void *userData)
-{
-	auto args = (MeshComputeChartFacesTaskArgs *)userData;
-	if (args->progress->cancel)
+static void runMeshComputeChartsTask(void *groupUserData, void *taskUserData) {
+	auto groupArgs = (MeshComputeChartsTaskGroupArgs *)groupUserData;
+	auto args = (MeshComputeChartsTaskArgs *)taskUserData;
+	if (groupArgs->progress->cancel)
 		return;
 	XA_PROFILE_START(computeChartsThread)
 	// Create face groups.
@@ -8009,7 +7404,7 @@ static void runMeshComputeChartFacesJob(void *userData)
 	meshFaceGroups->compute();
 	const uint32_t chartGroupCount = meshFaceGroups->groupCount();
 	XA_PROFILE_END(createFaceGroups)
-	if (args->progress->cancel)
+	if (groupArgs->progress->cancel)
 		goto cleanup;
 #if XA_DEBUG_EXPORT_OBJ_FACE_GROUPS
 	{
@@ -8053,33 +7448,41 @@ static void runMeshComputeChartFacesJob(void *userData)
 	for (uint32_t i = 0; i < chartGroupCount; i++)
 		(*args->chartGroups)[i] = XA_NEW_ARGS(MemTag::Default, ChartGroup, i, args->sourceMesh, meshFaceGroups, MeshFaceGroups::Handle(i));
 	// Extract invalid geometry via the invalid face group (MeshFaceGroups::kInvalid).
-	XA_PROFILE_START(extractInvalidMeshGeometry)
-	args->invalidMeshGeometry->extract(args->sourceMesh, meshFaceGroups);
-	XA_PROFILE_END(extractInvalidMeshGeometry)
-	// One task for each chart group - compute chart faces.
+	{
+		XA_PROFILE_START(extractInvalidMeshGeometry)
+		args->invalidMeshGeometry->extract(args->sourceMesh, meshFaceGroups);
+		XA_PROFILE_END(extractInvalidMeshGeometry)
+	}
+	// One task for each chart group - compute charts.
 	{
 		XA_PROFILE_START(chartGroupComputeChartsReal)
-		Array<ChartGroupComputeChartFacesTaskArgs> taskArgs;
-		taskArgs.resize(chartGroupCount);
-		for (uint32_t i = 0; i < chartGroupCount; i++) {
-			taskArgs[i].atlas = args->atlas;
-			taskArgs[i].chartGroup = (*args->chartGroups)[i];
-			taskArgs[i].options = args->options;
-			taskArgs[i].progress = args->progress;
-		}
-		TaskGroupHandle taskGroup = args->taskScheduler->createTaskGroup(chartGroupCount);
+		// Sort chart groups by face count.
+		Array<float> chartGroupSortData;
+		chartGroupSortData.resize(chartGroupCount);
+		for (uint32_t i = 0; i < chartGroupCount; i++)
+			chartGroupSortData[i] = (float)(*args->chartGroups)[i]->faceCount();
+		RadixSort chartGroupSort;
+		chartGroupSort.sort(chartGroupSortData);
+		// Larger chart groups are added first to reduce the chance of thread starvation.
+		ChartGroupComputeChartsTaskGroupArgs taskGroupArgs;
+		taskGroupArgs.atlas = groupArgs->atlas;
+		taskGroupArgs.options = groupArgs->options;
+		taskGroupArgs.progress = groupArgs->progress;
+		taskGroupArgs.taskScheduler = groupArgs->taskScheduler;
+		taskGroupArgs.boundaryGrid = groupArgs->boundaryGrid;
+		taskGroupArgs.chartBuffers = groupArgs->chartBuffers;
+		taskGroupArgs.piecewiseParam = groupArgs->piecewiseParam;
+		TaskGroupHandle taskGroup = groupArgs->taskScheduler->createTaskGroup(&taskGroupArgs, chartGroupCount);
 		for (uint32_t i = 0; i < chartGroupCount; i++) {
 			Task task;
-			task.userData = &taskArgs[i];
-			task.func = runChartGroupComputeChartFacesJob;
-			args->taskScheduler->run(taskGroup, task);
+			task.userData = (*args->chartGroups)[chartGroupCount - i - 1];
+			task.func = runChartGroupComputeChartsTask;
+			groupArgs->taskScheduler->run(taskGroup, task);
 		}
-		args->taskScheduler->wait(&taskGroup);
+		groupArgs->taskScheduler->wait(&taskGroup);
 		XA_PROFILE_END(chartGroupComputeChartsReal)
 	}
 	XA_PROFILE_END(computeChartsThread)
-	args->progress->value++;
-	args->progress->update();
 cleanup:
 	if (meshFaceGroups) {
 		meshFaceGroups->~MeshFaceGroups();
@@ -8087,43 +7490,13 @@ cleanup:
 	}
 }
 
-struct ParameterizeChartsTaskArgs
-{
-	TaskScheduler *taskScheduler;
-	ChartGroup *chartGroup;
-	const ParameterizeOptions *options;
-	ThreadLocal<UniformGrid2> *boundaryGrid;
-	ThreadLocal<ChartCtorBuffers> *chartBuffers;
-#if XA_RECOMPUTE_CHARTS
-	ThreadLocal<PiecewiseParam> *piecewiseParam;
-#endif
-	Progress *progress;
-};
-
-static void runParameterizeChartsJob(void *userData)
-{
-	auto args = (ParameterizeChartsTaskArgs *)userData;
-	if (args->progress->cancel)
-		return;
-	XA_PROFILE_START(parameterizeChartsThread)
-#if XA_RECOMPUTE_CHARTS
-	args->chartGroup->parameterizeCharts(args->taskScheduler, *args->options, args->boundaryGrid, args->chartBuffers, args->piecewiseParam);
-#else
-	args->chartGroup->parameterizeCharts(args->taskScheduler, *args->options, args->boundaryGrid, args->chartBuffers);
-#endif
-	XA_PROFILE_END(parameterizeChartsThread)
-	args->progress->value++;
-	args->progress->update();
-}
-
 /// An atlas is a set of chart groups.
-class Atlas
-{
+class Atlas {
 public:
-	Atlas() : m_chartsComputed(false), m_chartsParameterized(false) {}
+	Atlas() :
+			m_chartsComputed(false) {}
 
-	~Atlas()
-	{
+	~Atlas() {
 		for (uint32_t i = 0; i < m_meshChartGroups.size(); i++) {
 			for (uint32_t j = 0; j < m_meshChartGroups[i].size(); j++) {
 				m_meshChartGroups[i][j]->~ChartGroup();
@@ -8137,22 +7510,25 @@ public:
 	uint32_t meshCount() const { return m_meshes.size(); }
 	const InvalidMeshGeometry &invalidMeshGeometry(uint32_t meshIndex) const { return m_invalidMeshGeometry[meshIndex]; }
 	bool chartsComputed() const { return m_chartsComputed; }
-	bool chartsParameterized() const { return m_chartsParameterized; }
 	uint32_t chartGroupCount(uint32_t mesh) const { return m_meshChartGroups[mesh].size(); }
 	const ChartGroup *chartGroupAt(uint32_t mesh, uint32_t group) const { return m_meshChartGroups[mesh][group]; }
 
-	void addMesh(const Mesh *mesh)
-	{
+	void addMesh(const Mesh *mesh) {
 		m_meshes.push_back(mesh);
 	}
 
-	bool computeCharts(TaskScheduler *taskScheduler, const ChartOptions &options, ProgressFunc progressFunc, void *progressUserData)
-	{
+	bool computeCharts(TaskScheduler *taskScheduler, const ChartOptions &options, ProgressFunc progressFunc, void *progressUserData) {
+		XA_PROFILE_START(computeChartsReal)
 #if XA_DEBUG_EXPORT_OBJ_PLANAR_REGIONS
 		segment::s_planarRegionsCurrentRegion = segment::s_planarRegionsCurrentVertex = 0;
 #endif
+		// Progress is per-face x 2 (1 for chart faces, 1 for parameterized chart faces).
+		const uint32_t meshCount = m_meshes.size();
+		uint32_t totalFaceCount = 0;
+		for (uint32_t i = 0; i < meshCount; i++)
+			totalFaceCount += m_meshes[i]->faceCount();
+		Progress progress(ProgressCategory::ComputeCharts, progressFunc, progressUserData, totalFaceCount * 2);
 		m_chartsComputed = false;
-		m_chartsParameterized = false;
 		// Clear chart groups, since this function may be called multiple times.
 		if (!m_meshChartGroups.isEmpty()) {
 			for (uint32_t i = 0; i < m_meshChartGroups.size(); i++) {
@@ -8162,27 +7538,20 @@ public:
 				}
 				m_meshChartGroups[i].clear();
 			}
-			XA_ASSERT(m_meshChartGroups.size() == m_meshes.size()); // The number of meshes shouldn't have changed.
+			XA_ASSERT(m_meshChartGroups.size() == meshCount); // The number of meshes shouldn't have changed.
 		}
-		m_meshChartGroups.resize(m_meshes.size());
+		m_meshChartGroups.resize(meshCount);
 		m_meshChartGroups.runCtors();
-		m_invalidMeshGeometry.resize(m_meshes.size());
+		m_invalidMeshGeometry.resize(meshCount);
 		m_invalidMeshGeometry.runCtors();
 		// One task per mesh.
-		const uint32_t meshCount = m_meshes.size();
-		Progress progress(ProgressCategory::ComputeCharts, progressFunc, progressUserData, meshCount);
-		ThreadLocal<segment::Atlas> atlas;
-		Array<MeshComputeChartFacesTaskArgs> taskArgs;
+		Array<MeshComputeChartsTaskArgs> taskArgs;
 		taskArgs.resize(meshCount);
 		for (uint32_t i = 0; i < meshCount; i++) {
-			MeshComputeChartFacesTaskArgs &args = taskArgs[i];
-			args.atlas = &atlas;
+			MeshComputeChartsTaskArgs &args = taskArgs[i];
+			args.sourceMesh = m_meshes[i];
 			args.chartGroups = &m_meshChartGroups[i];
 			args.invalidMeshGeometry = &m_invalidMeshGeometry[i];
-			args.options = &options;
-			args.progress = &progress;
-			args.sourceMesh = m_meshes[i];
-			args.taskScheduler = taskScheduler;
 		}
 		// Sort meshes by indexCount.
 		Array<float> meshSortData;
@@ -8192,105 +7561,53 @@ public:
 		RadixSort meshSort;
 		meshSort.sort(meshSortData);
 		// Larger meshes are added first to reduce the chance of thread starvation.
-		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(meshCount);
-		for (uint32_t i = 0; i < meshCount; i++) {
-			Task task;
-			task.userData = &taskArgs[meshSort.ranks()[meshCount - i - 1]];
-			task.func = runMeshComputeChartFacesJob;
-			taskScheduler->run(taskGroup, task);
-		}
-		taskScheduler->wait(&taskGroup);
-		if (progress.cancel)
-			return false;
-		m_chartsComputed = true;
-		return true;
-	}
-
-	bool parameterizeCharts(TaskScheduler *taskScheduler, const ParameterizeOptions &options, ProgressFunc progressFunc, void *progressUserData)
-	{
-		m_chartsParameterized = false;
-		uint32_t chartGroupCount = 0;
-		for (uint32_t i = 0; i < m_meshChartGroups.size(); i++)
-			chartGroupCount += m_meshChartGroups[i].size();
-		Progress progress(ProgressCategory::ParameterizeCharts, progressFunc, progressUserData, chartGroupCount);
+		ThreadLocal<segment::Atlas> atlas;
 		ThreadLocal<UniformGrid2> boundaryGrid; // For Quality boundary intersection.
 		ThreadLocal<ChartCtorBuffers> chartBuffers;
-#if XA_RECOMPUTE_CHARTS
 		ThreadLocal<PiecewiseParam> piecewiseParam;
-#endif
-		Array<ParameterizeChartsTaskArgs> taskArgs;
-		taskArgs.resize(chartGroupCount);
-		{
-			uint32_t k = 0;
-			for (uint32_t i = 0; i < m_meshChartGroups.size(); i++) {
-				const uint32_t count = m_meshChartGroups[i].size();
-				for (uint32_t j = 0; j < count; j++) {
-					ParameterizeChartsTaskArgs &args = taskArgs[k];
-					args.taskScheduler = taskScheduler;
-					args.chartGroup = m_meshChartGroups[i][j];
-					args.options = &options;
-					args.boundaryGrid = &boundaryGrid;
-					args.chartBuffers = &chartBuffers;
-#if XA_RECOMPUTE_CHARTS
-					args.piecewiseParam = &piecewiseParam;
-#endif
-					args.progress = &progress;
-					k++;
-				}
-			}
-		}
-		// Sort chart groups by face count.
-		Array<float> chartGroupSortData;
-		chartGroupSortData.resize(chartGroupCount);
-		{
-			uint32_t k = 0;
-			for (uint32_t i = 0; i < m_meshChartGroups.size(); i++) {
-				const uint32_t count = m_meshChartGroups[i].size();
-				for (uint32_t j = 0; j < count; j++) {
-					chartGroupSortData[k++] = (float)m_meshChartGroups[i][j]->faceCount();
-				}
-			}
-		}
-		RadixSort chartGroupSort;
-		chartGroupSort.sort(chartGroupSortData);
-		// Larger chart groups are added first to reduce the chance of thread starvation.
-		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(chartGroupCount);
-		for (uint32_t i = 0; i < chartGroupCount; i++) {
+		MeshComputeChartsTaskGroupArgs taskGroupArgs;
+		taskGroupArgs.atlas = &atlas;
+		taskGroupArgs.options = &options;
+		taskGroupArgs.progress = &progress;
+		taskGroupArgs.taskScheduler = taskScheduler;
+		taskGroupArgs.boundaryGrid = &boundaryGrid;
+		taskGroupArgs.chartBuffers = &chartBuffers;
+		taskGroupArgs.piecewiseParam = &piecewiseParam;
+		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(&taskGroupArgs, meshCount);
+		for (uint32_t i = 0; i < meshCount; i++) {
 			Task task;
-			task.userData = &taskArgs[chartGroupSort.ranks()[chartGroupCount - i - 1]];
-			task.func = runParameterizeChartsJob;
+			task.userData = &taskArgs[meshSort.ranks()[meshCount - i - 1]];
+			task.func = runMeshComputeChartsTask;
 			taskScheduler->run(taskGroup, task);
 		}
 		taskScheduler->wait(&taskGroup);
+		XA_PROFILE_END(computeChartsReal)
 		if (progress.cancel)
 			return false;
-		m_chartsParameterized = true;
+		m_chartsComputed = true;
 		return true;
 	}
 
 private:
 	Array<const Mesh *> m_meshes;
 	Array<InvalidMeshGeometry> m_invalidMeshGeometry; // 1 per mesh.
-	Array<Array<ChartGroup *> > m_meshChartGroups;
+	Array<Array<ChartGroup *>> m_meshChartGroups;
 	bool m_chartsComputed;
-	bool m_chartsParameterized;
 };
 
 } // namespace param
 
 namespace pack {
 
-class AtlasImage
-{
+class AtlasImage {
 public:
-	AtlasImage(uint32_t width, uint32_t height) : m_width(width), m_height(height)
-	{
+	AtlasImage(uint32_t width, uint32_t height) :
+			m_width(width), m_height(height) {
 		m_data.resize(m_width * m_height);
 		memset(m_data.data(), 0, sizeof(uint32_t) * m_data.size());
 	}
 
-	void resize(uint32_t width, uint32_t height)
-	{
+	void resize(uint32_t width, uint32_t height) {
 		Array<uint32_t> data;
 		data.resize(width * height);
 		memset(data.data(), 0, sizeof(uint32_t) * data.size());
@@ -8301,8 +7618,7 @@ public:
 		data.moveTo(m_data);
 	}
 
-	void addChart(uint32_t chartIndex, const BitImage *image, const BitImage *imageBilinear, const BitImage *imagePadding, int atlas_w, int atlas_h, int offset_x, int offset_y)
-	{
+	void addChart(uint32_t chartIndex, const BitImage *image, const BitImage *imageBilinear, const BitImage *imagePadding, int atlas_w, int atlas_h, int offset_x, int offset_y) {
 		const int w = image->width();
 		const int h = image->height();
 		for (int y = 0; y < h; y++) {
@@ -8328,15 +7644,13 @@ public:
 		}
 	}
 
-	void copyTo(uint32_t *dest, uint32_t destWidth, uint32_t destHeight, int padding) const
-	{
+	void copyTo(uint32_t *dest, uint32_t destWidth, uint32_t destHeight, int padding) const {
 		for (uint32_t y = 0; y < destHeight; y++)
 			memcpy(&dest[y * destWidth], &m_data[padding + (y + padding) * m_width], destWidth * sizeof(uint32_t));
 	}
 
 #if XA_DEBUG_EXPORT_ATLAS_IMAGES
-	void writeTga(const char *filename, uint32_t width, uint32_t height) const
-	{
+	void writeTga(const char *filename, uint32_t width, uint32_t height) const {
 		Array<uint8_t> image;
 		image.resize(width * height * 3);
 		for (uint32_t y = 0; y < height; y++) {
@@ -8378,18 +7692,14 @@ private:
 	Array<uint32_t> m_data;
 };
 
-struct Chart
-{
+struct Chart {
 	int32_t atlasIndex;
 	uint32_t material;
-	uint32_t indexCount;
-	const uint32_t *indices;
+	ConstArrayView<uint32_t> indices;
 	float parametricArea;
 	float surfaceArea;
-	Vector2 *vertices;
-	uint32_t vertexCount;
+	ArrayView<Vector2> vertices;
 	Array<uint32_t> uniqueVertices;
-	bool allowRotate;
 	// bounding box
 	Vector2 majorAxis, minorAxis, minCorner, maxCorner;
 	// Mesh only
@@ -8398,29 +7708,26 @@ struct Chart
 	Array<uint32_t> faces;
 
 	Vector2 &uniqueVertexAt(uint32_t v) { return uniqueVertices.isEmpty() ? vertices[v] : vertices[uniqueVertices[v]]; }
-	uint32_t uniqueVertexCount() const { return uniqueVertices.isEmpty() ? vertexCount : uniqueVertices.size(); }
+	uint32_t uniqueVertexCount() const { return uniqueVertices.isEmpty() ? vertices.length : uniqueVertices.size(); }
 };
 
-struct AddChartTaskArgs
-{
-	ThreadLocal<BoundingBox2D> *boundingBox;
+struct AddChartTaskArgs {
 	param::Chart *paramChart;
 	Chart *chart; // out
 };
 
-static void runAddChartTask(void *userData)
-{
+static void runAddChartTask(void *groupUserData, void *taskUserData) {
 	XA_PROFILE_START(packChartsAddChartsThread)
-	auto args = (AddChartTaskArgs *)userData;
+	auto boundingBox = (ThreadLocal<BoundingBox2D> *)groupUserData;
+	auto args = (AddChartTaskArgs *)taskUserData;
 	param::Chart *paramChart = args->paramChart;
 	XA_PROFILE_START(packChartsAddChartsRestoreTexcoords)
 	paramChart->restoreTexcoords();
 	XA_PROFILE_END(packChartsAddChartsRestoreTexcoords)
-	Mesh *mesh = paramChart->mesh();
+	Mesh *mesh = paramChart->unifiedMesh();
 	Chart *chart = args->chart = XA_NEW(MemTag::Default, Chart);
 	chart->atlasIndex = -1;
 	chart->material = 0;
-	chart->indexCount = mesh->indexCount();
 	chart->indices = mesh->indices();
 	chart->parametricArea = mesh->computeParametricArea();
 	if (chart->parametricArea < kAreaEpsilon) {
@@ -8430,17 +7737,15 @@ static void runAddChartTask(void *userData)
 	}
 	chart->surfaceArea = mesh->computeSurfaceArea();
 	chart->vertices = mesh->texcoords();
-	chart->vertexCount = mesh->vertexCount();
-	chart->allowRotate = true;
 	chart->boundaryEdges = &mesh->boundaryEdges();
 	// Compute bounding box of chart.
-	BoundingBox2D &bb = args->boundingBox->get();
+	BoundingBox2D &bb = boundingBox->get();
 	bb.clear();
-	for (uint32_t v = 0; v < chart->vertexCount; v++) {
+	for (uint32_t v = 0; v < chart->vertices.length; v++) {
 		if (mesh->isBoundaryVertex(v))
 			bb.appendBoundaryVertex(mesh->texcoord(v));
 	}
-	bb.compute(mesh->texcoords(), mesh->vertexCount());
+	bb.compute(mesh->texcoords());
 	chart->majorAxis = bb.majorAxis;
 	chart->minorAxis = bb.minorAxis;
 	chart->minCorner = bb.minCorner;
@@ -8448,10 +7753,8 @@ static void runAddChartTask(void *userData)
 	XA_PROFILE_END(packChartsAddChartsThread)
 }
 
-struct Atlas
-{
-	~Atlas()
-	{
+struct Atlas {
+	~Atlas() {
 		for (uint32_t i = 0; i < m_atlasImages.size(); i++) {
 			m_atlasImages[i]->~AtlasImage();
 			XA_FREE(m_atlasImages[i]);
@@ -8475,8 +7778,7 @@ struct Atlas
 	const Array<AtlasImage *> &getImages() const { return m_atlasImages; }
 	float getUtilization(uint32_t atlas) const { return m_utilization[atlas]; }
 
-	void addCharts(TaskScheduler *taskScheduler, param::Atlas *paramAtlas)
-	{
+	void addCharts(TaskScheduler *taskScheduler, param::Atlas *paramAtlas) {
 		// Count charts.
 		uint32_t chartCount = 0;
 		for (uint32_t i = 0; i < paramAtlas->meshCount(); i++) {
@@ -8489,11 +7791,11 @@ struct Atlas
 		if (chartCount == 0)
 			return;
 		// Run one task per chart.
+		ThreadLocal<BoundingBox2D> boundingBox;
+		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(&boundingBox, chartCount);
 		Array<AddChartTaskArgs> taskArgs;
 		taskArgs.resize(chartCount);
-		TaskGroupHandle taskGroup = taskScheduler->createTaskGroup(chartCount);
 		uint32_t chartIndex = 0;
-		ThreadLocal<BoundingBox2D> boundingBox;
 		for (uint32_t i = 0; i < paramAtlas->meshCount(); i++) {
 			const uint32_t chartGroupsCount = paramAtlas->chartGroupCount(i);
 			for (uint32_t j = 0; j < chartGroupsCount; j++) {
@@ -8501,7 +7803,6 @@ struct Atlas
 				const uint32_t count = chartGroup->chartCount();
 				for (uint32_t k = 0; k < count; k++) {
 					AddChartTaskArgs &args = taskArgs[chartIndex];
-					args.boundingBox = &boundingBox;
 					args.paramChart = chartGroup->chartAt(k);
 					Task task;
 					task.userData = &taskArgs[chartIndex];
@@ -8518,8 +7819,10 @@ struct Atlas
 			m_charts[i] = taskArgs[i].chart;
 	}
 
-	void addUvMeshCharts(UvMeshInstance *mesh)
-	{
+	void addUvMeshCharts(UvMeshInstance *mesh) {
+		// Copy texcoords from mesh.
+		mesh->texcoords.resize(mesh->mesh->texcoords.size());
+		memcpy(mesh->texcoords.data(), mesh->mesh->texcoords.data(), mesh->texcoords.size() * sizeof(Vector2));
 		BitArray vertexUsed(mesh->texcoords.size());
 		BoundingBox2D boundingBox;
 		for (uint32_t c = 0; c < mesh->mesh->charts.size(); c++) {
@@ -8527,17 +7830,14 @@ struct Atlas
 			Chart *chart = XA_NEW(MemTag::Default, Chart);
 			chart->atlasIndex = -1;
 			chart->material = uvChart->material;
-			chart->indexCount = uvChart->indices.size();
-			chart->indices = uvChart->indices.data();
-			chart->vertices = mesh->texcoords.data();
-			chart->vertexCount = mesh->texcoords.size();
-			chart->allowRotate = mesh->rotateCharts;
+			chart->indices = uvChart->indices;
+			chart->vertices = mesh->texcoords;
 			chart->boundaryEdges = nullptr;
 			chart->faces.resize(uvChart->faces.size());
 			memcpy(chart->faces.data(), uvChart->faces.data(), sizeof(uint32_t) * uvChart->faces.size());
 			// Find unique vertices.
 			vertexUsed.zeroOutMemory();
-			for (uint32_t i = 0; i < chart->indexCount; i++) {
+			for (uint32_t i = 0; i < chart->indices.length; i++) {
 				const uint32_t vertex = chart->indices[i];
 				if (!vertexUsed.get(vertex)) {
 					vertexUsed.set(vertex);
@@ -8546,14 +7846,13 @@ struct Atlas
 			}
 			// Compute parametric and surface areas.
 			chart->parametricArea = 0.0f;
-			for (uint32_t f = 0; f < chart->indexCount / 3; f++) {
+			for (uint32_t f = 0; f < chart->indices.length / 3; f++) {
 				const Vector2 &v1 = chart->vertices[chart->indices[f * 3 + 0]];
 				const Vector2 &v2 = chart->vertices[chart->indices[f * 3 + 1]];
 				const Vector2 &v3 = chart->vertices[chart->indices[f * 3 + 2]];
 				chart->parametricArea += fabsf(triangleArea(v1, v2, v3));
 			}
 			chart->parametricArea *= 0.5f;
-			chart->surfaceArea = chart->parametricArea; // Identical for UV meshes.
 			if (chart->parametricArea < kAreaEpsilon) {
 				// When the parametric area is too small we use a rough approximation to prevent divisions by very small numbers.
 				Vector2 minCorner(FLT_MAX, FLT_MAX);
@@ -8565,6 +7864,9 @@ struct Atlas
 				const Vector2 bounds = (maxCorner - minCorner) * 0.5f;
 				chart->parametricArea = bounds.x * bounds.y;
 			}
+			XA_DEBUG_ASSERT(isFinite(chart->parametricArea));
+			XA_DEBUG_ASSERT(!isNan(chart->parametricArea));
+			chart->surfaceArea = chart->parametricArea; // Identical for UV meshes.
 			// Compute bounding box of chart.
 			// Using all unique vertices for simplicity, can compute real boundaries if this is too slow.
 			boundingBox.clear();
@@ -8580,8 +7882,7 @@ struct Atlas
 	}
 
 	// Pack charts in the smallest possible rectangle.
-	bool packCharts(const PackOptions &options, ProgressFunc progressFunc, void *progressUserData)
-	{
+	bool packCharts(const PackOptions &options, ProgressFunc progressFunc, void *progressUserData) {
 		if (progressFunc) {
 			if (!progressFunc(ProgressCategory::PackCharts, 0, progressUserData))
 				return false;
@@ -8627,19 +7928,19 @@ struct Atlas
 			// Compute chart scale
 			float scale = 1.0f;
 			if (chart->parametricArea != 0.0f) {
-				scale = (chart->surfaceArea / chart->parametricArea) * m_texelsPerUnit;
+				scale = sqrtf(chart->surfaceArea / chart->parametricArea) * m_texelsPerUnit;
 				XA_ASSERT(isFinite(scale));
 			}
 			// Translate, rotate and scale vertices. Compute extents.
 			Vector2 minCorner(FLT_MAX, FLT_MAX);
-			if (!chart->allowRotate) {
+			if (!options.rotateChartsToAxis) {
 				for (uint32_t i = 0; i < chart->uniqueVertexCount(); i++)
 					minCorner = min(minCorner, chart->uniqueVertexAt(i));
 			}
 			Vector2 extents(0.0f);
 			for (uint32_t i = 0; i < chart->uniqueVertexCount(); i++) {
 				Vector2 &texcoord = chart->uniqueVertexAt(i);
-				if (chart->allowRotate) {
+				if (options.rotateChartsToAxis) {
 					const float x = dot(texcoord, chart->majorAxis);
 					const float y = dot(texcoord, chart->minorAxis);
 					texcoord.x = x;
@@ -8750,27 +8051,27 @@ struct Atlas
 			// Resize and clear (discard = true) chart images.
 			// Leave room for padding at extents.
 			chartImage.resize(ftoi_ceil(chartExtents[c].x) + options.padding, ftoi_ceil(chartExtents[c].y) + options.padding, true);
-			if (chart->allowRotate)
+			if (options.rotateCharts)
 				chartImageRotated.resize(chartImage.height(), chartImage.width(), true);
 			if (options.bilinear) {
 				chartImageBilinear.resize(chartImage.width(), chartImage.height(), true);
-				if (chart->allowRotate)
+				if (options.rotateCharts)
 					chartImageBilinearRotated.resize(chartImage.height(), chartImage.width(), true);
 			}
 			// Rasterize chart faces.
-			const uint32_t faceCount = chart->indexCount / 3;
+			const uint32_t faceCount = chart->indices.length / 3;
 			for (uint32_t f = 0; f < faceCount; f++) {
 				Vector2 vertices[3];
 				for (uint32_t v = 0; v < 3; v++)
 					vertices[v] = chart->vertices[chart->indices[f * 3 + v]];
 				DrawTriangleCallbackArgs args;
 				args.chartBitImage = &chartImage;
-				args.chartBitImageRotated = chart->allowRotate ? &chartImageRotated : nullptr;
+				args.chartBitImageRotated = options.rotateCharts ? &chartImageRotated : nullptr;
 				raster::drawTriangle(Vector2((float)chartImage.width(), (float)chartImage.height()), vertices, drawTriangleCallback, &args);
 			}
 			// Expand chart by pixels sampled by bilinear interpolation.
 			if (options.bilinear)
-				bilinearExpand(chart, &chartImage, &chartImageBilinear, chart->allowRotate ? &chartImageBilinearRotated : nullptr, boundaryEdgeGrid);
+				bilinearExpand(chart, &chartImage, &chartImageBilinear, options.rotateCharts ? &chartImageBilinearRotated : nullptr, boundaryEdgeGrid);
 			// Expand chart by padding pixels (dilation).
 			if (options.padding > 0) {
 				// Copy into the same BitImage instances for every chart to avoid reallocating BitImage buffers (largest chart is packed first).
@@ -8780,7 +8081,7 @@ struct Atlas
 				else
 					chartImage.copyTo(chartImagePadding);
 				chartImagePadding.dilate(options.padding);
-				if (chart->allowRotate) {
+				if (options.rotateCharts) {
 					if (options.bilinear)
 						chartImageBilinearRotated.copyTo(chartImagePaddingRotated);
 					else
@@ -8815,23 +8116,25 @@ struct Atlas
 			int best_x = 0, best_y = 0;
 			int best_cw = 0, best_ch = 0;
 			int best_r = 0;
-			for (;;)
-			{
+			for (;;) {
+#if XA_DEBUG
 				bool firstChartInBitImage = false;
-				XA_UNUSED(firstChartInBitImage);
+#endif
 				if (currentAtlas + 1 > m_bitImages.size()) {
 					// Chart doesn't fit in the current bitImage, create a new one.
 					BitImage *bi = XA_NEW_ARGS(MemTag::Default, BitImage, resolution, resolution);
 					m_bitImages.push_back(bi);
 					atlasSizes.push_back(Vector2i(0, 0));
+#if XA_DEBUG
 					firstChartInBitImage = true;
+#endif
 					if (createImage)
 						m_atlasImages.push_back(XA_NEW_ARGS(MemTag::Default, AtlasImage, resolution, resolution));
 					// Start positions are per-atlas, so create a new one of those too.
 					chartStartPositions.push_back(Vector2i(0, 0));
 				}
 				XA_PROFILE_START(packChartsFindLocation)
-				const bool foundLocation = findChartLocation(chartStartPositions[currentAtlas], options.bruteForce, m_bitImages[currentAtlas], chartImageToPack, chartImageToPackRotated, atlasSizes[currentAtlas].x, atlasSizes[currentAtlas].y, &best_x, &best_y, &best_cw, &best_ch, &best_r, options.blockAlign, maxResolution, chart->allowRotate);
+				const bool foundLocation = findChartLocation(options, chartStartPositions[currentAtlas], m_bitImages[currentAtlas], chartImageToPack, chartImageToPackRotated, atlasSizes[currentAtlas].x, atlasSizes[currentAtlas].y, &best_x, &best_y, &best_cw, &best_ch, &best_r, maxResolution);
 				XA_PROFILE_END(packChartsFindLocation)
 				XA_DEBUG_ASSERT(!(firstChartInBitImage && !foundLocation)); // Chart doesn't fit in an empty, newly allocated bitImage. Shouldn't happen, since charts are resized if they are too big to fit in the atlas.
 				if (maxResolution == 0) {
@@ -8849,8 +8152,7 @@ struct Atlas
 				if (best_x + best_cw > atlasSizes[currentAtlas].x || best_y + best_ch > atlasSizes[currentAtlas].y) {
 					for (uint32_t j = 0; j < chartStartPositions.size(); j++)
 						chartStartPositions[j] = Vector2i(0, 0);
-				}
-				else {
+				} else {
 					chartStartPositions[currentAtlas] = Vector2i(best_x, best_y);
 				}
 			}
@@ -8897,7 +8199,7 @@ struct Atlas
 				Vector2 &texcoord = chart->uniqueVertexAt(v);
 				Vector2 t = texcoord;
 				if (best_r) {
-					XA_DEBUG_ASSERT(chart->allowRotate);
+					XA_DEBUG_ASSERT(options.rotateCharts);
 					swap(t.x, t.y);
 				}
 				texcoord.x = best_x + t.x;
@@ -8938,8 +8240,7 @@ struct Atlas
 			}
 			if (m_utilization.size() > 1) {
 				XA_PRINT("   %u: %f%% utilization\n", i, m_utilization[i] * 100.0f);
-			}
-			else {
+			} else {
 				XA_PRINT("   %f%% utilization\n", m_utilization[i] * 100.0f);
 			}
 		}
@@ -8958,28 +8259,22 @@ struct Atlas
 	}
 
 private:
-	// IC: Brute force is slow, and random may take too much time to converge. We start inserting large charts in a small atlas. Using brute force is lame, because most of the space
-	// is occupied at this point. At the end we have many small charts and a large atlas with sparse holes. Finding those holes randomly is slow. A better approach would be to
-	// start stacking large charts as if they were tetris pieces. Once charts get small try to place them randomly. It may be interesting to try a intermediate strategy, first try
-	// along one axis and then try exhaustively along that axis.
-	bool findChartLocation(const Vector2i &startPosition, bool bruteForce, const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, bool blockAligned, uint32_t maxResolution, bool allowRotate)
-	{
+	bool findChartLocation(const PackOptions &options, const Vector2i &startPosition, const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, uint32_t maxResolution) {
 		const int attempts = 4096;
-		if (bruteForce || attempts >= w * h)
-			return findChartLocation_bruteForce(startPosition, atlasBitImage, chartBitImage, chartBitImageRotated, w, h, best_x, best_y, best_w, best_h, best_r, blockAligned, maxResolution, allowRotate);
-		return findChartLocation_random(atlasBitImage, chartBitImage, chartBitImageRotated, w, h, best_x, best_y, best_w, best_h, best_r, attempts, blockAligned, maxResolution, allowRotate);
+		if (options.bruteForce || attempts >= w * h)
+			return findChartLocation_bruteForce(options, startPosition, atlasBitImage, chartBitImage, chartBitImageRotated, w, h, best_x, best_y, best_w, best_h, best_r, maxResolution);
+		return findChartLocation_random(options, atlasBitImage, chartBitImage, chartBitImageRotated, w, h, best_x, best_y, best_w, best_h, best_r, attempts, maxResolution);
 	}
 
-	bool findChartLocation_bruteForce(const Vector2i &startPosition, const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, bool blockAligned, uint32_t maxResolution, bool allowRotate)
-	{
-		const int stepSize = blockAligned ? 4 : 1;
+	bool findChartLocation_bruteForce(const PackOptions &options, const Vector2i &startPosition, const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, uint32_t maxResolution) {
+		const int stepSize = options.blockAlign ? 4 : 1;
 		int best_metric = INT_MAX;
 		// Try two different orientations.
 		for (int r = 0; r < 2; r++) {
 			int cw = chartBitImage->width();
 			int ch = chartBitImage->height();
 			if (r == 1) {
-				if (allowRotate)
+				if (options.rotateCharts)
 					swap(cw, ch);
 				else
 					break;
@@ -9016,15 +8311,14 @@ private:
 		return best_metric != INT_MAX;
 	}
 
-	bool findChartLocation_random(const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, int minTrialCount, bool blockAligned, uint32_t maxResolution, bool allowRotate)
-	{
+	bool findChartLocation_random(const PackOptions &options, const BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int w, int h, int *best_x, int *best_y, int *best_w, int *best_h, int *best_r, int attempts, uint32_t maxResolution) {
 		bool result = false;
 		const int BLOCK_SIZE = 4;
 		int best_metric = INT_MAX;
-		for (int i = 0; i < minTrialCount; i++) {
+		for (int i = 0; i < attempts; i++) {
 			int cw = chartBitImage->width();
 			int ch = chartBitImage->height();
-			int r = allowRotate ? m_rand.getRange(1) : 0;
+			int r = options.rotateCharts ? m_rand.getRange(1) : 0;
 			if (r == 1)
 				swap(cw, ch);
 			// + 1 to extend atlas in case atlas full. We may want to use a higher number to increase probability of extending atlas.
@@ -9037,7 +8331,7 @@ private:
 			}
 			int x = m_rand.getRange(xRange);
 			int y = m_rand.getRange(yRange);
-			if (blockAligned) {
+			if (options.blockAlign) {
 				x = align(x, BLOCK_SIZE);
 				y = align(y, BLOCK_SIZE);
 				if (maxResolution > 0 && (x > (int)maxResolution - cw || y > (int)maxResolution - ch))
@@ -9062,7 +8356,7 @@ private:
 				*best_y = y;
 				*best_w = cw;
 				*best_h = ch;
-				*best_r = allowRotate ? r : 0;
+				*best_r = options.rotateCharts ? r : 0;
 				if (area == w * h) {
 					// Chart is completely inside, do not look at any other location.
 					break;
@@ -9072,8 +8366,7 @@ private:
 		return result;
 	}
 
-	void addChart(BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int atlas_w, int atlas_h, int offset_x, int offset_y, int r)
-	{
+	void addChart(BitImage *atlasBitImage, const BitImage *chartBitImage, const BitImage *chartBitImageRotated, int atlas_w, int atlas_h, int offset_x, int offset_y, int r) {
 		XA_DEBUG_ASSERT(r == 0 || r == 1);
 		const BitImage *image = r == 0 ? chartBitImage : chartBitImageRotated;
 		const int w = image->width();
@@ -9096,15 +8389,14 @@ private:
 		}
 	}
 
-	void bilinearExpand(const Chart *chart, BitImage *source, BitImage *dest, BitImage *destRotated, UniformGrid2 &boundaryEdgeGrid) const
-	{
+	void bilinearExpand(const Chart *chart, BitImage *source, BitImage *dest, BitImage *destRotated, UniformGrid2 &boundaryEdgeGrid) const {
 		boundaryEdgeGrid.reset(chart->vertices, chart->indices);
 		if (chart->boundaryEdges) {
 			const uint32_t edgeCount = chart->boundaryEdges->size();
 			for (uint32_t i = 0; i < edgeCount; i++)
 				boundaryEdgeGrid.append((*chart->boundaryEdges)[i]);
 		} else {
-			for (uint32_t i = 0; i < chart->indexCount; i++)
+			for (uint32_t i = 0; i < chart->indices.length; i++)
 				boundaryEdgeGrid.append(i);
 		}
 		const int xOffsets[] = { -1, 0, 1, -1, 1, -1, 0, 1 };
@@ -9152,13 +8444,11 @@ private:
 		}
 	}
 
-	struct DrawTriangleCallbackArgs
-	{
+	struct DrawTriangleCallbackArgs {
 		BitImage *chartBitImage, *chartBitImageRotated;
 	};
 
-	static bool drawTriangleCallback(void *param, int x, int y)
-	{
+	static bool drawTriangleCallback(void *param, int x, int y) {
 		auto args = (DrawTriangleCallbackArgs *)param;
 		args->chartBitImage->set(x, y);
 		if (args->chartBitImageRotated)
@@ -9180,8 +8470,14 @@ private:
 } // namespace pack
 } // namespace internal
 
-struct Context
-{
+// Used to map triangulated polygons back to polygons.
+struct MeshPolygonMapping {
+	internal::Array<uint8_t> faceVertexCount; // Copied from MeshDecl::faceVertexCount.
+	internal::Array<uint32_t> triangleToPolygonMap; // Triangle index (mesh face index) to polygon index.
+	internal::Array<uint32_t> triangleToPolygonIndicesMap; // Triangle indices to polygon indices.
+};
+
+struct Context {
 	Atlas atlas;
 	internal::Progress *addMeshProgress = nullptr;
 	internal::TaskGroupHandle addMeshTaskGroup;
@@ -9190,20 +8486,20 @@ struct Context
 	void *progressUserData = nullptr;
 	internal::TaskScheduler *taskScheduler;
 	internal::Array<internal::Mesh *> meshes;
+	internal::Array<MeshPolygonMapping *> meshPolygonMappings;
 	internal::Array<internal::UvMesh *> uvMeshes;
 	internal::Array<internal::UvMeshInstance *> uvMeshInstances;
+	bool uvMeshChartsComputed = false;
 };
 
-Atlas *Create()
-{
+Atlas *Create() {
 	Context *ctx = XA_NEW(internal::MemTag::Default, Context);
 	memset(&ctx->atlas, 0, sizeof(Atlas));
 	ctx->taskScheduler = XA_NEW(internal::MemTag::Default, internal::TaskScheduler);
 	return &ctx->atlas;
 }
 
-static void DestroyOutputMeshes(Context *ctx)
-{
+static void DestroyOutputMeshes(Context *ctx) {
 	if (!ctx->atlas.meshes)
 		return;
 	for (int i = 0; i < (int)ctx->atlas.meshCount; i++) {
@@ -9224,8 +8520,7 @@ static void DestroyOutputMeshes(Context *ctx)
 	ctx->atlas.meshes = nullptr;
 }
 
-void Destroy(Atlas *atlas)
-{
+void Destroy(Atlas *atlas) {
 	XA_DEBUG_ASSERT(atlas);
 	Context *ctx = (Context *)atlas;
 	if (atlas->utilization)
@@ -9244,6 +8539,13 @@ void Destroy(Atlas *atlas)
 		mesh->~Mesh();
 		XA_FREE(mesh);
 	}
+	for (uint32_t i = 0; i < ctx->meshPolygonMappings.size(); i++) {
+		MeshPolygonMapping *mapping = ctx->meshPolygonMappings[i];
+		if (mapping) {
+			mapping->~MeshPolygonMapping();
+			XA_FREE(mapping);
+		}
+	}
 	for (uint32_t i = 0; i < ctx->uvMeshes.size(); i++) {
 		internal::UvMesh *mesh = ctx->uvMeshes[i];
 		for (uint32_t j = 0; j < mesh->charts.size(); j++) {
@@ -9265,66 +8567,52 @@ void Destroy(Atlas *atlas)
 #endif
 }
 
-struct AddMeshTaskArgs
-{
-	Context *ctx;
-	internal::Mesh *mesh;
-};
-
-static void runAddMeshTask(void *userData)
-{
+static void runAddMeshTask(void *groupUserData, void *taskUserData) {
 	XA_PROFILE_START(addMeshThread)
-	auto args = (AddMeshTaskArgs *)userData; // Responsible for freeing this.
-	internal::Mesh *mesh = args->mesh;
-	internal::Progress *progress = args->ctx->addMeshProgress;
-	if (progress->cancel)
-		goto cleanup;
-	{
-		XA_PROFILE_START(addMeshCreateColocals)
-		mesh->createColocals();
-		XA_PROFILE_END(addMeshCreateColocals)
+	auto ctx = (Context *)groupUserData;
+	auto mesh = (internal::Mesh *)taskUserData;
+	internal::Progress *progress = ctx->addMeshProgress;
+	if (progress->cancel) {
+		XA_PROFILE_END(addMeshThread)
+		return;
 	}
-	if (progress->cancel)
-		goto cleanup;
-	progress->value++;
-	progress->update();
-cleanup:
-	args->~AddMeshTaskArgs();
-	XA_FREE(args);
+	XA_PROFILE_START(addMeshCreateColocals)
+	mesh->createColocals();
+	XA_PROFILE_END(addMeshCreateColocals)
+	if (progress->cancel) {
+		XA_PROFILE_END(addMeshThread)
+		return;
+	}
+	progress->increment(1);
 	XA_PROFILE_END(addMeshThread)
 }
 
-static internal::Vector3 DecodePosition(const MeshDecl &meshDecl, uint32_t index)
-{
+static internal::Vector3 DecodePosition(const MeshDecl &meshDecl, uint32_t index) {
 	XA_DEBUG_ASSERT(meshDecl.vertexPositionData);
 	XA_DEBUG_ASSERT(meshDecl.vertexPositionStride > 0);
 	return *((const internal::Vector3 *)&((const uint8_t *)meshDecl.vertexPositionData)[meshDecl.vertexPositionStride * index]);
 }
 
-static internal::Vector3 DecodeNormal(const MeshDecl &meshDecl, uint32_t index)
-{
+static internal::Vector3 DecodeNormal(const MeshDecl &meshDecl, uint32_t index) {
 	XA_DEBUG_ASSERT(meshDecl.vertexNormalData);
 	XA_DEBUG_ASSERT(meshDecl.vertexNormalStride > 0);
 	return *((const internal::Vector3 *)&((const uint8_t *)meshDecl.vertexNormalData)[meshDecl.vertexNormalStride * index]);
 }
 
-static internal::Vector2 DecodeUv(const MeshDecl &meshDecl, uint32_t index)
-{
+static internal::Vector2 DecodeUv(const MeshDecl &meshDecl, uint32_t index) {
 	XA_DEBUG_ASSERT(meshDecl.vertexUvData);
 	XA_DEBUG_ASSERT(meshDecl.vertexUvStride > 0);
 	return *((const internal::Vector2 *)&((const uint8_t *)meshDecl.vertexUvData)[meshDecl.vertexUvStride * index]);
 }
 
-static uint32_t DecodeIndex(IndexFormat::Enum format, const void *indexData, int32_t offset, uint32_t i)
-{
+static uint32_t DecodeIndex(IndexFormat format, const void *indexData, int32_t offset, uint32_t i) {
 	XA_DEBUG_ASSERT(indexData);
 	if (format == IndexFormat::UInt16)
 		return uint16_t((int32_t)((const uint16_t *)indexData)[i] + offset);
 	return uint32_t((int32_t)((const uint32_t *)indexData)[i] + offset);
 }
 
-AddMeshError::Enum AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountHint)
-{
+AddMeshError AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountHint) {
 	XA_DEBUG_ASSERT(atlas);
 	if (!atlas) {
 		XA_PRINT_WARNING("AddMesh: atlas is null.\n");
@@ -9337,33 +8625,36 @@ AddMeshError::Enum AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t mesh
 	}
 #if XA_PROFILE
 	if (ctx->meshes.isEmpty())
-		internal::s_profile.addMeshReal = clock();
+		internal::s_profile.addMeshRealStart = std::chrono::high_resolution_clock::now();
 #endif
 	// Don't know how many times AddMesh will be called, so progress needs to adjusted each time.
 	if (!ctx->addMeshProgress) {
 		ctx->addMeshProgress = XA_NEW_ARGS(internal::MemTag::Default, internal::Progress, ProgressCategory::AddMesh, ctx->progressFunc, ctx->progressUserData, 1);
-	}
-	else {
+	} else {
 		ctx->addMeshProgress->setMaxValue(internal::max(ctx->meshes.size() + 1, meshCountHint));
 	}
 	XA_PROFILE_START(addMeshCopyData)
 	const bool hasIndices = meshDecl.indexCount > 0;
 	const uint32_t indexCount = hasIndices ? meshDecl.indexCount : meshDecl.vertexCount;
-	XA_PRINT("Adding mesh %d: %u vertices, %u triangles\n", ctx->meshes.size(), meshDecl.vertexCount, indexCount / 3);
-	// Expecting triangle faces.
-	if ((indexCount % 3) != 0)
-		return AddMeshError::InvalidIndexCount;
-	if (hasIndices) {
-		// Check if any index is out of range.
-		for (uint32_t i = 0; i < indexCount; i++) {
-			const uint32_t index = DecodeIndex(meshDecl.indexFormat, meshDecl.indexData, meshDecl.indexOffset, i);
-			if (index >= meshDecl.vertexCount)
-				return AddMeshError::IndexOutOfRange;
+	uint32_t faceCount = indexCount / 3;
+	if (meshDecl.faceVertexCount) {
+		faceCount = meshDecl.faceCount;
+		XA_PRINT("Adding mesh %d: %u vertices, %u polygons\n", ctx->meshes.size(), meshDecl.vertexCount, faceCount);
+		for (uint32_t f = 0; f < faceCount; f++) {
+			if (meshDecl.faceVertexCount[f] < 3)
+				return AddMeshError::InvalidFaceVertexCount;
 		}
+	} else {
+		XA_PRINT("Adding mesh %d: %u vertices, %u triangles\n", ctx->meshes.size(), meshDecl.vertexCount, faceCount);
+		// Expecting triangle faces unless otherwise specified.
+		if ((indexCount % 3) != 0)
+			return AddMeshError::InvalidIndexCount;
 	}
 	uint32_t meshFlags = internal::MeshFlags::HasIgnoredFaces;
 	if (meshDecl.vertexNormalData)
 		meshFlags |= internal::MeshFlags::HasNormals;
+	if (meshDecl.faceMaterialData)
+		meshFlags |= internal::MeshFlags::HasMaterials;
 	internal::Mesh *mesh = XA_NEW_ARGS(internal::MemTag::Mesh, internal::Mesh, meshDecl.epsilon, meshDecl.vertexCount, indexCount / 3, meshFlags, ctx->meshes.size());
 	for (uint32_t i = 0; i < meshDecl.vertexCount; i++) {
 		internal::Vector3 normal(0.0f);
@@ -9374,17 +8665,42 @@ AddMeshError::Enum AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t mesh
 			texcoord = DecodeUv(meshDecl, i);
 		mesh->addVertex(DecodePosition(meshDecl, i), normal, texcoord);
 	}
+	MeshPolygonMapping *meshPolygonMapping = nullptr;
+	if (meshDecl.faceVertexCount) {
+		meshPolygonMapping = XA_NEW(internal::MemTag::Default, MeshPolygonMapping);
+		// Copy MeshDecl::faceVertexCount so it can be used later when building output meshes.
+		meshPolygonMapping->faceVertexCount.copyFrom(meshDecl.faceVertexCount, meshDecl.faceCount);
+		// There should be at least as many triangles as polygons.
+		meshPolygonMapping->triangleToPolygonMap.reserve(meshDecl.faceCount);
+		meshPolygonMapping->triangleToPolygonIndicesMap.reserve(meshDecl.indexCount);
+	}
 	const uint32_t kMaxWarnings = 50;
 	uint32_t warningCount = 0;
-	for (uint32_t i = 0; i < indexCount / 3; i++) {
-		uint32_t tri[3];
-		for (int j = 0; j < 3; j++)
-			tri[j] = hasIndices ? DecodeIndex(meshDecl.indexFormat, meshDecl.indexData, meshDecl.indexOffset, i * 3 + j) : i * 3 + j;
+	internal::Array<uint32_t> triIndices;
+	uint32_t firstFaceIndex = 0;
+	internal::Triangulator triangulator;
+	for (uint32_t face = 0; face < faceCount; face++) {
+		// Decode face indices.
+		const uint32_t faceVertexCount = meshDecl.faceVertexCount ? (uint32_t)meshDecl.faceVertexCount[face] : 3;
+		uint32_t polygon[UINT8_MAX];
+		for (uint32_t i = 0; i < faceVertexCount; i++) {
+			if (hasIndices) {
+				polygon[i] = DecodeIndex(meshDecl.indexFormat, meshDecl.indexData, meshDecl.indexOffset, face * faceVertexCount + i);
+				// Check if any index is out of range.
+				if (polygon[i] >= meshDecl.vertexCount) {
+					mesh->~Mesh();
+					XA_FREE(mesh);
+					return AddMeshError::IndexOutOfRange;
+				}
+			} else {
+				polygon[i] = face * faceVertexCount + i;
+			}
+		}
+		// Ignore faces with degenerate or zero length edges.
 		bool ignore = false;
-		// Check for degenerate or zero length edges.
-		for (int j = 0; j < 3; j++) {
-			const uint32_t index1 = tri[j];
-			const uint32_t index2 = tri[(j + 1) % 3];
+		for (uint32_t i = 0; i < faceVertexCount; i++) {
+			const uint32_t index1 = polygon[i];
+			const uint32_t index2 = polygon[(i + 1) % 3];
 			if (index1 == index2) {
 				ignore = true;
 				if (++warningCount <= kMaxWarnings)
@@ -9402,119 +8718,136 @@ AddMeshError::Enum AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t mesh
 		}
 		// Ignore faces with any nan vertex attributes.
 		if (!ignore) {
-			for (int j = 0; j < 3; j++) {
-				const internal::Vector3 &pos = mesh->position(tri[j]);
+			for (uint32_t i = 0; i < faceVertexCount; i++) {
+				const internal::Vector3 &pos = mesh->position(polygon[i]);
 				if (internal::isNan(pos.x) || internal::isNan(pos.y) || internal::isNan(pos.z)) {
 					if (++warningCount <= kMaxWarnings)
-						XA_PRINT("   NAN position in face: %d\n", i);
+						XA_PRINT("   NAN position in face: %d\n", face);
 					ignore = true;
 					break;
 				}
 				if (meshDecl.vertexNormalData) {
-					const internal::Vector3 &normal = mesh->normal(tri[j]);
+					const internal::Vector3 &normal = mesh->normal(polygon[i]);
 					if (internal::isNan(normal.x) || internal::isNan(normal.y) || internal::isNan(normal.z)) {
 						if (++warningCount <= kMaxWarnings)
-							XA_PRINT("   NAN normal in face: %d\n", i);
+							XA_PRINT("   NAN normal in face: %d\n", face);
 						ignore = true;
 						break;
 					}
 				}
 				if (meshDecl.vertexUvData) {
-					const internal::Vector2 &uv = mesh->texcoord(tri[j]);
+					const internal::Vector2 &uv = mesh->texcoord(polygon[i]);
 					if (internal::isNan(uv.x) || internal::isNan(uv.y)) {
 						if (++warningCount <= kMaxWarnings)
-							XA_PRINT("   NAN texture coordinate in face: %d\n", i);
+							XA_PRINT("   NAN texture coordinate in face: %d\n", face);
 						ignore = true;
 						break;
 					}
 				}
 			}
 		}
-		const internal::Vector3 &a = mesh->position(tri[0]);
-		const internal::Vector3 &b = mesh->position(tri[1]);
-		const internal::Vector3 &c = mesh->position(tri[2]);
-		// Check for zero area faces.
-		float area = 0.0f;
-		if (!ignore) {
-			area = internal::length(internal::cross(b - a, c - a)) * 0.5f;
-			if (area <= internal::kAreaEpsilon) {
-				ignore = true;
-				if (++warningCount <= kMaxWarnings)
-					XA_PRINT("   Zero area face: %d, indices (%d %d %d), area is %f\n", i, tri[0], tri[1], tri[2], area);
-			}
+		// Triangulate if necessary.
+		triIndices.clear();
+		if (faceVertexCount == 3) {
+			triIndices.push_back(polygon[0]);
+			triIndices.push_back(polygon[1]);
+			triIndices.push_back(polygon[2]);
+		} else {
+			triangulator.triangulatePolygon(mesh->positions(), internal::ConstArrayView<uint32_t>(polygon, faceVertexCount), triIndices);
 		}
+		// Check for zero area faces.
 		if (!ignore) {
-			if (internal::equal(a, b, meshDecl.epsilon) || internal::equal(a, c, meshDecl.epsilon) || internal::equal(b, c, meshDecl.epsilon)) {
-				ignore = true;
-				if (++warningCount <= kMaxWarnings)
-					XA_PRINT("   Degenerate face: %d, area is %f\n", i, area);
+			for (uint32_t i = 0; i < triIndices.size(); i += 3) {
+				const internal::Vector3 &a = mesh->position(triIndices[i + 0]);
+				const internal::Vector3 &b = mesh->position(triIndices[i + 1]);
+				const internal::Vector3 &c = mesh->position(triIndices[i + 2]);
+				const float area = internal::length(internal::cross(b - a, c - a)) * 0.5f;
+				if (area <= internal::kAreaEpsilon) {
+					ignore = true;
+					if (++warningCount <= kMaxWarnings)
+						XA_PRINT("   Zero area face: %d, area is %f\n", face, area);
+					break;
+				}
 			}
 		}
-		if (meshDecl.faceIgnoreData && meshDecl.faceIgnoreData[i])
+		// User face ignore.
+		if (meshDecl.faceIgnoreData && meshDecl.faceIgnoreData[face])
 			ignore = true;
-		mesh->addFace(tri[0], tri[1], tri[2], ignore);
+		// User material.
+		uint32_t material = UINT32_MAX;
+		if (meshDecl.faceMaterialData)
+			material = meshDecl.faceMaterialData[face];
+		// Add the face(s).
+		for (uint32_t i = 0; i < triIndices.size(); i += 3) {
+			mesh->addFace(&triIndices[i], ignore, material);
+			if (meshPolygonMapping)
+				meshPolygonMapping->triangleToPolygonMap.push_back(face);
+		}
+		if (meshPolygonMapping) {
+			for (uint32_t i = 0; i < triIndices.size(); i++)
+				meshPolygonMapping->triangleToPolygonIndicesMap.push_back(triIndices[i]);
+		}
+		firstFaceIndex += faceVertexCount;
 	}
 	if (warningCount > kMaxWarnings)
 		XA_PRINT("   %u additional warnings truncated\n", warningCount - kMaxWarnings);
 	XA_PROFILE_END(addMeshCopyData)
 	ctx->meshes.push_back(mesh);
+	ctx->meshPolygonMappings.push_back(meshPolygonMapping);
 	ctx->paramAtlas.addMesh(mesh);
 	if (ctx->addMeshTaskGroup.value == UINT32_MAX)
-		ctx->addMeshTaskGroup = ctx->taskScheduler->createTaskGroup();
-	AddMeshTaskArgs *taskArgs = XA_NEW(internal::MemTag::Default, AddMeshTaskArgs); // The task frees this.
-	taskArgs->ctx = ctx;
-	taskArgs->mesh = mesh;
+		ctx->addMeshTaskGroup = ctx->taskScheduler->createTaskGroup(ctx);
 	internal::Task task;
-	task.userData = taskArgs;
+	task.userData = mesh;
 	task.func = runAddMeshTask;
 	ctx->taskScheduler->run(ctx->addMeshTaskGroup, task);
 	return AddMeshError::Success;
 }
 
-void AddMeshJoin(Atlas *atlas)
-{
+void AddMeshJoin(Atlas *atlas) {
 	XA_DEBUG_ASSERT(atlas);
 	if (!atlas) {
 		XA_PRINT_WARNING("AddMeshJoin: atlas is null.\n");
 		return;
 	}
 	Context *ctx = (Context *)atlas;
-	if (!ctx->addMeshProgress)
-		return;
-	ctx->taskScheduler->wait(&ctx->addMeshTaskGroup);
-	ctx->addMeshProgress->~Progress();
-	XA_FREE(ctx->addMeshProgress);
-	ctx->addMeshProgress = nullptr;
+	if (!ctx->uvMeshes.isEmpty()) {
 #if XA_PROFILE
-	XA_PRINT("Added %u meshes\n", ctx->meshes.size());
-	internal::s_profile.addMeshReal = clock() - internal::s_profile.addMeshReal;
+		XA_PRINT("Added %u UV meshes\n", ctx->uvMeshes.size());
+		internal::s_profile.addMeshReal = uint64_t(std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - internal::s_profile.addMeshRealStart).count());
 #endif
-	XA_PROFILE_PRINT_AND_RESET("   Total (real): ", addMeshReal)
-	XA_PROFILE_PRINT_AND_RESET("      Copy data: ", addMeshCopyData)
-	XA_PROFILE_PRINT_AND_RESET("   Total (thread): ", addMeshThread)
-	XA_PROFILE_PRINT_AND_RESET("      Create colocals: ", addMeshCreateColocals)
+		XA_PROFILE_PRINT_AND_RESET("   Total: ", addMeshReal)
+		XA_PROFILE_PRINT_AND_RESET("      Copy data: ", addMeshCopyData)
 #if XA_PROFILE_ALLOC
-	XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
+		XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
 #endif
-	XA_PRINT_MEM_USAGE
+		XA_PRINT_MEM_USAGE
+	} else {
+		if (!ctx->addMeshProgress)
+			return;
+		ctx->taskScheduler->wait(&ctx->addMeshTaskGroup);
+		ctx->addMeshProgress->~Progress();
+		XA_FREE(ctx->addMeshProgress);
+		ctx->addMeshProgress = nullptr;
+#if XA_PROFILE
+		XA_PRINT("Added %u meshes\n", ctx->meshes.size());
+		internal::s_profile.addMeshReal = uint64_t(std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - internal::s_profile.addMeshRealStart).count());
+#endif
+		XA_PROFILE_PRINT_AND_RESET("   Total (real): ", addMeshReal)
+		XA_PROFILE_PRINT_AND_RESET("      Copy data: ", addMeshCopyData)
+		XA_PROFILE_PRINT_AND_RESET("   Total (thread): ", addMeshThread)
+		XA_PROFILE_PRINT_AND_RESET("      Create colocals: ", addMeshCreateColocals)
+#if XA_PROFILE_ALLOC
+		XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
+#endif
+		XA_PRINT_MEM_USAGE
 #if XA_DEBUG_EXPORT_OBJ_FACE_GROUPS
-	internal::param::s_faceGroupsCurrentVertex = 0;
+		internal::param::s_faceGroupsCurrentVertex = 0;
 #endif
+	}
 }
 
-struct EdgeKey
-{
-	EdgeKey() {}
-	EdgeKey(const EdgeKey &k) : v0(k.v0), v1(k.v1) {}
-	EdgeKey(uint32_t v0, uint32_t v1) : v0(v0), v1(v1) {}
-	bool operator==(const EdgeKey &k) const { return v0 == k.v0 && v1 == k.v1; }
-
-	uint32_t v0;
-	uint32_t v1;
-};
-
-AddMeshError::Enum AddUvMesh(Atlas *atlas, const UvMeshDecl &decl)
-{
+AddMeshError AddUvMesh(Atlas *atlas, const UvMeshDecl &decl) {
 	XA_DEBUG_ASSERT(atlas);
 	if (!atlas) {
 		XA_PRINT_WARNING("AddUvMesh: atlas is null.\n");
@@ -9525,13 +8858,18 @@ AddMeshError::Enum AddUvMesh(Atlas *atlas, const UvMeshDecl &decl)
 		XA_PRINT_WARNING("AddUvMesh: Meshes and UV meshes cannot be added to the same atlas.\n");
 		return AddMeshError::Error;
 	}
-	const bool decoded = (decl.indexCount <= 0);
-	const uint32_t indexCount = decoded ? decl.vertexCount : decl.indexCount;
+#if XA_PROFILE
+	if (ctx->uvMeshInstances.isEmpty())
+		internal::s_profile.addMeshRealStart = std::chrono::high_resolution_clock::now();
+#endif
+	XA_PROFILE_START(addMeshCopyData)
+	const bool hasIndices = decl.indexCount > 0;
+	const uint32_t indexCount = hasIndices ? decl.indexCount : decl.vertexCount;
 	XA_PRINT("Adding UV mesh %d: %u vertices, %u triangles\n", ctx->uvMeshes.size(), decl.vertexCount, indexCount / 3);
 	// Expecting triangle faces.
 	if ((indexCount % 3) != 0)
 		return AddMeshError::InvalidIndexCount;
-	if (!decoded) {
+	if (hasIndices) {
 		// Check if any index is out of range.
 		for (uint32_t i = 0; i < indexCount; i++) {
 			const uint32_t index = DecodeIndex(decl.indexFormat, decl.indexData, decl.indexOffset, i);
@@ -9539,319 +8877,266 @@ AddMeshError::Enum AddUvMesh(Atlas *atlas, const UvMeshDecl &decl)
 				return AddMeshError::IndexOutOfRange;
 		}
 	}
+	// Create a mesh instance.
 	internal::UvMeshInstance *meshInstance = XA_NEW(internal::MemTag::Default, internal::UvMeshInstance);
-	meshInstance->texcoords.resize(decl.vertexCount);
-	for (uint32_t i = 0; i < decl.vertexCount; i++) {
-		internal::Vector2 texcoord = *((const internal::Vector2 *)&((const uint8_t *)decl.vertexUvData)[decl.vertexStride * i]);
-		// Set nan values to 0.
-		if (internal::isNan(texcoord.x) || internal::isNan(texcoord.y))
-			texcoord.x = texcoord.y = 0.0f;
-		meshInstance->texcoords[i] = texcoord;
-	}
-	meshInstance->rotateCharts = decl.rotateCharts;
+	meshInstance->mesh = nullptr;
+	ctx->uvMeshInstances.push_back(meshInstance);
 	// See if this is an instance of an already existing mesh.
 	internal::UvMesh *mesh = nullptr;
 	for (uint32_t m = 0; m < ctx->uvMeshes.size(); m++) {
 		if (memcmp(&ctx->uvMeshes[m]->decl, &decl, sizeof(UvMeshDecl)) == 0) {
-			meshInstance->mesh = mesh = ctx->uvMeshes[m];
+			mesh = ctx->uvMeshes[m];
+			XA_PRINT("   instance of a previous UV mesh\n");
 			break;
 		}
 	}
 	if (!mesh) {
 		// Copy geometry to mesh.
-		meshInstance->mesh = mesh = XA_NEW(internal::MemTag::Default, internal::UvMesh);
+		mesh = XA_NEW(internal::MemTag::Default, internal::UvMesh);
+		ctx->uvMeshes.push_back(mesh);
 		mesh->decl = decl;
+		if (decl.faceMaterialData) {
+			mesh->faceMaterials.resize(decl.indexCount / 3);
+			memcpy(mesh->faceMaterials.data(), decl.faceMaterialData, mesh->faceMaterials.size() * sizeof(uint32_t));
+		}
 		mesh->indices.resize(decl.indexCount);
 		for (uint32_t i = 0; i < indexCount; i++)
-			mesh->indices[i] = decoded ? i : DecodeIndex(decl.indexFormat, decl.indexData, decl.indexOffset, i);
-		mesh->vertexToChartMap.resize(decl.vertexCount);
-		for (uint32_t i = 0; i < mesh->vertexToChartMap.size(); i++)
-			mesh->vertexToChartMap[i] = UINT32_MAX;
-		// Calculate charts (incident faces).
-		internal::HashMap<internal::Vector2> vertexToFaceMap(internal::MemTag::Default, indexCount); // Face is index / 3
-		const uint32_t faceCount = indexCount / 3;
-		for (uint32_t i = 0; i < indexCount; i++)
-			vertexToFaceMap.add(meshInstance->texcoords[mesh->indices[i]]);
-		internal::BitArray faceAssigned(faceCount);
-		faceAssigned.zeroOutMemory();
-		for (uint32_t f = 0; f < faceCount; f++) {
-			if (faceAssigned.get(f))
-				continue;
-			// Found an unassigned face, create a new chart.
-			internal::UvMeshChart *chart = XA_NEW(internal::MemTag::Default, internal::UvMeshChart);
-			chart->material = decl.faceMaterialData ? decl.faceMaterialData[f] : 0;
-			// Walk incident faces and assign them to the chart.
-			faceAssigned.set(f);
-			chart->faces.push_back(f);
-			for (;;) {
-				bool newFaceAssigned = false;
-				const uint32_t faceCount2 = chart->faces.size();
-				for (uint32_t f2 = 0; f2 < faceCount2; f2++) {
-					const uint32_t face = chart->faces[f2];
-					for (uint32_t i = 0; i < 3; i++) {
-						const internal::Vector2 &texcoord = meshInstance->texcoords[meshInstance->mesh->indices[face * 3 + i]];
-						uint32_t mapIndex = vertexToFaceMap.get(texcoord);
-						while (mapIndex != UINT32_MAX) {
-							const uint32_t face2 = mapIndex / 3; // 3 vertices added per face.
-							// Materials must match.
-							if (!faceAssigned.get(face2) && (!decl.faceMaterialData || decl.faceMaterialData[face] == decl.faceMaterialData[face2])) {
-								faceAssigned.set(face2);
-								chart->faces.push_back(face2);
-								newFaceAssigned = true;
-							}
-							mapIndex = vertexToFaceMap.getNext(mapIndex);
-						}
-					}
-				}
-				if (!newFaceAssigned)
+			mesh->indices[i] = hasIndices ? DecodeIndex(decl.indexFormat, decl.indexData, decl.indexOffset, i) : i;
+		mesh->texcoords.resize(decl.vertexCount);
+		for (uint32_t i = 0; i < decl.vertexCount; i++)
+			mesh->texcoords[i] = *((const internal::Vector2 *)&((const uint8_t *)decl.vertexUvData)[decl.vertexStride * i]);
+		// Validate.
+		mesh->faceIgnore.resize(decl.indexCount / 3);
+		mesh->faceIgnore.zeroOutMemory();
+		const uint32_t kMaxWarnings = 50;
+		uint32_t warningCount = 0;
+		for (uint32_t f = 0; f < indexCount / 3; f++) {
+			bool ignore = false;
+			uint32_t tri[3];
+			for (uint32_t i = 0; i < 3; i++)
+				tri[i] = mesh->indices[f * 3 + i];
+			// Check for nan UVs.
+			for (uint32_t i = 0; i < 3; i++) {
+				const uint32_t vertex = tri[i];
+				if (internal::isNan(mesh->texcoords[vertex].x) || internal::isNan(mesh->texcoords[vertex].y)) {
+					ignore = true;
+					if (++warningCount <= kMaxWarnings)
+						XA_PRINT("   NAN texture coordinate in vertex %u\n", vertex);
 					break;
+				}
 			}
-			for (uint32_t i = 0; i < chart->faces.size(); i++) {
-				for (uint32_t j = 0; j < 3; j++) {
-					const uint32_t vertex = meshInstance->mesh->indices[chart->faces[i] * 3 + j];
-					chart->indices.push_back(vertex);
-					mesh->vertexToChartMap[vertex] = mesh->charts.size();
+			// Check for zero area faces.
+			if (!ignore) {
+				const internal::Vector2 &v1 = mesh->texcoords[tri[0]];
+				const internal::Vector2 &v2 = mesh->texcoords[tri[1]];
+				const internal::Vector2 &v3 = mesh->texcoords[tri[2]];
+				const float area = fabsf(((v2.x - v1.x) * (v3.y - v1.y) - (v3.x - v1.x) * (v2.y - v1.y)) * 0.5f);
+				if (area <= internal::kAreaEpsilon) {
+					ignore = true;
+					if (++warningCount <= kMaxWarnings)
+						XA_PRINT("   Zero area face: %d, indices (%d %d %d), area is %f\n", f, tri[0], tri[1], tri[2], area);
 				}
 			}
-			mesh->charts.push_back(chart);
+			if (ignore)
+				mesh->faceIgnore.set(f);
 		}
-		ctx->uvMeshes.push_back(mesh);
-	} else {
-		XA_PRINT("   instance of a previous UV mesh\n");
+		if (warningCount > kMaxWarnings)
+			XA_PRINT("   %u additional warnings truncated\n", warningCount - kMaxWarnings);
 	}
-	XA_PRINT("   %u charts\n", meshInstance->mesh->charts.size());
-	ctx->uvMeshInstances.push_back(meshInstance);
+	meshInstance->mesh = mesh;
+	XA_PROFILE_END(addMeshCopyData)
 	return AddMeshError::Success;
 }
 
-void ComputeCharts(Atlas *atlas, ChartOptions options)
-{
+void ComputeCharts(Atlas *atlas, ChartOptions options) {
 	if (!atlas) {
 		XA_PRINT_WARNING("ComputeCharts: atlas is null.\n");
 		return;
 	}
 	Context *ctx = (Context *)atlas;
-	if (!ctx->uvMeshInstances.isEmpty()) {
-		XA_PRINT_WARNING("ComputeCharts: This function should not be called with UV meshes.\n");
-		return;
-	}
 	AddMeshJoin(atlas);
-	if (ctx->meshes.isEmpty()) {
-		XA_PRINT_WARNING("ComputeCharts: No meshes. Call AddMesh first.\n");
-		return;
-	}
-	XA_PRINT("Computing charts\n");
-	XA_PROFILE_START(computeChartsReal)
-	if (!ctx->paramAtlas.computeCharts(ctx->taskScheduler, options, ctx->progressFunc, ctx->progressUserData)) {
-		XA_PRINT("   Cancelled by user\n");
-		return;
-	}
-	XA_PROFILE_END(computeChartsReal)
-	// Count charts.
-	uint32_t chartCount = 0;
-	const uint32_t meshCount = ctx->meshes.size();
-	for (uint32_t i = 0; i < meshCount; i++) {
-		for (uint32_t j = 0; j < ctx->paramAtlas.chartGroupCount(i); j++) {
-			const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, j);
-			chartCount += chartGroup->segmentChartCount();
-		}
-	}
-	XA_PRINT("   %u charts\n", chartCount);
-#if XA_PROFILE
-	XA_PRINT("   Chart groups\n");
-	uint32_t chartGroupCount = 0;
-	for (uint32_t i = 0; i < meshCount; i++) {
-		XA_PRINT("      Mesh %u: %u chart groups\n", i, ctx->paramAtlas.chartGroupCount(i));
-		chartGroupCount += ctx->paramAtlas.chartGroupCount(i);
-	}
-	XA_PRINT("      %u total\n", chartGroupCount);
-#endif
-	XA_PROFILE_PRINT_AND_RESET("   Total (real): ", computeChartsReal)
-	XA_PROFILE_PRINT_AND_RESET("   Total (thread): ", computeChartsThread)
-	XA_PROFILE_PRINT_AND_RESET("      Create face groups: ", createFaceGroups)
-	XA_PROFILE_PRINT_AND_RESET("      Extract invalid mesh geometry: ", extractInvalidMeshGeometry)
-	XA_PROFILE_PRINT_AND_RESET("      Chart group compute charts (real): ", chartGroupComputeChartsReal)
-	XA_PROFILE_PRINT_AND_RESET("      Chart group compute charts (thread): ", chartGroupComputeChartsThread)
-	XA_PROFILE_PRINT_AND_RESET("         Create chart group mesh: ", createChartGroupMesh)
-	XA_PROFILE_PRINT_AND_RESET("            Create colocals: ", createChartGroupMeshColocals)
-	XA_PROFILE_PRINT_AND_RESET("            Create boundaries: ", createChartGroupMeshBoundaries)
-	XA_PROFILE_PRINT_AND_RESET("         Build atlas: ", buildAtlas)
-	XA_PROFILE_PRINT_AND_RESET("            Init: ", buildAtlasInit)
-	XA_PROFILE_PRINT_AND_RESET("            Planar charts: ", planarCharts)
-	XA_PROFILE_PRINT_AND_RESET("            Clustered charts: ", clusteredCharts)
-	XA_PROFILE_PRINT_AND_RESET("               Place seeds: ", clusteredChartsPlaceSeeds)
-	XA_PROFILE_PRINT_AND_RESET("                  Boundary intersection: ", clusteredChartsPlaceSeedsBoundaryIntersection)
-	XA_PROFILE_PRINT_AND_RESET("               Relocate seeds: ", clusteredChartsRelocateSeeds)
-	XA_PROFILE_PRINT_AND_RESET("               Reset: ", clusteredChartsReset)
-	XA_PROFILE_PRINT_AND_RESET("               Grow: ", clusteredChartsGrow)
-	XA_PROFILE_PRINT_AND_RESET("                  Boundary intersection: ", clusteredChartsGrowBoundaryIntersection)
-	XA_PROFILE_PRINT_AND_RESET("               Merge: ", clusteredChartsMerge)
-	XA_PROFILE_PRINT_AND_RESET("               Fill holes: ", clusteredChartsFillHoles)
-	XA_PROFILE_PRINT_AND_RESET("         Copy chart faces: ", copyChartFaces)
-#if XA_PROFILE_ALLOC
-	XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
-#endif
-	XA_PRINT_MEM_USAGE
-}
-
-void ParameterizeCharts(Atlas *atlas, ParameterizeOptions options)
-{
-	if (!atlas) {
-		XA_PRINT_WARNING("ParameterizeCharts: atlas is null.\n");
-		return;
-	}
-	Context *ctx = (Context *)atlas;
-	if (!ctx->uvMeshInstances.isEmpty()) {
-		XA_PRINT_WARNING("ParameterizeCharts: This function should not be called with UV meshes.\n");
-		return;
-	}
-	if (!ctx->paramAtlas.chartsComputed()) {
-		XA_PRINT_WARNING("ParameterizeCharts: ComputeCharts must be called first.\n");
+	if (ctx->meshes.isEmpty() && ctx->uvMeshInstances.isEmpty()) {
+		XA_PRINT_WARNING("ComputeCharts: No meshes. Call AddMesh or AddUvMesh first.\n");
 		return;
 	}
-	atlas->atlasCount = 0;
-	atlas->height = 0;
-	atlas->texelsPerUnit = 0;
-	atlas->width = 0;
-	if (atlas->utilization) {
+	// Reset atlas state. This function may be called multiple times, or again after PackCharts.
+	if (atlas->utilization)
 		XA_FREE(atlas->utilization);
-		atlas->utilization = nullptr;
-	}
-	if (atlas->image) {
+	if (atlas->image)
 		XA_FREE(atlas->image);
-		atlas->image = nullptr;
-	}
 	DestroyOutputMeshes(ctx);
-	XA_PRINT("Parameterizing charts\n");
-	XA_PROFILE_START(parameterizeChartsReal)
-	if (!ctx->paramAtlas.parameterizeCharts(ctx->taskScheduler, options, ctx->progressFunc, ctx->progressUserData)) {
-		XA_PRINT("   Cancelled by user\n");
+	memset(&ctx->atlas, 0, sizeof(Atlas));
+	XA_PRINT("Computing charts\n");
+	if (!ctx->meshes.isEmpty()) {
+		if (!ctx->paramAtlas.computeCharts(ctx->taskScheduler, options, ctx->progressFunc, ctx->progressUserData)) {
+			XA_PRINT("   Cancelled by user\n");
 			return;
-	}
-	XA_PROFILE_END(parameterizeChartsReal)
-	const uint32_t meshCount = ctx->meshes.size();
-	uint32_t chartCount = 0, chartsWithHolesCount = 0, holesCount = 0, chartsWithTJunctionsCount = 0, tJunctionsCount = 0, orthoChartsCount = 0, planarChartsCount = 0, lscmChartsCount = 0, piecewiseChartsCount = 0, chartsAddedCount = 0, chartsDeletedCount = 0;
-	for (uint32_t i = 0; i < meshCount; i++) {
-		for (uint32_t j = 0; j < ctx->paramAtlas.chartGroupCount(i); j++) {
-			const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, j);
-			for (uint32_t k = 0; k < chartGroup->chartCount(); k++) {
-				const internal::param::Chart *chart = chartGroup->chartAt(k);
-#if XA_PRINT_CHART_WARNINGS
-				if (chart->warningFlags() & internal::param::ChartWarningFlags::CloseHolesFailed)
-					XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u): failed to close holes\n", chartCount, i, j, k);
-				if (chart->warningFlags() & internal::param::ChartWarningFlags::FixTJunctionsDuplicatedEdge)
-					XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u): fixing t-junctions created non-manifold geometry\n", chartCount, i, j, k);
-				if (chart->warningFlags() & internal::param::ChartWarningFlags::FixTJunctionsFailed)
-					XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u): fixing t-junctions failed\n", chartCount, i, j, k);
-				if (chart->warningFlags() & internal::param::ChartWarningFlags::TriangulateDuplicatedEdge)
-					XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u): triangulation created non-manifold geometry\n", chartCount, i, j, k);
-#endif
-				holesCount += chart->closedHolesCount();
-				if (chart->closedHolesCount() > 0)
-					chartsWithHolesCount++;
-				tJunctionsCount += chart->fixedTJunctionsCount();
-				if (chart->fixedTJunctionsCount() > 0)
-					chartsWithTJunctionsCount++;
-				if (chart->type() == ChartType::Planar)
-					planarChartsCount++;
-				else if (chart->type() == ChartType::Ortho)
-					orthoChartsCount++;
-				else if (chart->type() == ChartType::LSCM)
-					lscmChartsCount++;
-				else if (chart->type() == ChartType::Piecewise)
-					piecewiseChartsCount++;
-			}
-			chartCount += chartGroup->chartCount();
-			chartsAddedCount += chartGroup->paramAddedChartsCount();
-			chartsDeletedCount += chartGroup->paramDeletedChartsCount();
-		}
-	}
-	if (holesCount > 0)
-		XA_PRINT("   %u holes closed in %u charts\n", holesCount, chartsWithHolesCount);
-	if (tJunctionsCount > 0)
-		XA_PRINT("   %u t-junctions fixed in %u charts\n", tJunctionsCount, chartsWithTJunctionsCount);
-	XA_PRINT("   %u planar charts, %u ortho charts, %u LSCM charts, %u piecewise charts\n", planarChartsCount, orthoChartsCount, lscmChartsCount, piecewiseChartsCount);
-	if (chartsDeletedCount > 0) {
-		XA_PRINT("   %u charts with invalid parameterizations replaced with %u new charts\n", chartsDeletedCount, chartsAddedCount);
+		}
+		uint32_t chartsWithTJunctionsCount = 0, tJunctionCount = 0, orthoChartsCount = 0, planarChartsCount = 0, lscmChartsCount = 0, piecewiseChartsCount = 0, originalUvChartsCount = 0;
+		uint32_t chartCount = 0;
+		const uint32_t meshCount = ctx->meshes.size();
+		for (uint32_t i = 0; i < meshCount; i++) {
+			for (uint32_t j = 0; j < ctx->paramAtlas.chartGroupCount(i); j++) {
+				const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, j);
+				for (uint32_t k = 0; k < chartGroup->chartCount(); k++) {
+					const internal::param::Chart *chart = chartGroup->chartAt(k);
+					tJunctionCount += chart->tjunctionCount();
+					if (chart->tjunctionCount() > 0)
+						chartsWithTJunctionsCount++;
+					if (chart->type() == ChartType::Planar)
+						planarChartsCount++;
+					else if (chart->type() == ChartType::Ortho)
+						orthoChartsCount++;
+					else if (chart->type() == ChartType::LSCM)
+						lscmChartsCount++;
+					else if (chart->type() == ChartType::Piecewise)
+						piecewiseChartsCount++;
+					if (chart->generatorType() == internal::segment::ChartGeneratorType::OriginalUv)
+						originalUvChartsCount++;
+				}
+				chartCount += chartGroup->chartCount();
+			}
+		}
+		if (tJunctionCount > 0)
+			XA_PRINT("   %u t-junctions found in %u charts\n", tJunctionCount, chartsWithTJunctionsCount);
 		XA_PRINT("   %u charts\n", chartCount);
-	}
-	uint32_t chartIndex = 0, invalidParamCount = 0;
-	for (uint32_t i = 0; i < meshCount; i++) {
-		for (uint32_t j = 0; j < ctx->paramAtlas.chartGroupCount(i); j++) {
-			const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, j);
-			for (uint32_t k = 0; k < chartGroup->chartCount(); k++) {
-				internal::param::Chart *chart = chartGroup->chartAt(k);
-				const internal::param::Quality &quality = chart->quality();
+		XA_PRINT("      %u planar, %u ortho, %u LSCM, %u piecewise\n", planarChartsCount, orthoChartsCount, lscmChartsCount, piecewiseChartsCount);
+		if (originalUvChartsCount > 0)
+			XA_PRINT("      %u with original UVs\n", originalUvChartsCount);
+		uint32_t chartIndex = 0, invalidParamCount = 0;
+		for (uint32_t i = 0; i < meshCount; i++) {
+			for (uint32_t j = 0; j < ctx->paramAtlas.chartGroupCount(i); j++) {
+				const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, j);
+				for (uint32_t k = 0; k < chartGroup->chartCount(); k++) {
+					internal::param::Chart *chart = chartGroup->chartAt(k);
+					const internal::param::Quality &quality = chart->quality();
 #if XA_DEBUG_EXPORT_OBJ_CHARTS_AFTER_PARAMETERIZATION
-				{
-					char filename[256];
-					XA_SPRINTF(filename, sizeof(filename), "debug_chart_%03u_after_parameterization.obj", chartIndex);
-					chart->unifiedMesh()->writeObjFile(filename);
-				}
-#endif
-				const char *type = "LSCM";
-				if (chart->type() == ChartType::Planar)
-					type = "planar";
-				else if (chart->type() == ChartType::Ortho)
-					type = "ortho";
-				else if (chart->type() == ChartType::Piecewise)
-					type = "piecewise";
-				if (chart->isInvalid()) {
-					if (quality.boundaryIntersection) {
-						XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u) (%s): invalid parameterization, self-intersecting boundary.\n", chartIndex, i, j, k, type);
-					}
-					if (quality.flippedTriangleCount > 0) {
-						XA_PRINT_WARNING("   Chart %u  (mesh %u, group %u, id %u) (%s): invalid parameterization, %u / %u flipped triangles.\n", chartIndex, i, j, k, type, quality.flippedTriangleCount, quality.totalTriangleCount);
+					{
+						char filename[256];
+						XA_SPRINTF(filename, sizeof(filename), "debug_chart_%03u_after_parameterization.obj", chartIndex);
+						chart->unifiedMesh()->writeObjFile(filename);
 					}
-					invalidParamCount++;
+#endif
+					const char *type = "LSCM";
+					if (chart->type() == ChartType::Planar)
+						type = "planar";
+					else if (chart->type() == ChartType::Ortho)
+						type = "ortho";
+					else if (chart->type() == ChartType::Piecewise)
+						type = "piecewise";
+					if (chart->isInvalid()) {
+						if (quality.boundaryIntersection) {
+							XA_PRINT_WARNING("   Chart %u (mesh %u, group %u, id %u) (%s): invalid parameterization, self-intersecting boundary.\n", chartIndex, i, j, k, type);
+						}
+						if (quality.flippedTriangleCount > 0) {
+							XA_PRINT_WARNING("   Chart %u  (mesh %u, group %u, id %u) (%s): invalid parameterization, %u / %u flipped triangles.\n", chartIndex, i, j, k, type, quality.flippedTriangleCount, quality.totalTriangleCount);
+						}
+						if (quality.zeroAreaTriangleCount > 0) {
+							XA_PRINT_WARNING("   Chart %u  (mesh %u, group %u, id %u) (%s): invalid parameterization, %u / %u zero area triangles.\n", chartIndex, i, j, k, type, quality.zeroAreaTriangleCount, quality.totalTriangleCount);
+						}
+						invalidParamCount++;
 #if XA_DEBUG_EXPORT_OBJ_INVALID_PARAMETERIZATION
-					char filename[256];
-					XA_SPRINTF(filename, sizeof(filename), "debug_chart_%03u_invalid_parameterization.obj", chartIndex);
-					const internal::Mesh *mesh = chart->unifiedMesh();
-					FILE *file;
-					XA_FOPEN(file, filename, "w");
-					if (file) {
-						mesh->writeObjVertices(file);
-						fprintf(file, "s off\n");
-						fprintf(file, "o object\n");
-						for (uint32_t f = 0; f < mesh->faceCount(); f++)
-							mesh->writeObjFace(file, f);
-						if (!chart->paramFlippedFaces().isEmpty()) {
-							fprintf(file, "o flipped_faces\n");
-							for (uint32_t f = 0; f < chart->paramFlippedFaces().size(); f++)
-								mesh->writeObjFace(file, chart->paramFlippedFaces()[f]);
+						char filename[256];
+						XA_SPRINTF(filename, sizeof(filename), "debug_chart_%03u_invalid_parameterization.obj", chartIndex);
+						const internal::Mesh *mesh = chart->unifiedMesh();
+						FILE *file;
+						XA_FOPEN(file, filename, "w");
+						if (file) {
+							mesh->writeObjVertices(file);
+							fprintf(file, "s off\n");
+							fprintf(file, "o object\n");
+							for (uint32_t f = 0; f < mesh->faceCount(); f++)
+								mesh->writeObjFace(file, f);
+							if (!chart->paramFlippedFaces().isEmpty()) {
+								fprintf(file, "o flipped_faces\n");
+								for (uint32_t f = 0; f < chart->paramFlippedFaces().size(); f++)
+									mesh->writeObjFace(file, chart->paramFlippedFaces()[f]);
+							}
+							mesh->writeObjBoundaryEges(file);
+							fclose(file);
 						}
-						mesh->writeObjBoundaryEges(file);
-						mesh->writeObjLinkedBoundaries(file);
-						fclose(file);
-					}
 #endif
+					}
+					chartIndex++;
 				}
-				chartIndex++;
 			}
 		}
+		if (invalidParamCount > 0)
+			XA_PRINT_WARNING("   %u charts with invalid parameterizations\n", invalidParamCount);
+#if XA_PROFILE
+		XA_PRINT("   Chart groups\n");
+		uint32_t chartGroupCount = 0;
+		for (uint32_t i = 0; i < meshCount; i++) {
+#if 0
+			XA_PRINT("      Mesh %u: %u chart groups\n", i, ctx->paramAtlas.chartGroupCount(i));
+#endif
+			chartGroupCount += ctx->paramAtlas.chartGroupCount(i);
+		}
+		XA_PRINT("      %u total\n", chartGroupCount);
+#endif
+		XA_PROFILE_PRINT_AND_RESET("   Compute charts total (real): ", computeChartsReal)
+		XA_PROFILE_PRINT_AND_RESET("   Compute charts total (thread): ", computeChartsThread)
+		XA_PROFILE_PRINT_AND_RESET("      Create face groups: ", createFaceGroups)
+		XA_PROFILE_PRINT_AND_RESET("      Extract invalid mesh geometry: ", extractInvalidMeshGeometry)
+		XA_PROFILE_PRINT_AND_RESET("      Chart group compute charts (real): ", chartGroupComputeChartsReal)
+		XA_PROFILE_PRINT_AND_RESET("      Chart group compute charts (thread): ", chartGroupComputeChartsThread)
+		XA_PROFILE_PRINT_AND_RESET("         Create chart group mesh: ", createChartGroupMesh)
+		XA_PROFILE_PRINT_AND_RESET("            Create colocals: ", createChartGroupMeshColocals)
+		XA_PROFILE_PRINT_AND_RESET("            Create boundaries: ", createChartGroupMeshBoundaries)
+		XA_PROFILE_PRINT_AND_RESET("         Build atlas: ", buildAtlas)
+		XA_PROFILE_PRINT_AND_RESET("            Init: ", buildAtlasInit)
+		XA_PROFILE_PRINT_AND_RESET("            Planar charts: ", planarCharts)
+		if (options.useInputMeshUvs) {
+			XA_PROFILE_PRINT_AND_RESET("            Original UV charts: ", originalUvCharts)
+		}
+		XA_PROFILE_PRINT_AND_RESET("            Clustered charts: ", clusteredCharts)
+		XA_PROFILE_PRINT_AND_RESET("               Place seeds: ", clusteredChartsPlaceSeeds)
+		XA_PROFILE_PRINT_AND_RESET("                  Boundary intersection: ", clusteredChartsPlaceSeedsBoundaryIntersection)
+		XA_PROFILE_PRINT_AND_RESET("               Relocate seeds: ", clusteredChartsRelocateSeeds)
+		XA_PROFILE_PRINT_AND_RESET("               Reset: ", clusteredChartsReset)
+		XA_PROFILE_PRINT_AND_RESET("               Grow: ", clusteredChartsGrow)
+		XA_PROFILE_PRINT_AND_RESET("                  Boundary intersection: ", clusteredChartsGrowBoundaryIntersection)
+		XA_PROFILE_PRINT_AND_RESET("               Merge: ", clusteredChartsMerge)
+		XA_PROFILE_PRINT_AND_RESET("               Fill holes: ", clusteredChartsFillHoles)
+		XA_PROFILE_PRINT_AND_RESET("         Copy chart faces: ", copyChartFaces)
+		XA_PROFILE_PRINT_AND_RESET("      Create chart mesh and parameterize (real): ", createChartMeshAndParameterizeReal)
+		XA_PROFILE_PRINT_AND_RESET("      Create chart mesh and parameterize (thread): ", createChartMeshAndParameterizeThread)
+		XA_PROFILE_PRINT_AND_RESET("         Create chart mesh: ", createChartMesh)
+		XA_PROFILE_PRINT_AND_RESET("         Parameterize charts: ", parameterizeCharts)
+		XA_PROFILE_PRINT_AND_RESET("            Orthogonal: ", parameterizeChartsOrthogonal)
+		XA_PROFILE_PRINT_AND_RESET("            LSCM: ", parameterizeChartsLSCM)
+		XA_PROFILE_PRINT_AND_RESET("            Recompute: ", parameterizeChartsRecompute)
+		XA_PROFILE_PRINT_AND_RESET("               Piecewise: ", parameterizeChartsPiecewise)
+		XA_PROFILE_PRINT_AND_RESET("                  Boundary intersection: ", parameterizeChartsPiecewiseBoundaryIntersection)
+		XA_PROFILE_PRINT_AND_RESET("            Evaluate quality: ", parameterizeChartsEvaluateQuality)
+#if XA_PROFILE_ALLOC
+		XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
+#endif
+		XA_PRINT_MEM_USAGE
+	} else {
+		XA_PROFILE_START(computeChartsReal)
+		if (!internal::segment::computeUvMeshCharts(ctx->taskScheduler, ctx->uvMeshes, ctx->progressFunc, ctx->progressUserData)) {
+			XA_PRINT("   Cancelled by user\n");
+			return;
+		}
+		XA_PROFILE_END(computeChartsReal)
+		ctx->uvMeshChartsComputed = true;
+		// Count charts.
+		uint32_t chartCount = 0;
+		const uint32_t meshCount = ctx->uvMeshes.size();
+		for (uint32_t i = 0; i < meshCount; i++)
+			chartCount += ctx->uvMeshes[i]->charts.size();
+		XA_PRINT("   %u charts\n", chartCount);
+		XA_PROFILE_PRINT_AND_RESET("   Total (real): ", computeChartsReal)
+		XA_PROFILE_PRINT_AND_RESET("   Total (thread): ", computeChartsThread)
 	}
-	if (invalidParamCount > 0)
-		XA_PRINT_WARNING("   %u charts with invalid parameterizations\n", invalidParamCount);
-	XA_PROFILE_PRINT_AND_RESET("   Total (real): ", parameterizeChartsReal)
-	XA_PROFILE_PRINT_AND_RESET("   Total (thread): ", parameterizeChartsThread)
-	XA_PROFILE_PRINT_AND_RESET("      Create chart mesh: ", createChartMesh)
-	XA_PROFILE_PRINT_AND_RESET("         Fix t-junctions: ", fixChartMeshTJunctions)
-	XA_PROFILE_PRINT_AND_RESET("         Close holes: ", closeChartMeshHoles)
-	XA_PROFILE_PRINT_AND_RESET("      Orthogonal: ", parameterizeChartsOrthogonal)
-	XA_PROFILE_PRINT_AND_RESET("      LSCM: ", parameterizeChartsLSCM)
-	XA_PROFILE_PRINT_AND_RESET("      Recompute: ", parameterizeChartsRecompute)
-	XA_PROFILE_PRINT_AND_RESET("         Piecewise: ", parameterizeChartsPiecewise)
-	XA_PROFILE_PRINT_AND_RESET("            Boundary intersection: ", parameterizeChartsPiecewiseBoundaryIntersection)
-	XA_PROFILE_PRINT_AND_RESET("      Evaluate quality: ", parameterizeChartsEvaluateQuality)
 #if XA_PROFILE_ALLOC
 	XA_PROFILE_PRINT_AND_RESET("   Alloc: ", alloc)
 #endif
 	XA_PRINT_MEM_USAGE
 }
 
-void PackCharts(Atlas *atlas, PackOptions packOptions)
-{
+void PackCharts(Atlas *atlas, PackOptions packOptions) {
 	// Validate arguments and context state.
 	if (!atlas) {
 		XA_PRINT_WARNING("PackCharts: atlas is null.\n");
@@ -9867,10 +9152,9 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 			XA_PRINT_WARNING("PackCharts: ComputeCharts must be called first.\n");
 			return;
 		}
-		if (!ctx->paramAtlas.chartsParameterized()) {
-			XA_PRINT_WARNING("PackCharts: ParameterizeCharts must be called first.\n");
-			return;
-		}
+	} else if (!ctx->uvMeshChartsComputed) {
+		XA_PRINT_WARNING("PackCharts: ComputeCharts must be called first.\n");
+		return;
 	}
 	if (packOptions.texelsPerUnit < 0.0f) {
 		XA_PRINT_WARNING("PackCharts: PackOptions::texelsPerUnit is negative.\n");
@@ -9893,8 +9177,7 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 	if (!ctx->uvMeshInstances.isEmpty()) {
 		for (uint32_t i = 0; i < ctx->uvMeshInstances.size(); i++)
 			packAtlas.addUvMeshCharts(ctx->uvMeshInstances[i]);
-	}
-	else
+	} else
 		packAtlas.addCharts(ctx->taskScheduler, &ctx->paramAtlas);
 	XA_PROFILE_END(packChartsAddCharts)
 	XA_PROFILE_START(packCharts)
@@ -9946,16 +9229,35 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 		uint32_t chartIndex = 0;
 		for (uint32_t i = 0; i < atlas->meshCount; i++) {
 			Mesh &outputMesh = atlas->meshes[i];
+			MeshPolygonMapping *meshPolygonMapping = ctx->meshPolygonMappings[i];
+			// One polygon can have many triangles. Don't want to process the same polygon more than once when counting indices, building chart faces etc.
+			internal::BitArray polygonTouched;
+			if (meshPolygonMapping) {
+				polygonTouched.resize(meshPolygonMapping->faceVertexCount.size());
+				polygonTouched.zeroOutMemory();
+			}
 			// Count and alloc arrays.
-			const internal::param::InvalidMeshGeometry &invalid = ctx->paramAtlas.invalidMeshGeometry(i);
+			const internal::InvalidMeshGeometry &invalid = ctx->paramAtlas.invalidMeshGeometry(i);
 			outputMesh.vertexCount += invalid.vertices().length;
 			outputMesh.indexCount += invalid.faces().length * 3;
 			for (uint32_t cg = 0; cg < ctx->paramAtlas.chartGroupCount(i); cg++) {
 				const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, cg);
 				for (uint32_t c = 0; c < chartGroup->chartCount(); c++) {
 					const internal::param::Chart *chart = chartGroup->chartAt(c);
-					outputMesh.vertexCount += chart->mesh()->vertexCount();
-					outputMesh.indexCount += chart->mesh()->faceCount() * 3;
+					outputMesh.vertexCount += chart->originalVertexCount();
+					const uint32_t faceCount = chart->unifiedMesh()->faceCount();
+					if (meshPolygonMapping) {
+						// Map triangles back to polygons and count the polygon vertices.
+						for (uint32_t f = 0; f < faceCount; f++) {
+							const uint32_t polygon = meshPolygonMapping->triangleToPolygonMap[chart->mapFaceToSourceFace(f)];
+							if (!polygonTouched.get(polygon)) {
+								polygonTouched.set(polygon);
+								outputMesh.indexCount += meshPolygonMapping->faceVertexCount[polygon];
+							}
+						}
+					} else {
+						outputMesh.indexCount += faceCount * 3;
+					}
 					outputMesh.chartCount++;
 				}
 			}
@@ -9966,7 +9268,7 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 			// Copy mesh data.
 			uint32_t firstVertex = 0;
 			{
-				const internal::param::InvalidMeshGeometry &mesh = ctx->paramAtlas.invalidMeshGeometry(i);
+				const internal::InvalidMeshGeometry &mesh = ctx->paramAtlas.invalidMeshGeometry(i);
 				internal::ConstArrayView<uint32_t> faces = mesh.faces();
 				internal::ConstArrayView<uint32_t> indices = mesh.indices();
 				internal::ConstArrayView<uint32_t> vertices = mesh.vertices();
@@ -9991,23 +9293,50 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 				const internal::param::ChartGroup *chartGroup = ctx->paramAtlas.chartGroupAt(i, cg);
 				for (uint32_t c = 0; c < chartGroup->chartCount(); c++) {
 					const internal::param::Chart *chart = chartGroup->chartAt(c);
-					const internal::Mesh *mesh = chart->mesh();
+					const internal::Mesh *unifiedMesh = chart->unifiedMesh();
+					const uint32_t faceCount = unifiedMesh->faceCount();
+#if XA_CHECK_PARAM_WINDING
+					uint32_t flippedCount = 0;
+					for (uint32_t f = 0; f < faceCount; f++) {
+						const float area = mesh->computeFaceParametricArea(f);
+						if (area < 0.0f)
+							flippedCount++;
+					}
+					const char *type = "LSCM";
+					if (chart->type() == ChartType::Planar)
+						type = "planar";
+					else if (chart->type() == ChartType::Ortho)
+						type = "ortho";
+					else if (chart->type() == ChartType::Piecewise)
+						type = "piecewise";
+					if (flippedCount > 0) {
+						if (flippedCount == faceCount) {
+							XA_PRINT_WARNING("chart %u (%s): all face flipped\n", chartIndex, type);
+						} else {
+							XA_PRINT_WARNING("chart %u (%s): %u / %u faces flipped\n", chartIndex, type, flippedCount, faceCount);
+						}
+					}
+#endif
 					// Vertices.
-					for (uint32_t v = 0; v < mesh->vertexCount(); v++) {
+					for (uint32_t v = 0; v < chart->originalVertexCount(); v++) {
 						Vertex &vertex = outputMesh.vertexArray[firstVertex + v];
 						vertex.atlasIndex = packAtlas.getChart(chartIndex)->atlasIndex;
 						XA_DEBUG_ASSERT(vertex.atlasIndex >= 0);
 						vertex.chartIndex = (int32_t)chartIndex;
-						const internal::Vector2 &uv = mesh->texcoord(v);
+						const internal::Vector2 &uv = unifiedMesh->texcoord(chart->originalVertexToUnifiedVertex(v));
 						vertex.uv[0] = internal::max(0.0f, uv.x);
 						vertex.uv[1] = internal::max(0.0f, uv.y);
 						vertex.xref = chart->mapChartVertexToSourceVertex(v);
 					}
 					// Indices.
-					for (uint32_t f = 0; f < mesh->faceCount(); f++) {
+					for (uint32_t f = 0; f < faceCount; f++) {
 						const uint32_t indexOffset = chart->mapFaceToSourceFace(f) * 3;
-						for (uint32_t j = 0; j < 3; j++)
-							outputMesh.indexArray[indexOffset + j] = firstVertex + mesh->vertexAt(f * 3 + j);
+						for (uint32_t j = 0; j < 3; j++) {
+							uint32_t outIndex = indexOffset + j;
+							if (meshPolygonMapping)
+								outIndex = meshPolygonMapping->triangleToPolygonIndicesMap[outIndex];
+							outputMesh.indexArray[outIndex] = firstVertex + chart->originalVertices()[f * 3 + j];
+						}
 					}
 					// Charts.
 					Chart *outputChart = &outputMesh.chartArray[meshChartIndex];
@@ -10015,14 +9344,38 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 					XA_DEBUG_ASSERT(atlasIndex >= 0);
 					outputChart->atlasIndex = (uint32_t)atlasIndex;
 					outputChart->type = chart->isInvalid() ? ChartType::Invalid : chart->type();
-					outputChart->faceCount = mesh->faceCount();
-					outputChart->faceArray = XA_ALLOC_ARRAY(internal::MemTag::Default, uint32_t, outputChart->faceCount);
-					for (uint32_t f = 0; f < outputChart->faceCount; f++)
-						outputChart->faceArray[f] = chart->mapFaceToSourceFace(f);
+					if (meshPolygonMapping) {
+						// Count polygons.
+						polygonTouched.zeroOutMemory();
+						outputChart->faceCount = 0;
+						for (uint32_t f = 0; f < faceCount; f++) {
+							const uint32_t polygon = meshPolygonMapping->triangleToPolygonMap[chart->mapFaceToSourceFace(f)];
+							if (!polygonTouched.get(polygon)) {
+								polygonTouched.set(polygon);
+								outputChart->faceCount++;
+							}
+						}
+						// Write polygons.
+						outputChart->faceArray = XA_ALLOC_ARRAY(internal::MemTag::Default, uint32_t, outputChart->faceCount);
+						polygonTouched.zeroOutMemory();
+						uint32_t of = 0;
+						for (uint32_t f = 0; f < faceCount; f++) {
+							const uint32_t polygon = meshPolygonMapping->triangleToPolygonMap[chart->mapFaceToSourceFace(f)];
+							if (!polygonTouched.get(polygon)) {
+								polygonTouched.set(polygon);
+								outputChart->faceArray[of++] = polygon;
+							}
+						}
+					} else {
+						outputChart->faceCount = faceCount;
+						outputChart->faceArray = XA_ALLOC_ARRAY(internal::MemTag::Default, uint32_t, outputChart->faceCount);
+						for (uint32_t f = 0; f < outputChart->faceCount; f++)
+							outputChart->faceArray[f] = chart->mapFaceToSourceFace(f);
+					}
 					outputChart->material = 0;
 					meshChartIndex++;
 					chartIndex++;
-					firstVertex += mesh->vertexCount();
+					firstVertex += chart->originalVertexCount();
 				}
 			}
 			XA_DEBUG_ASSERT(outputMesh.vertexCount == firstVertex);
@@ -10102,28 +9455,21 @@ void PackCharts(Atlas *atlas, PackOptions packOptions)
 	XA_PRINT_MEM_USAGE
 }
 
-void Generate(Atlas *atlas, ChartOptions chartOptions, ParameterizeOptions parameterizeOptions, PackOptions packOptions)
-{
+void Generate(Atlas *atlas, ChartOptions chartOptions, PackOptions packOptions) {
 	if (!atlas) {
 		XA_PRINT_WARNING("Generate: atlas is null.\n");
 		return;
 	}
 	Context *ctx = (Context *)atlas;
-	if (!ctx->uvMeshInstances.isEmpty()) {
-		XA_PRINT_WARNING("Generate: This function should not be called with UV meshes.\n");
-		return;
-	}
-	if (ctx->meshes.isEmpty()) {
-		XA_PRINT_WARNING("Generate: No meshes. Call AddMesh first.\n");
+	if (ctx->meshes.isEmpty() && ctx->uvMeshInstances.isEmpty()) {
+		XA_PRINT_WARNING("Generate: No meshes. Call AddMesh or AddUvMesh first.\n");
 		return;
 	}
 	ComputeCharts(atlas, chartOptions);
-	ParameterizeCharts(atlas, parameterizeOptions);
 	PackCharts(atlas, packOptions);
 }
 
-void SetProgressCallback(Atlas *atlas, ProgressFunc progressFunc, void *progressUserData)
-{
+void SetProgressCallback(Atlas *atlas, ProgressFunc progressFunc, void *progressUserData) {
 	if (!atlas) {
 		XA_PRINT_WARNING("SetProgressCallback: atlas is null.\n");
 		return;
@@ -10133,37 +9479,33 @@ void SetProgressCallback(Atlas *atlas, ProgressFunc progressFunc, void *progress
 	ctx->progressUserData = progressUserData;
 }
 
-void SetAlloc(ReallocFunc reallocFunc, FreeFunc freeFunc)
-{
+void SetAlloc(ReallocFunc reallocFunc, FreeFunc freeFunc) {
 	internal::s_realloc = reallocFunc;
 	internal::s_free = freeFunc;
 }
 
-void SetPrint(PrintFunc print, bool verbose)
-{
+void SetPrint(PrintFunc print, bool verbose) {
 	internal::s_print = print;
 	internal::s_printVerbose = verbose;
 }
 
-const char *StringForEnum(AddMeshError::Enum error)
-{
+const char *StringForEnum(AddMeshError error) {
 	if (error == AddMeshError::Error)
 		return "Unspecified error";
 	if (error == AddMeshError::IndexOutOfRange)
 		return "Index out of range";
+	if (error == AddMeshError::InvalidFaceVertexCount)
+		return "Invalid face vertex count";
 	if (error == AddMeshError::InvalidIndexCount)
 		return "Invalid index count";
 	return "Success";
 }
 
-const char *StringForEnum(ProgressCategory::Enum category)
-{
+const char *StringForEnum(ProgressCategory category) {
 	if (category == ProgressCategory::AddMesh)
 		return "Adding mesh(es)";
 	if (category == ProgressCategory::ComputeCharts)
 		return "Computing charts";
-	if (category == ProgressCategory::ParameterizeCharts)
-		return "Parameterizing charts";
 	if (category == ProgressCategory::PackCharts)
 		return "Packing charts";
 	if (category == ProgressCategory::BuildOutputMeshes)
@@ -10172,3 +9514,96 @@ const char *StringForEnum(ProgressCategory::Enum category)
 }
 
 } // namespace xatlas
+
+#if XATLAS_C_API
+static_assert(sizeof(xatlas::Chart) == sizeof(xatlasChart), "xatlasChart size mismatch");
+static_assert(sizeof(xatlas::Vertex) == sizeof(xatlasVertex), "xatlasVertex size mismatch");
+static_assert(sizeof(xatlas::Mesh) == sizeof(xatlasMesh), "xatlasMesh size mismatch");
+static_assert(sizeof(xatlas::Atlas) == sizeof(xatlasAtlas), "xatlasAtlas size mismatch");
+static_assert(sizeof(xatlas::MeshDecl) == sizeof(xatlasMeshDecl), "xatlasMeshDecl size mismatch");
+static_assert(sizeof(xatlas::UvMeshDecl) == sizeof(xatlasUvMeshDecl), "xatlasUvMeshDecl size mismatch");
+static_assert(sizeof(xatlas::ChartOptions) == sizeof(xatlasChartOptions), "xatlasChartOptions size mismatch");
+static_assert(sizeof(xatlas::PackOptions) == sizeof(xatlasPackOptions), "xatlasPackOptions size mismatch");
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+xatlasAtlas *xatlasCreate() {
+	return (xatlasAtlas *)xatlas::Create();
+}
+
+void xatlasDestroy(xatlasAtlas *atlas) {
+	xatlas::Destroy((xatlas::Atlas *)atlas);
+}
+
+xatlasAddMeshError xatlasAddMesh(xatlasAtlas *atlas, const xatlasMeshDecl *meshDecl, uint32_t meshCountHint) {
+	return (xatlasAddMeshError)xatlas::AddMesh((xatlas::Atlas *)atlas, *(const xatlas::MeshDecl *)meshDecl, meshCountHint);
+}
+
+void xatlasAddMeshJoin(xatlasAtlas *atlas) {
+	xatlas::AddMeshJoin((xatlas::Atlas *)atlas);
+}
+
+xatlasAddMeshError xatlasAddUvMesh(xatlasAtlas *atlas, const xatlasUvMeshDecl *decl) {
+	return (xatlasAddMeshError)xatlas::AddUvMesh((xatlas::Atlas *)atlas, *(const xatlas::UvMeshDecl *)decl);
+}
+
+void xatlasComputeCharts(xatlasAtlas *atlas, const xatlasChartOptions *chartOptions) {
+	xatlas::ComputeCharts((xatlas::Atlas *)atlas, chartOptions ? *(xatlas::ChartOptions *)chartOptions : xatlas::ChartOptions());
+}
+
+void xatlasPackCharts(xatlasAtlas *atlas, const xatlasPackOptions *packOptions) {
+	xatlas::PackCharts((xatlas::Atlas *)atlas, packOptions ? *(xatlas::PackOptions *)packOptions : xatlas::PackOptions());
+}
+
+void xatlasGenerate(xatlasAtlas *atlas, const xatlasChartOptions *chartOptions, const xatlasPackOptions *packOptions) {
+	xatlas::Generate((xatlas::Atlas *)atlas, chartOptions ? *(xatlas::ChartOptions *)chartOptions : xatlas::ChartOptions(), packOptions ? *(xatlas::PackOptions *)packOptions : xatlas::PackOptions());
+}
+
+void xatlasSetProgressCallback(xatlasAtlas *atlas, xatlasProgressFunc progressFunc, void *progressUserData) {
+	xatlas::ProgressFunc pf;
+	*(void **)&pf = (void *)progressFunc;
+	xatlas::SetProgressCallback((xatlas::Atlas *)atlas, pf, progressUserData);
+}
+
+void xatlasSetAlloc(xatlasReallocFunc reallocFunc, xatlasFreeFunc freeFunc) {
+	xatlas::SetAlloc((xatlas::ReallocFunc)reallocFunc, (xatlas::FreeFunc)freeFunc);
+}
+
+void xatlasSetPrint(xatlasPrintFunc print, bool verbose) {
+	xatlas::SetPrint((xatlas::PrintFunc)print, verbose);
+}
+
+const char *xatlasAddMeshErrorString(xatlasAddMeshError error) {
+	return xatlas::StringForEnum((xatlas::AddMeshError)error);
+}
+
+const char *xatlasProgressCategoryString(xatlasProgressCategory category) {
+	return xatlas::StringForEnum((xatlas::ProgressCategory)category);
+}
+
+void xatlasMeshDeclInit(xatlasMeshDecl *meshDecl) {
+	xatlas::MeshDecl init;
+	memcpy(meshDecl, &init, sizeof(init));
+}
+
+void xatlasUvMeshDeclInit(xatlasUvMeshDecl *uvMeshDecl) {
+	xatlas::UvMeshDecl init;
+	memcpy(uvMeshDecl, &init, sizeof(init));
+}
+
+void xatlasChartOptionsInit(xatlasChartOptions *chartOptions) {
+	xatlas::ChartOptions init;
+	memcpy(chartOptions, &init, sizeof(init));
+}
+
+void xatlasPackOptionsInit(xatlasPackOptions *packOptions) {
+	xatlas::PackOptions init;
+	memcpy(packOptions, &init, sizeof(init));
+}
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#endif // XATLAS_C_API
diff --git a/thirdparty/xatlas/xatlas.h b/thirdparty/xatlas/xatlas.h
index cc47f4837e..fc40d9d49c 100644
--- a/thirdparty/xatlas/xatlas.h
+++ b/thirdparty/xatlas/xatlas.h
@@ -31,35 +31,30 @@ Copyright NVIDIA Corporation 2006 -- Ignacio Castano <icastano@nvidia.com>
 #pragma once
 #ifndef XATLAS_H
 #define XATLAS_H
+#include <stddef.h>
 #include <stdint.h>
 
 namespace xatlas {
 
-struct ChartType
-{
-	enum Enum
-	{
-		Planar,
-		Ortho,
-		LSCM,
-		Piecewise,
-		Invalid
-	};
+enum class ChartType {
+	Planar,
+	Ortho,
+	LSCM,
+	Piecewise,
+	Invalid
 };
 
 // A group of connected faces, belonging to a single atlas.
-struct Chart
-{
+struct Chart {
 	uint32_t *faceArray;
 	uint32_t atlasIndex; // Sub-atlas index.
 	uint32_t faceCount;
-	ChartType::Enum type;
+	ChartType type;
 	uint32_t material;
 };
 
 // Output vertex.
-struct Vertex
-{
+struct Vertex {
 	int32_t atlasIndex; // Sub-atlas index. -1 if the vertex doesn't exist in any atlas.
 	int32_t chartIndex; // -1 if the vertex doesn't exist in any chart.
 	float uv[2]; // Not normalized - values are in Atlas width and height range.
@@ -67,8 +62,7 @@ struct Vertex
 };
 
 // Output mesh.
-struct Mesh
-{
+struct Mesh {
 	Chart *chartArray;
 	uint32_t *indexArray;
 	Vertex *vertexArray;
@@ -83,16 +77,15 @@ static const uint32_t kImageIsBilinearBit = 0x40000000;
 static const uint32_t kImageIsPaddingBit = 0x20000000;
 
 // Empty on creation. Populated after charts are packed.
-struct Atlas
-{
+struct Atlas {
 	uint32_t *image;
 	Mesh *meshes; // The output meshes, corresponding to each AddMesh call.
+	float *utilization; // Normalized atlas texel utilization array. E.g. a value of 0.8 means 20% empty space. atlasCount in length.
 	uint32_t width; // Atlas width in texels.
 	uint32_t height; // Atlas height in texels.
 	uint32_t atlasCount; // Number of sub-atlases. Equal to 0 unless PackOptions resolution is changed from default (0).
 	uint32_t chartCount; // Total number of charts in all meshes.
 	uint32_t meshCount; // Number of output meshes. Equal to the number of times AddMesh was called.
-	float *utilization; // Normalized atlas texel utilization array. E.g. a value of 0.8 means 20% empty space. atlasCount in length.
 	float texelsPerUnit; // Equal to PackOptions texelsPerUnit if texelsPerUnit > 0, otherwise an estimated value to match PackOptions resolution.
 };
 
@@ -101,73 +94,76 @@ Atlas *Create();
 
 void Destroy(Atlas *atlas);
 
-struct IndexFormat
-{
-	enum Enum
-	{
-		UInt16,
-		UInt32
-	};
+enum class IndexFormat {
+	UInt16,
+	UInt32
 };
 
 // Input mesh declaration.
-struct MeshDecl
-{
+struct MeshDecl {
 	const void *vertexPositionData = nullptr;
 	const void *vertexNormalData = nullptr; // optional
 	const void *vertexUvData = nullptr; // optional. The input UVs are provided as a hint to the chart generator.
 	const void *indexData = nullptr; // optional
-	
-	// Optional. indexCount / 3 (triangle count) in length.
+
+	// Optional. Must be faceCount in length.
 	// Don't atlas faces set to true. Ignored faces still exist in the output meshes, Vertex uv is set to (0, 0) and Vertex atlasIndex to -1.
 	const bool *faceIgnoreData = nullptr;
 
+	// Optional. Must be faceCount in length.
+	// Only faces with the same material will be assigned to the same chart.
+	const uint32_t *faceMaterialData = nullptr;
+
+	// Optional. Must be faceCount in length.
+	// Polygon / n-gon support. Faces are assumed to be triangles if this is null.
+	const uint8_t *faceVertexCount = nullptr;
+
 	uint32_t vertexCount = 0;
 	uint32_t vertexPositionStride = 0;
 	uint32_t vertexNormalStride = 0; // optional
 	uint32_t vertexUvStride = 0; // optional
 	uint32_t indexCount = 0;
 	int32_t indexOffset = 0; // optional. Add this offset to all indices.
-	IndexFormat::Enum indexFormat = IndexFormat::UInt16;
+	uint32_t faceCount = 0; // Optional if faceVertexCount is null. Otherwise assumed to be indexCount / 3.
+	IndexFormat indexFormat = IndexFormat::UInt16;
 
 	// Vertex positions within epsilon distance of each other are considered colocal.
 	float epsilon = 1.192092896e-07F;
 };
 
-struct AddMeshError
-{
-	enum Enum
-	{
-		Success, // No error.
-		Error, // Unspecified error.
-		IndexOutOfRange, // An index is >= MeshDecl vertexCount.
-		InvalidIndexCount // Not evenly divisible by 3 - expecting triangles.
-	};
+enum class AddMeshError {
+	Success, // No error.
+	Error, // Unspecified error.
+	IndexOutOfRange, // An index is >= MeshDecl vertexCount.
+	InvalidFaceVertexCount, // Must be >= 3.
+	InvalidIndexCount // Not evenly divisible by 3 - expecting triangles.
 };
 
 // Add a mesh to the atlas. MeshDecl data is copied, so it can be freed after AddMesh returns.
-AddMeshError::Enum AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountHint = 0);
+AddMeshError AddMesh(Atlas *atlas, const MeshDecl &meshDecl, uint32_t meshCountHint = 0);
 
 // Wait for AddMesh async processing to finish. ComputeCharts / Generate call this internally.
 void AddMeshJoin(Atlas *atlas);
 
-struct UvMeshDecl
-{
+struct UvMeshDecl {
 	const void *vertexUvData = nullptr;
 	const void *indexData = nullptr; // optional
-	const uint32_t *faceMaterialData = nullptr; // Optional. Faces with different materials won't be assigned to the same chart. Must be indexCount / 3 in length.
+	const uint32_t *faceMaterialData = nullptr; // Optional. Overlapping UVs should be assigned a different material. Must be indexCount / 3 in length.
 	uint32_t vertexCount = 0;
 	uint32_t vertexStride = 0;
 	uint32_t indexCount = 0;
 	int32_t indexOffset = 0; // optional. Add this offset to all indices.
-	IndexFormat::Enum indexFormat = IndexFormat::UInt16;
-	bool rotateCharts = true;
+	IndexFormat indexFormat = IndexFormat::UInt16;
 };
 
-AddMeshError::Enum AddUvMesh(Atlas *atlas, const UvMeshDecl &decl);
+AddMeshError AddUvMesh(Atlas *atlas, const UvMeshDecl &decl);
+
+// Custom parameterization function. texcoords initial values are an orthogonal parameterization.
+typedef void (*ParameterizeFunc)(const float *positions, float *texcoords, uint32_t vertexCount, const uint32_t *indices, uint32_t indexCount);
+
+struct ChartOptions {
+	ParameterizeFunc paramFunc = nullptr;
 
-struct ChartOptions
-{
 	float maxChartArea = 0.0f; // Don't grow charts to be larger than this. 0 means no limit.
 	float maxBoundaryLength = 0.0f; // Don't grow charts to have a longer boundary than this. 0 means no limit.
 
@@ -180,26 +176,31 @@ struct ChartOptions
 
 	float maxCost = 2.0f; // If total of all metrics * weights > maxCost, don't grow chart. Lower values result in more charts.
 	uint32_t maxIterations = 1; // Number of iterations of the chart growing and seeding phases. Higher values result in better charts.
+
+	bool useInputMeshUvs = false; // Use MeshDecl::vertexUvData for charts.
+	bool fixWinding = false; // Enforce consistent texture coordinate winding.
 };
 
 // Call after all AddMesh calls. Can be called multiple times to recompute charts with different options.
 void ComputeCharts(Atlas *atlas, ChartOptions options = ChartOptions());
 
-// Custom parameterization function. texcoords initial values are an orthogonal parameterization.
-typedef void (*ParameterizeFunc)(const float *positions, float *texcoords, uint32_t vertexCount, const uint32_t *indices, uint32_t indexCount);
+struct PackOptions {
+	// Charts larger than this will be scaled down. 0 means no limit.
+	uint32_t maxChartSize = 0;
 
-struct ParameterizeOptions
-{
-	ParameterizeFunc func = nullptr;
-	bool closeHoles = true; // If the custom parameterization function works with multiple boundaries, this can be set to false to improve performance.
-	bool fixTJunctions = true; // If meshes don't have T-junctions, this can be set to false to improve performance.
-};
+	// Number of pixels to pad charts with.
+	uint32_t padding = 0;
+
+	// Unit to texel scale. e.g. a 1x1 quad with texelsPerUnit of 32 will take up approximately 32x32 texels in the atlas.
+	// If 0, an estimated value will be calculated to approximately match the given resolution.
+	// If resolution is also 0, the estimated value will approximately match a 1024x1024 atlas.
+	float texelsPerUnit = 0.0f;
 
-// Call after ComputeCharts. Can be called multiple times to re-parameterize charts with a different ParameterizeFunc.
-void ParameterizeCharts(Atlas *atlas, ParameterizeOptions options = ParameterizeOptions());
+	// If 0, generate a single atlas with texelsPerUnit determining the final resolution.
+	// If not 0, and texelsPerUnit is not 0, generate one or more atlases with that exact resolution.
+	// If not 0, and texelsPerUnit is 0, texelsPerUnit is estimated to approximately match the resolution.
+	uint32_t resolution = 0;
 
-struct PackOptions
-{
 	// Leave space around charts for texels that would be sampled by bilinear filtering.
 	bool bilinear = true;
 
@@ -212,44 +213,29 @@ struct PackOptions
 	// Create Atlas::image
 	bool createImage = false;
 
-	// Charts larger than this will be scaled down. 0 means no limit.
-	uint32_t maxChartSize = 0;
-
-	// Number of pixels to pad charts with.
-	uint32_t padding = 0;
+	// Rotate charts to the axis of their convex hull.
+	bool rotateChartsToAxis = true;
 
-	// Unit to texel scale. e.g. a 1x1 quad with texelsPerUnit of 32 will take up approximately 32x32 texels in the atlas.
-	// If 0, an estimated value will be calculated to approximately match the given resolution.
-	// If resolution is also 0, the estimated value will approximately match a 1024x1024 atlas.
-	float texelsPerUnit = 0.0f;
-
-	// If 0, generate a single atlas with texelsPerUnit determining the final resolution.
-	// If not 0, and texelsPerUnit is not 0, generate one or more atlases with that exact resolution.
-	// If not 0, and texelsPerUnit is 0, texelsPerUnit is estimated to approximately match the resolution.
-	uint32_t resolution = 0;
+	// Rotate charts to improve packing.
+	bool rotateCharts = true;
 };
 
-// Call after ParameterizeCharts. Can be called multiple times to re-pack charts with different options.
+// Call after ComputeCharts. Can be called multiple times to re-pack charts with different options.
 void PackCharts(Atlas *atlas, PackOptions packOptions = PackOptions());
 
-// Equivalent to calling ComputeCharts, ParameterizeCharts and PackCharts in sequence. Can be called multiple times to regenerate with different options.
-void Generate(Atlas *atlas, ChartOptions chartOptions = ChartOptions(), ParameterizeOptions parameterizeOptions = ParameterizeOptions(), PackOptions packOptions = PackOptions());
+// Equivalent to calling ComputeCharts and PackCharts in sequence. Can be called multiple times to regenerate with different options.
+void Generate(Atlas *atlas, ChartOptions chartOptions = ChartOptions(), PackOptions packOptions = PackOptions());
 
 // Progress tracking.
-struct ProgressCategory
-{
-	enum Enum
-	{
-		AddMesh,
-		ComputeCharts,
-		ParameterizeCharts,
-		PackCharts,
-		BuildOutputMeshes
-	};
+enum class ProgressCategory {
+	AddMesh,
+	ComputeCharts,
+	PackCharts,
+	BuildOutputMeshes
 };
 
 // May be called from any thread. Return false to cancel.
-typedef bool (*ProgressFunc)(ProgressCategory::Enum category, int progress, void *userData);
+typedef bool (*ProgressFunc)(ProgressCategory category, int progress, void *userData);
 
 void SetProgressCallback(Atlas *atlas, ProgressFunc progressFunc = nullptr, void *progressUserData = nullptr);
 
@@ -263,8 +249,8 @@ typedef int (*PrintFunc)(const char *, ...);
 void SetPrint(PrintFunc print, bool verbose);
 
 // Helper functions for error messages.
-const char *StringForEnum(AddMeshError::Enum error);
-const char *StringForEnum(ProgressCategory::Enum category);
+const char *StringForEnum(AddMeshError error);
+const char *StringForEnum(ProgressCategory category);
 
 } // namespace xatlas