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// This code is in the public domain -- castanyo@yahoo.es
#include "nvmesh.h" // pch
#include "Face.h"
#include "Vertex.h"
#include "nvmath/Fitting.h"
#include "nvmath/Plane.h"
#include "nvmath/Vector.inl"
#include "nvcore/Array.h"
using namespace nv;
using namespace HalfEdge;
/// Get face area.
float Face::area() const
{
float area = 0;
const Vector3 & v0 = edge->from()->pos;
for (ConstEdgeIterator it(edges(edge->next)); it.current() != edge->prev; it.advance())
{
const Edge * e = it.current();
const Vector3 & v1 = e->vertex->pos;
const Vector3 & v2 = e->next->vertex->pos;
area += length(cross(v1-v0, v2-v0));
}
return area * 0.5f;
}
float Face::parametricArea() const
{
float area = 0;
const Vector2 & v0 = edge->from()->tex;
for (ConstEdgeIterator it(edges(edge->next)); it.current() != edge->prev; it.advance())
{
const Edge * e = it.current();
const Vector2 & v1 = e->vertex->tex;
const Vector2 & v2 = e->next->vertex->tex;
area += triangleArea(v0, v1, v2);
}
return area * 0.5f;
}
/// Get boundary length.
float Face::boundaryLength() const
{
float bl = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
bl += edge->length();
}
return bl;
}
/// Get face normal.
Vector3 Face::normal() const
{
Vector3 n(0);
const Vertex * vertex0 = NULL;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
nvCheck(edge != NULL);
if (vertex0 == NULL)
{
vertex0 = edge->vertex;
}
else if (edge->next->vertex != vertex0)
{
const HalfEdge::Vertex * vertex1 = edge->from();
const HalfEdge::Vertex * vertex2 = edge->to();
const Vector3 & p0 = vertex0->pos;
const Vector3 & p1 = vertex1->pos;
const Vector3 & p2 = vertex2->pos;
Vector3 v10 = p1 - p0;
Vector3 v20 = p2 - p0;
n += cross(v10, v20);
}
}
return normalizeSafe(n, Vector3(0, 0, 1), 0.0f);
// Get face points eliminating duplicates.
/*Array<Vector3> points(4);
points.append(m_edge->prev()->from()->pos);
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
nvDebugCheck(edge != NULL);
const Vector3 & p = edge->from()->pos;
if (points.back() != p)
{
points.append(edge->from()->pos);
}
}
points.popBack();
if (points.count() < 3)
{
// Invalid normal.
return Vector3(0.0f);
}
else
{
// Compute regular normal.
Vector3 normal = normalizeSafe(cross(points[1] - points[0], points[2] - points[0]), Vector3(0.0f), 0.0f);
#pragma NV_MESSAGE("TODO: make sure these three points are not colinear")
if (points.count() > 3)
{
// Compute best fitting plane to the points.
Plane plane = Fit::bestPlane(points.count(), points.buffer());
// Adjust normal orientation.
if (dot(normal, plane.vector()) > 0) {
normal = plane.vector();
}
else {
normal = -plane.vector();
}
}
nvDebugCheck(isNormalized(normal));
return normal;
}*/
}
Vector3 Face::centroid() const
{
Vector3 sum(0.0f);
uint count = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
sum += edge->from()->pos;
count++;
}
return sum / float(count);
}
bool Face::isValid() const
{
uint count = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
if (edge->face != this) return false;
if (!edge->isValid()) return false;
if (!edge->pair->isValid()) return false;
count++;
}
if (count < 3) return false;
return true;
}
// Determine if this face contains the given edge.
bool Face::contains(const Edge * e) const
{
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
if(it.current() == e) return true;
}
return false;
}
// Returns index in this face of the given edge.
uint Face::edgeIndex(const Edge * e) const
{
int i = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance(), i++)
{
if(it.current() == e) return i;
}
return NIL;
}
Edge * Face::edgeAt(uint idx)
{
int i = 0;
for(EdgeIterator it(edges()); !it.isDone(); it.advance(), i++) {
if (i == idx) return it.current();
}
return NULL;
}
const Edge * Face::edgeAt(uint idx) const
{
int i = 0;
for(ConstEdgeIterator it(edges()); !it.isDone(); it.advance(), i++) {
if (i == idx) return it.current();
}
return NULL;
}
// Count the number of edges in this face.
uint Face::edgeCount() const
{
uint count = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance()) { ++count; }
return count;
}
// Determine if this is a boundary face.
bool Face::isBoundary() const
{
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
nvDebugCheck(edge->pair != NULL);
if (edge->pair->face == NULL) {
return true;
}
}
return false;
}
// Count the number of boundary edges in the face.
uint Face::boundaryCount() const
{
uint count = 0;
for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
{
const Edge * edge = it.current();
nvDebugCheck(edge->pair != NULL);
if (edge->pair->face == NULL) {
count++;
}
}
return count;
}
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