1 files changed, 49 insertions, 5 deletions

diff --git a/core/math/convex_hull.cpp b/core/math/convex_hull.cpp
index 996f4f4d67..561970d2ee 100644
--- a/core/math/convex_hull.cpp
+++ b/core/math/convex_hull.cpp
@@ -62,6 +62,7 @@ subject to the following restrictions:
 #include "core/math/aabb.h"
 #include "core/math/math_defs.h"
 #include "core/os/memory.h"
+#include "core/templates/oa_hash_map.h"
 #include "core/templates/paged_allocator.h"
 
 #include <string.h>
@@ -2252,19 +2253,62 @@ Error ConvexHullComputer::convex_hull(const Vector<Vector3> &p_points, Geometry3
 
 	r_mesh.vertices = ch.vertices;
 
+	// Tag which face each edge belongs to
+	LocalVector<int32_t> edge_faces;
+	edge_faces.resize(ch.edges.size());
+
+	for (uint32_t i = 0; i < ch.edges.size(); i++) {
+		edge_faces[i] = -1;
+	}
+
+	for (uint32_t i = 0; i < ch.faces.size(); i++) {
+		const Edge *e_start = &ch.edges[ch.faces[i]];
+		const Edge *e = e_start;
+		do {
+			int64_t ofs = e - ch.edges.ptr();
+			edge_faces[ofs] = i;
+
+			e = e->get_next_edge_of_face();
+		} while (e != e_start);
+	}
+
 	// Copy the edges over. There's two "half-edges" for every edge, so we pick only one of them.
 	r_mesh.edges.resize(ch.edges.size() / 2);
+	OAHashMap<uint64_t, int32_t> edge_map;
+	edge_map.reserve(ch.edges.size() * 4); // The higher the capacity, the faster the insert
+
 	uint32_t edges_copied = 0;
 	for (uint32_t i = 0; i < ch.edges.size(); i++) {
+		ERR_CONTINUE(edge_faces[i] == -1); // Sanity check
+
 		uint32_t a = (&ch.edges[i])->get_source_vertex();
 		uint32_t b = (&ch.edges[i])->get_target_vertex();
 		if (a < b) { // Copy only the "canonical" edge. For the reverse edge, this will be false.
 			ERR_BREAK(edges_copied >= (uint32_t)r_mesh.edges.size());
-			r_mesh.edges.write[edges_copied].a = a;
-			r_mesh.edges.write[edges_copied].b = b;
+			r_mesh.edges[edges_copied].vertex_a = a;
+			r_mesh.edges[edges_copied].vertex_b = b;
+			r_mesh.edges[edges_copied].face_a = edge_faces[i];
+			r_mesh.edges[edges_copied].face_b = -1;
+
+			uint64_t key = a;
+			key <<= 32;
+			key |= b;
+			edge_map.insert(key, edges_copied);
+
 			edges_copied++;
+		} else {
+			uint64_t key = b;
+			key <<= 32;
+			key |= a;
+			int32_t index;
+			if (!edge_map.lookup(key, index)) {
+				ERR_PRINT("Invalid edge");
+			} else {
+				r_mesh.edges[index].face_b = edge_faces[i];
+			}
 		}
 	}
+
 	if (edges_copied != (uint32_t)r_mesh.edges.size()) {
 		ERR_PRINT("Invalid edge count.");
 	}
@@ -2273,7 +2317,7 @@ Error ConvexHullComputer::convex_hull(const Vector<Vector3> &p_points, Geometry3
 	for (uint32_t i = 0; i < ch.faces.size(); i++) {
 		const Edge *e_start = &ch.edges[ch.faces[i]];
 		const Edge *e = e_start;
-		Geometry3D::MeshData::Face &face = r_mesh.faces.write[i];
+		Geometry3D::MeshData::Face &face = r_mesh.faces[i];
 
 		do {
 			face.indices.push_back(e->get_target_vertex());
@@ -2284,8 +2328,8 @@ Error ConvexHullComputer::convex_hull(const Vector<Vector3> &p_points, Geometry3
 		// reverse indices: Godot wants clockwise, but this is counter-clockwise
 		if (face.indices.size() > 2) {
 			// reverse all but the first index.
-			int *indices = face.indices.ptrw();
-			for (int c = 0; c < (face.indices.size() - 1) / 2; c++) {
+			int *indices = face.indices.ptr();
+			for (uint32_t c = 0; c < (face.indices.size() - 1) / 2; c++) {
 				SWAP(indices[c + 1], indices[face.indices.size() - 1 - c]);
 			}
 		}