Fix GetTriangles

bindings/java/version.txt

@@ -1 +1 @@
-2.0.2
+2.0.3

src/manifold.cpp

@@ -1053,13 +1053,30 @@ std::vector<float> Manifold::GetVertices() const {
 
 std::vector<int> Manifold::GetTriangles() const {
   const Impl& impl = *GetCsgLeafNode().GetImpl();
-  const Vec<ivec3> triVerts = impl.meshRelation_.triProperties;
+  Vec<ivec3> triVerts = impl.meshRelation_.triProperties;
+  int numTri = impl.NumTri();
   std::vector<int> ret;
-  ret.reserve(triVerts.size() * 3);
-  for (auto& triVert: triVerts) {
-    ret.push_back(triVert[0]);
-    ret.push_back(triVert[1]);
-    ret.push_back(triVert[2]);
+  ret.reserve(numTri);
+  std::vector<int> triNew2Old(numTri);
+
+  std::iota(triNew2Old.begin(), triNew2Old.end(), 0);
+  const bool isOriginal = impl.meshRelation_.originalID >= 0;
+  VecView<const TriRef> triRef = impl.meshRelation_.triRef;
+  // Don't sort originals - keep them in order
+  if (!isOriginal) {
+    std::sort(triNew2Old.begin(), triNew2Old.end(), [triRef](int a, int b) {
+      return triRef[a].originalID == triRef[b].originalID
+                 ? triRef[a].meshID < triRef[b].meshID
+                 : triRef[a].originalID < triRef[b].originalID;
+    });
+  }
+
+
+  for (int tri = 0; tri < numTri; ++tri) {
+    const int oldTri = triNew2Old[tri];
+    for (const int i : {0, 1, 2})
+      ret.push_back(impl.halfedge_[3 * oldTri + i].startVert);
+
   }
   return ret;
 

test/manifold_test.cpp

@@ -465,6 +465,13 @@ TEST(Manifold, Slices) {
 }
 #endif
 
+TEST(Manifold, GetTriangles) {
+  Manifold man = Manifold::Cube();
+  std::vector<int> triangles = man.GetTriangles();
+  EXPECT_EQ(man.NumTri(), 12);
+  EXPECT_EQ(triangles.size(), 12*3);
+}
+
 TEST(Manifold, MeshRelation) {
   MeshGL gyroidMeshGL = WithPositionColors(Gyroid()).AsOriginal().GetMeshGL();
   Manifold gyroid(gyroidMeshGL);
@@ -1007,4 +1014,4 @@ TEST(Manifold, MergeRefine) {
   manifold = manifold.RefineToLength(1.0);
   EXPECT_NEAR(manifold.Volume(), 31.21, 0.01);
 }
-#endif
+#endif