From f1a86930164b360765c5e04d633aae4d617acdd1 Mon Sep 17 00:00:00 2001
From: Emmett Lalish <elalish@gmail.com>
Date: Tue, 3 Dec 2024 15:19:41 -0800
Subject: [PATCH] Fix DedupePropVerts (#1092)

* added test

* fixed dedupePropVerts

* size_t
---
 src/impl.cpp           | 11 ++++++----
 test/manifold_test.cpp | 48 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/src/impl.cpp b/src/impl.cpp
index 9582b2c12..59cc0293d 100644
--- a/src/impl.cpp
+++ b/src/impl.cpp
@@ -194,13 +194,14 @@ int GetLabels(std::vector<int>& components,
 }
 
 void DedupePropVerts(manifold::Vec<ivec3>& triProp,
-                     const Vec<std::pair<int, int>>& vert2vert) {
+                     const Vec<std::pair<int, int>>& vert2vert,
+                     size_t numPropVert) {
   ZoneScoped;
   std::vector<int> vertLabels;
-  const int numLabels = GetLabels(vertLabels, vert2vert, vert2vert.size());
+  const int numLabels = GetLabels(vertLabels, vert2vert, numPropVert);
 
   std::vector<int> label2vert(numLabels);
-  for (size_t v = 0; v < vert2vert.size(); ++v) label2vert[vertLabels[v]] = v;
+  for (size_t v = 0; v < numPropVert; ++v) label2vert[vertLabels[v]] = v;
   for (auto& prop : triProp)
     for (int i : {0, 1, 2}) prop[i] = label2vert[vertLabels[prop[i]]];
 }
@@ -343,6 +344,8 @@ void Manifold::Impl::CreateFaces() {
           const int prop1 =
               meshRelation_
                   .triProperties[pairFace][jointNum == 2 ? 0 : jointNum + 1];
+          if (prop0 == prop1) return;
+
           bool propEqual = true;
           for (size_t p = 0; p < numProp; ++p) {
             if (meshRelation_.properties[numProp * prop0 + p] !=
@@ -355,7 +358,7 @@ void Manifold::Impl::CreateFaces() {
             vert2vert[edgeIdx] = std::make_pair(prop0, prop1);
           }
         });
-    DedupePropVerts(meshRelation_.triProperties, vert2vert);
+    DedupePropVerts(meshRelation_.triProperties, vert2vert, NumPropVert());
   }
 
   for_each_n(autoPolicy(halfedge_.size(), 1e4), countAt(0), halfedge_.size(),
diff --git a/test/manifold_test.cpp b/test/manifold_test.cpp
index 3d561a1c8..ddaefd2bb 100644
--- a/test/manifold_test.cpp
+++ b/test/manifold_test.cpp
@@ -555,6 +555,54 @@ TEST(Manifold, Merge) {
   CheckCube(cubeSTL);
 }
 
+TEST(Manifold, MergeEmpty) {
+  MeshGL shape;
+  shape.numProp = 7;
+  shape.triVerts = {0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  10, 11,
+                    12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,
+                    24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35};
+  shape.vertProperties = {0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  0.5,  -0.43450000882149, 0.0, 0.0, 0.0, 1.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          0.0,  -0.5, 0.434500008821487, 0.0, 0.0, 1.0, 0.0,
+                          0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          -0.0, 0.5,  0.434500008821487, 0.0, 0.0, 0.0, 1.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          0.0,  0.5,  -0.43450000882149, 0.0, 0.0, 1.0, 0.0,
+                          0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  -0.5, 0.434500008821487, 0.0, 0.0, 0.0, 1.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  0.5,  0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, 0.5,  0.434500008821487, 0.0, 0.0, 1.0, 0.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 1.0, 1.0,
+                          -0.0, 0.5,  0.434500008821487, 0.0, 0.0, 0.0, 1.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 1.0, 1.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 0.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  -0.5, 0.434500008821487, 0.0, 0.0, 0.0, 1.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          -0.0, -0.5, 0.434500008821487, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 0.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  0.5,  -0.43450000882149, 0.0, 0.0, 0.0, 1.0,
+                          -0.0, 0.5,  -0.43450000882149, 0.0, 0.0, 1.0, 1.0,
+                          0.0,  -0.5, -0.43450000882149, 0.0, 0.0, 0.0, 0.0,
+                          -0.0, -0.5, -0.43450000882149, 0.0, 0.0, 1.0, 0.0};
+  EXPECT_TRUE(shape.Merge());
+  Manifold man(shape);
+  EXPECT_EQ(man.Status(), Manifold::Error::NoError);
+  EXPECT_TRUE(man.IsEmpty());
+}
+
 TEST(Manifold, PinchedVert) {
   MeshGL shape;
   shape.numProp = 3;