Fixed a crash in the modified butterfly subdivider with vertices with valance larger than 30.

src/OpenMesh/Tools/Subdivider/Uniform/ModifiedButterFlyT.hh

@@ -179,6 +179,17 @@ protected:
 
     ///TODO:Implement fixed positions
 
+    // Compute the maximal vertex valence in the mesh
+    unsigned int maxValence = 0;
+    for ( auto vertex : _m.vertices() ) {
+        maxValence = std::max(maxValence,_m.valence(vertex));
+    }
+
+    // We pre initialized with 30. If it's larger, we update the weights
+    if (maxValence >= 30) {
+        init_weights( maxValence + 1 );
+    }
+
     // Do _n subdivisions
     for (size_t i=0; i < _n; ++i)
     {

src/Unittests/unittests_subdivider_uniform.cc

@@ -1027,6 +1027,28 @@ TEST_F(OpenMeshSubdividerUniform_Triangle, Modified_Butterfly) {
 
 
 
+TEST_F(OpenMeshSubdividerUniform_Triangle, Modified_Butterfly_cylinder) {
+    mesh_.clear();
+
+    OpenMesh::IO::read_mesh(mesh_, "cylinder.om");
+
+    // Initialize subdivider
+    OpenMesh::Subdivider::Uniform::ModifiedButterflyT<Mesh> butter;
+
+    // Check setup
+    EXPECT_EQ(66u, mesh_.n_vertices() ) << "Wrong number of vertices";
+    EXPECT_EQ(128u, mesh_.n_faces() )    << "Wrong number of faces";
+
+    // Execute 3 subdivision steps
+    butter( mesh_,3,true );
+
+    // Check setup
+    EXPECT_EQ(4098u, mesh_.n_vertices() ) << "Wrong number of vertices after subdivision with loop";
+    EXPECT_EQ(8192u, mesh_.n_faces() )    << "Wrong number of faces after subdivision with loop";
+}
+
+
+
 TEST_F(OpenMeshSubdividerUniform_Triangle, Modified_Butterfly_delete_vertex) {
 
   for (bool collect_garbage : { false, true })