+ def prepare_triangles(self, progress):
+ face_count = len(self.faces)
+ for i in range(face_count):
+ f = self.faces[i]
+ nverts = len(f.vertices)
+ if nverts==3:
+ continue
+
+ # Calculate normals at each vertex of the face
+ edge_vecs = []
+ for j in range(nverts):
+ edge_vecs.append(f.vertices[(j+1)%nverts].co-f.vertices[j].co)
+
+ normals = []
+ for j in range(nverts):
+ normals.append(edge_vecs[j-1].cross(edge_vecs[j]).normalized())
+
+ # Check which diagonal results in a flatter triangulation
+ flatness1 = normals[0].dot(normals[2])
+ flatness2 = normals[1].dot(normals[3])
+ cut_index = 1 if flatness1>flatness2 else 0
+
+ nf = Face(f)
+ nf.index = len(self.faces)
+ self.faces.append(nf)
+
+ ne = Edge(None)
+ ne.index = len(self.edges)
+ self.edges.append(ne)
+
+ nf.vertices = [f.vertices[cut_index], f.vertices[2], f.vertices[3]]
+ nf.loop_indices = [f.loop_indices[cut_index], f.loop_indices[2], f.loop_indices[3]]
+ for v in nf.vertices:
+ v.faces.append(nf)
+
+ ne.vertices = [f.vertices[cut_index], f.vertices[2+cut_index]]
+ for v in ne.vertices:
+ v.edges.append(ne)
+ ne.key = make_edge_key(ne.vertices[0].index, ne.vertices[1].index)
+ ne.smooth = True
+
+ f.vertices[3-cut_index].faces.remove(f)
+ del f.vertices[3-cut_index]
+ f.loop_indices = [f.loop_indices[0], f.loop_indices[1], f.loop_indices[2+cut_index]]
+
+ ne.faces = [f, nf]
+ if cut_index==0:
+ nf.edges = [ne, f.edges[2], f.edges[3]]
+ f.edges = [f.edges[0], f.edges[1], ne]
+ else:
+ nf.edges = [f.edges[1], f.edges[2], ne]
+ f.edges = [f.edges[0], ne, f.edges[3]]
+ for e in nf.edges:
+ if e!=ne:
+ e.faces.remove(f)
+ e.faces.append(nf)
+
+ f.normal = normals[1-cut_index]
+ nf.normal = normals[3-cut_index]
+
+ progress.set_progress(i/face_count)
+
+ def prepare_smoothing(self, progress):