allow MeshEditor.StitchUnorderedEdges to optionally return partial-success result. Allows us to handle any holes further downstream. Common failure cases is input bowtie vertex, can't do the stitch because it would be non-manifold, but only leaves a one-triangle hole that we can easily repair.

Author: rms80

mesh/MeshEditor.cs

@@ -182,29 +182,39 @@ public virtual int[] StitchLoop(int[] vloop1, int[] vloop2, int group_id = -1)
  /// <summary>
  /// Stitch two sets of boundary edges that are provided as unordered pairs of edges, by
  /// adding triangulated quads between each edge pair. 
- /// If a failure is encountered during stitching, the triangles added up to that point are removed.
+ /// If bAbortOnFailure==true and a failure is encountered during stitching, the triangles added up to that point are removed.
+ /// If bAbortOnFailure==false, failures are ignored and the returned triangle list may contain invalid values!
  /// </summary>
- public virtual int[] StitchUnorderedEdges(List<Index2i> EdgePairs, int group_id = -1)
+ public virtual int[] StitchUnorderedEdges(List<Index2i> EdgePairs, int group_id, bool bAbortOnFailure, out bool stitch_incomplete)
  {
  int N = EdgePairs.Count;
  int[] new_tris = new int[N * 2];
+ if (bAbortOnFailure == false) {
+ for (int k = 0; k < new_tris.Length; ++k)
+ new_tris[k] = DMesh3.InvalidID;
+ }
+ stitch_incomplete = false;
 
  int i = 0;
  for (; i < N; ++i) {
  Index2i edges = EdgePairs[i];
 
  // look up and orient the first edge
  Index4i edge_a = Mesh.GetEdge(edges.a);
- if ( edge_a.d != DMesh3.InvalidID )
- goto operation_failed;
+ if (edge_a.d != DMesh3.InvalidID) {
+ if (bAbortOnFailure) goto operation_failed;
+ else { stitch_incomplete = true; continue; }
+ }
  Index3i edge_a_tri = Mesh.GetTriangle(edge_a.c);
  int a = edge_a.a, b = edge_a.b;
  IndexUtil.orient_tri_edge(ref a, ref b, edge_a_tri);
 
  // look up and orient the second edge
  Index4i edge_b = Mesh.GetEdge(edges.b);
- if (edge_b.d != DMesh3.InvalidID)
- goto operation_failed;
+ if (edge_b.d != DMesh3.InvalidID) {
+ if (bAbortOnFailure) goto operation_failed;
+ else { stitch_incomplete = true; continue; }
+ }
  Index3i edge_b_tri = Mesh.GetTriangle(edge_b.c);
  int c = edge_b.a, d = edge_b.b;
  IndexUtil.orient_tri_edge(ref c, ref d, edge_b_tri);
@@ -218,8 +228,10 @@ public virtual int[] StitchUnorderedEdges(List<Index2i> EdgePairs, int group_id
  int tid1 = Mesh.AppendTriangle(t1, group_id);
  int tid2 = Mesh.AppendTriangle(t2, group_id);
 
- if (tid1 < 0 || tid2 < 0)
- goto operation_failed;
+ if (tid1 < 0 || tid2 < 0) {
+ if (bAbortOnFailure) goto operation_failed;
+ else { stitch_incomplete = true; continue; }
+ }
 
  new_tris[2 * i] = tid1;
  new_tris[2 * i + 1] = tid2;
@@ -235,6 +247,11 @@ public virtual int[] StitchUnorderedEdges(List<Index2i> EdgePairs, int group_id
  }
  return null;
  }
+ public virtual int[] StitchUnorderedEdges(List<Index2i> EdgePairs, int group_id = -1, bool bAbortOnFailure = true)
+ {
+ bool incomplete = false;
+ return StitchUnorderedEdges(EdgePairs, group_id, bAbortOnFailure, out incomplete);
+ }