private void AddEdge(int v0, int v1, float cost)
{
// remove all edges crossing our clipping edge (TODO: could we split them instead?)
Edge clippingEdge = new Edge(v0, v1, cost);
Stack <Edge> candidates = new Stack <Edge>();
candidates.Push(clippingEdge);
while (candidates.Count > 0)
{
Edge cEdge = candidates.Pop();
bool isect = false;
if ((vertices[cEdge.v[0]] - vertices[cEdge.v[1]]).Length() > 1e-3f)
{
foreach (Edge e in edges)
{
Vertex p;
if (e.v[0] != cEdge.v[0] && e.v[0] != cEdge.v[1] &&
e.v[1] != cEdge.v[0] && e.v[1] != cEdge.v[1] &&
GeomUtils.SegmentIntersect(vertices[e.v[0]], vertices[e.v[1]], vertices[cEdge.v[0]], vertices[cEdge.v[1]], out p))
{
vertices.Add(p);
int isectIdx = vertices.Count - 1;
edges.Remove(e);
edges.Add(new Edge(e.v[0], isectIdx, e.cost));
edges.Add(new Edge(isectIdx, e.v[1], e.cost));
candidates.Push(new Edge(cEdge.v[0], isectIdx, cost));
candidates.Push(new Edge(isectIdx, cEdge.v[1], cost));
isect = true;
break;
}
}
if (!isect)
{
edges.Add(cEdge);
}
}
}
}
public bool FlipTriangles(int tri1, int tri2, out int[] result)
{
Triangle triangle1 = triangles[tri1];
Debug.Assert(triangle1.valid);
Triangle triangle2 = triangles[tri2];
Debug.Assert(triangle2.valid);
int commonEdgeIdx = CommonEdge(triangle1, triangle2);
Debug.Assert(commonEdgeIdx >= 0);
Edge commonEdge = edges[commonEdgeIdx];
Debug.Assert(commonEdge.triangles[0] == tri1 || commonEdge.triangles[0] == tri2);
Debug.Assert(commonEdge.triangles[1] == tri1 || commonEdge.triangles[1] == tri2);
// Tri1 = A,B,C
// Tri2 = B,D,C
// commonEdge = B,C
int localEdgeT1 = triangle1.LocalEdgeIndex(commonEdgeIdx);
Debug.Assert(localEdgeT1 >= 0);
int localEdgeT2 = triangle2.LocalEdgeIndex(commonEdgeIdx);
Debug.Assert(localEdgeT2 >= 0);
int A = VertexOutOfTriEdge(tri1, localEdgeT1);
int D = VertexOutOfTriEdge(tri2, localEdgeT2);
Debug.Assert(A >= 0);
Debug.Assert(D >= 0);
int B = (commonEdge.triangles[0] == tri1 ? commonEdge.vertices[0] : commonEdge.vertices[1]);
int C = (B == commonEdge.vertices[0] ? commonEdge.vertices[1] : commonEdge.vertices[0]);
Debug.Assert(A != B && A != C && A != D && B != C && B != D && C != D);
result = new int[2];
if (!GeomUtils.SegmentIntersect(vertices[A], vertices[D], vertices[B], vertices[C]))
{
// can't flip
result[0] = result[1] = -1;
return(false);
}
float closestAngleBefore = Math.Min(ClosestAngleOnTri(A, B, C), ClosestAngleOnTri(B, D, C));
if (!IsWorthFlipping(A, B, C, D))
{
// The resulting triangles would not improve the triangulation, don't bother
return(false);
}
RemoveTriangle(tri1);
RemoveTriangle(tri2);
result[0] = CreateTriangle(A, B, D);
result[1] = CreateTriangle(A, D, C);
float closestAngleAfter = Math.Min(ClosestAngleOnTri(A, B, D), ClosestAngleOnTri(A, D, C));
//Debug.Assert(closestAngleBefore < closestAngleAfter);
#if DEBUG
Debug.Assert(CheckConsistency());
#endif
return(true);
}