private static void FixWindingOrder(ref SortedVertex edgeV1, ref SortedVertex edgeV2, SortedVertex v1)
{
var crossProduct = TriangulationHelper.CrossProduct(edgeV2.Vertex - edgeV1.Vertex, v1.Vertex - edgeV2.Vertex);
if (crossProduct > 0)
{
TriangulationHelper.Swap(ref edgeV1, ref edgeV2);
}
}
public static bool Validate(int leftVertexIndex, int rightVertexIndex, int outerVertexIndex, int innerVertexIndex,
IReadOnlyList<SortedVertex> vertices)
{
var leftVertex = vertices[leftVertexIndex].Vertex;
var rightVertex = vertices[rightVertexIndex].Vertex;
var outerVertex = vertices[outerVertexIndex].Vertex;
var innerVertex = vertices[innerVertexIndex].Vertex;
if (outerVertexIndex == innerVertexIndex)
{
return true;
}
if (TriangulationHelper.CrossProduct(leftVertex - outerVertex, innerVertex - outerVertex) < 0 ||
TriangulationHelper.CrossProduct(rightVertex - outerVertex, innerVertex - outerVertex) > 0)
{
return true;
}
var sa = (outerVertex.x - rightVertex.x) * (outerVertex.x - leftVertex.x) +
(outerVertex.y - rightVertex.y) * (outerVertex.y - leftVertex.y);
var sb = (innerVertex.x - rightVertex.x) * (innerVertex.x - leftVertex.x) +
(innerVertex.y - rightVertex.y) * (innerVertex.y - leftVertex.y);
if (sa > -Eps && sb > -Eps)
{
return true;
}
if (sa < 0 && sb < 0)
{
return false;
}
var sc = TriangulationHelper.CrossProduct(outerVertex - rightVertex, outerVertex - leftVertex);
var sd = TriangulationHelper.CrossProduct(innerVertex - rightVertex, innerVertex - leftVertex);
if (sc < 0)
sc = -sc;
if (sd < 0)
sd = -sd;
return sc * sb + sa * sd > -Eps;
}