public static Vertex Intersect(HalfEdge he0, HalfEdge he1)
{
var edge0 = he0.Edge;
var edge1 = he1.Edge;
if (edge0 == null || edge1 == null)
{
return(null);
}
if (edge0.RightSite == edge1.RightSite)
{
return(null);
}
var determinant = edge0.A * edge1.B - edge0.B * edge1.A;
if (-1.0e-10 < determinant && determinant < 1.0e-10)
{
return(null);
}
var intersectionX = (edge0.C * edge1.B - edge1.C * edge0.B) / determinant;
var intersectionY = (edge1.C * edge0.A - edge0.C * edge1.A) / determinant;
HalfEdge halfEdge;
Edge edge;
if (Voronoi.CompareByYThenX(edge0.RightSite, edge1.RightSite) < 0)
{
halfEdge = he0;
edge = edge0;
}
else
{
halfEdge = he1;
edge = edge1;
}
var rightOfSite = intersectionX >= edge.RightSite.X;
if ((rightOfSite && halfEdge.LeftRight == LR.Left) || (!rightOfSite && halfEdge.LeftRight == LR.Right))
{
return(null);
}
return(Create(intersectionX, intersectionY));
}
public int Compare(Site s1, Site s2)
{
var ret = Voronoi.CompareByYThenX(s1, s2);
if (ret == -1)
{
if (s1._siteIndex > s2._siteIndex)
{
var tempIndex = s1._siteIndex;
s1._siteIndex = s2._siteIndex;
s2._siteIndex = tempIndex;
}
else if (ret == 1)
{
var tempIndex = s2._siteIndex;
s2._siteIndex = s1._siteIndex;
s1._siteIndex = tempIndex;
}
}
return(ret);
}