/**
* sort sites on y, then x, coord
* also change each site's _siteIndex to match its new position in the list
* so the _siteIndex can be used to identify the site for nearest-neighbor queries
*
* haha "also" - means more than one responsibility...
*
*/
public int CompareTo(object obj)
// XXX: Really, really worried about this because it depends on how sorting works in AS3 impl - Julian
{
var s2 = (Site)obj;
var returnValue = Voronoi.CompareByYThenX(this, s2);
// swap _siteIndex values if necessary to match new ordering:
uint tempIndex;
if (returnValue == -1)
{
if (_siteIndex > s2._siteIndex)
{
tempIndex = _siteIndex;
_siteIndex = s2._siteIndex;
s2._siteIndex = tempIndex;
}
}
else if (returnValue == 1)
{
if (s2._siteIndex > _siteIndex)
{
tempIndex = s2._siteIndex;
s2._siteIndex = _siteIndex;
_siteIndex = tempIndex;
}
}
return(returnValue);
}
/**
* This is the only way to make a Vertex
*
* @param halfedge0
* @param halfedge1
* @return
*
*/
public static Vertex Intersect(HalfEdge halfedge0, HalfEdge halfedge1)
{
Edge edge;
HalfEdge halfEdge;
var edge0 = halfedge0.Edge;
var edge1 = halfedge1.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)
{
// the edges are parallel
return(null);
}
var intersectionX = (edge0.C * edge1.B - edge1.C * edge0.B) / determinant;
var intersectionY = (edge1.C * edge0.A - edge0.C * edge1.A) / determinant;
if (Voronoi.CompareByYThenX(edge0.RightSite, edge1.RightSite) < 0)
{
halfEdge = halfedge0;
edge = edge0;
}
else
{
halfEdge = halfedge1;
edge = edge1;
}
var rightOfSite = intersectionX >= edge.RightSite.X;
if ((rightOfSite && halfEdge.LeftRight == Side.Left) ||
(!rightOfSite && halfEdge.LeftRight == Side.Right))
{
return(null);
}
return(Create(intersectionX, intersectionY));
}