private void FortunesAlgorithm()
{
var newIntStar = Vector2.zero;
var dataBounds = sites.GetSiteBounds();
var sqrtSiteCount = (int)(Mathf.Sqrt(sites.Count + 4));
var heap = new HalfEdgePriorityQueue(dataBounds.y, dataBounds.height, sqrtSiteCount);
var edgeList = new EdgeList(dataBounds.x, dataBounds.width, sqrtSiteCount);
var halfEdges = new List <HalfEdge>();
var vertices = new List <Vertex>();
var bottomMostSite = sites.Next();
var newSite = sites.Next();
for (;;)
{
if (heap.Empty() == false)
{
newIntStar = heap.Min();
}
Site bottomSite;
Vertex vertex;
HalfEdge lbnd;
HalfEdge rbnd;
HalfEdge bisector;
Edge edge;
if (newSite != null &&
(heap.Empty() || CompareByYThenX(newSite, newIntStar) < 0))
{
/* new site is smallest */
//trace("smallest: new site " + newSite);
// Step 8:
lbnd = edgeList.EdgeListLeftNeighbor(newSite.Coordinate); // the Halfedge just to the left of newSite
//trace("lbnd: " + lbnd);
rbnd = lbnd.EdgeListRightNeighbor; // the Halfedge just to the right
//trace("rbnd: " + rbnd);
bottomSite = RightRegion(lbnd, bottomMostSite); // this is the same as leftRegion(rbnd)
// this Site determines the region containing the new site
//trace("new Site is in region of existing site: " + bottomSite);
// Step 9:
edge = Edge.CreateBisectingEdge(bottomSite, newSite);
//trace("new edge: " + edge);
Edges.Add(edge);
bisector = HalfEdge.Create(edge, Side.Left);
halfEdges.Add(bisector);
// inserting two Halfedges into edgeList constitutes Step 10:
// insert bisector to the right of lbnd:
edgeList.Insert(lbnd, bisector);
// first half of Step 11:
if ((vertex = Vertex.Intersect(lbnd, bisector)) != null)
{
vertices.Add(vertex);
heap.Remove(lbnd);
lbnd.Vertex = vertex;
lbnd.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(lbnd);
}
lbnd = bisector;
bisector = HalfEdge.Create(edge, Side.Right);
halfEdges.Add(bisector);
// second Halfedge for Step 10:
// insert bisector to the right of lbnd:
edgeList.Insert(lbnd, bisector);
// second half of Step 11:
if ((vertex = Vertex.Intersect(bisector, rbnd)) != null)
{
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + newSite.Distance(vertex);
heap.Insert(bisector);
}
newSite = sites.Next();
}
else if (heap.Empty() == false)
{
/* intersection is smallest */
lbnd = heap.ExtractMin();
var llbnd = lbnd.EdgeListLeftNeighbor;
rbnd = lbnd.EdgeListRightNeighbor;
var rrbnd = rbnd.EdgeListRightNeighbor;
bottomSite = LeftRegion(lbnd, bottomMostSite);
var topSite = RightRegion(rbnd, bottomMostSite);
// these three sites define a Delaunay triangle
// (not actually using these for anything...)
//_triangles.push(new Triangle(bottomSite, topSite, rightRegion(lbnd)));
var v = lbnd.Vertex;
v.SetIndex();
lbnd.Edge.SetVertex((Side)lbnd.LeftOrRight, v);
rbnd.Edge.SetVertex((Side)rbnd.LeftOrRight, v);
edgeList.Remove(lbnd);
heap.Remove(rbnd);
edgeList.Remove(rbnd);
var leftRight = Side.Left;
if (bottomSite.Y > topSite.Y)
{
var tempSite = bottomSite;
bottomSite = topSite;
topSite = tempSite;
leftRight = Side.Right;
}
edge = Edge.CreateBisectingEdge(bottomSite, topSite);
Edges.Add(edge);
bisector = HalfEdge.Create(edge, leftRight);
halfEdges.Add(bisector);
edgeList.Insert(llbnd, bisector);
edge.SetVertex(SideHelper.Other(leftRight), v);
if ((vertex = Vertex.Intersect(llbnd, bisector)) != null)
{
vertices.Add(vertex);
heap.Remove(llbnd);
llbnd.Vertex = vertex;
llbnd.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(llbnd);
}
if ((vertex = Vertex.Intersect(bisector, rrbnd)) != null)
{
vertices.Add(vertex);
bisector.Vertex = vertex;
bisector.YStar = vertex.Y + bottomSite.Distance(vertex);
heap.Insert(bisector);
}
}
else
{
break;
}
}
// heap should be empty now
heap.Dispose();
edgeList.Dispose();
foreach (var halfEdge in halfEdges)
{
halfEdge.ReallyDispose();
}
halfEdges.Clear();
// we need the vertices to clip the edges
foreach (var e in Edges)
{
e.ClipVertices(Bounds);
}
// but we don't actually ever use them again!
foreach (var v in vertices)
{
v.Dispose();
}
vertices.Clear();
}
