Delaunay.Voronoi.FortunesAlgorithm C# (CSharp) Method

		private void FortunesAlgorithm ()
		{
			Site newSite, bottomSite, topSite, tempSite;
			Vertex v, vertex;
			Vector2 newintstar = Vector2.zero; //Because the compiler doesn't know that it will have a value - Julian
			Side leftRight;
			Halfedge lbnd, rbnd, llbnd, rrbnd, bisector;
			Edge edge;
			
			Rect dataBounds = _sites.GetSitesBounds ();
			
			int sqrt_nsites = (int)(Mathf.Sqrt (_sites.Count + 4));
			HalfedgePriorityQueue heap = new HalfedgePriorityQueue (dataBounds.y, dataBounds.height, sqrt_nsites);
			EdgeList edgeList = new EdgeList (dataBounds.x, dataBounds.width, sqrt_nsites);
			List<Halfedge> halfEdges = new List<Halfedge> ();
			List<Vertex> vertices = new List<Vertex> ();
			
			fortunesAlgorithm_bottomMostSite = _sites.Next ();
			newSite = _sites.Next ();
			
			for (;;) {
				if (heap.Empty () == false) {
					newintstar = heap.Min ();
				}
			
				if (newSite != null 
					&& (heap.Empty () || CompareByYThenX (newSite, newintstar) < 0)) {
					/* new site is smallest */
					//trace("smallest: new site " + newSite);
					
					// Step 8:
					lbnd = edgeList.EdgeListLeftNeighbor (newSite.Coord);	// the Halfedge just to the left of newSite
					//trace("lbnd: " + lbnd);
					rbnd = lbnd.edgeListRightNeighbor;		// the Halfedge just to the right
					//trace("rbnd: " + rbnd);
					bottomSite = FortunesAlgorithm_rightRegion (lbnd);		// 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.Dist (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.Dist (vertex);
						heap.Insert (bisector);	
					}
					
					newSite = _sites.Next ();	
				} else if (heap.Empty () == false) {
					/* intersection is smallest */
					lbnd = heap.ExtractMin ();
					llbnd = lbnd.edgeListLeftNeighbor;
					rbnd = lbnd.edgeListRightNeighbor;
					rrbnd = rbnd.edgeListRightNeighbor;
					bottomSite = FortunesAlgorithm_leftRegion (lbnd);
					topSite = FortunesAlgorithm_rightRegion (rbnd);
					// these three sites define a Delaunay triangle
					// (not actually using these for anything...)
                    _triangles.Add(new Triangle(bottomSite, topSite, FortunesAlgorithm_rightRegion(lbnd)));
					
					v = lbnd.vertex;
					v.SetIndex ();
					lbnd.edge.SetVertex ((Side)lbnd.leftRight, v);
					rbnd.edge.SetVertex ((Side)rbnd.leftRight, v);
					edgeList.Remove (lbnd); 
					heap.Remove (rbnd);
					edgeList.Remove (rbnd); 
					leftRight = Side.LEFT;
					if (bottomSite.y > topSite.y) {
						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.Dist (vertex);
						heap.Insert (llbnd);
					}
					if ((vertex = Vertex.Intersect (bisector, rrbnd)) != null) {
						vertices.Add (vertex);
						bisector.vertex = vertex;
						bisector.ystar = vertex.y + bottomSite.Dist (vertex);
						heap.Insert (bisector);
					}
				} else {
					break;
				}
			}
			
			// heap should be empty now
			heap.Dispose ();
			edgeList.Dispose ();
			
			for (int hIndex = 0; hIndex<halfEdges.Count; hIndex++) {
				Halfedge halfEdge = halfEdges [hIndex];
				halfEdge.ReallyDispose ();
			}
			halfEdges.Clear ();
			
			// we need the vertices to clip the edges
			for (int eIndex = 0; eIndex<_edges.Count; eIndex++) {
				edge = _edges [eIndex];
				edge.ClipVertices (_plotBounds);
			}
			// but we don't actually ever use them again!
			for (int vIndex = 0; vIndex<vertices.Count; vIndex++) {
				vertex = vertices [vIndex];
				vertex.Dispose ();
			}
			vertices.Clear ();
		}