Delaunay.Halfedge.Create C# (CSharp) Method

        public static Halfedge Create(Edge edge, LR lr)
        {
            if (_pool.Count > 0)
            {
                return _pool.Pop().Init(edge, lr);
            }
            else
            {
                return new Halfedge(typeof(PrivateConstructorEnforcer), edge, lr);
            }
        }

        private void FortunesAlgorithm()
        {
            Site     newSite, bottomSite, topSite, tempSite;
            Vertex   v, vertex;
            PointF   newintstar = PointF.Empty;
            LR       leftRight;
            Halfedge lbnd, rbnd, llbnd, rrbnd, bisector;
            Edge     edge;

            RectangleF dataBounds = _sites.GetSitesBounds();

            int sqrt_nsites            = (int)(Math.Sqrt(_sites.Length + 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>();

            Site 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 = 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, LR.LEFT);
                    halfEdges.Add(bisector);
                    // inserting two Halfedges into edgeList static readonlyitutes 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, LR.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 = LeftRegion(lbnd, bottomMostSite);
                    topSite    = RightRegion(rbnd, bottomMostSite);
                    // these three sites define a Delaunay triangle
                    // (not actually using these for anything...)
                    //_triangles.Add(new Triangle(bottomSite, topSite, rightRegion(lbnd)));

                    v = lbnd.vertex;
                    v.SetIndex();
                    lbnd.edge.SetVertex(lbnd.leftRight, v);
                    rbnd.edge.SetVertex(rbnd.leftRight, v);
                    edgeList.Remove(lbnd);
                    heap.Remove(rbnd);
                    edgeList.Remove(rbnd);
                    leftRight = LR.LEFT;
                    if (bottomSite.Y > topSite.Y)
                    {
                        tempSite = bottomSite; bottomSite = topSite; topSite = tempSite; leftRight = LR.RIGHT;
                    }
                    edge = Edge.CreateBisectingEdge(bottomSite, topSite);
                    _edges.Add(edge);
                    bisector = Halfedge.Create(edge, leftRight);
                    halfEdges.Add(bisector);
                    edgeList.Insert(llbnd, bisector);
                    edge.SetVertex(LR.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();

            foreach (Halfedge halfEdge in halfEdges)
            {
                halfEdge.ReallyDispose();
            }
            halfEdges.Clear();

            // we need the vertices to clip the edges
            foreach (Edge edge2 in _edges)
            {
                edge2.ClipVertices(_plotBounds);
            }
            // but we don't actually ever use them again!
            foreach (Vertex vertex2 in vertices)
            {
                vertex2.Dispose();
            }
            vertices.Clear();
        }