private static AdvancingFrontNode NewFrontTriangle(DTSweepContext tcx, TriangulationPoint point, AdvancingFrontNode node)
        {
            AdvancingFrontNode newNode;
            DelaunayTriangle   triangle;

            triangle = new DelaunayTriangle(point, node.Point, node.Next.Point);
            triangle.MarkNeighbor(node.Triangle);
            tcx.Triangles.Add(triangle);

            newNode        = new AdvancingFrontNode(point);
            newNode.Next   = node.Next;
            newNode.Prev   = node;
            node.Next.Prev = newNode;
            node.Next      = newNode;

            tcx.AddNode(newNode);

            if (tcx.IsDebugEnabled)
            {
                tcx.DTDebugContext.ActiveNode = newNode;
            }

            if (!Legalize(tcx, triangle))
            {
                tcx.MapTriangleToNodes(triangle);
            }

            return(newNode);
        }
        private static AdvancingFrontNode PointEvent(DTSweepContext tcx, TriangulationPoint point)
        {
            AdvancingFrontNode node, newNode;

            node = tcx.LocateNode(point);
            if (tcx.IsDebugEnabled)
            {
                tcx.DTDebugContext.ActiveNode = node;
            }
            if (node == null || point == null)
            {
                return(null);
            }
            newNode = NewFrontTriangle(tcx, point, node);

            if (point.X <= node.Point.X + MathUtil.EPSILON)
            {
                Fill(tcx, node);
            }

            tcx.AddNode(newNode);

            FillAdvancingFront(tcx, newNode);
            return(newNode);
        }