C# DelaunayTriangle.MarkNeighbor方法代码示例

        /// <summary>
        /// Creates a new front triangle and legalize it
        /// </summary>
        private static AdvancingFrontNode NewFrontTriangle(DTSweepContext tcx, TriangulationPoint point, AdvancingFrontNode node)
        {
            DelaunayTriangle triangle = new DelaunayTriangle(point, node.Point, node.Next.Point);
            triangle.MarkNeighbor(node.Triangle);
            tcx.Triangles.Add(triangle);

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

            tcx.AddNode(newNode); // XXX: BST

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

            return newNode;
        }

        /// <summary>
        /// Rotates a triangle pair one vertex CW
        ///       n2                    n2
        ///  P +-----+             P +-----+
        ///    | t  /|               |\  t |  
        ///    |   / |               | \   |
        ///  n1|  /  |n3           n1|  \  |n3
        ///    | /   |    after CW   |   \ |
        ///    |/ oT |               | oT \|
        ///    +-----+ oP            +-----+
        ///       n4                    n4
        /// </summary>
        private static void RotateTrianglePair(DelaunayTriangle t, TriangulationPoint p, DelaunayTriangle ot, TriangulationPoint op)
        {
            DelaunayTriangle n1 = t.NeighborCCW(p);
            DelaunayTriangle n2 = t.NeighborCW(p);
            DelaunayTriangle n3 = ot.NeighborCCW(op);
            DelaunayTriangle n4 = ot.NeighborCW(op);

            bool ce1 = t.GetConstrainedEdgeCCW(p);
            bool ce2 = t.GetConstrainedEdgeCW(p);
            bool ce3 = ot.GetConstrainedEdgeCCW(op);
            bool ce4 = ot.GetConstrainedEdgeCW(op);

            bool de1 = t.GetDelaunayEdgeCCW(p);
            bool de2 = t.GetDelaunayEdgeCW(p);
            bool de3 = ot.GetDelaunayEdgeCCW(op);
            bool de4 = ot.GetDelaunayEdgeCW(op);

            t.Legalize(p, op);
            ot.Legalize(op, p);

            // Remap dEdge
            ot.SetDelaunayEdgeCCW(p, de1);
            t.SetDelaunayEdgeCW(p, de2);
            t.SetDelaunayEdgeCCW(op, de3);
            ot.SetDelaunayEdgeCW(op, de4);

            // Remap cEdge
            ot.SetConstrainedEdgeCCW(p, ce1);
            t.SetConstrainedEdgeCW(p, ce2);
            t.SetConstrainedEdgeCCW(op, ce3);
            ot.SetConstrainedEdgeCW(op, ce4);

            // Remap neighbors
            // XXX: might optimize the markNeighbor by keeping track of
            //      what side should be assigned to what neighbor after the
            //      rotation. Now mark neighbor does lots of testing to find
            //      the right side.
            t.Neighbors.Clear();
            ot.Neighbors.Clear();
            if (n1 != null) ot.MarkNeighbor(n1);
            if (n2 != null) t.MarkNeighbor(n2);
            if (n3 != null) t.MarkNeighbor(n3);
            if (n4 != null) ot.MarkNeighbor(n4);
            t.MarkNeighbor(ot);
        }

        /// <summary>
        /// Adds a triangle to the advancing front to fill a hole.
        /// </summary>
        /// <param name="tcx"></param>
        /// <param name="node">middle node, that is the bottom of the hole</param>
        private static void Fill(DTSweepContext tcx, AdvancingFrontNode node)
        {
            DelaunayTriangle triangle = new DelaunayTriangle(node.Prev.Point, node.Point, node.Next.Point);
            // TODO: should copy the cEdge value from neighbor triangles
            //       for now cEdge values are copied during the legalize
            triangle.MarkNeighbor(node.Prev.Triangle);
            triangle.MarkNeighbor(node.Triangle);
            tcx.Triangles.Add(triangle);

            // Update the advancing front
            node.Prev.Next = node.Next;
            node.Next.Prev = node.Prev;
            tcx.RemoveNode(node);

            // If it was legalized the triangle has already been mapped
            if (!Legalize(tcx, triangle))
            {
                tcx.MapTriangleToNodes(triangle);
            }
        }

        /// <summary>
        /// Creates a new front triangle and legalize it
        /// </summary>
        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) {Next = node.Next, Prev = node};
            node.Next.Prev = newNode;
            node.Next = newNode;

            tcx.AddNode(newNode); // XXX: BST

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

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

            return newNode;
        }