C# DelaunayTriangle.MarkNeighbor方法代码示例

		/// <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, n2, n3, n4;
			n1 = t.NeighborCCWFrom(p);
			n2 = t.NeighborCWFrom(p);
			n3 = ot.NeighborCCWFrom(op);
			n4 = ot.NeighborCWFrom(op);

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

			bool de1, de2, de3, de4;
			de1 = t.GetDelaunayEdgeCCW(p);
			de2 = t.GetDelaunayEdgeCW(p);
			de3 = ot.GetDelaunayEdgeCCW(op);
			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>
		/// 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);
			newNode.Next = node.Next;
			newNode.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;
		}

		/// <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>
        /// Exhaustive search to update neighbor pointers
        /// </summary>
        public void MarkNeighbor(DelaunayTriangle t)
        {
            // Points of this triangle also belonging to t
            bool a = t.Contains(Points[0]);
            bool b = t.Contains(Points[1]);
            bool c = t.Contains(Points[2]);

            if (b && c)
            {
                Neighbors[0] = t;
                t.MarkNeighbor(Points[1], Points[2], this);
            }
            else if (a && c)
            {
                Neighbors[1] = t;
                t.MarkNeighbor(Points[0], Points[2], this);
            }
            else if (a && b)
            {
                Neighbors[2] = t;
                t.MarkNeighbor(Points[0], Points[1], this);
            }
            //            else
            //            {
            //                throw new Exception("Failed to mark neighbor, doesn't share an edge!");
            //            }
        }