Пример #1
0
        private static void FlipEdgeEvent(DTSweepContext tcx, TriangulationPoint ep, TriangulationPoint eq, DelaunayTriangle t, TriangulationPoint p)
        {
            DelaunayTriangle   ot = t.NeighborAcrossFrom(p);
            TriangulationPoint op = ot.OppositePoint(t, p);

            if (ot == null)
            {
                // If we want to integrate the fillEdgeEvent do it here
                // With current implementation we should never get here
                throw new InvalidOperationException("[BUG:FIXME] FLIP failed due to missing triangle");
            }

            if (tcx.IsDebugEnabled)
            {
                tcx.DTDebugContext.PrimaryTriangle   = t;
                tcx.DTDebugContext.SecondaryTriangle = ot;
            } // TODO: remove

            bool inScanArea = TriangulationUtil.InScanArea(p, t.PointCCWFrom(p), t.PointCWFrom(p), op);

            if (inScanArea)
            {
                // Lets rotate shared edge one vertex CW
                RotateTrianglePair(t, p, ot, op);
                tcx.MapTriangleToNodes(t);
                tcx.MapTriangleToNodes(ot);

                if (p == eq && op == ep)
                {
                    if (eq == tcx.EdgeEvent.ConstrainedEdge.Q && ep == tcx.EdgeEvent.ConstrainedEdge.P)
                    {
                        if (tcx.IsDebugEnabled)
                        {
//                            Console.WriteLine("[FLIP] - constrained edge done"); // TODO: remove
                        }
                        t.MarkConstrainedEdge(ep, eq);
                        ot.MarkConstrainedEdge(ep, eq);
                        Legalize(tcx, t);
                        Legalize(tcx, ot);
                    }
                    else
                    {
                        if (tcx.IsDebugEnabled)
                        {
//                            Console.WriteLine("[FLIP] - subedge done"); // TODO: remove
                        }
                        // XXX: I think one of the triangles should be legalized here?
                    }
                }
                else
                {
                    if (tcx.IsDebugEnabled)
                    {
//                        Console.WriteLine("[FLIP] - flipping and continuing with triangle still crossing edge"); // TODO: remove
                    }
                    Orientation o = TriangulationUtil.Orient2d(eq, op, ep);
                    t = NextFlipTriangle(tcx, o, t, ot, p, op);
                    FlipEdgeEvent(tcx, ep, eq, t, p);
                }
            }
            else
            {
                TriangulationPoint newP = null;
                if (NextFlipPoint(ep, eq, ot, op, out newP))
                {
                    FlipScanEdgeEvent(tcx, ep, eq, t, ot, newP);
                    EdgeEvent(tcx, ep, eq, t, p);
                }
            }
        }
Пример #2
0
        private static void EdgeEvent(DTSweepContext tcx, TriangulationPoint ep, TriangulationPoint eq, DelaunayTriangle triangle, TriangulationPoint point)
        {
            TriangulationPoint p1, p2;

            if (tcx.IsDebugEnabled)
            {
                tcx.DTDebugContext.PrimaryTriangle = triangle;
            }

            if (IsEdgeSideOfTriangle(triangle, ep, eq))
            {
                return;
            }

            p1 = triangle.PointCCWFrom(point);
            Orientation o1 = TriangulationUtil.Orient2d(eq, p1, ep);

            if (o1 == Orientation.Collinear)
            {
                if (triangle.Contains(eq) && triangle.Contains(p1))
                {
                    triangle.MarkConstrainedEdge(eq, p1);
                    // We are modifying the constraint maybe it would be better to
                    // not change the given constraint and just keep a variable for the new constraint
                    tcx.EdgeEvent.ConstrainedEdge.Q = p1;
                    triangle = triangle.NeighborAcrossFrom(point);
                    EdgeEvent(tcx, ep, p1, triangle, p1);
                }
                else
                {
                    throw new PointOnEdgeException("EdgeEvent - Point on constrained edge not supported yet", ep, eq, p1);
                }
                if (tcx.IsDebugEnabled)
                {
//                    Console.WriteLine("EdgeEvent - Point on constrained edge");
                }

                return;
            }

            p2 = triangle.PointCWFrom(point);
            Orientation o2 = TriangulationUtil.Orient2d(eq, p2, ep);

            if (o2 == Orientation.Collinear)
            {
                if (triangle.Contains(eq) && triangle.Contains(p2))
                {
                    triangle.MarkConstrainedEdge(eq, p2);
                    // We are modifying the constraint maybe it would be better to
                    // not change the given constraint and just keep a variable for the new constraint
                    tcx.EdgeEvent.ConstrainedEdge.Q = p2;
                    triangle = triangle.NeighborAcrossFrom(point);
                    EdgeEvent(tcx, ep, p2, triangle, p2);
                }
                else
                {
                    throw new PointOnEdgeException("EdgeEvent - Point on constrained edge not supported yet", ep, eq, p2);
                }
                if (tcx.IsDebugEnabled)
                {
//                    Console.WriteLine("EdgeEvent - Point on constrained edge");
                }

                return;
            }

            if (o1 == o2)
            {
                // Need to decide if we are rotating CW or CCW to get to a triangle
                // that will cross edge
                if (o1 == Orientation.CW)
                {
                    triangle = triangle.NeighborCCWFrom(point);
                }
                else
                {
                    triangle = triangle.NeighborCWFrom(point);
                }
                EdgeEvent(tcx, ep, eq, triangle, point);
            }
            else
            {
                // This triangle crosses constraint so lets flippin start!
                FlipEdgeEvent(tcx, ep, eq, triangle, point);
            }
        }