private static void FinalizationConvexHull(DTSweepContext tcx)
        {
            AdvancingFrontNode n1, n2;
            DelaunayTriangle   t1, t2;
            TriangulationPoint first, p1;

            n1    = tcx.Front.Head.Next;
            n2    = n1.Next;
            first = n1.Point;

            TurnAdvancingFrontConvex(tcx, n1, n2);

            n1 = tcx.Front.Tail.Prev;
            if (n1.Triangle.Contains(n1.Next.Point) && n1.Triangle.Contains(n1.Prev.Point))
            {
                t1 = n1.Triangle.NeighborAcrossFrom(n1.Point);
                RotateTrianglePair(n1.Triangle, n1.Point, t1, t1.OppositePoint(n1.Triangle, n1.Point));
                tcx.MapTriangleToNodes(n1.Triangle);
                tcx.MapTriangleToNodes(t1);
            }
            n1 = tcx.Front.Head.Next;
            if (n1.Triangle.Contains(n1.Prev.Point) && n1.Triangle.Contains(n1.Next.Point))
            {
                t1 = n1.Triangle.NeighborAcrossFrom(n1.Point);
                RotateTrianglePair(n1.Triangle, n1.Point, t1, t1.OppositePoint(n1.Triangle, n1.Point));
                tcx.MapTriangleToNodes(n1.Triangle);
                tcx.MapTriangleToNodes(t1);
            }

            first       = tcx.Front.Head.Point;
            n2          = tcx.Front.Tail.Prev;
            t1          = n2.Triangle;
            p1          = n2.Point;
            n2.Triangle = null;
            do
            {
                tcx.RemoveFromList(t1);
                p1 = t1.PointCCWFrom(p1);
                if (p1 == first)
                {
                    break;
                }
                t2 = t1.NeighborCCWFrom(p1);
                t1.Clear();
                t1 = t2;
            } while (true);

            first = tcx.Front.Head.Next.Point;
            p1    = t1.PointCWFrom(tcx.Front.Head.Point);
            t2    = t1.NeighborCWFrom(tcx.Front.Head.Point);
            t1.Clear();
            t1 = t2;
            while (p1 != first)
            {
                tcx.RemoveFromList(t1);
                p1 = t1.PointCCWFrom(p1);
                t2 = t1.NeighborCCWFrom(p1);
                t1.Clear();
                t1 = t2;
            }

            tcx.Front.Head      = tcx.Front.Head.Next;
            tcx.Front.Head.Prev = null;
            tcx.Front.Tail      = tcx.Front.Tail.Prev;
            tcx.Front.Tail.Next = null;
        }
        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);

                    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);

                    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)
            {
                if (o1 == Orientation.CW)
                {
                    triangle = triangle.NeighborCCWFrom(point);
                }
                else
                {
                    triangle = triangle.NeighborCWFrom(point);
                }
                EdgeEvent(tcx, ep, eq, triangle, point);
            }
            else
            {
                FlipEdgeEvent(tcx, ep, eq, triangle, point);
            }
        }
        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)
            {
                throw new InvalidOperationException("[BUG:FIXME] FLIP failed due to missing triangle");
            }

            if (tcx.IsDebugEnabled)
            {
                tcx.DTDebugContext.PrimaryTriangle   = t;
                tcx.DTDebugContext.SecondaryTriangle = ot;
            }

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

            if (inScanArea)
            {
                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");
                        }
                        t.MarkConstrainedEdge(ep, eq);
                        ot.MarkConstrainedEdge(ep, eq);
                        Legalize(tcx, t);
                        Legalize(tcx, ot);
                    }
                    else
                    {
                        if (tcx.IsDebugEnabled)
                        {
                            Console.WriteLine("[FLIP] - subedge done");
                        }
                    }
                }
                else
                {
                    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);
                }
            }
        }
 public DTSweepDebugContext(DTSweepContext tcx) : base(tcx)
 {
 }