Пример #1
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        /// <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!");
        }
Пример #2
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 public void AddTriangle(DelaunayTriangle t)
 {
     Triangles.Add(t);
 }
Пример #3
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 public void MarkEdge(DelaunayTriangle triangle)
 {
     for (int i = 0; i < 3; i++) if ( EdgeIsConstrained[i] ) {
         triangle.MarkConstrainedEdge(Points[(i+1)%3], Points[(i+2)%3]);
     }
 }
Пример #4
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 /// <summary>
 /// After a flip we have two triangles and know that only one will still be
 /// intersecting the edge. So decide which to contiune with and legalize the other
 /// </summary>
 /// <param name="tcx"></param>
 /// <param name="o">should be the result of an TriangulationUtil.orient2d( eq, op, ep )</param>
 /// <param name="t">triangle 1</param>
 /// <param name="ot">triangle 2</param>
 /// <param name="p">a point shared by both triangles</param>
 /// <param name="op">another point shared by both triangles</param>
 /// <returns>returns the triangle still intersecting the edge</returns>
 private static DelaunayTriangle NextFlipTriangle( DTSweepContext tcx, Orientation o, DelaunayTriangle t, DelaunayTriangle ot, TriangulationPoint p, TriangulationPoint op )
 {
     int edgeIndex;
     if (o == Orientation.CCW) {
         // ot is not crossing edge after flip
         edgeIndex = ot.EdgeIndex(p, op);
         ot.EdgeIsDelaunay[edgeIndex] = true;
         Legalize(tcx, ot);
         ot.EdgeIsDelaunay.Clear();
         return t;
     }
     // t is not crossing edge after flip
     edgeIndex = t.EdgeIndex(p, op);
     t.EdgeIsDelaunay[edgeIndex] = true;
     Legalize(tcx, t);
     t.EdgeIsDelaunay.Clear();
     return ot;
 }
Пример #5
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        /// <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);
        }
Пример #6
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 public void RemoveFromList(DelaunayTriangle triangle)
 {
     base.Triangles.Remove(triangle);
 }
Пример #7
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 /// <summary>
 /// When we need to traverse from one triangle to the next we need 
 /// the point in current triangle that is the opposite point to the next
 /// triangle. 
 /// </summary>
 private static TriangulationPoint NextFlipPoint( TriangulationPoint ep, TriangulationPoint eq, DelaunayTriangle ot, TriangulationPoint op )
 {
     Orientation o2d = TriangulationUtil.Orient2d(eq, op, ep);
     switch ( o2d ) {
     case Orientation.CW: return ot.PointCCWFrom(op);
     case Orientation.CCW: return ot.PointCWFrom(op);
     case Orientation.Collinear:
         // TODO: implement support for point on constraint edge
         throw new PointOnEdgeException("Point on constrained edge not supported yet",eq,op,ep);
     default:
         throw new NotImplementedException("Orientation not handled");
     }
 }
Пример #8
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 private static bool IsEdgeSideOfTriangle( DelaunayTriangle triangle, TriangulationPoint ep, TriangulationPoint eq )
 {
     int index = triangle.EdgeIndex(ep, eq);
     if ( index == -1 ) return false;
     triangle.MarkConstrainedEdge(index);
     triangle = triangle.Neighbors[index];
     if (triangle != null) triangle.MarkConstrainedEdge(ep, eq);
     return true;
 }
Пример #9
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        /// <summary>
        /// Returns true if triangle was legalized
        /// </summary>
        private static bool Legalize( DTSweepContext tcx, DelaunayTriangle t )
        {
            // To legalize a triangle we start by finding if any of the three edges
            // violate the Delaunay condition
            for (int i = 0; i < 3; i++) {
                // TODO: fix so that cEdge is always valid when creating new triangles then we can check it here
                //       instead of below with ot
                if (t.EdgeIsDelaunay[i]) continue;

                DelaunayTriangle ot = t.Neighbors[i];
                if (ot == null) continue;

                TriangulationPoint p = t.Points[i];
                TriangulationPoint op = ot.OppositePoint(t, p);
                int oi = ot.IndexOf(op);
                // If this is a Constrained Edge or a Delaunay Edge(only during recursive legalization)
                // then we should not try to legalize
                if (ot.EdgeIsConstrained[oi] || ot.EdgeIsDelaunay[oi]) {
                    t.EdgeIsConstrained[i] = ot.EdgeIsConstrained[oi]; // XXX: have no good way of setting this property when creating new triangles so lets set it here
                    continue;
                }

                if (!TriangulationUtil.SmartIncircle(p,t.PointCCWFrom(p),t.PointCWFrom(p),op)) continue;

                // Lets mark this shared edge as Delaunay
                t.EdgeIsDelaunay[i] = true;
                ot.EdgeIsDelaunay[oi] = true;

                // Lets rotate shared edge one vertex CW to legalize it
                RotateTrianglePair(t, p, ot, op);

                // We now got one valid Delaunay Edge shared by two triangles
                // This gives us 4 new edges to check for Delaunay

                // Make sure that triangle to node mapping is done only one time for a specific triangle
                if (!Legalize(tcx, t)) tcx.MapTriangleToNodes(t);
                if (!Legalize(tcx, ot)) tcx.MapTriangleToNodes(ot);

                // Reset the Delaunay edges, since they only are valid Delaunay edges
                // until we add a new triangle or point.
                // XXX: need to think about this. Can these edges be tried after we
                //      return to previous recursive level?
                t.EdgeIsDelaunay[i] = false;
                ot.EdgeIsDelaunay[oi] = false;

                // If triangle have been legalized no need to check the other edges since
                // the recursive legalization will handles those so we can end here.
                return true;
            }
            return false;
        }
Пример #10
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        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 = NextFlipPoint(ep, eq, ot, op);
                FlipScanEdgeEvent(tcx, ep, eq, t, ot, newP);
                EdgeEvent(tcx, ep, eq, t, p);
            }
        }
Пример #11
0
        /// <summary>
        /// Scan part of the FlipScan algorithm<br>
        /// When a triangle pair isn't flippable we will scan for the next 
        /// point that is inside the flip triangle scan area. When found 
        /// we generate a new flipEdgeEvent
        /// </summary>
        /// <param name="tcx"></param>
        /// <param name="ep">last point on the edge we are traversing</param>
        /// <param name="eq">first point on the edge we are traversing</param>
        /// <param name="flipTriangle">the current triangle sharing the point eq with edge</param>
        /// <param name="t"></param>
        /// <param name="p"></param>
        private static void FlipScanEdgeEvent( DTSweepContext tcx, TriangulationPoint ep, TriangulationPoint eq, DelaunayTriangle flipTriangle, DelaunayTriangle t, TriangulationPoint p )
        {
            DelaunayTriangle ot;
            TriangulationPoint op, newP;
            bool inScanArea;

            ot = t.NeighborAcrossFrom(p);
            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 Exception("[BUG:FIXME] FLIP failed due to missing triangle");
            }

            if (tcx.IsDebugEnabled) {
                Console.WriteLine("[FLIP:SCAN] - scan next point"); // TODO: remove
                tcx.DTDebugContext.PrimaryTriangle = t;
                tcx.DTDebugContext.SecondaryTriangle = ot;
            }

            inScanArea = TriangulationUtil.InScanArea(eq, flipTriangle.PointCCWFrom(eq), flipTriangle.PointCWFrom(eq), op);
            if (inScanArea) {
                // flip with new edge op->eq
                FlipEdgeEvent(tcx, eq, op, ot, op);
                // TODO: Actually I just figured out that it should be possible to
                //       improve this by getting the next ot and op before the the above
                //       flip and continue the flipScanEdgeEvent here
                // set new ot and op here and loop back to inScanArea test
                // also need to set a new flipTriangle first
                // Turns out at first glance that this is somewhat complicated
                // so it will have to wait.
            } else {
                newP = NextFlipPoint(ep, eq, ot, op);
                FlipScanEdgeEvent(tcx, ep, eq, flipTriangle, ot, newP);
            }
        }
Пример #12
0
        /// <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);
        }
Пример #13
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        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) {
                // TODO: Split edge in two
                ////            splitEdge( ep, eq, p1 );
                //            edgeEvent( tcx, p1, eq, triangle, point );
                //            edgeEvent( tcx, ep, p1, triangle, p1 );
                //            return;
                throw new PointOnEdgeException("EdgeEvent - Point on constrained edge not supported yet",eq,p1,ep);
            }

            p2 = triangle.PointCWFrom(point);
            Orientation o2 = TriangulationUtil.Orient2d(eq, p2, ep);
            if (o2 == Orientation.Collinear) {
                // TODO: Split edge in two
                //            edgeEvent( tcx, p2, eq, triangle, point );
                //            edgeEvent( tcx, ep, p2, triangle, p2 );
                //            return;
                throw new PointOnEdgeException("EdgeEvent - Point on constrained edge not supported yet",eq,p2,ep);
            }

            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);
            }
        }
Пример #14
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 public void MeshClean(DelaunayTriangle triangle)
 {
     this.MeshCleanReq(triangle);
 }
Пример #15
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 /// <param name="t">Opposite triangle</param>
 /// <param name="p">The point in t that isn't shared between the triangles</param>
 public TriangulationPoint OppositePoint(DelaunayTriangle t, TriangulationPoint p)
 {
     Debug.Assert(t != this, "self-pointer error");
     return PointCWFrom(t.PointCWFrom(p));
 }
Пример #16
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        /// <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;
        }
Пример #17
0
 /// <summary>
 /// Update neighbor pointers
 /// </summary>
 /// <param name="p1">Point 1 of the shared edge</param>
 /// <param name="p2">Point 2 of the shared edge</param>
 /// <param name="t">This triangle's new neighbor</param>
 private void MarkNeighbor( TriangulationPoint p1, TriangulationPoint p2, DelaunayTriangle t )
 {
     int i = EdgeIndex(p1,p2);
     if ( i==-1 ) throw new Exception( "Error marking neighbors -- t doesn't contain edge p1-p2!" );
     Neighbors[i] = t;
 }
Пример #18
0
 public void AddTriangle(DelaunayTriangle t)
 {
     _triangles.Add(t);
 }