private static bool Legalize(DTSweepContext tcx, DelaunayTriangle t)
{
for (int i = 0; i < 3; i++)
{
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 (ot.EdgeIsConstrained[oi] || ot.EdgeIsDelaunay[oi])
{
t.SetConstrainedEdgeAcross(p, ot.EdgeIsConstrained[oi]);
continue;
}
if (!TriangulationUtil.SmartIncircle(p, t.PointCCWFrom(p), t.PointCWFrom(p), op))
{
continue;
}
t.EdgeIsDelaunay[i] = true;
ot.EdgeIsDelaunay[oi] = true;
RotateTrianglePair(t, p, ot, op);
if (!Legalize(tcx, t))
{
tcx.MapTriangleToNodes(t);
}
if (!Legalize(tcx, ot))
{
tcx.MapTriangleToNodes(ot);
}
t.EdgeIsDelaunay[i] = false;
ot.EdgeIsDelaunay[oi] = false;
return(true);
}
return(false);
}
public void MapTriangleToNodes(DelaunayTriangle t)
{
for (int i = 0; i < 3; i++)
{
if (t.Neighbors[i] == null)
{
AdvancingFrontNode n = Front.LocatePoint(t.PointCWFrom(t.Points[i]));
if (n != null)
{
n.Triangle = t;
}
}
}
}
private static bool NextFlipPoint(TriangulationPoint ep, TriangulationPoint eq, DelaunayTriangle ot, TriangulationPoint op, out TriangulationPoint newP)
{
newP = null;
Orientation o2d = TriangulationUtil.Orient2d(eq, op, ep);
switch (o2d)
{
case Orientation.CW:
newP = ot.PointCCWFrom(op);
return(true);
case Orientation.CCW:
newP = ot.PointCWFrom(op);
return(true);
case Orientation.Collinear:
return(false);
default:
throw new NotImplementedException("Orientation not handled");
}
}
public TriangulationPoint OppositePoint(DelaunayTriangle t, TriangulationPoint p)
{
Debug.Assert(t != this, "self-pointer error");
return(PointCWFrom(t.PointCWFrom(p)));
}
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)
{
throw new Exception("FLIP failed due to missing triangle");
}
if (tcx.IsDebugEnabled)
{
Console.WriteLine("scan next point");
tcx.DTDebugContext.PrimaryTriangle = t;
tcx.DTDebugContext.SecondaryTriangle = ot;
}
inScanArea = TriangulationUtil.InScanArea(eq, flipTriangle.PointCCWFrom(eq), flipTriangle.PointCWFrom(eq), op);
if (inScanArea)
{
FlipEdgeEvent(tcx, eq, op, ot, op);
}
else
{
if (NextFlipPoint(ep, eq, ot, op, out newP))
{
FlipScanEdgeEvent(tcx, ep, eq, flipTriangle, ot, newP);
}
}
}
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);
}
}
}
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);
}
}