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);
}
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);
if (tcx.IsDebugEnabled)
{
tcx.DTDebugContext.ActiveNode = newNode;
}
if (!Legalize(tcx, triangle))
{
tcx.MapTriangleToNodes(triangle);
}
return(newNode);
}
private static void Fill(DTSweepContext tcx, AdvancingFrontNode node)
{
DelaunayTriangle triangle = new DelaunayTriangle(node.Prev.Point, node.Point, node.Next.Point);
triangle.MarkNeighbor(node.Prev.Triangle);
triangle.MarkNeighbor(node.Triangle);
tcx.Triangles.Add(triangle);
node.Prev.Next = node.Next;
node.Next.Prev = node.Prev;
tcx.RemoveNode(node);
if (!Legalize(tcx, triangle))
{
tcx.MapTriangleToNodes(triangle);
}
}
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 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);
}
}
}