private void FillBasinReq(SweepContext tcx, Node node)
{
// if shallow stop filling
if (IsShallow(tcx, node))
{
return;
}
Fill(tcx, node);
if (node.Prev == tcx.Basin.LeftNode && node.Next == tcx.Basin.RightNode)
{
return;
}
else if (node.Prev == tcx.Basin.LeftNode)
{
Winding o = TriUtil.Orient2d(node.Point, node.Next.Point, node.Next.Next.Point);
if (o == Winding.CW)
{
return;
}
node = node.Next;
}
else if (node.Next == tcx.Basin.RightNode)
{
Winding o = TriUtil.Orient2d(node.Point, node.Prev.Point, node.Prev.Prev.Point);
if (o == Winding.CCW)
{
return;
}
node = node.Prev;
}
else
{
// Continue with the neighbor node with lowest Y value
if (node.Prev.Point.Y < node.Next.Point.Y)
{
node = node.Prev;
}
else
{
node = node.Next;
}
}
FillBasinReq(tcx, node);
}
private void FillLeftAboveEdgeEvent(SweepContext tcx, Edge edge, Node node)
{
while (node.Prev.Point.X > edge.P.X)
{
// Check if next node is below the edge
if (TriUtil.Orient2d(edge.Q, node.Prev.Point, edge.P) == Winding.CW)
{
FillLeftBelowEdgeEvent(tcx, edge, node);
}
else
{
node = node.Prev;
}
}
}
private TriPoint NextFlipPoint(TriPoint ep, TriPoint eq, Triangle ot, TriPoint op)
{
Winding o2d = TriUtil.Orient2d(eq, op, ep);
if (o2d == Winding.CW)
{
// Right
return(ot.PointCCW(op));
}
else if (o2d == Winding.CCW)
{
// Left
return(ot.PointCW(op));
}
throw new NotSupportedException("[Unsupported] Opposing point on constrained edge");
}
private void FillLeftBelowEdgeEvent(SweepContext tcx, Edge edge, Node node)
{
if (node.Point.X > edge.P.X)
{
if (TriUtil.Orient2d(node.Point, node.Prev.Point, node.Prev.Prev.Point) == Winding.CW)
{
// Concave
FillLeftConcaveEdgeEvent(tcx, edge, node);
}
else
{
// Convex
FillLeftConvexEdgeEvent(tcx, edge, node);
// Retry this one
FillLeftBelowEdgeEvent(tcx, edge, node);
}
}
}
private void FillBasin(SweepContext tcx, Node node)
{
if (TriUtil.Orient2d(node.Point, node.Next.Point, node.Next.Next.Point) == Winding.CCW)
{
tcx.Basin.LeftNode = node.Next.Next;
}
else
{
tcx.Basin.LeftNode = node.Next;
}
// Find the bottom and right node
tcx.Basin.BottomNode = tcx.Basin.LeftNode;
while (tcx.Basin.BottomNode.Next != null &&
tcx.Basin.BottomNode.Point.Y >= tcx.Basin.BottomNode.Next.Point.Y)
{
tcx.Basin.BottomNode = tcx.Basin.BottomNode.Next;
}
if (tcx.Basin.BottomNode == tcx.Basin.LeftNode)
{
// No valid basin
return;
}
tcx.Basin.RightNode = tcx.Basin.BottomNode;
while (tcx.Basin.RightNode.Next != null &&
tcx.Basin.RightNode.Point.Y < tcx.Basin.RightNode.Next.Point.Y)
{
tcx.Basin.RightNode = tcx.Basin.RightNode.Next;
}
if (tcx.Basin.RightNode == tcx.Basin.BottomNode)
{
// No valid basins
return;
}
tcx.Basin.Width = tcx.Basin.RightNode.Point.X - tcx.Basin.LeftNode.Point.X;
tcx.Basin.LeftHighest = tcx.Basin.LeftNode.Point.Y > tcx.Basin.RightNode.Point.Y;
FillBasinReq(tcx, tcx.Basin.BottomNode);
}
private void FillLeftConcaveEdgeEvent(SweepContext tcx, Edge edge, Node node)
{
Fill(tcx, node.Prev);
if (node.Prev.Point != edge.P)
{
// Next above or below edge?
if (TriUtil.Orient2d(edge.Q, node.Prev.Point, edge.P) == Winding.CW)
{
// Below
if (TriUtil.Orient2d(node.Point, node.Prev.Point, node.Prev.Prev.Point) == Winding.CW)
{
// Next is concave
FillLeftConcaveEdgeEvent(tcx, edge, node);
}
else
{
// Next is convex
}
}
}
}
private void FlipEdgeEvent(SweepContext tcx, TriPoint ep, TriPoint eq, Triangle t, TriPoint p)
{
Triangle ot = t.NeighborAcross(p);
TriPoint op = ot.OppositePoint(t, p);
if (TriUtil.InScanArea(p, t.PointCCW(p), t.PointCW(p), op))
{
// 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)
{
t.MarkConstrainedEdge(ep, eq);
ot.MarkConstrainedEdge(ep, eq);
Legalize(tcx, t);
Legalize(tcx, ot);
}
else
{
// XXX: I think one of the triangles should be legalized here?
}
}
else
{
Winding o = TriUtil.Orient2d(eq, op, ep);
t = NextFlipTriangle(tcx, o, t, ot, p, op);
FlipEdgeEvent(tcx, ep, eq, t, p);
}
}
else
{
TriPoint newP = NextFlipPoint(ep, eq, ot, op);
FlipScanEdgeEvent(tcx, ep, eq, t, ot, newP);
EdgeEvent(tcx, ep, eq, t, p);
}
}
private void FlipScanEdgeEvent(SweepContext tcx, TriPoint ep, TriPoint eq, Triangle flip_triangle, Triangle t, TriPoint p)
{
Triangle ot = t.NeighborAcross(p);
TriPoint op = ot.OppositePoint(t, p);
if (TriUtil.InScanArea(eq, flip_triangle.PointCCW(eq), flip_triangle.PointCW(eq), op))
{
// 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 flip_triangle first
// Turns out at first glance that this is somewhat complicated
// so it will have to wait.
}
else
{
TriPoint newP = NextFlipPoint(ep, eq, ot, op);
FlipScanEdgeEvent(tcx, ep, eq, flip_triangle, ot, newP);
}
}
private void FillRightConvexEdgeEvent(SweepContext tcx, Edge edge, Node node)
{
// Next concave or convex?
if (TriUtil.Orient2d(node.Next.Point, node.Next.Next.Point, node.Next.Next.Next.Point) == Winding.CCW)
{
// Concave
FillRightConcaveEdgeEvent(tcx, edge, node.Next);
}
else
{
// Convex
// Next above or below edge?
if (TriUtil.Orient2d(edge.Q, node.Next.Next.Point, edge.P) == Winding.CCW)
{
// Below
FillRightConvexEdgeEvent(tcx, edge, node.Next);
}
else
{
// Above
}
}
}
private void EdgeEvent(SweepContext tcx, TriPoint ep, TriPoint eq, Triangle triangle, TriPoint point)
{
if (IsEdgeSideOfTriangle(triangle, ep, eq))
{
return;
}
TriPoint p1 = triangle.PointCCW(point);
Winding o1 = TriUtil.Orient2d(eq, p1, ep);
if (o1 == Winding.Collinear)
{
if (triangle.Contains(eq, 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.NeighborAcross(point);
EdgeEvent(tcx, ep, p1, triangle, p1);
}
else
{
throw new NotSupportedException("EdgeEvent - collinear points not supported");
}
return;
}
TriPoint p2 = triangle.PointCW(point);
Winding o2 = TriUtil.Orient2d(eq, p2, ep);
if (o2 == Winding.Collinear)
{
if (triangle.Contains(eq, 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.NeighborAcross(point);
EdgeEvent(tcx, ep, p2, triangle, p2);
}
else
{
throw new NotSupportedException("EdgeEvent - collinear points not supported");
}
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 == Winding.CW)
{
triangle = triangle.NeighborCCW(point);
}
else
{
triangle = triangle.NeighborCW(point);
}
EdgeEvent(tcx, ep, eq, triangle, point);
}
else
{
// This triangle crosses constraint so lets flippin start!
FlipEdgeEvent(tcx, ep, eq, triangle, point);
}
}