/// <summary>
/// Creates a new front triangle and legalize it
/// </summary>
///
/// <param name="tcx"></param>
/// <param name="point"></param>
/// <param name="node"></param>
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.addToList(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.getDebugContext().setActiveNode(newNode);
}
if (!legalize(tcx, triangle))
{
tcx.mapTriangleToNodes(triangle);
}
return(newNode);
}
/// <summary>
/// Exhaustive search to update neighbor pointers
/// </summary>
/// <param name="t">triangle</param>
public void markNeighbor(DelaunayTriangle t)
{
if (t.contains(points[1], points[2]))
{
neighbors[0] = t;
t.markNeighbor(points[1], points[2], this);
}
else if (t.contains(points[0], points[2]))
{
neighbors[1] = t;
t.markNeighbor(points[0], points[2], this);
}
else if (t.contains(points[0], points[1]))
{
neighbors[2] = t;
t.markNeighbor(points[0], points[1], this);
}
else
{
logger.Error("markNeighbor failed");
}
}
/// <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.addToList(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);
}
}
/// <summary>
/// Rotates a triangle pair one vertex CW
/// <code>
/// n2 n2
/// P +-----+ P +-----+
/// | t /| |\ t |
/// | / | | \ |
/// n1| / |n3 n1| \ |n3
/// | / | after CW | \ |
/// |/ oT | | oT \|
/// +-----+ oP +-----+
/// n4 n4
/// </code>
/// </summary>
private static void rotateTrianglePair(DelaunayTriangle t,
TriangulationPoint p,
DelaunayTriangle ot,
TriangulationPoint op)
{
DelaunayTriangle n1, n2, n3, n4;
n1 = t.neighborCCW(p);
n2 = t.neighborCW(p);
n3 = ot.neighborCCW(op);
n4 = ot.neighborCW(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.getDelunayEdgeCCW(p);
de2 = t.getDelunayEdgeCW(p);
de3 = ot.getDelunayEdgeCCW(op);
de4 = ot.getDelunayEdgeCW(op);
t.legalize(p, op);
ot.legalize(op, p);
// Remap dEdge
ot.setDelunayEdgeCCW(p, de1);
t.setDelunayEdgeCW(p, de2);
t.setDelunayEdgeCCW(op, de3);
ot.setDelunayEdgeCW(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.clearNeighbors();
ot.clearNeighbors();
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);
}