/// <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);
}
/// <summary>
/// Find closes node to the left of the new point and
/// create a new triangle. If needed new holes and basins
/// will be filled to.
/// </summary>
private static AdvancingFrontNode PointEvent(DTSweepContext tcx, TriangulationPoint point)
{
AdvancingFrontNode node, newNode;
node = tcx.LocateNode(point);
if (tcx.IsDebugEnabled)
{
tcx.DTDebugContext.ActiveNode = node;
}
if (node == null || point == null)
{
return(null);
}
newNode = NewFrontTriangle(tcx, point, node);
// Only need to check +epsilon since point never have smaller
// x value than node due to how we fetch nodes from the front
if (point.X <= node.Point.X + MathUtil.EPSILON)
{
Fill(tcx, node);
}
tcx.AddNode(newNode);
FillAdvancingFront(tcx, newNode);
return(newNode);
}