/// <summary>
/// Fills the edge event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void FillEdgeEvent(DtSweepContext tcx, DtSweepConstraint edge, AdvancingFrontNode node)
{
if (tcx.EdgeEvent.Right)
{
FillRightAboveEdgeEvent(tcx, edge, node);
}
else
{
FillLeftAboveEdgeEvent(tcx, edge, node);
}
}
/// <summary>
/// Fills the left above edge event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void FillLeftAboveEdgeEvent(DtSweepContext tcx, DtSweepConstraint edge, AdvancingFrontNode node)
{
while (node.Prev.Point.X > edge.P.X)
{
// Check if next node is below the edge
Orientation o1 = TriangulationUtil.Orient2d(edge.Q, node.Prev.Point, edge.P);
if (o1 == Orientation.Cw)
{
FillLeftBelowEdgeEvent(tcx, edge, node);
}
else
{
node = node.Prev;
}
}
}
/// <summary>
/// Fills the left concave edge event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void FillLeftConcaveEdgeEvent(DtSweepContext tcx, DtSweepConstraint edge,
AdvancingFrontNode node)
{
Fill(tcx, node.Prev);
if (node.Prev.Point != edge.P)
{
// GetNext above or below edge?
if (TriangulationUtil.Orient2d(edge.Q, node.Prev.Point, edge.P) == Orientation.Cw)
{
// Below
if (TriangulationUtil.Orient2d(node.Point, node.Prev.Point, node.Prev.Prev.Point) == Orientation.Cw)
{
// GetNext is concave
FillLeftConcaveEdgeEvent(tcx, edge, node);
}
}
}
}
/// <summary>
/// Fills the left below edge event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void FillLeftBelowEdgeEvent(DtSweepContext tcx, DtSweepConstraint edge, AdvancingFrontNode node)
{
if (node.Point.X > edge.P.X)
{
if (TriangulationUtil.Orient2d(node.Point, node.Prev.Point, node.Prev.Prev.Point) == Orientation.Cw)
{
// Concave
FillLeftConcaveEdgeEvent(tcx, edge, node);
}
else
{
// Convex
FillLeftConvexEdgeEvent(tcx, edge, node);
// Retry this one
FillLeftBelowEdgeEvent(tcx, edge, node);
}
}
}
/// <summary>
/// Fills the right convex edge event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void FillRightConvexEdgeEvent(DtSweepContext tcx, DtSweepConstraint edge,
AdvancingFrontNode node)
{
// GetNext concave or convex?
if (TriangulationUtil.Orient2d(node.Next.Point, node.Next.Next.Point, node.Next.Next.Next.Point) ==
Orientation.Ccw)
{
// Concave
FillRightConcaveEdgeEvent(tcx, edge, node.Next);
}
else
{
// Convex
// GetNext above or below edge?
if (TriangulationUtil.Orient2d(edge.Q, node.Next.Next.Point, edge.P) == Orientation.Ccw)
{
// Below
FillRightConvexEdgeEvent(tcx, edge, node.Next);
}
}
}
/// <summary>
/// Edges the event using the specified tcx
/// </summary>
/// <param name="tcx">The tcx</param>
/// <param name="edge">The edge</param>
/// <param name="node">The node</param>
private static void EdgeEvent(DtSweepContext tcx, DtSweepConstraint edge, AdvancingFrontNode node)
{
try
{
tcx.EdgeEvent.ConstrainedEdge = edge;
tcx.EdgeEvent.Right = edge.P.X > edge.Q.X;
if (IsEdgeSideOfTriangle(node.Triangle, edge.P, edge.Q))
{
return;
}
// For now we will do all needed filling
// TODO: integrate with flip process might give some better performance
// but for now this avoid the issue with cases that needs both flips and fills
FillEdgeEvent(tcx, edge, node);
EdgeEvent(tcx, edge.P, edge.Q, node.Triangle, edge.Q);
}
catch (PointOnEdgeException e)
{
Debug.WriteLine("Skipping Edge: {0}", e.Message);
}
}
