private void Initialize()
{
sweepline = new OA_Sweepline();
eventQueue = new RBTreeSet <OA_EventPoint>(OA_EventPoint.Compare);
outputSubdivision = new DCEL_Subdivision();
foreach (DCEL_Subdivision inputSubdivision in inputSubdivisions)
{
foreach (DCEL_HalfEdge inputHalfEdge in inputSubdivision.HalfEdges.Keys)
{
OA_EventPoint upper = new OA_EventPoint(inputHalfEdge.Origin.Position);
OA_EventPoint lower = new OA_EventPoint(inputHalfEdge.Destination.Position);
//We want to take only one of the twins from every pair of half edges.
if (upper.CompareTo(lower) > 0)
{
continue;
}
RBTreeSetNode <OA_EventPoint> upper_node = new RBTreeSetNode <OA_EventPoint>(upper);
RBTreeSetNode <OA_EventPoint> lower_node = new RBTreeSetNode <OA_EventPoint>(lower);
//If we didn't add the newly created event point, it already existed.
if (!eventQueue.Add(ref upper_node))
{
upper = upper_node.Key;
}
if (!eventQueue.Add(ref lower_node))
{
lower = lower_node.Key;
}
OA_Segment segment = new OA_Segment(sweepline);
segment.Source.Add(new OA_Source <DCEL_HalfEdge>(inputSubdivision, inputHalfEdge));
segment.Upper = upper;
segment.Lower = lower;
//***May be adding a duplicate if segment is in both subdivisions!
upper.UpperList.Add(segment);
if (!upper.Source.Any(OA_Source <DCEL_Vertex> .IsFrom(inputSubdivision)))
{
upper.Source.Add(new OA_Source <DCEL_Vertex>(inputSubdivision, inputHalfEdge.Origin));
}
if (!lower.Source.Any(OA_Source <DCEL_Vertex> .IsFrom(inputSubdivision)))
{
lower.Source.Add(new OA_Source <DCEL_Vertex>(inputSubdivision, inputHalfEdge.Destination));
}
}
}
foreach (OA_EventPoint eventPoint in eventQueue.Keys)
{
//***Remove those duplicates here, joining their source lists.
eventPoint.UpperList.RemoveDuplicates(OA_Segment.CompareEndpoints, OA_Segment.JoinSource);
}
}
private void HandleIntersection_SplittingPhase(OA_EventPoint eventPoint, List <OA_Segment> upperList, List <OA_Segment> middleList, List <OA_Segment> lowerList)
{
//if (upperList.Count() + middleList.Count() + lowerList.Count() <= 1)
if (middleList.Count == 0)
{
return;
}
//If there are any subdivisions which don't have a vertex at this location,
//then we will create one momentarily. For the moment, set the
//(key, value) = (subdivision, null).
Dictionary <DCEL_Subdivision, DCEL_Vertex> vertexLookup = CreateSourceLookup(eventPoint);
//Make all segments meet at a vertex here, within each subdivision.
//HalfEdges associated with segments in the middleList will be transformed
//into HalfEdges associated with segments in the upperList. (With the associated
//segments transforming as well.)
foreach (OA_Segment middle in middleList)
{
foreach (OA_Source <DCEL_HalfEdge> source in middle.Source)
{
DCEL_Subdivision subdivision = source.Subdivision;
DCEL_HalfEdge halfEdge = source.Element;
DCEL_Vertex vertex = vertexLookup[subdivision];
//Create the vertex on-demand if it doesn't exist
if (vertex == null)
{
vertex = new DCEL_Vertex(eventPoint.Position);
vertexLookup[subdivision] = vertex;
subdivision.Vertices.Add(new RBTreeSetNode <DCEL_Vertex>(vertex));
}
SplitEdge(subdivision, halfEdge, vertex);
if (!eventPoint.Source.Any(OA_Source <DCEL_Vertex> .IsFrom(subdivision)))
{
eventPoint.Source.Add(new OA_Source <DCEL_Vertex>(subdivision, vertex));
}
}
}
}
