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);
}
}
/// <summary>
/// Merge subdivisionA and subdivisionB into a single subdivision, destroying subdivisionA and subdivisionB in the process.
/// </summary>
public static DCEL_Subdivision Overlay(DCEL_Subdivision subdivisionA, DCEL_Subdivision subdivisionB)
{
OA_Algorithm algorithm = new OA_Algorithm(new[] { subdivisionA, subdivisionB });
subdivisionA.WriteToFile("subdivisionA_pre_splitting.xml");
subdivisionB.WriteToFile("subdivisionB_pre_splitting.xml");
subdivisionA.WriteToFile_Faces("subdivisionA_pre_splitting_faces.xml");
subdivisionB.WriteToFile_Faces("subdivisionB_pre_splitting_faces.xml");
algorithm.phase = Phase.SplittingPhase;
algorithm.Initialize();
algorithm.Sweep();
subdivisionA.WriteToFile("subdivisionA_post_splitting.xml");
subdivisionB.WriteToFile("subdivisionB_post_splitting.xml");
subdivisionA.WriteToFile_Faces("subdivisionA_post_splitting_faces.xml");
subdivisionB.WriteToFile_Faces("subdivisionB_post_splitting_faces.xml");
algorithm.phase = Phase.MergingPhase;
algorithm.Initialize();
algorithm.Sweep();
algorithm.outputSubdivision.WriteToFile("outputSubdivision_post_merging.xml");
algorithm.phase = Phase.FacingPhase;
algorithm.CreateFaces();
algorithm.outputSubdivision.WriteToFile("outputSubdivision_final.xml");
algorithm.outputSubdivision.WriteToFile_Faces("outputSubdivision_final_faces.xml");
//The inputSubdivisions have been destroyed, so clear them.
foreach (DCEL_Subdivision inputSubdivision in algorithm.inputSubdivisions)
{
inputSubdivision.Clear();
}
return(algorithm.outputSubdivision);
}
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));
}
}
}
}
/// <summary>
/// halfEdge should be Upper->Lower so that the persistent half edges become:
/// o halfEdge (Upper->Lower) ==> (vertex->Lower)
/// o halfEdge.Twin (Lower->Upper) ==> (Lower->vertex)
/// And the two newly created half edges are (vertex->Upper) and (Upper->vertex).
/// </summary>
private static void SplitEdge(DCEL_Subdivision subdivision, DCEL_HalfEdge halfEdge, DCEL_Vertex vertex)
{
Debug.Assert(VecRat2.CompareReadingOrder(halfEdge.Origin.Position, halfEdge.Destination.Position) < 0);
DCEL_HalfEdge e1 = halfEdge;
DCEL_HalfEdge e2 = e1.Twin;
DCEL_HalfEdge e1_prev = e1.Prev;
DCEL_HalfEdge e2_next = e2.Next;
DCEL_Vertex e1_origin = e1.Origin;
DCEL_HalfEdge e1_top = new DCEL_HalfEdge();
DCEL_HalfEdge e2_top = new DCEL_HalfEdge();
DCEL_Helper.JoinTwin(e1_top, e2_top);
e1_top.IncidentFace = e1.IncidentFace;
e2_top.IncidentFace = e2.IncidentFace;
DCEL_Helper.JoinIncidentEdge(vertex, e2_top);
DCEL_Helper.JoinIncidentEdge(vertex, e1);
DCEL_Helper.JoinIncidentEdge(e1_origin, e1_top);
if (e2_next == e1)
{
DCEL_Helper.JoinNext(e2, e2_top);
DCEL_Helper.JoinNext(e2_top, e1_top);
DCEL_Helper.JoinNext(e1_top, e1);
}
else
{
DCEL_Helper.JoinPrevNext(e2, e2_top, e2_next);
DCEL_Helper.JoinPrevNext(e1_prev, e1_top, e1);
}
if (subdivision != null)
{
subdivision.HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(e1_top));
subdivision.HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(e2_top));
}
}
public static Func <OA_Source <DCEL_T>, bool> IsFrom(DCEL_Subdivision subdivision)
{
return(source => (source.Subdivision == subdivision));
}
public OA_Source(DCEL_Subdivision subdivision, DCEL_T element)
{
Subdivision = subdivision;
Element = element;
}
