private static CycleType GetCycleType(DCEL_HalfEdge cycle)
{
if (GeomAid.TurnTest(cycle.Prev.Origin.Position, cycle.Origin.Position, cycle.Destination.Position) > 0)
{
return(CycleType.Interior);
}
else
{
return(CycleType.Exterior);
}
}
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));
}
}
/// <summary>
/// Create a subdivision from a single segment (u, v).
/// </summary>
public DCEL_Subdivision(VecRat2 u, VecRat2 v)
: this()
{
if (u == v)
{
throw new Exception("Tried to create a DCELSubdivision with a segment of length 0.");
}
DCEL_Vertex vertex_u = new DCEL_Vertex(u);
DCEL_Vertex vertex_v = new DCEL_Vertex(v);
DCEL_HalfEdge halfedge_uv = new DCEL_HalfEdge();
DCEL_HalfEdge halfedge_vu = new DCEL_HalfEdge();
DCEL_Face face = new DCEL_Face();
vertex_u.IncidentEdge = halfedge_uv;
vertex_v.IncidentEdge = halfedge_vu;
halfedge_uv.Origin = vertex_u;
halfedge_uv.Twin = halfedge_vu;
halfedge_uv.IncidentFace = face;
halfedge_uv.Prev = halfedge_vu;
halfedge_uv.Next = halfedge_vu;
halfedge_vu.Origin = vertex_v;
halfedge_vu.Twin = halfedge_uv;
halfedge_vu.IncidentFace = face;
halfedge_vu.Prev = halfedge_uv;
halfedge_vu.Next = halfedge_uv;
face.InnerComponents.AddLast(halfedge_uv);
Vertices.Add(new RBTreeSetNode <DCEL_Vertex>(vertex_u));
Vertices.Add(new RBTreeSetNode <DCEL_Vertex>(vertex_u));
HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(halfedge_uv));
HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(halfedge_vu));
Faces.Add(new RBTreeSetNode <DCEL_Face>(face));
UnboundedFace = face;
}
public Segment(DCEL_HalfEdge source, Sweepline sweepline)
{
Source = source;
EventPoint origin = new EventPoint(source.Origin);
EventPoint destination = new EventPoint(source.Destination);
int comp = origin.CompareTo(destination);
if (comp < 0)
{
Upper = origin;
Lower = destination;
}
else if (comp > 0)
{
Upper = destination;
Lower = origin;
}
else
{
throw new InvalidOperationException("Trivial line segment.");
}
Sweepline = sweepline;
}
public DCEL_Vertex(VecRat2 position)
: base()
{
Position = position;
IncidentEdge = null;
}
private void CreateFaces()
{
RBTreeMap <DCEL_HalfEdge, HalfEdgeData> halfEdgesData = new RBTreeMap <DCEL_HalfEdge, HalfEdgeData>(DCEL_Element.Compare);
foreach (DCEL_HalfEdge halfEdge in outputSubdivision.HalfEdges.Keys)
{
halfEdgesData.Add(new RBTreeMapNode <DCEL_HalfEdge, HalfEdgeData>(halfEdge, new HalfEdgeData()));
}
RBTreeMap <DCEL_HalfEdge, CycleData> cyclesData = new RBTreeMap <DCEL_HalfEdge, CycleData>(DCEL_Element.Compare);
List <bool> visited = outputSubdivision.HalfEdges.Keys.Select(e => false).ToList();
DCEL_Face unboundedFace = new DCEL_Face();
outputSubdivision.UnboundedFace = unboundedFace;
outputSubdivision.Faces.Add(new RBTreeSetNode <DCEL_Face>(unboundedFace));
foreach (var halfEdgeNode in halfEdgesData.Nodes)
{
DCEL_HalfEdge halfEdge = halfEdgeNode.Key;
if (halfEdgeNode.Value.Visited)
{
continue;
}
DCEL_HalfEdge cycle = halfEdge.CycleNext.Min((a, b) => a.Origin.CompareTo(b.Origin));
{
cycle = cycle.CycleNext.Where(e => e.Origin == cycle.Origin).Max(AngleComparisonUpperList_HalfEdge(cycle.Origin.Position));
}
CycleType cycleType = GetCycleType(cycle);
if (cycleType == CycleType.Interior)
{
DCEL_Face interiorFace = new DCEL_Face();
outputSubdivision.Faces.Add(new RBTreeSetNode <DCEL_Face>(interiorFace));
interiorFace.OuterComponent = cycle;
foreach (DCEL_HalfEdge cycleHalfEdge in cycle.CycleNext)
{
cycleHalfEdge.IncidentFace = interiorFace;
}
}
cyclesData.Add(new RBTreeMapNode <DCEL_HalfEdge, CycleData>(cycle, new CycleData(cycleType)));
foreach (DCEL_HalfEdge cycleHalfEdge in halfEdge.CycleNext)
{
HalfEdgeData data = halfEdgesData[cycleHalfEdge].Value;
data.Cycle = cycle;
}
}
foreach (var cycleNode in cyclesData.Nodes)
{
if (cycleNode.Value.CycleType == CycleType.Interior)
{
continue;
}
DCEL_HalfEdge cycle = cycleNode.Key;
DCEL_HalfEdge leftPick = leftPicksMap[cycle.Origin].Value;
if (leftPick == null)
{
unboundedFace.InnerComponents.AddLast(cycle);
foreach (DCEL_HalfEdge cycleHalfEdge in cycle.CycleNext)
{
cycleHalfEdge.IncidentFace = unboundedFace;
}
continue;
}
DCEL_HalfEdge leftPickCycle = halfEdgesData[leftPick].Value.Cycle;
CycleType leftPickCycleType = cyclesData[leftPickCycle].Value.CycleType;
//if (leftPickCycleType == CycleType.Interior)
//{
// leftPickCycle.IncidentFace.InnerComponents.AddLast(cycle);
// foreach (DCEL_HalfEdge cycleHalfEdge in cycle.CycleNext)
// cycleHalfEdge.IncidentFace = leftPickCycle.IncidentFace;
//}
cyclesData[leftPickCycle].Value.Children.Add(cycle);
cycleNode.Value.IsRoot = false;
}
foreach (var cycleChildrenNode in cyclesData.Nodes)
{
if (!cycleChildrenNode.Value.IsRoot)
{
continue;
}
DCEL_HalfEdge parentCycle = cycleChildrenNode.Key;
CycleType parentCycleType = cyclesData[parentCycle].Value.CycleType;
DCEL_Face face = parentCycle.IncidentFace;
List <DCEL_HalfEdge> childCycles = cycleChildrenNode.Value.Children;
Stack <DCEL_HalfEdge> unattachedCycles = new Stack <DCEL_HalfEdge>();
foreach (DCEL_HalfEdge childCycle in childCycles)
{
unattachedCycles.Push(childCycle);
}
while (!unattachedCycles.IsEmpty())
{
DCEL_HalfEdge exteriorCycle = unattachedCycles.Pop();
face.InnerComponents.AddLast(exteriorCycle);
foreach (DCEL_HalfEdge exteriorCycleHalfEdge in exteriorCycle.CycleNext)
{
exteriorCycleHalfEdge.IncidentFace = face;
}
foreach (DCEL_HalfEdge child in cyclesData[exteriorCycle].Value.Children)
{
unattachedCycles.Push(child);
}
}
}
}
private void HandleIntersection_MergingPhase(OA_EventPoint eventPoint, List <OA_Segment> upperList, List <OA_Segment> middleList, List <OA_Segment> lowerList)
{
if (middleList.Count != 0)
{
throw new Exception("MergingPhase: Something went wrong in the SplittingPhase, because there is an intersection with nonempty middleList.");
}
//Dictionary<DCEL_Subdivision, DCEL_Vertex> vertexLookup = CreateSourceLookup(eventPoint);
//DCEL_Vertex mergedVertex = vertexLookup.Values.First();
DCEL_Vertex mergedVertex = eventPoint.Source.First().Element;
lowerList.Sort(AngleComparisonLowerList(mergedVertex.Position));
upperList.Sort(AngleComparisonUpperList(mergedVertex.Position));
//JoinNext all consecutive pairs around circle, and join origins to mergedVertex
{
//Outgoing half edges in CCW order
List <DCEL_HalfEdge> bothList = new List <DCEL_HalfEdge>();
bothList.AddRange(lowerList.Select(segment => segment.Source.First().Element.Twin));
bothList.AddRange(upperList.Select(segment => segment.Source.First().Element));
if (bothList.Count > 1)
{
DCEL_HalfEdge e, e_next;
for (int i = 1; i < bothList.Count; i++)
{
e = bothList[i].Twin;
e_next = bothList[i - 1];
DCEL_Helper.JoinNext(e, e_next);
}
e = bothList.First().Twin;
e_next = bothList.Last();
DCEL_Helper.JoinNext(e, e_next);
}
else
{
DCEL_HalfEdge e = bothList[0].Twin;
DCEL_HalfEdge e_next = e.Twin;
DCEL_Helper.JoinNext(e, e_next);
}
//Set the origins to the mergedVertex
foreach (DCEL_HalfEdge e in bothList)
{
e.Origin = mergedVertex;
}
mergedVertex.IncidentEdge = bothList.First();
}
outputSubdivision.Vertices.Add(new RBTreeSetNode <DCEL_Vertex>(mergedVertex));
foreach (OA_Segment upper in upperList)
{
DCEL_HalfEdge e = upper.Source.First().Element;
outputSubdivision.HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(e));
outputSubdivision.HalfEdges.Add(new RBTreeSetNode <DCEL_HalfEdge>(e.Twin));
//HACK?/////////////////////////////////////////
e.IncidentFace = null;
e.Twin.IncidentFace = null;
//HACK?/////////////////////////////////////////
}
//Store the left pick for the mergedVertex
if (eventPoint.LeftPick != null)
{
leftPicksMap.Add(new RBTreeMapNode <DCEL_Vertex, DCEL_HalfEdge>(mergedVertex, eventPoint.LeftPick.Source.First().Element));
}
else
{
leftPicksMap.Add(new RBTreeMapNode <DCEL_Vertex, DCEL_HalfEdge>(mergedVertex, null));
}
}
public static void JoinIncidentEdge(DCEL_Vertex e_origin, DCEL_HalfEdge e)
{
e_origin.IncidentEdge = e;
e.Origin = e_origin;
}
public static void JoinTwin(DCEL_HalfEdge e, DCEL_HalfEdge e_twin)
{
e.Twin = e_twin;
e_twin.Twin = e;
}
public static void JoinNext(DCEL_HalfEdge e, DCEL_HalfEdge e_next)
{
e.Next = e_next;
e_next.Prev = e;
}
public static void JoinPrevNext(DCEL_HalfEdge e_prev, DCEL_HalfEdge e, DCEL_HalfEdge e_next)
{
JoinNext(e_prev, e);
JoinNext(e, e_next);
}