private bool AppendGroupCrossingsThroughPoint(VisibilityGraph vg, Point lastPoint)
{
if (null == GroupBoundaryPointAndCrossingsList)
{
return(false);
}
bool found = false;
while (GroupBoundaryPointAndCrossingsList.CurrentIsBeforeOrAt(lastPoint))
{
// We will only create crossing Edges that the segment actually crosses, not those it ends before crossing.
// For those terminal crossings, the adjacent segment creates the interior vertex and crossing edge.
PointAndCrossings pac = GroupBoundaryPointAndCrossingsList.Pop();
GroupBoundaryCrossing[] lowDirCrossings = null;
GroupBoundaryCrossing[] highDirCrossings = null;
if (PointComparer.Compare(pac.Location, Start) > 0)
{
lowDirCrossings = PointAndCrossingsList.ToCrossingArray(pac.Crossings,
ScanDirection.OppositeDirection);
}
if (PointComparer.Compare(pac.Location, End) < 0)
{
highDirCrossings = PointAndCrossingsList.ToCrossingArray(pac.Crossings, ScanDirection.Direction);
}
found = true;
VisibilityVertex crossingVertex = vg.FindVertex(pac.Location) ?? vg.AddVertex(pac.Location);
if ((null != lowDirCrossings) || (null != highDirCrossings))
{
AddLowCrossings(vg, crossingVertex, lowDirCrossings);
AddHighCrossings(vg, crossingVertex, highDirCrossings);
}
else
{
// This is at this.Start with only lower-direction toward group interior(s), or at this.End with only
// higher-direction toward group interior(s). Therefore an adjacent ScanSegment will create the crossing
// edge, so create the crossing vertex here and we'll link to it.
if (null == LowestVisibilityVertex)
{
SetInitialVisibilityVertex(crossingVertex);
}
else
{
Debug.Assert(PointComparer.Equal(End, crossingVertex.Point), "Expected this.End crossingVertex");
AppendHighestVisibilityVertex(crossingVertex);
}
}
}
return(found);
}
private void SpliceGroupBoundaryCrossing(VisibilityVertex currentVertex, PointAndCrossings pac, Directions dirToInside)
{
GroupBoundaryCrossing[] crossings = PointAndCrossingsList.ToCrossingArray(pac.Crossings, dirToInside);
if (null != crossings)
{
var outerVertex = VisGraph.FindVertex(pac.Location) ?? AddVertex(pac.Location);
if (currentVertex.Point != outerVertex.Point)
{
FindOrAddEdge(currentVertex, outerVertex);
}
var interiorPoint = crossings[0].GetInteriorVertexPoint(pac.Location);
var interiorVertex = VisGraph.FindVertex(interiorPoint) ?? AddVertex(interiorPoint);
// FindOrAddEdge splits an existing edge so may not return the portion bracketed by outerVertex and interiorVertex.
FindOrAddEdge(outerVertex, interiorVertex);
var edge = VisGraph.FindEdge(outerVertex.Point, interiorVertex.Point);
var crossingsArray = crossings.Select(c => c.Group.InputShape).ToArray();
edge.IsPassable = delegate { return(crossingsArray.Any(s => s.IsTransparent)); };
}
}