void AddIntersectionOfBothDirectionSweepsToTheResult(VisibilityGraph vg0, VisibilityGraph vg1) {
foreach (var edge in vg0.Edges)
if (vg1.FindEdge(edge.SourcePoint, edge.TargetPoint) != null)
_visibilityGraph.AddEdge(edge.SourcePoint, edge.TargetPoint);
}
private void AddCrossingEdge(VisibilityGraph vg, VisibilityVertex lowVertex, VisibilityVertex highVertex, GroupBoundaryCrossing[] crossings) {
VisibilityEdge edge = null;
if (null != HighestVisibilityVertex) {
// We may have a case where point xx.xxxxx8 has added an ascending-direction crossing, and now we're on
// xx.xxxxx9 adding a descending-direction crossing. In that case there should already be a VisibilityEdge
// in the direction we want.
if (PointComparer.Equal(this.HighestVisibilityVertex.Point, highVertex.Point)) {
edge = vg.FindEdge(lowVertex.Point, highVertex.Point);
Debug.Assert(edge != null, "Inconsistent forward-backward sequencing in HighVisibilityVertex");
} else {
AppendHighestVisibilityVertex(lowVertex);
}
}
if (edge == null) {
edge = AddVisibilityEdge(lowVertex, highVertex);
}
var crossingsArray = crossings.Select(c => c.Group.InputShape).ToArray();
var prevIsPassable = edge.IsPassable;
if (prevIsPassable == null) {
edge.IsPassable = delegate { return crossingsArray.Any(s => s.IsTransparent); };
} else {
// Because we don't have access to the previous delegate's internals, we have to chain. Fortunately this
// will never be more than two deep. File Test: Groups_Forward_Backward_Between_Same_Vertices.
edge.IsPassable = delegate { return crossingsArray.Any(s => s.IsTransparent) || prevIsPassable(); };
}
if (null == LowestVisibilityVertex) {
SetInitialVisibilityVertex(lowVertex);
}
HighestVisibilityVertex = highVertex;
}
static internal VisibilityEdge FindNextEdge(VisibilityGraph vg, VisibilityVertex vertex, Directions dir) {
VisibilityVertex nextVertex = FindNextVertex(vertex, dir);
return (null == nextVertex) ? null : vg.FindEdge(vertex.Point, nextVertex.Point);
}
// Append a vertex before LowestVisibilityVertex or after HighestVisibilityVertex.
internal void AppendVisibilityVertex(VisibilityGraph vg, VisibilityVertex newVertex) {
Debug.Assert(null != newVertex, "newVertex must not be null");
Debug.Assert((null == LowestVisibilityVertex) == (null == HighestVisibilityVertex), "Mismatched null Lowest/HighestVisibilityVertex");
Debug.Assert(StaticGraphUtility.PointIsOnSegment(this, newVertex.Point), "newVertex is out of segment range");
if (null == HighestVisibilityVertex) {
if (!AddGroupCrossingsBeforeHighestVisibilityVertex(vg, newVertex)) {
SetInitialVisibilityVertex(newVertex);
}
} else {
// In the event of overlaps where ScanSegments share a Start/End at a border, SegmentIntersector
// may be appending the same Vertex twice. If that point is on the border of a group,
// then we may have just added the border-crossing edge as well.
if (PointComparer.IsPureLower(newVertex.Point, HighestVisibilityVertex.Point)) {
Debug.Assert(null != vg.FindEdge(newVertex.Point, HighestVisibilityVertex.Point)
, "unexpected low/middle insertion to ScanSegment");
return;
}
// Add the new edge. This will always be in the ascending direction.
if (!AddGroupCrossingsBeforeHighestVisibilityVertex(vg, newVertex)) {
AppendHighestVisibilityVertex(newVertex);
}
}
}
