internal RBNode <ScanSegment> FindLowestIntersectorNode(Point start, Point end)
{
Debug.Assert(ScanDirection.IsPerpendicular(start, end), "non-perpendicular segment passed");
// Find the last segment that starts at or before 'start'.
this.lookupSegment.Update(start, start);
RBNode <ScanSegment> node = this.segmentTree.FindLast(this.findIntersectorPred);
// We have a segment that intersects start/end, or one that ends before 'start' and thus we
// must iterate to find the lowest bisector. TODOperf: see how much that iteration costs us
// (here and Highest); consider a BSP tree or interval tree (maybe 2-d RBTree for updatability).
if (PointComparer.Equal(start, end))
{
if ((null != node) && (ScanDirection.Compare(node.Item.End, start) < 0))
{
node = null;
}
}
else
{
this.lookupSegment.Update(start, end);
while ((null != node) && !node.Item.IntersectsSegment(this.lookupSegment))
{
// If the node segment starts after 'end', no intersection was found.
if (ScanDirection.Compare(node.Item.Start, end) > 0)
{
return(null);
}
node = this.segmentTree.Next(node);
}
}
return(node);
}
// Find the highest perpendicular scanseg that intersects the segment endpoints.
internal ScanSegment FindHighestIntersector(Point start, Point end)
{
Debug.Assert(ScanDirection.IsPerpendicular(start, end), "non-perpendicular segment passed");
// Find the last segment that starts at or before 'end'.
this.lookupSegment.Update(end, end);
RBNode <ScanSegment> node = this.segmentTree.FindLast(this.findIntersectorPred);
// Now we either have a segment that intersects start/end, or one that ends before
// 'end' and need to iterate to find the highest bisector.
if (PointComparer.Equal(start, end))
{
if ((null != node) && (ScanDirection.Compare(node.Item.End, start) < 0))
{
node = null;
}
}
else
{
this.lookupSegment.Update(start, end);
while ((null != node) && !node.Item.IntersectsSegment(this.lookupSegment))
{
// If the node segment ends before 'start', no intersection was found.
if (ScanDirection.Compare(node.Item.End, start) < 0)
{
return(null);
}
node = this.segmentTree.Previous(node);
}
}
return((null != node) ? node.Item : null);
}
internal BasicObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir, bool traverseClockwise)
: base(startVertex)
{
Obstacle = obstacle;
endVertex = traverseClockwise ? startVertex.NextOnPolyline : startVertex.PrevOnPolyline;
if (!scanDir.IsPerpendicular(startVertex.Point, endVertex.Point))
{
Slope = StaticGraphUtility.Slope(startVertex.Point, endVertex.Point, scanDir);
SlopeInverse = 1.0 / Slope;
}
}
internal BasicObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir, bool traverseClockwise)
: base(startVertex)
{
Obstacle = obstacle;
endVertex = traverseClockwise ? startVertex.NextOnPolyline : startVertex.PrevOnPolyline;
if (!scanDir.IsPerpendicular(startVertex.Point, endVertex.Point))
{
Slope = StaticGraphUtility.Slope(startVertex.Point, endVertex.Point, scanDir);
SlopeInverse = 1.0 / Slope;
}
}
internal ScanSegment Find(Point start, Point end)
{
Debug.Assert(PointComparer.Equal(start, end) || !ScanDirection.IsPerpendicular(start, end)
, "perpendicular segment passed");
this.lookupSegment.Update(start, end);
RBNode <ScanSegment> node = this.segmentTree.Find(this.lookupSegment);
if ((null != node) && PointComparer.Equal(node.Item.End, end))
{
return(node.Item);
}
return(null);
}
