// Set the initial ActiveLowSide and ActiveHighSide of the obstacle starting at this point.
internal void CreateInitialSides(PolylinePoint startPoint, ScanDirection scanDir)
{
Debug.Assert((null == ActiveLowSide) && (null == ActiveHighSide)
, "Cannot call SetInitialSides when sides are already set");
ActiveLowSide = new LowObstacleSide(this, startPoint, scanDir);
ActiveHighSide = new HighObstacleSide(this, startPoint, scanDir);
if (scanDir.IsFlat(ActiveHighSide))
{
// No flat sides in the scanline; we'll do lookahead processing in the scanline to handle overlaps
// with existing segments, and normal neighbor handling will take care of collinear OpenVertexEvents.
ActiveHighSide = new HighObstacleSide(this, ActiveHighSide.EndVertex, scanDir);
}
}
internal RBNode <BasicObstacleSide> Insert(BasicObstacleSide side, Point scanPos)
{
DevTraceInfo(1, "prev LinePos = {0}, new LinePos = {1}, inserting side = {2}", this.linePositionAtLastInsertOrRemove, scanPos, side.ToString());
Assert(!scanDirection.IsFlat(side), "Flat sides are not allowed in the scanline");
Assert(null == Find(side), "side already exists in the ScanLine");
this.linePositionAtLastInsertOrRemove = scanPos;
// RBTree's internal operations on insert/remove etc. mean the node can't cache the
// RBNode returned by insert(); instead we must do find() on each call. But we can
// use the returned node to get predecessor/successor.
var node = SideTree.Insert(side);
DevTraceDump(2);
return(node);
}
internal static Point ScanLineIntersectSide(Point site, BasicObstacleSide side, ScanDirection scanDir)
{
// Note: we don't assert that site and side are not PointComparer.Equal, because ScanLine calls
// this on sides that share vertices.
Debug.Assert(!scanDir.IsFlat(side), "flat sides should not be in the scanline or encountered on lookahead scan");
// We know that we will have an intersection if the side is adjacent in the scanline, so
// we can optimize the calculation to project along the slope of the BasicObstacleSide.
// Also, due to rounding, we need to make sure that when intersecting the side, we're not
// falling short due to rounding error; that can be a problem if we're right at a vertex
// of that obstacle, because then there is no intersection with the perpendicular line
// from that vertex. So make sure we are at least to the nearest coordinate of that side.
// Note: Calculate slope here using 'dir' rather than side.SlopeInverse because Reflection
// lookaheads calculate the perpendicular intersection and side.Slope(Inverse) is always
// relative to the scanline parallel.
Point dir = side.Direction;
#if SHARPKIT //https://code.google.com/p/sharpkit/issues/detail?id=369
Point intersect = side.Start.Clone();
#else
Point intersect = side.Start;
#endif
if (scanDir.IsHorizontal) {
intersect.X += (dir.X / dir.Y) * (site.Y - side.Start.Y);
intersect.X = SpliceUtility.MungeIntersect(site.X, intersect.X, side.Start.X, side.End.X);
intersect.Y = site.Y;
}
else {
intersect.X = site.X;
intersect.Y += (dir.Y / dir.X) * (site.X - side.Start.X);
intersect.Y = SpliceUtility.MungeIntersect(site.Y, intersect.Y, side.Start.Y, side.End.Y);
}
return intersect;
}
void AssertValidSegmentForInsertion(ScanSegment seg)
{
Debug.Assert((seg.End.X >= seg.Start.X) && (seg.End.Y >= seg.Start.Y), "Reversed direction in ScanSegment");
Debug.Assert(ScanDirection.IsFlat(seg.Start, seg.End), "non-flat segment cannot be inserted");
}
// Set the initial ActiveLowSide and ActiveHighSide of the obstacle starting at this point.
internal void CreateInitialSides(PolylinePoint startPoint, ScanDirection scanDir) {
Debug.Assert((null == ActiveLowSide) && (null == ActiveHighSide)
, "Cannot call SetInitialSides when sides are already set");
ActiveLowSide = new LowObstacleSide(this, startPoint, scanDir);
ActiveHighSide = new HighObstacleSide(this, startPoint, scanDir);
if (scanDir.IsFlat(ActiveHighSide)) {
// No flat sides in the scanline; we'll do lookahead processing in the scanline to handle overlaps
// with existing segments, and normal neighbor handling will take care of collinear OpenVertexEvents.
ActiveHighSide = new HighObstacleSide(this, ActiveHighSide.EndVertex, scanDir);
}
}
