internal ScanSegmentTree(ScanDirection scanDir)
{
ScanDirection = scanDir;
this.segmentTree = new RbTree <ScanSegment>(this);
this.findIntersectorPred = new Func <ScanSegment, bool>(this.CompareIntersector);
this.findPointPred = new Func <ScanSegment, bool>(this.CompareToPoint);
}
protected VisibilityGraphGenerator(bool wantReflections) {
this.ScanDirection = ScanDirection.HorizontalInstance;
this.eventQueue = new EventQueue();
this.HorizontalScanSegments = new ScanSegmentTree(ScanDirection.HorizontalInstance);
this.VerticalScanSegments = new ScanSegmentTree(ScanDirection.VerticalInstance);
this.wantReflections = wantReflections;
}
internal ScanSegment FindSegmentOverlappingPoints(Point start, Point end, bool allowUnfound)
{
this.lookupSegment.Update(start, end);
RBNode <ScanSegment> node = this.segmentTree.FindFirst(this.findPointPred);
// If we had any segments in the tree that end after 'start', node has the first one.
// Now we need to that it starts before 'end'. ScanSegment.CompareToPointPositionFullLength
// asserts the point is on the segment which we don't want to require here, so
// compare the endpoints directly.
if (null != node)
{
ScanSegment seg = node.Item;
if (ScanDirection.Compare(seg.Start, end) <= 0)
{
return(seg);
}
}
// Not found.
if (!allowUnfound)
{
Debug.Assert(false, "Could not find expected segment");
}
return(null);
}
// 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 static Obstacle CreateSentinel(Point a, Point b, ScanDirection scanDir, int scanlineOrdinal)
{
var sentinel = new Obstacle(a, b, scanlineOrdinal);
sentinel.CreateInitialSides(sentinel.PaddedPolyline.StartPoint, scanDir);
return(sentinel);
}
bool CompareToPoint(ScanSegment treeSeg)
{
// Test if treeSeg overlaps the LookupSegment.Start point. We're using FindFirst,
// so we'll just return false for everything that ends before the point and true for anything
// that ends at or after it, then the caller will verify overlap.
return(ScanDirection.Compare(treeSeg.End, this.lookupSegment.Start) >= 0);
}
static internal double Slope(Point start, Point end, ScanDirection scanDir)
{
// Find the slope relative to scanline - how much scan coord changes per sweep change.
Point lineDirAsPoint = end - start;
return((lineDirAsPoint * scanDir.PerpDirectionAsPoint) / (lineDirAsPoint * scanDir.DirectionAsPoint));
}
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);
}
/// <summary>
/// For ordering the line segments inserted by the ScanLine. Assuming vertical sweep (sweeping up from
/// bottom, scanning horizontally) then order ScanSegments first by lowest Y coord, then by lowest X coord.
/// </summary>
/// <param name="first"></param>
/// <param name="second"></param>
/// <returns></returns>
public int Compare(ScanSegment first, ScanSegment second)
{
if (first == second)
{
return(0);
}
if (first == null)
{
return(-1);
}
if (second == null)
{
return(1);
}
// This orders on both axes.
int cmp = ScanDirection.Compare(first.Start, second.Start);
if (0 == cmp)
{
// Longer segments come first, to make overlap removal easier.
cmp = -ScanDirection.Compare(first.End, second.End);
}
return(cmp);
}
// Hit-testing.
internal bool IntersectionIsInsideAnotherObstacle(Obstacle sideObstacle, Obstacle eventObstacle, Point intersect, ScanDirection scanDirection)
{
insideHitTestIgnoreObstacle1 = eventObstacle;
insideHitTestIgnoreObstacle2 = sideObstacle;
insideHitTestScanDirection = scanDirection;
RectangleNode <Obstacle, Point> obstacleNode = Root.FirstHitNode(intersect, InsideObstacleHitTest);
return(null != obstacleNode);
}
internal bool PointIsInsideAnObstacle(Point intersect, ScanDirection scanDirection)
{
insideHitTestIgnoreObstacle1 = null;
insideHitTestIgnoreObstacle2 = null;
insideHitTestScanDirection = scanDirection;
RectangleNode <Obstacle, Point> obstacleNode = Root.FirstHitNode(intersect, InsideObstacleHitTest);
return(null != obstacleNode);
}
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;
}
}
// 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 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);
}
RBNode <ScanSegment> MergeAndRemoveNextNode(ScanSegment currentSegment, RBNode <ScanSegment> nextSegNode)
{
// Merge at the ends only - if we're here, start will be the same or greater.
if (-1 == ScanDirection.Compare(currentSegment.End, nextSegNode.Item.End))
{
currentSegment.Update(currentSegment.Start, nextSegNode.Item.End);
}
// Removing the node can revise the tree's RBNodes internally so re-get the current segment.
currentSegment.MergeGroupBoundaryCrossingList(nextSegNode.Item.GroupBoundaryPointAndCrossingsList);
this.segmentTree.DeleteNodeInternal(nextSegNode);
return(this.segmentTree.Find(currentSegment));
}
private void SetVectorsAndCoordMaps(ScanDirection scanDir)
{
if (scanDir.IsHorizontal)
{
this.parallelSegmentVector = this.horizontalScanSegmentVector;
this.perpendicularSegmentVector = this.verticalScanSegmentVector;
this.perpendicularCoordMap = this.verticalCoordMap;
}
else
{
this.parallelSegmentVector = this.verticalScanSegmentVector;
this.perpendicularSegmentVector = this.horizontalScanSegmentVector;
this.perpendicularCoordMap = this.horizontalCoordMap;
}
}
private void AddAxisCoordinateEvents(ScanDirection scanDir)
{
// Normal event ordering will apply - and will thus order the ScanSegments created in the vectors.
if (scanDir.IsHorizontal)
{
foreach (var coord in yCoordAccumulator)
{
base.eventQueue.Enqueue(new AxisCoordinateEvent(new Point(ObstacleTree.GraphBox.Left - SentinelOffset, coord)));
}
return;
}
foreach (var coord in xCoordAccumulator)
{
base.eventQueue.Enqueue(new AxisCoordinateEvent(new Point(coord, ObstacleTree.GraphBox.Bottom - SentinelOffset)));
}
}
internal HighObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir)
: base(obstacle, startVertex, scanDir, scanDir.IsVertical /*traverseClockwise*/)
{
}
internal bool PointIsInsideAnObstacle(Point intersect, ScanDirection scanDirection) {
insideHitTestIgnoreObstacle1 = null;
insideHitTestIgnoreObstacle2 = null;
insideHitTestScanDirection = scanDirection;
RectangleNode<Obstacle> obstacleNode = Root.FirstHitNode(intersect, InsideObstacleHitTest);
return (null != obstacleNode);
}
static internal double Slope(SegmentBase seg, ScanDirection scanDir)
{
return(Slope(seg.Start, seg.End, scanDir));
}
// If we have collinear segments, then we may be able to just update the previous one
// instead of growing the ScanSegmentTree.
// - For multiple collinear OpenVertexEvents, neighbors to the high side have not yet
// been seen, so a segment is created that spans the lowest and highest neighbors.
// A subsequent collinear OpenVertexEvent will be to the high side and will add a
// subsegment of that segment, so we subsume it into LastAddedSegment.
// - For multiple collinear CloseVertexEvents, closing neighbors to the high side are
// still open, so a segment is created from the lowest neighbor to the next-highest
// collinear obstacle to be closed. When that next-highest CloseVertexEvent is
// encountered, it will extend LastAddedSegment.
// - For multiple collinear mixed Open and Close events, we'll do all Opens first,
// followed by all closes (per EventQueue opening), so we may add multiple discrete
// segments, which ScanSegmentTree will merge.
internal static bool Subsume(ref ScanSegment seg, Point newStart, Point newEnd,
double weight, PointAndCrossingsList gbcList,
ScanDirection scanDir, ScanSegmentTree tree, out bool extendStart,
out bool extendEnd)
{
// Initialize these to the non-subsumed state; the endpoints were extended (or on a
// different line).
extendStart = true;
extendEnd = true;
if (null == seg)
{
return(false);
}
// If they don't overlap (including touching at an endpoint), we don't subsume.
if (!StaticGraphUtility.IntervalsOverlap(seg.Start, seg.End, newStart, newEnd))
{
return(false);
}
// If the overlapped-ness isn't the same, we don't subsume. ScanSegmentTree::MergeSegments
// will mark that the low-to-high direction needs a VisibilityVertex to link the two segments.
// These may differ by more than Curve.DistanceEpsilon in the case of reflection lookahead
// segments collinear with vertex-derived segments, so have a looser tolerance here and we'll
// adjust the segments in ScanSegmentTree.MergeSegments.
if (seg.Weight != weight)
{
if ((seg.Start == newStart) && (seg.End == newEnd))
{
// This is probably because of a rounding difference by one DistanceEpsilon reporting being
// inside an obstacle vs. the scanline intersection calculation side-ordering.
// Test is RectilinearFileTests.Overlap_Rounding_Vertex_Intersects_Side.
seg.Weight = Math.Min(seg.Weight, weight);
return(true);
}
// In the case of groups, we go through the group boundary; this may coincide with a
// reflection segment. RectilinearFileTests.ReflectionSubsumedBySegmentExitingGroup.
Debug.Assert((seg.Weight == OverlappedWeight) == (weight == OverlappedWeight) ||
ApproximateComparer.CloseIntersections(seg.End, newStart) ||
ApproximateComparer.CloseIntersections(seg.Start, newEnd)
, "non-equal overlap-mismatched ScanSegments overlap by more than just Start/End");
return(false);
}
// Subsume the input segment. Return whether the start/end points were extended (newStart
// is before this.Start, or newEnd is after this.End), so the caller can generate reflections
// and so we can merge group border crossings.
extendStart = (-1 == scanDir.CompareScanCoord(newStart, seg.Start));
extendEnd = (1 == scanDir.CompareScanCoord(newEnd, seg.End));
if (extendStart || extendEnd)
{
// We order by start and end so need to replace this in the tree regardless of which end changes.
tree.Remove(seg);
seg.startPoint = scanDir.Min(seg.Start, newStart);
seg.endPoint = scanDir.Max(seg.End, newEnd);
seg = tree.InsertUnique(seg).Item;
seg.MergeGroupBoundaryCrossingList(gbcList);
}
return(true);
}
internal HighObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir)
: base(obstacle, startVertex, scanDir, scanDir.IsVertical /*traverseClockwise*/)
{
}
internal virtual void InitializeEventQueue(ScanDirection scanDir) {
ScanDirection = scanDir;
eventQueue.Reset(ScanDirection);
EnqueueBottomVertexEvents();
scanLine = new RectilinearScanLine(ScanDirection, ObstacleTree.GraphBox.LeftBottom);
lookaheadScan = new LookaheadScan(ScanDirection);
}
internal override void InitializeEventQueue(ScanDirection scanDir)
{
base.InitializeEventQueue(scanDir);
hintScanSegment = null;
}
internal override void InitializeEventQueue(ScanDirection scanDir) {
base.InitializeEventQueue(scanDir);
hintScanSegment = null;
}
internal void Reset(ScanDirection scanDir)
{
Debug.Assert(0 == eventTree.Count, "Stray events in EventQueue.Reset");
scanDirection = scanDir;
}
bool CompareIntersector(ScanSegment seg)
{
// We're looking for the last segment that starts before LookupSegment.Start.
return(ScanDirection.Compare(seg.Start, this.lookupSegment.Start) <= 0);
}
static internal double Slope(SegmentBase seg, ScanDirection scanDir) {
return Slope(seg.Start, seg.End, scanDir);
}
internal LookaheadScan(ScanDirection scanDir)
{
scanDirection = scanDir;
eventTree = new RbTree <BasicReflectionEvent>(this);
findFirstPred = new Func <BasicReflectionEvent, bool>(n => CompareToFindFirstPoint(n.Site) >= 0);
}
internal ObstaclePortEntrance(ObstaclePort oport, Point unpaddedBorderIntersect, Direction outDir, ObstacleTree obstacleTree)
{
ObstaclePort = oport;
UnpaddedBorderIntersect = unpaddedBorderIntersect;
OutwardDirection = outDir;
// Get the padded intersection.
var lineSeg = new LineSegment(UnpaddedBorderIntersect, StaticGraphUtility.RectangleBorderIntersect(
oport.Obstacle.VisibilityBoundingBox, UnpaddedBorderIntersect, outDir));
IList <IntersectionInfo> xxs = Curve.GetAllIntersections(lineSeg, oport.Obstacle.VisibilityPolyline, true /*liftIntersections*/);
Debug.Assert(1 == xxs.Count, "Expected one intersection");
this.VisibilityBorderIntersect = ApproximateComparer.Round(SpliceUtility.RawIntersection(xxs[0], UnpaddedBorderIntersect));
this.MaxVisibilitySegment = obstacleTree.CreateMaxVisibilitySegment(this.VisibilityBorderIntersect,
this.OutwardDirection, out this.pointAndCrossingsList);
// Groups are never in a clump (overlapped) but they may still have their port entrance overlapped.
if (this.Obstacle.IsOverlapped || (this.Obstacle.IsGroup && !this.Obstacle.IsInConvexHull))
{
this.IsOverlapped = obstacleTree.IntersectionIsInsideAnotherObstacle(/*sideObstacle:*/ null, this.Obstacle
, this.VisibilityBorderIntersect, ScanDirection.GetInstance(OutwardDirection));
if (!this.Obstacle.IsGroup || this.IsOverlapped || this.InteriorEdgeCrossesObstacle(obstacleTree))
{
unpaddedToPaddedBorderWeight = ScanSegment.OverlappedWeight;
}
}
if (this.Obstacle.IsInConvexHull && (unpaddedToPaddedBorderWeight == ScanSegment.NormalWeight))
{
SetUnpaddedToPaddedBorderWeightFromHullSiblingOverlaps(obstacleTree);
}
}
// Hit-testing.
internal bool IntersectionIsInsideAnotherObstacle(Obstacle sideObstacle, Obstacle eventObstacle, Point intersect, ScanDirection scanDirection) {
insideHitTestIgnoreObstacle1 = eventObstacle;
insideHitTestIgnoreObstacle2 = sideObstacle;
insideHitTestScanDirection = scanDirection;
RectangleNode<Obstacle> obstacleNode = Root.FirstHitNode(intersect, InsideObstacleHitTest);
return (null != obstacleNode);
}
internal RectilinearScanLine(ScanDirection scanDir, Point start)
{
scanDirection = scanDir;
SideTree = new RbTree <BasicObstacleSide>(this);
this.linePositionAtLastInsertOrRemove = start;
}
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");
}
internal LowObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir)
: base(obstacle, startVertex, scanDir, scanDir.IsHorizontal /*traverseClockwise*/)
{
}
internal LowObstacleSide(Obstacle obstacle, PolylinePoint startVertex, ScanDirection scanDir)
: base(obstacle, startVertex, scanDir, scanDir.IsHorizontal /*traverseClockwise*/)
{
}
internal bool PointIsInsideAnObstacle(Point intersect, Directions direction)
{
return(PointIsInsideAnObstacle(intersect, ScanDirection.GetInstance(direction)));
}
internal override void InitializeEventQueue(ScanDirection scanDir)
{
base.InitializeEventQueue(scanDir);
this.SetVectorsAndCoordMaps(scanDir);
this.AddAxisCoordinateEvents(scanDir);
}
internal void MergeSegments()
{
// As described in the doc, hintScanSegment handles all the non-overlapped non-reflection cases.
DevTraceInfo(1, "{0} ScanSegmentTree MergeSegments, count = {1}"
, ScanDirection.IsHorizontal ? "Horizontal" : "Vertical", this.segmentTree.Count);
if (this.segmentTree.Count < 2)
{
return;
}
RBNode <ScanSegment> currentSegNode = this.segmentTree.TreeMinimum();
RBNode <ScanSegment> nextSegNode = this.segmentTree.Next(currentSegNode);
for ( ; null != nextSegNode; nextSegNode = this.segmentTree.Next(currentSegNode))
{
DevTraceInfo(2, "Current {0} Next {1}", currentSegNode.Item, nextSegNode.Item);
int cmp = ScanDirection.Compare(nextSegNode.Item.Start, currentSegNode.Item.End);
switch (cmp)
{
case 1:
// Next segment starts after the current one.
currentSegNode = nextSegNode;
break;
case 0:
if (nextSegNode.Item.IsOverlapped == currentSegNode.Item.IsOverlapped)
{
// Overlapping is the same, so merge. Because the ordering in the tree is that
// same-Start nodes are ordered by longest-End first, this will retain the tree ordering.
DevTraceInfo(2, " (merged; start-at-end with same overlap)");
currentSegNode = MergeAndRemoveNextNode(currentSegNode.Item, nextSegNode);
}
else
{
// Touching start/end with differing IsOverlapped so they need a connecting vertex.
DevTraceInfo(2, " (marked with NeedFinalOverlapVertex)");
currentSegNode.Item.NeedEndOverlapVertex = true;
nextSegNode.Item.NeedStartOverlapVertex = true;
currentSegNode = nextSegNode;
}
break;
default: // -1 == cmp
// nextSegNode.Item.Start is before currentSegNode.Item.End.
Debug.Assert((nextSegNode.Item.Start != currentSegNode.Item.Start) ||
(nextSegNode.Item.End < currentSegNode.Item.End)
, "Identical segments are not allowed, and longer ones must come first");
// Because longer segments are ordered before shorter ones at the same start position,
// nextSegNode.Item must be a duplicate segment or is partially or totally overlapped.
// In the case of reflection lookahead segments, the side-intersection calculated from
// horizontal vs. vertical directions may be slightly different along the parallel
// coordinate from an overlapped segment, so let non-overlapped win that disagreement.
if (currentSegNode.Item.IsOverlapped != nextSegNode.Item.IsOverlapped)
{
Debug.Assert(ApproximateComparer.CloseIntersections(currentSegNode.Item.End, nextSegNode.Item.Start)
, "Segments share a span with different IsOverlapped");
if (currentSegNode.Item.IsOverlapped)
{
// If the Starts are different, then currentSegNode is the only item at its
// start, so we don't need to re-insert. Otherwise, we need to remove it and
// re-find nextSegNode's side.
if (currentSegNode.Item.Start == nextSegNode.Item.Start)
{
// currentSegNode is a tiny overlapped segment between two non-overlapped segments (so
// we'll have another merge later, when we hit the other non-overlapped segment).
// Notice reversed params. TestNote: No longer have repro with the change to convex hulls;
// this may no longer happen since overlapped edges will now always be inside rectangular
// obstacles so there are no angled-side calculations.
currentSegNode = MergeAndRemoveNextNode(nextSegNode.Item, currentSegNode);
DevTraceInfo(2, " (identical starts so discarding isOverlapped currentSegNode)");
}
else
{
currentSegNode.Item.Update(currentSegNode.Item.Start, nextSegNode.Item.Start);
DevTraceInfo(2, " (trimming isOverlapped currentSegNode to {0})", currentSegNode.Item);
currentSegNode = nextSegNode;
}
}
else
{
if (currentSegNode.Item.End == nextSegNode.Item.End)
{
// nextSegNode is a tiny non-overlapped segment between two overlapped segments (so
// we'll have another merge later, when we hit the other non-overlapped segment).
// TestNote: No longer have repro with the change to convex hulls;
// this may no longer happen since overlapped edges will now always be inside rectangular
// obstacles so there are no angled-side calculations.
currentSegNode = MergeAndRemoveNextNode(currentSegNode.Item, nextSegNode);
DevTraceInfo(2, " (identical ends so discarding isOverlapped currentSegNode)");
}
else
{
// Remove nextSegNode, increment its start to be after currentSegment, re-insert nextSegNode, and
// re-find currentSegNode (there may be more segments between nextSegment.Start and currentSegment.End).
ScanSegment nextSegment = nextSegNode.Item;
ScanSegment currentSegment = currentSegNode.Item;
this.segmentTree.DeleteNodeInternal(nextSegNode);
nextSegment.Update(currentSegment.End, nextSegment.End);
this.segmentTree.Insert(nextSegment);
nextSegment.TrimGroupBoundaryCrossingList();
DevTraceInfo(2, " (trimming isOverlapped nextSegNode to {0})", nextSegment);
currentSegNode = this.segmentTree.Find(currentSegment);
}
}
break;
}
// Overlaps match so do a normal merge operation.
DevTraceInfo(2, " (merged; start-before-end)");
currentSegNode = MergeAndRemoveNextNode(currentSegNode.Item, nextSegNode);
break;
} // endswitch
} // endfor
#if DEVTRACE
DevTraceInfo(1, "{0} ScanSegmentTree after MergeSegments, count = {1}"
, ScanDirection.IsHorizontal ? "Horizontal" : "Vertical", this.segmentTree.Count);
if (this.scanSegmentVerify.IsLevel(1))
{
DevTraceInfo(1, "{0} ScanSegmentTree Consistency Check"
, ScanDirection.IsHorizontal ? "Horizontal" : "Vertical");
bool retval = true;
RBNode <ScanSegment> prevSegNode = this.segmentTree.TreeMinimum();
currentSegNode = this.segmentTree.Next(prevSegNode);
while (null != currentSegNode)
{
DevTraceInfo(4, currentSegNode.Item.ToString());
// We should only have end-to-end touching, and that only if differing IsOverlapped.
if ((-1 != Compare(prevSegNode.Item, currentSegNode.Item)) ||
(1 != ScanDirection.Compare(currentSegNode.Item.Start, prevSegNode.Item.Start) ||
((0 == ScanDirection.Compare(currentSegNode.Item.Start, prevSegNode.Item.End)) &&
(currentSegNode.Item.IsOverlapped == prevSegNode.Item.IsOverlapped))))
{
this.scanSegmentTrace.WriteError(0, "Segments are not strictly increasing:");
this.scanSegmentTrace.WriteFollowup(0, prevSegNode.Item.ToString());
this.scanSegmentTrace.WriteFollowup(0, currentSegNode.Item.ToString());
retval = false;
}
prevSegNode = currentSegNode;
currentSegNode = this.segmentTree.Next(currentSegNode);
}
Debug.Assert(retval, "ScanSegments are not strictly increasing");
}
#endif // DEVTRACE
}
static internal double Slope(Point start, Point end, ScanDirection scanDir) {
// Find the slope relative to scanline - how much scan coord changes per sweep change.
Point lineDirAsPoint = end - start;
return (lineDirAsPoint * scanDir.PerpDirectionAsPoint) / (lineDirAsPoint * scanDir.DirectionAsPoint);
}
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;
}
internal static Obstacle CreateSentinel(Point a, Point b, ScanDirection scanDir, int scanlineOrdinal) {
var sentinel = new Obstacle(a, b, scanlineOrdinal);
sentinel.CreateInitialSides(sentinel.PaddedPolyline.StartPoint, scanDir);
return sentinel;
}
// 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);
}
}
// If we have collinear segments, then we may be able to just update the previous one
// instead of growing the ScanSegmentTree.
// - For multiple collinear OpenVertexEvents, neighbors to the high side have not yet
// been seen, so a segment is created that spans the lowest and highest neighbors.
// A subsequent collinear OpenVertexEvent will be to the high side and will add a
// subsegment of that segment, so we subsume it into LastAddedSegment.
// - For multiple collinear CloseVertexEvents, closing neighbors to the high side are
// still open, so a segment is created from the lowest neighbor to the next-highest
// collinear obstacle to be closed. When that next-highest CloseVertexEvent is
// encountered, it will extend LastAddedSegment.
// - For multiple collinear mixed Open and Close events, we'll do all Opens first,
// followed by all closes (per EventQueue opening), so we may add multiple discrete
// segments, which ScanSegmentTree will merge.
internal static bool Subsume(ref ScanSegment seg, Point newStart, Point newEnd,
double weight, PointAndCrossingsList gbcList,
ScanDirection scanDir, ScanSegmentTree tree, out bool extendStart,
out bool extendEnd) {
// Initialize these to the non-subsumed state; the endpoints were extended (or on a
// different line).
extendStart = true;
extendEnd = true;
if (null == seg) {
return false;
}
// If they don't overlap (including touching at an endpoint), we don't subsume.
if (!StaticGraphUtility.IntervalsOverlap(seg.Start, seg.End, newStart, newEnd)) {
return false;
}
// If the overlapped-ness isn't the same, we don't subsume. ScanSegmentTree::MergeSegments
// will mark that the low-to-high direction needs a VisibilityVertex to link the two segments.
// These may differ by more than Curve.DistanceEpsilon in the case of reflection lookahead
// segments collinear with vertex-derived segments, so have a looser tolerance here and we'll
// adjust the segments in ScanSegmentTree.MergeSegments.
if (seg.Weight != weight) {
if ((seg.Start == newStart) && (seg.End == newEnd)) {
// This is probably because of a rounding difference by one DistanceEpsilon reporting being
// inside an obstacle vs. the scanline intersection calculation side-ordering.
// Test is RectilinearFileTests.Overlap_Rounding_Vertex_Intersects_Side.
seg.Weight = Math.Min(seg.Weight, weight);
return true;
}
// In the case of groups, we go through the group boundary; this may coincide with a
// reflection segment. RectilinearFileTests.ReflectionSubsumedBySegmentExitingGroup.
Debug.Assert((seg.Weight == OverlappedWeight) == (weight == OverlappedWeight) ||
ApproximateComparer.CloseIntersections(seg.End, newStart) ||
ApproximateComparer.CloseIntersections(seg.Start, newEnd)
, "non-equal overlap-mismatched ScanSegments overlap by more than just Start/End");
return false;
}
// Subsume the input segment. Return whether the start/end points were extended (newStart
// is before this.Start, or newEnd is after this.End), so the caller can generate reflections
// and so we can merge group border crossings.
extendStart = (-1 == scanDir.CompareScanCoord(newStart, seg.Start));
extendEnd = (1 == scanDir.CompareScanCoord(newEnd, seg.End));
if (extendStart || extendEnd) {
// We order by start and end so need to replace this in the tree regardless of which end changes.
tree.Remove(seg);
seg.startPoint = scanDir.Min(seg.Start, newStart);
seg.endPoint = scanDir.Max(seg.End, newEnd);
seg = tree.InsertUnique(seg).Item;
seg.MergeGroupBoundaryCrossingList(gbcList);
}
return true;
}
