} // public void ComputeIntersectsForChain( int chainIndex0,
private void ComputeIntersectsForChain(int start0,
int end0,
MonotoneChainEdge mce,
int start1,
int end1,
SegmentIntersector ei)
{
Coordinate p00 = _pts[start0];
Coordinate p01 = _pts[end0];
Coordinate p10 = mce.Coordinates[start1];
Coordinate p11 = mce.Coordinates[end1];
//Debug.println("computeIntersectsForChain:" + p00 + p01 + p10 + p11);
// terminating condition for the recursion
if (end0 - start0 == 1 && end1 - start1 == 1)
{
ei.AddIntersections(_e, start0, mce.Edge, start1);
return;
}
// nothing to do if the envelopes of these chains don't overlap
_env1.Initialize(p00, p01);
_env2.Initialize(p10, p11);
if (!_env1.Intersects(_env2))
{
return;
}
// the chains overlap, so split each in half and iterate (binary search)
int mid0 = (start0 + end0) / 2;
int mid1 = (start1 + end1) / 2;
// Assert: mid != start or end (since we checked above for end - start <= 1)
// check terminating conditions before recursing
if (start0 < mid0)
{
if (start1 < mid1)
{
ComputeIntersectsForChain(start0, mid0, mce, start1, mid1, ei);
}
if (mid1 < end1)
{
ComputeIntersectsForChain(start0, mid0, mce, mid1, end1, ei);
}
}
if (mid0 < end0)
{
if (start1 < mid1)
{
ComputeIntersectsForChain(mid0, end0, mce, start1, mid1, ei);
}
if (mid1 < end1)
{
ComputeIntersectsForChain(mid0, end0, mce, mid1, end1, ei);
}
}
} // private void ComputeIntersectsForChain( int start0,...
private void ComputeIntersectsForChain( int start0,
int end0,
MonotoneChainEdge mce,
int start1,
int end1,
SegmentIntersector ei )
{
Coordinate p00 = _pts[start0];
Coordinate p01 = _pts[end0];
Coordinate p10 = mce.Coordinates[start1];
Coordinate p11 = mce.Coordinates[end1];
//Debug.println("computeIntersectsForChain:" + p00 + p01 + p10 + p11);
// terminating condition for the recursion
if (end0 - start0 == 1 && end1 - start1 == 1)
{
ei.AddIntersections( _e, start0, mce.Edge, start1);
return;
}
// nothing to do if the envelopes of these chains don't overlap
_env1.Initialize(p00, p01);
_env2.Initialize(p10, p11);
if ( !_env1.Intersects( _env2 ) ) return;
// the chains overlap, so split each in half and iterate (binary search)
int mid0 = (start0 + end0) / 2;
int mid1 = (start1 + end1) / 2;
// Assert: mid != start or end (since we checked above for end - start <= 1)
// check terminating conditions before recursing
if (start0 < mid0)
{
if (start1 < mid1)
{
ComputeIntersectsForChain( start0, mid0, mce, start1, mid1, ei );
}
if (mid1 < end1)
{
ComputeIntersectsForChain( start0, mid0, mce, mid1, end1, ei );
}
}
if (mid0 < end0)
{
if (start1 < mid1)
{
ComputeIntersectsForChain( mid0, end0, mce, start1, mid1, ei);
}
if (mid1 < end1)
{
ComputeIntersectsForChain( mid0, end0, mce, mid1, end1, ei);
}
}
}
/// <summary>
/// Computes the intersections.
/// </summary>
public void ComputeIntersections(SweepLineSegment sweepLineSegment, SegmentIntersector segmentIntersector)
{
segmentIntersector.AddIntersections(_edge, _ptIndex, sweepLineSegment.Edge, sweepLineSegment.PointIndex);
}
