/*private*/
void
MonotoneChain::computeOverlaps(size_t start0, size_t end0,
MonotoneChain& mc,
size_t start1, size_t end1,
MonotoneChainOverlapAction& mco)
{
//Debug.println("computeIntersectsForChain:"+p00+p01+p10+p11);
// terminating condition for the recursion
if (end0-start0==1 && end1-start1==1)
{
mco.overlap(*this, start0, mc, start1);
return;
}
const Coordinate& p00 = pts[start0];
const Coordinate& p01 = pts[end0];
const Coordinate& p10 = mc.pts[start1];
const Coordinate& p11 = mc.pts[end1];
// nothing to do if the envelopes of these chains don't overlap
mco.tempEnv1.init(p00, p01);
mco.tempEnv2.init(p10, p11);
if (!mco.tempEnv1.intersects(mco.tempEnv2)) return;
// the chains overlap,so split each in half and iterate (binary search)
size_t mid0=(start0+end0)/2;
size_t 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)
computeOverlaps(start0, mid0, mc, start1, mid1, mco);
if (mid1<end1)
computeOverlaps(start0, mid0, mc, mid1, end1, mco);
}
if (mid0<end0)
{
if (start1<mid1)
computeOverlaps(mid0, end0, mc, start1, mid1, mco);
if (mid1<end1)
computeOverlaps(mid0, end0, mc, mid1, end1, mco);
}
}
/*private*/
void
MonotoneChain::computeOverlaps(size_t start0, size_t end0,
MonotoneChain& mc,
size_t start1, size_t end1,
MonotoneChainOverlapAction& mco)
{
// terminating condition for the recursion
if(end0 - start0 == 1 && end1 - start1 == 1) {
mco.overlap(*this, start0, mc, start1);
return;
}
// nothing to do if the envelopes of these subchains don't overlap
if(!overlaps(start0, end0, mc, start1, end1)) {
return;
}
// the chains overlap,so split each in half and iterate (binary search)
size_t mid0 = (start0 + end0) / 2;
size_t 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) {
computeOverlaps(start0, mid0, mc, start1, mid1, mco);
}
if(mid1 < end1) {
computeOverlaps(start0, mid0, mc, mid1, end1, mco);
}
}
if(mid0 < end0) {
if(start1 < mid1) {
computeOverlaps(mid0, end0, mc, start1, mid1, mco);
}
if(mid1 < end1) {
computeOverlaps(mid0, end0, mc, mid1, end1, mco);
}
}
}
