예제 #1
0
        private void ComputeOverlaps(int start0, int end0, MonotoneChain mc, int start1, int 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 sub-chains don't overlap
            if (!Overlaps(start0, end0, mc, start1, end1))
            {
                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)
                {
                    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);
                }
            }
        }
예제 #2
0
 /// <summary>
 /// Determine all the line segments in two chains which may overlap, and process them.
 /// </summary>
 /// <remarks>
 /// The monotone chain search algorithm attempts to optimize
 /// performance by not calling the overlap action on chain segments
 /// which it can determine do not overlap.
 /// However, it *may* call the overlap action on segments
 /// which do not actually interact.
 /// This saves on the overhead of checking intersection
 /// each time, since clients may be able to do this more efficiently.
 /// </remarks>
 /// <param name="mc">The monotone chain</param>
 /// <param name="mco">The overlap action to execute on selected segments</param>
 public void ComputeOverlaps(MonotoneChain mc, MonotoneChainOverlapAction mco)
 {
     ComputeOverlaps(_start, _end, mc, mc._start, mc._end, mco);
 }