private void AddTilesIntersectingEnvelopeAt(SpaceFillingCurveConfiguration config, SpaceFillingCurveMonitor monitor, int depth, int maxDepth, SearchEnvelope search, SearchEnvelope currentExtent, CurveRule curve, long left, long right, List <LongRange> results) { if (right - left == 1) { long[] coord = NormalizedCoordinateFor(left, _maxLevel); if (search.Contains(coord)) { LongRange current = (results.Count > 0) ? results[results.Count - 1] : null; if (current != null && current.Max == left - 1) { current.ExpandToMax(left); } else { current = new LongRange(left); results.Add(current); } if (monitor != null) { monitor.AddRangeAtDepth(depth); monitor.AddToCoveredArea(currentExtent.Area); } } } else if (search.Intersects(currentExtent)) { double overlap = search.FractionOf(currentExtent); if (config.StopAtThisDepth(overlap, depth, maxDepth)) { // Note that LongRange upper bound is inclusive, hence the '-1' in several places LongRange current = (results.Count > 0) ? results[results.Count - 1] : null; if (current != null && current.Max == left - 1) { current.ExpandToMax(right - 1); } else { current = new LongRange(left, right - 1); results.Add(current); } if (monitor != null) { monitor.AddRangeAtDepth(depth); monitor.AddToCoveredArea(currentExtent.Area); } } else { long width = (right - left) / _quadFactor; for (int i = 0; i < _quadFactor; i++) { int npoint = curve.NpointForIndex(i); SearchEnvelope quadrant = currentExtent.Quadrant(BitValues(npoint)); AddTilesIntersectingEnvelopeAt(config, monitor, depth + 1, maxDepth, search, quadrant, curve.ChildAt(i), left + i * width, left + (i + 1) * width, results); } } } }