// min bounding rectangle of node children from k to p-1
public BBox <T> DistBBox(int k, int p)
{
var destNode = new BBox <T>();
destNode.Reset();
for (int i = k; i < p; i++)
{
var child = Children[i];
destNode.Extend(child); //node.Leaf ? toBBox(child) : child);
}
return(destNode);
}
public List <IBBox <T> > SearchParentsOrNull(IBBox <T> bbox)
{
var node = _data;
//_cacheListResult.Clear();
//var result = _cacheListResult;
var result = new List <IBBox <T> >();
if (!node.Contains(bbox))
{
return(null);
}
var nodesToSearch = new Stack <Node>();
while (node != null)
{
for (int i = 0, len = node.Children.Count; i < len; i++)
{
Node child = node.Children[i];
BBox <T> childBBox = child;
if (childBBox.Contains(bbox))
{
if (node.Leaf)
{
result.Add(child.ExternalObject);
}
else if (BBox <T> .Contains(bbox, childBBox))
{
AllCombine(child, ref result);
}
else
{
nodesToSearch.Push(child);
}
}
}
node = nodesToSearch.Count > 0 ? nodesToSearch.Pop() : null;
}
return(result.Count == 0 ? null : result.ToList());
}
public static int ChooseSplitIndex(Node node, int minEntries, int nodeChildsCount)
{
int index = 0;
var minOverlap = float.MaxValue;
var minArea = float.MaxValue;
for (int i = minEntries; i <= nodeChildsCount - minEntries; i++)
{
BBox <T> bbox1 = node.DistBBox(0, i);
BBox <T> bbox2 = node.DistBBox(i, nodeChildsCount);
float overlap = bbox1.IntersectionArea(bbox2);
float area = bbox1.Area + bbox2.Area;
// choose distribution with minimum overlap
if (overlap < minOverlap)
{
minOverlap = overlap;
index = i;
minArea = area < minArea ? area : minArea;
}
else if (overlap == minOverlap)
{
// otherwise choose distribution with minimum area
if (area < minArea)
{
minArea = area;
index = i;
}
}
}
return(index);
}
private int CompareMinY(T a, T b) => BBox.CompareMinY(_geomSelecter(a), _geomSelecter(b));