private AabbTreeNode <T> RebuildNode(List <AabbTreeNode <T> > leaves, AabbTreeNode <T> parent)
{
int expectedChildren = maxChildren - 1;
if (leaves.Count <= expectedChildren)
{
var n = new AabbTreeNode <T>
{
children = leaves,
depth = MaxDepth(leaves) + 1,
parent = parent,
};
foreach (var leaf in leaves)
{
leaf.parent = n;
}
return(n);
}
var unionrect = AaRects.MergeAll(leaves.Select(l => l.bounds));
if (unionrect.GetSize().x > unionrect.GetSize().y)
{
leaves.Sort(OrderNodeByX);
}
else
{
leaves.Sort(OrderNodeByY);
}
var result = new AabbTreeNode <T>
{
children = new List <AabbTreeNode <T> >(),
parent = parent,
};
for (int i = 0; i < expectedChildren; i++)
{
var i0 = i * leaves.Count / expectedChildren;
var i1 = (i + 1) * leaves.Count / expectedChildren;
result.children.Add(RebuildNode(leaves.GetRange(i0, i1 - i0), result));
}
ShallowUpdateNode(result, true);
return(result);
}
private void ShallowUpdateNode(AabbTreeNode <T> node, bool recalculateBounds)
{
if (node.leaf)
{
return;
}
var maxnode = GetMaxDepthChild(node);
if (node == null)
{
throw new InvalidOperationException();
}
if (maxnode == null)
{
throw new InvalidOperationException();
}
node.depth = maxnode.depth + 1;
if (recalculateBounds)
{
node.bounds = AaRects.MergeAll(node.children.Select(c => c.bounds));
}
}