/// <summary>
/// Default collapsing strategy
/// </summary>
public void Collapse <T>(KdNode <T> target) where T : IVector
{
if (!target.Leaf)
{
throw new IntermediateNodeException();
}
if (target.Root)
{
throw new RootNodeException();
}
KdNode <T> parent = target.Parent;
if (parent.Left.Leaf && parent.Right.Leaf)
{
// When both children are leaves we push their content to the parent
int capacity = parent.Left.Vectors.Count + parent.Right.Vectors.Count;
parent.Vectors = new List <T>(capacity);
parent.Vectors.AddRange(parent.Left.Vectors);
parent.Vectors.AddRange(parent.Right.Vectors);
AABB aabb = parent.InternalBounds;
AABB.Union(parent.Left.InternalBounds, parent.Right.InternalBounds, ref aabb);
parent.UnSetLeftChild();
parent.UnSetRightChild();
}
else
{
// The sibling of 'target' is not a leaf. We replace the content of parent with the content of the sibling.
KdNode <T> sibling = (parent.ContainsInLeftSubTree(target) ? parent.Right : parent.Left);
parent.UnSetLeftChild();
parent.UnSetRightChild();
// Copy kdtree content
parent.SplitDimension = sibling.SplitDimension;
parent.SplitLocation = sibling.SplitLocation;
parent.Vectors = sibling.Vectors;
parent.InternalBounds = sibling.InternalBounds;
// Copy structural info
KdNode <T> sibling_left = sibling.UnSetLeftChild();
KdNode <T> sibling_right = sibling.UnSetRightChild();
parent.Left = sibling_left;
parent.Right = sibling_right;
}
}
