private static int CompareNodesByMinY(RTreeNode <T> a, RTreeNode <T> b)
{
return(a.Envelope.Y1.CompareTo(b.Envelope.Y1));
}
// calculate node's bbox from bboxes of its children
private static void RefreshEnvelope(RTreeNode <T> node)
{
node.Envelope = SumChildBounds(node, 0, node.Children.Count);
}
public void Insert(RTreeNode <T> item)
{
Insert(item, root.Height - 1);
}
public void Remove(T item, Envelope envelope)
{
var node = root;
var itemEnvelope = envelope;
var path = new Stack <RTreeNode <T> >();
var indexes = new Stack <int>();
var i = 0;
var goingUp = false;
RTreeNode <T> parent = null;
// depth-first iterative tree traversal
while (node != null || path.Count > 0)
{
if (node == null)
{
// go up
node = path.TryPop();
parent = path.TryPeek();
i = indexes.TryPop();
goingUp = true;
}
if (node != null && node.IsLeaf)
{
// check current node
var index = node.Children.FindIndex(n => Comparer.Equals(item, n.Data));
if (index != -1)
{
// item found, remove the item and condense tree upwards
node.Children.RemoveAt(index);
path.Push(node);
CondenseNodes(path.ToArray());
return;
}
}
if (!goingUp && !node.IsLeaf && node.Envelope.Contains(itemEnvelope))
{
// go down
path.Push(node);
indexes.Push(i);
i = 0;
parent = node;
node = node.Children[0];
}
else if (parent != null)
{
i++;
if (i == parent.Children.Count)
{
// end of list; will go up
node = null;
}
else
{
// go right
node = parent.Children[i];
goingUp = false;
}
}
else
{
node = null; // nothing found
}
}
}
public void Clear()
{
root = new RTreeNode <T> {
IsLeaf = true, Height = 1
};
}