/// <summary>
/// Inserts a leaf node with the specified `aabb` values and associated `data`.
/// </summary>
/// <returns>The index of the inserted node.</returns>
public Node <T> Add(T data, AABB insertedAABB)
{
// create new node and fatten its aabb
var leafNode = new Node <T>(insertedAABB, data, null);
leafNode.aabb.inflate(FattenDelta, FattenDelta);
leafNode.invHeight = 0;
NumLeaves++;
if (_root == null)
{
_root = leafNode;
return(leafNode);
}
// find best sibling to insert the leaf
var leafAABB = leafNode.aabb;
var combinedAABB = new AABB();
Node <T> left;
Node <T> right;
var node = _root;
while (!node.isLeaf())
{
bool breakWhile = false;
switch (InsertStrategy.choose(leafAABB, node))
{
case InsertChoice.PARENT:
breakWhile = true;
break;
case InsertChoice.DESCEND_LEFT:
node = node.left;
break;
case InsertChoice.DESCEND_RIGHT:
node = node.right;
break;
}
if (breakWhile)
{
break;
}
}
var sibling = node;
// create a new parent
var oldParent = sibling.parent;
combinedAABB.asUnionOf(leafAABB, sibling.aabb);
var newParent = new Node <T>(combinedAABB.x, combinedAABB.y, combinedAABB.width, combinedAABB.height, default(T),
oldParent);
newParent.invHeight = sibling.invHeight + 1;
// the sibling was not the root
if (oldParent != null)
{
if (oldParent.left == sibling)
{
oldParent.left = newParent;
}
else
{
oldParent.right = newParent;
}
}
else
{
// the sibling was the root
_root = newParent;
}
newParent.left = sibling;
newParent.right = leafNode;
sibling.parent = newParent;
leafNode.parent = newParent;
// walk back up the tree fixing heights and AABBs
node = leafNode.parent;
while (node != null)
{
node = Balance(node);
left = node.left;
right = node.right;
Assert(left != null);
Assert(right != null);
node.invHeight = 1 + (Math.Max(left.invHeight, right.invHeight));
node.aabb.asUnionOf(left.aabb, right.aabb);
node = node.parent;
}
Validate();
return(leafNode);
}
