createAABBForNode
Creates an axis-aligned bounding box for a quadtree node at the given tree-space coordinates and level. This AABB is in the tree's local space (where the root node of the tree is a unit cube in its own local space).
Return
The axis-aligned bounding box for the node.
Parameters
x
The x coordinate of the node.
y
The y coordinate of the node.
level
The level of the node.