title: How to store game objects in quadtree efficiently
body: <p>I'm implementing a quadtree structure, for simplifying collision code,. but I'm unsure as to the best practice for doing so. Currently, the quadtree creates subtrees during setup down to a preset maximum depth, then I insert objects into its appropriate tree, for use in pair generation(the actual maths stuff).
  However, I've heard of other approaches, which only generate subtrees when a certain number of objects are stored.
  I know my method has a space overhead, but might be computationally faster during update cycles.
  What would be the best way to handle it? </p>