The mapper engine computes 2D bounding rectangles for arbitrary objects.

Instance variables:
bounds <Rectangle> The currently recorded bounds for any object.
boundsMap <IdentityDictionary of: (Object -> Rectangle)> The bounds of all objects.

	initialize
	initialize loadFrom:

	private-rendering
	primProcessVB:size:into: processVertexBuffer: renderPrimitive

	accessing	top
	bounds
	boundsMap
	render:

	initialize	top
	initialize
	loadFrom: Load our components from the given render engine. The idea is that all of the state is shared so that transformations send during picking will be preserved in the given render engine.

	private-rendering	top
	primProcessVB:size:into:
	processVertexBuffer: Process the given vertex buffer in this part of the engine.
	renderPrimitive This is the main rendering loop for all operations