=== To Do ===
* reorganize framework code so that vertex shader receives product of world, view, and projection matrices
** store viewProjection matrix as an instance variable in Display
** add viewProjection query to Display to extract product of view and projection matrices
** retrieve viewProjection in *::draw() method
** pre-multiply viewProjection by world to obtain composite matrix to pass to vertex shader
** add composite matrix to the constant table in the vertex shader
* reorganize framework code to minimize duplication of heading normalization
** perform normalization of heading in Display::beginDraw()
== Week 6 - Feb 13 ==