This example demonstrates a point light and its effect upon a tesselated
sphere, both with and without texturing.  The controls move the light.  A red
plus sign icon shows the position of the light.  The draw mode may be changed
to see the texture colors and lighting colors by themselves, as well as the
combined result.

The key commands are:

i, k - translate light in x
j, l - translate light in y
Space - reset light transforms
d - change draw mode (lit and textured, lit, textured)
