BLEND COLOR / BLEND EQUATION CONFORMANCE
Jon Leech, SGI (ljp@engr.sgi.com)

Coverage:
	For BlendColor, add all the new blend functions to the coverage test
	CallBlendFunc(). Create a new coverage test CallBlendColor() which
	checks BlendColor(0,0,0,0).

	For BlendEquation, add a test CallBlendEquation().
	Test all 5 blend equations.

Mustpass:
	For BlendColor, pick a random blend color. Set the color and verify
	that it is read back correctly by Get(BLEND_COLOR). Add the four
	CONSTANT_{ALPHA,COLOR} blend modes to the lists used by blend.c and
	test them against the random blend color.

	For BlendEquation, run the tests in blend.c for all 5 blend
	equations. Alternatively, if this is too great a combinatorial
	explosion of tests, run the tests for all equations except FUNC_ADD
	using only source and destination blend functions ZERO and ONE.
	Before running the tests for an equation, check that the equation
	was set and is read back correctly by Get(BLEND_EQUATION).

** blend.c
** Blend Test.
**
** Description -
**    Two random colors are picked. They are verified to exist in
**    the color buffer by drawing points with these colors then
**    reading back the rendered colors. With blending disabled, a
**    point is now drawn at a random location using one of the
**    colors (destination color). Blending is then enabled and
**    another point is drawn to the same location using the other
**    color (source color). The resulting blended color is read
**    and compared to a correct result calculated by the test.