Perform tests of OpenGL alpha blending by drawing to the screen using
‘PutImage’, reading back the actual values on the Screen using
‘GetImage’ and comparing the actual values to predicted values
calcualated in MATLAB.
Measure the precision of alpha values between 0 and 1 (Screen 0 and 255) by
drawing to the screen, then taking the difference between what was
drawn to the screen and results of simulated blending done with
Test that addition of source and destination terms has perfect