Blending Demo

Red = [1, 0, 0, 1]
Green = [0, 1, 0, 0.3]
Blue = [0, 0, 1, 0.7]

SRC_ALPHA, ONE     SRC_ALPHA, ONE_MINUS_SRC_ALPHA
SRC_ALPHA, DST_ALPHA     SRC_ALPHA, ONE_MINUS_DST_ALPHA
ONE, ONE_MINUS_DST_ALPHA     ONE, ONE