glPixelTransfer()
GL_INDEX_ SHIFT OFFSET GL_ RED GREEN BLUE ALPHA DEPTH _SCALE _BIAS
SHIFT OFFSET GL_ RED GREEN BLUE ALPHA DEPTH _SCALE _BIAS
GL_ RED GREEN BLUE ALPHA DEPTH _SCALE _BIAS
RED GREEN BLUE ALPHA DEPTH _SCALE _BIAS
_SCALE _BIAS
GL_POST_CONVOLUTION_ RED GREEN BLUE ALPHA _SCALE_EXT _BIAS_EXT
RED GREEN BLUE ALPHA _SCALE_EXT _BIAS_EXT
_SCALE_EXT _BIAS_EXT
GL_POST_COLOR_MATRIX_ RED GREEN BLUE ALPHA _SCALE_EXT _BIAS_EXT