Encoding blend weights: I(x,y) = (aR, aG, aB, a)
color at p =
Implement this in two steps:
1.
accumulate: add up the (a premultiplied) RGBa values at each pixel
2.
normalize: divide each pixel’s
accumulated RGB by its a value
Q:
what if a = 0?
Alpha Blending
Optional: see Blinn (CGA, 1994) for details:
I1
I2
I3
p
