03/13/2003
15-462 Graphics I
37
Blending
•Frame
buffer
–Simple
color model: R, G, B; 8 bits each
– a-channel
A, another 8 bits
•Alpha
determines opacity,
pixel-by-pixel
– a =
1: opaque
– a =
0: transparent
•Blend
translucent objects during rendering
•Achieve
other effects (e.g., shadows)