2.6 Vertex Attributes 117
are to be combined to produce a single color for each pixel. Generally, this is called
blending and is easy enough to implement with shader programming.
2.6.4 Transparency, Opacity, and Blending
Given two RGBA colors, one called the source color and one called the destination
color, the term alpha blending refers to the general process of combining the source
and destination into yet another RGBA color. The source color is (r
s
, g
s
, b
s
, a
s
),
and the destination color is (r
d
, g
d
, b
d
, a
d
). The blended result is the final color
(r
f
, g
f
, b
f
, a
f
). All color channel values in this discussion are assumed to be in the
interval [0, 1]. Material colors and texture image colors both can have alpha channels.
The classical method for blending ...