Game Development Reference
Figure 5.1 The Alpha Levels.aep
areas, white represents opaque areas, and around the edges of
the fractal fi re, you will see some gray zones, which indicate par-
tially transparent areas (Fig. 5.2).
First, let us look at the Input Black Level parameter at the top
of the options in the Effect Controls panel. Increasing the Input
Black Level value increases the intensity of the alpha channel.
This typically removes semi-transparent pixels around the edge
of an object. This can eliminate antialiasing, which can create
blockiness in the edges.
Reducing the Input White Level increases the opacity of semi-
transparent areas. I'm going to reduce the Input White Level
value to 50. This causes the partially transparent areas around the
edges of the fi re to grow more opaque (Figs. 5.3 and 5.4).
Working with Alpha
As a general rule,
with the Alpha
Levels effect, the properties
that deal with black (e.g.
Input Black Level and
Output Black Level) adjust
transparent areas. White
properties adjust the
Figure 5.2 The alpha channel