Game Development Reference
Figure 12.64 The options in the
Noise drop down.
option, and a squared option. Uniform noise has less contrast,
while selecting a squared noise option adds contrast. The squared
options are like deselecting the Clip Noise Values option in the
When one of the Random settings is chosen, the noise can be
animated by using the Random Seed option at the bottom of the
effect. Animating Random Seed creates new, random noise on
every frame. If you select one of the Animation settings from the
Noise drop down, the Random Seed value morphs into the Noise
Phase value. Animating the Noise Phase value produces a much
smoother interpolation, almost like the Evolution parameter in
Fractal Noise. Note that opening the Noise Options area gives you
access to noise cycling options to create seamlessly looping ani-
mations of noise. Their function is identical to the cycling/looping
options in Fractal Noise and Cell Pattern.
The other option that gives you a lot of control in the Noise
Alpha effect is the Original Alpha drop down. These settings give
you control over how the effect affects the layer's alpha channel.
The default value is Clamp, which is very similar to Scale, only
that Scale usually reduces the opacity of the layer. Move the
Original Alpha value to Add to introduce noise into the alpha
channel as well as on the opaque pixels (Fig. 12.65).
The other option worth discussing in this drop down is Edges.
This allows the alpha channel to be reduced by noise, but only
in the semitransparent edges of the object. Currently, our layer
doesn't have any semitransparent edges. So, turn on the Fast Blur
effect (already applied for you), and then change the Original
Alpha value to Edges. You can then see the transparent noise in
the edges of the layer. This can be really useful for creating edge
effects like an animated corona around an object (Fig. 12.66).
The Noise HLS Effect
The Noise HLS effect resides somewhere between the power
and features of the Add Grain effect, and the simplicity and ease
of use of the Noise effect. HLS stands for Hue, Lightness, and