Select
Function
This powerful function allows you to construct different compositing branches
and choose between them based on an arbitrary rule you create. This rule can
be an animated curve, a rule based on time, a rule based on a node's parameter,
or anything else you might want to do.
Example
This tree has two input images, Asteroid and Earth. We want
the Earth to orbit around the asteroid. We animate it with the Move2D,
and then plug both into 2 Over commands, switching foreground elements
for each. The Select function then picks one of the Over commands,
based on time to make it look like the Earth is orbiting around the Asteroid.
The branch expression says "if the current frame is greater than 14 and
less than 32, then use OverA, otherwise, use OverB". You
can also just animate the branch number by hand. This is only us being clever.
You can, of course, just animate the branch with a curve...
|
Select statement: time>14&&time<32?1:2 |
|
Earth, Asteroid |
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OverA, OverB |
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Select1, |
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Synopsis
image Select( int branch, image, image, image, image );
Script
image = Select( branch, image, image, image, image);
Command Line
shake -select branch image image image image