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Implementing PShader.set() October 5, 2013

Posted by Andor Saga in JavaScript, Processing, Processing.js, PShader.
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I was in the process of writing ref tests for my implementation of PShader.set() in Processing.js, when I ran into a nasty problem. PShader.set() can take on a variety of types including single floats and integers to set uniform shader variables. For example, we can have the following:

pShader.set("i", 1);
pShader.set("f", 1.0);

If the second argument is an integer, we must call uniform1i on the WebGL context, otherwise uniform1f needs to be called. But in JavaScript, we can’t distinguish between 1.0 and 1. I briefly considered modifying the the interface for this method, but knew there was a better solution. No, the last thing I wanted was to change the interface. So I just thought about it until I came up with an interesting solution. I figured, why not call both uniform1i and uniform1f right after each other? What would happen? It turns out, it works! It seems one will always fail and the other will succeed, leaving us with the proper uniform set!