glsl-token-function-shaker

glsl-token-function-shaker

Shakes out any unused functions from your GLSL shaders. Especially useful alongside tools such as glslify.

This is done by running through your shader and checking that each function is actually called. This even works with functions that share the same name but use a different number of arguments! For example, take the following shader:

precision mediump float;

float noise(float x, float y) {
  return 0.0; // K.I.S.S.
}

float noise(float x, float y, float z) {
  return 0.0;
}

float noise(float x, float y, float z, float w) {
  return 0.0;
}

void main() {
  gl_FragColor = vec4(noise(gl_FragCoord.x, gl_FragCoord.y), 0, 0, 1);
}

After running it through glsl-token-function-shaker, you should get something like this in return:

precision mediump float;

float noise(float x, float y) {
  return 0.0; // K.I.S.S.
}

void main() {
  gl_FragColor = vec4(noise(gl_FragCoord.x, gl_FragCoord.y), 0, 0, 1);
}

This keeps the size of your shaders down, but can also be used to cut out errors in unused functions.

Usage

Install glsl-token-function-shaker using npm:

npm install --save glsl-token-function-shaker

shake(tokens[, options])

Takes an array of tokens from glsl-tokenizer and removes unused functions. Accepts the following options:

• ignore: an array of strings containing the names of functions you'd like to keep in the shader, even if they're not being used. void main(); is always preserved, as is the last function in the shader.

Modifies the tokens array in place, and returns some simple stats:

• functionsRemoved: the number of function declarations removed.
• tokensRemoved: the number of GLSL tokens removed.
• iterations: the number of function shaking iterations made.

const shake = require('glsl-token-function-shaker')
const stringify = require('glsl-token-string')
const tokenize = require('glsl-tokenizer')
const fs = require('fs')

const src = fs.readFileSync('shader.glsl', 'utf8')
const tokens = tokenize(src)

shake(tokens, { ignore: ['vert'] })

const shaken = stringify(tokens)

License

MIT, see LICENSE.md for details.