glsl-transpiler

glsl-transpiler

Transforms glsl source to optimized js code. It converts vectors and matrices to arrays, expands swizzles, applies expressions optimizations and provides stdlib for environment compatibility.

Usage

import GLSL from 'glsl-transpiler'

var compile = GLSL({
	uniform: function (name) {
		return `uniforms.${name}`
	},
	attribute: function (name) {
		return `attributes.${name}`
	}
})

compile(`
	precision mediump float
	attribute vec2 uv
	attribute vec4 color
	varying vec4 fColor
	uniform vec2 uScreenSize

	void main (void) {
		fColor = color
		vec2 position = vec2(uv.x, -uv.y) * 1.0
		position.x *= uScreenSize.y / uScreenSize.x
		gl_Position = vec4(position, 0, 1)
	}
`)

// result:

`
var uv = attributes.uv
var color = attributes.color
var fColor = [0, 0, 0, 0]
var uScreenSize = uniforms.uScreenSize

function main () {
	fColor = color
	var position = [uv[0], -uv[1]]
	position[0] *= uScreenSize[1] / uScreenSize[0]
	gl_Position = [position[0], position[1], 0, 1]
}
`

API

glsl-transpiler

To apply compilation to glsl AST or string, require glsl-transpiler:

import GLSL from 'glsl-transpiler'

let compile = GLSL({
	// Enable expressions optimizations.
	optimize: true,

	// Apply preprocessing. Pass custom preprocessor function `(srcString) => resultString;` to set own preprocessing.
	preprocess: true,

	// A function replacing each uniform declaration. Eg: ``(name, node) => `uniforms["${name}"]`;`` will render each uniform declaration as `var <name> = uniforms["<name>"]`.
	uniform: false,

	// Same as `uniform`, but for attribute declarations.
	attribute: false,

	// Same as `uniform`, but for varying declarations.
	varying: false,

	// GLSL shader version, one of `'300 es'` or `'100 es'`.
	version: '100 es',

	// Append stdlib includes for the result. Can be bool or an object with defined stdlib functions to include, eg. `{normalize: false, min: false}`.
	includes: true,

	// Enable debugging facilities: `print(anything)` will log to console a string of transpiled code with it’s type separated by colon, `show(anything)` will print the rendered descriptor of passed fragment of code. Note also that you can safely use `console.log(value)` to debug shader runtime.
	debug: false
})

//compile source code
let result = compile('...source.glsl')

//get collected info
let {
	attributes,
	uniforms,
	varyings,
	structs,
	functions,
	scopes
} = compile.compiler


//clean collected info
compiler.reset()

Note that texture2D function expects whether ndarray instance or defined width and height parameters on passed array.

glsl-transpiler/stream

glsl-transpiler can also be used as a stream. For each node from the glsl-parser it will return compiled js chunk:

import compile from 'glsl-transpiler/stream.js'
import parse from 'glsl-parser/stream.js'
import tokenize from 'glsl-tokenizer/stream.js'

fs.createReadStream('./source.glsl')
.pipe(tokenize())
.pipe(parse())
.pipe(compile(options?))
.once('end', function () {
	//this.source contains the actual version of the compiled code
	//and gets updated on each input chunk of data.
	console.log(this.source)
})

Dependencies

• glsl-parser — build glsl AST.
  
• glsl-tokenizer — detect glsl tokens.
  

Used by

• nogl-shader-output — evaluate fragment shader on rectangular vertex input, gl-less.
  
• GLSLRun – debug shader via adding print() function.

Similar

• glsl.js — an alternative glsl to asm.js compiler by @devongovett, built with jison instead of glsl-parser. Project is abandoned :(.
  
• js2glsl — transform js subset to glsl.
  
• glsl-simulator — OpenGL1.0 simulation in js.
  
• turbo/js — webgl-based computation.
• shaderdsl
• wgsl_reflect
• glm-js