glslify

What is glslify?

glslify is a module system for GLSL (OpenGL Shading Language) that allows you to write modular shader code. It enables you to import and export GLSL code, making it easier to manage and reuse shader code across different projects.

What are glslify's main functionalities?

Importing GLSL Modules

This feature allows you to import GLSL code from other files, making it easier to manage and reuse shader code. The `glslify` function takes the path to a GLSL file and returns the shader code as a string.

const glslify = require('glslify');
const shader = glslify('./shader.glsl');

Using GLSL Modules

You can use `glslify` to import both vertex and fragment shaders, allowing you to modularize your shader code. This makes it easier to maintain and update your shaders.

const glslify = require('glslify');
const vertexShader = glslify('./vertex.glsl');
const fragmentShader = glslify('./fragment.glsl');

Inlining GLSL Code

You can also inline GLSL code directly within your JavaScript files using template literals. This is useful for small shaders or for quick prototyping.

const glslify = require('glslify');
const shader = glslify(`
  precision mediump float;
  void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
  }
`);

Transforming GLSL Code

glslify supports transforming GLSL code using plugins. In this example, the `glslify-hex` plugin is used to transform the GLSL code. This allows you to extend the functionality of glslify with custom transformations.

const glslify = require('glslify');
const shader = glslify('./shader.glsl', { transform: ['glslify-hex'] });

Other packages similar to glslify

shader-loader

shader-loader is a Webpack loader that allows you to import GLSL shaders into your JavaScript code. It is similar to glslify in that it helps manage and import shader code, but it is specifically designed to work with Webpack.

glslify-loader

glslify-loader is a Webpack loader that integrates glslify with Webpack. It allows you to use glslify's module system within a Webpack build process. This makes it easier to use glslify in projects that are already using Webpack.

README

glslify

A node.js-style module system for GLSL!

This module contains:

• glslify's command-line interface (CLI)
• glslify node/electron interface
• browserify transform

It forms one of the core components of the stack.gl ecosystem, allowing you to install GLSL modules from npm and use them in your shaders. This makes it trivial to piece together different effects and techniques from the community, including but certainly not limited to fog, noise, film grain, raymarching helpers, easing functions and lighting models.

A full list can be found on the stack.gl packages list under the "Shader Components" category.

Because glslify just outputs a single shader file as a string, it's easy to use it with any WebGL framework of your choosing, provided they accept custom shaders. Integration is planned for three.js and pex, with more on the way! Open an issue here if you'd like to discuss integrating glslify with your platform of choice.

If you're interested in playing around with glslify, you should check out glslb.in: it's a fragment shader sandbox similar to Shadertoy and GLSL Sandbox with built in support for glslify.

Example

var glsl = require('glslify')
console.log(glsl`
  #pragma glslify: noise = require('glsl-noise/simplex/3d')

  precision mediump float;
  varying vec3 vpos;
  void main () {
    gl_FragColor = vec4(noise(vpos*25.0),1);
  }
`)

Module API

var glsl = require('glslify')

var src = glsl\shader source...``

Compile a shader inline using glsl as a tagged template string function.

var src = glsl(file, opts)

var src = glsl(shaderSource, opts)

Compile a shader using an inline shader string or a file name.

These are convencience methods provided that call glsl.compile() or glsl.file() accordingly. These methods are also provided for backwards compatibility with the previous < 6 interface.

Optionally provide:

• opts.basedir - directory to resolve relative paths
• opts.transform - an array of transform functions, transform module name

var src = glsl.compile(src, opts)

Compile a shader string from a string src.

• opts.basedir - directory to resolve relative paths in src
• opts.transform - an array of transform functions, transform module name strings, or [trname,tropts] pairs

var src = glsl.file(filename, opts)

Compile a shader from a filename.

• opts.basedir - directory to resolve relative paths in src
• opts.transform - an array of transform functions, transform module name strings, or [trname,tropts] pairs

Installation

To install the command-line interface, install glslify globally like so:

npm install -g glslify

To install glslify for use as a browserify transform, you should install it locally instead:

npm install glslify

Getting Started

CLI

The CLI can take a file as its first argument, and output to a file using the -o flag:

glslify index.glsl -o output.glsl

It can also read input from stdin and output to stdout:

cat index.glsl | glslify > output.glsl

Browserify Transform

If using browserify from the command-line, simply pass glslify in as a transform using the -t/--transform flag:

browserify -t glslify index.js -o bundle.js

Alternatively, you may include glslify as a browserify.transform in your package.json file:

{
  "name": "my-app",
  "dependencies": {
    "glslify": "^2.0.0"
  },
  "browserify": {
    "transform": ["glslify"]
  }
}

When writing your app, you should be able to require and call glslify the same as the node/electron interface, like so:

// index.js
var glsl = require('glslify')

var src = glsl.file('./shader.glsl')
console.log(src)

or using tagged template strings:

var glsl = require('glslify')
console.log(glsl`
  #pragma glslify: noise = require('glsl-noise/simplex/3d')

  precision mediump float;
  varying vec3 vpos;
  void main () {
    gl_FragColor = vec4(noise(vpos*25.0),1);
  }
`)

Your glslify calls will be replaced with bundled GLSL strings at build time automatically for you!

// index.js
var src = "#define GLSLIFY 1\n\nprecision mediump float; ..."

console.log(src)

Webpack Loader

You can use the glslify-loader module to bundle shaders through glslify with Webpack. Check out the repository for further information.

Babel Plugin

You can use glslify-babel as a Babel plugin. This allows you to use all ES6 features with glslify, including import statements and tagged template strings. Check out the repository to learn more.

Usage

Installing a GLSL Module

Much like plain JavaScript modules, GLSL modules are stored on npm. The main difference is that GLSL modules contain an index.glsl file instead of an index.js. Generally, these modules start with glsl- in their name.

To install glsl-noise in your current directory:

npm install glsl-noise

This will download glsl-noise and any of its dependencies, placing them in a node_modules directory for glslify to use.

Importing a GLSL Module

You can import a module using the following #pragma syntax:

#pragma glslify: noise = require(glsl-noise/simplex/2d)

void main() {
  float brightness = noise(gl_FragCoord.xy);

  gl_FragColor = vec4(vec3(brightness), 1.);
}

Shader dependencies are resolved using the same algorithm as node, so the above will load ./node_modules/simplex/2d.glsl from the shader's directory.

The above example would result in the following output:

#define GLSLIFY 1

//
// Description : Array and textureless GLSL 2D simplex noise function.
//      Author : Ian McEwan, Ashima Arts.
//  Maintainer : ijm
//     Lastmod : 20110822 (ijm)
//     License : Copyright (C) 2011 Ashima Arts. All rights reserved.
//               Distributed under the MIT License. See LICENSE file.
//               https://github.com/ashima/webgl-noise
//

vec3 mod289_1_0(vec3 x) {
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec2 mod289_1_0(vec2 x) {
  return x - floor(x * (1.0 / 289.0)) * 289.0;
}

vec3 permute_1_1(vec3 x) {
  return mod289_1_0(((x*34.0)+1.0)*x);
}

float snoise_1_2(vec2 v)
  {
  const vec4 C = vec4(0.211324865405187,  // (3.0-sqrt(3.0))/6.0
                      0.366025403784439,  // 0.5*(sqrt(3.0)-1.0)
                     -0.577350269189626,  // -1.0 + 2.0 * C.x
                      0.024390243902439); // 1.0 / 41.0
// First corner
  vec2 i  = floor(v + dot(v, C.yy) );
  vec2 x0 = v -   i + dot(i, C.xx);

// Other corners
  vec2 i1;
  //i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
  //i1.y = 1.0 - i1.x;
  i1 = (x0.x > x0.y) ? vec2(1.0, 0.0) : vec2(0.0, 1.0);
  // x0 = x0 - 0.0 + 0.0 * C.xx ;
  // x1 = x0 - i1 + 1.0 * C.xx ;
  // x2 = x0 - 1.0 + 2.0 * C.xx ;
  vec4 x12 = x0.xyxy + C.xxzz;
  x12.xy -= i1;

// Permutations
  i = mod289_1_0(i); // Avoid truncation effects in permutation
  vec3 p = permute_1_1( permute_1_1( i.y + vec3(0.0, i1.y, 1.0 ))
    + i.x + vec3(0.0, i1.x, 1.0 ));

  vec3 m = max(0.5 - vec3(dot(x0,x0), dot(x12.xy,x12.xy), dot(x12.zw,x12.zw)), 0.0);
  m = m*m ;
  m = m*m ;

// Gradients: 41 points uniformly over a line, mapped onto a diamond.
// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)

  vec3 x = 2.0 * fract(p * C.www) - 1.0;
  vec3 h = abs(x) - 0.5;
  vec3 ox = floor(x + 0.5);
  vec3 a0 = x - ox;

// Normalise gradients implicitly by scaling m
// Approximation of: m *= inversesqrt( a0*a0 + h*h );
  m *= 1.79284291400159 - 0.85373472095314 * ( a0*a0 + h*h );

// Compute final noise value at P
  vec3 g;
  g.x  = a0.x  * x0.x  + h.x  * x0.y;
  g.yz = a0.yz * x12.xz + h.yz * x12.yw;
  return 130.0 * dot(m, g);
}




void main() {
  float brightness = snoise_1_2(gl_FragCoord.xy);

  gl_FragColor = vec4(vec3(brightness), 1.);
}

Exporting a GLSL Module

You can export a token from a module using the glslify: export pragma, like so:

float myFunction(vec3 normal) {
  return dot(vec3(0, 1, 0), normal);
}

#pragma glslify: export(myFunction)

This means that when you import this module file elsewhere, you'll get myFunction in return:

#pragma glslify: topDot = require(./my-function.glsl)

topDot(vec3(0, 1, 0)); // 1

If you check the output shader source, you'll notice that variables have been renamed to avoid conflicts between multiple shader files.

You're not limited to exporting functions either: you should be able to export any GLSL token, such as a struct for reuse between your modules:

struct Light {
  vec3 position;
  vec3 color;
};

#pragma glslify: export(Light)

Passing references between modules

Normally, glslify renames tokens to avoid conflicts across contexts. Sometimes, however, you want to reference the same thing from different contexts. The require function lets you explicitly fix reference names in order to guarantee that two different modules are talking about the same reference.

Give some-module access to locally declared bar whenever it looks for foo internally:

int bar;
#pragma glslify: require('some-module',foo=bar,...)

It's important to make sure that bar has already been declared when you invoke #pragma glslify: require(...).

Now time for some imagination. Let's pretend that we have some float[500] arrays that we'd like to be summed up.

Here's a module that performs a reduction using a function map.

float accumulate(float list[N]) {
  float z = 0;
  for (int i = 0; i<N; i++) {
    z = map(z,list[i]);
  }
  return z;
}
#pragma glslify: export(accumulate)

But notice that this module doesn't actually declare const int N; or define a function map anywhere. We have to make sure they are already defined when we require the module, and pass their names along with the require function:

const int M = 500;
float add(float a, float b){ return a+b; }

#pragma glslify: sum500 = require('./accumulator.glsl',N=M,map=add)

The accumulator has been imported and glslified into a sum function. We can also multiply all of the floats in some float[17] arrays the same way:

const int M = 500;
const int L = 17;
float add(float a, float b){ return a+b; }
float mul(float a, float b){ return a*b; }

#pragma glslify: sum500 = require('./accumulator.glsl',N=M,map=add)
#pragma glslify: product17 = require('./accumulator.glsl',N=L,map=mul)

Glsl-hash-blur is an example of a module that uses this feature.

Source Transforms

Source transforms are a feature inspired by browserify, allowing you to modify your GLSL source at build time on a per-package basis. This is useful both for transpilation (e.g. converting from or to HLSL) or for making incremental improvements to GLSL syntax. (e.g. you can use glslify-hex to include CSS-style hex strings for colors in place of vec3s).

There are three kinds of source transform:

• Local transforms, the default. These are applied per-file, and only applied to a single package. If you're defining it via the CLI using -t it'll only apply itself to files outside of node_modules, but you can include it in package.json too: these will be applied only to that package without interfering with any of the package's parents or children.
• Global transforms are applied after local transforms to every file, regardless of whether or not it's a dependency.
• Post transforms are applied to the entire output file once it's been bundled. Generally, you want to reserve this for very specific use cases such as whole-shader optimisation.

There are a number of ways to use a transform. Start by installing it in your project:

npm install --save glslify-hex

The preferred way to enable a transform is through your project's package.json file's glslify.transform property, like so:

{
  "name": "my-project",
  "dependencies": {
    "glslify-hex": "^2.0.0",
    "glslify": "^2.0.0"
  },
  "glslify": {
    "transform": ["glslify-hex"]
  }
}

You may also include arguments to your transform as you would with browserify:

{
  "name": "my-project",
  "dependencies": {
    "glslify-hex": "^2.0.0",
    "glslify": "^2.0.0"
  },
  "glslify": {
    "transform": [
      ["glslify-hex", {
        "option-1": true,
        "option-2": 42
      }]
    ]
  }
}

Note that this method is only available for local transforms.

You may also specify transforms via the CLI:

glslify -t 'local-transform' -g 'global-transform' -p 'post-transform'

Or when using the browserify transform by including them as options like so:

var glslify = require('glslify')

glslify.file(__dirname + '/shader.glsl', {
  transform: [
    ["glslify-hex", {
      "option-1": true,
      "option-2": 42
    }],
    ["global-transform", { global: true }],
    ["post-transform", { post: true }]
  ]
})

Further Reading

• stack.gl Packages List (see "Shader Components").
• Modular and Versioned GLSL by @mattdesl.
• Module Best Practices by @mattdesl.
• Art of Node by @maxogden.
• Browserify Handbook by @substack.
• WebGL Insights includes a chapter introducing glslify in detail.
• Shader School by @mikolalysenko, chrisdickinson and @hughskennedy.
• Book of Shaders by Patricio Gonzalez Vivo.
• Pragmatic Physically Based Rendering by @marcinignac.
• glslifyでGLSLをモジュール化しよう by @yuichiroharaiJP.

glslify in the Wild

• Plotly
• Audiograph
• KAMRA: Deja Vu
• Swiss Army Man
• Connecting Europe
• Kuva
• The Law of The Jungle
• Make Me Pulse
• SMASHING Mega Scene
• Takumi Hasegawa
• ectoplasmid
• glslb.in
• N|Solid

Contributing

See stackgl/contributing for details.

License

MIT. See LICENSE.md for details.