Phaser 2 GLSL Loader

This is a simple GLSL loader that is meant to work with Phaser 2 and Webpack 1.x.x.

IMPORTANT: IF YOU ARE USING PHASER 3, this isn't for you.

Check out my other project create-phaser-app for up-to-date phaser 3 tooling

The Problem:

Lets say you're working in phaser, and you see a really cool looking fragment shader you want to use.

So you go to the phaser examples, and they show you to integrate your code just like this:

var game = new Phaser.Game(800, 600, Phaser.AUTO, 'phaser-example', { create: create, update: update });

var filter;
var sprite;

function create() {

    //  From http://glslsandbox.com/e#20450.0

    var fragmentSrc = [
        "precision mediump float;",
        "uniform vec2      resolution;",
        "uniform float     time;",

        "float size = 0.002;",

        "void main( void ) {",
            "vec2 view = ( gl_FragCoord.xy - resolution / 2.0 ) / ( resolution.y / 2.0);",
            "float time = time + length(view)*8.;",
            "vec4 color = vec4(0);",
            "vec2 center = vec2(0);",
            "float rotationVelocity = 2.0;",
            "for( int j = 0; j < 20; j++ ) {",
                "for( int i = 0; i < 20; i++ ) {",
                    "float amplitude = ( cos( time / 10.0 ) + sin(  time /5.0 ) ) / 2.0;",
                    "float angle =   sin( float(j) * time) * rotationVelocity + 2.0 * 3.14 * float(i) / 20.0;",
                    "center.x = cos( 7.0 * float(j) / 20.0 * 2.0 * 3.14 ) + sin( time / 4.0);",
                    "center.y = sin( 3.0 * float(j) / 20.0 * 2.0 *  3.14 )+ cos( time / 8.0);",
                    "vec2 light = center + amplitude * vec2( cos( angle ), sin( angle ));",
                    "//size = sin( time ) * 0.005;",
                    "float l = size / length( view - light );",
                    "vec4 c = vec4( l / 20.0, l, l, 1.0 ) / 5.0;",
                    "color += c;",
                "}",
            "}",
            "gl_FragColor = color;",
        "}"
    ];

    filter = new Phaser.Filter(game, null, fragmentSrc);
    filter.setResolution(800, 600);

    sprite = game.add.sprite();
    sprite.width = 800;
    sprite.height = 600;

    sprite.filters = [ filter ];

}

function update() {
    filter.update();
}

Man, what mess! Wouldnt it be awesome if you could just put the shader into a seperate file and load it that way?

var fragmentSrc = require('../shaders/cubething.frag'),

You could cut all that code out into a simple require statement! That is what this loader is for.

The Solution

First, you need to add the loader to your list of loaders, most likely in your webpack.config.js file.

Something like this:

var path = require('path');
var glFragmentLoader = path.join(__dirname, '/node_modules/phaser-glsl-loader');

module.exports = {
  module: {
    loaders: [
      {
        test: /\.frag$/i,
        loader: 'gl-fragment-loader'
      }
    ]
  },
  resolveLoader: {
    alias: {
      'gl-fragment-loader': glFragmentLoader,
    }
  }
};

Then you'll be able to reference external files, instead of basically including a large array of strings!