phaser/src/renderer/webgl/shaders/FXVignette-frag.js

A fast, free and fun HTML5 Game Framework for Desktop and Mobile web browsers from the team at Phaser Studio Inc.

module.exports = [
    '#define SHADER_NAME VIGNETTE_FS',
    'precision mediump float;',
    'uniform sampler2D uMainSampler;',
    'uniform float radius;',
    'uniform float strength;',
    'uniform vec2 position;',
    'varying vec2 outTexCoord;',
    'void main ()',
    '{',
    '    vec4 col = vec4(1.0);',
    '    float d = length(outTexCoord - position);',
    '    if (d <= radius)',
    '    {',
    '        float g = d / radius;',
    '        g = sin(g * 3.14 * strength);',
    '    	col = vec4(g * g * g);',
    '    }',
    '    vec4 texture = texture2D(uMainSampler, outTexCoord);',
    '    gl_FragColor = texture * (1.0 - col);',
    '}',
].join('\n');