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/**
* @author tapio / http://tapio.github.com/
*
* Hue and saturation adjustment
* https://github.com/evanw/glfx.js
* hue: -1 to 1 (-1 is 180 degrees in the negative direction, 0 is no change, etc.
* saturation: -1 to 1 (-1 is solid gray, 0 is no change, and 1 is maximum contrast)
*/
var HueSaturationShader = {
uniforms: {
"tDiffuse": { value: null },
"hue": { value: 0 },
"saturation": { value: 0 }
},
vertexShader: [
"varying vec2 vUv;",
"void main() {",
" vUv = uv;",
" gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
"}"
].join( "\n" ),
fragmentShader: [
"uniform sampler2D tDiffuse;",
"uniform float hue;",
"uniform float saturation;",
"varying vec2 vUv;",
"void main() {",
" gl_FragColor = texture2D( tDiffuse, vUv );",
// hue
" float angle = hue * 3.14159265;",
" float s = sin(angle), c = cos(angle);",
" vec3 weights = (vec3(2.0 * c, -sqrt(3.0) * s - c, sqrt(3.0) * s - c) + 1.0) / 3.0;",
" float len = length(gl_FragColor.rgb);",
" gl_FragColor.rgb = vec3(",
" dot(gl_FragColor.rgb, weights.xyz),",
" dot(gl_FragColor.rgb, weights.zxy),",
" dot(gl_FragColor.rgb, weights.yzx)",
" );",
// saturation
" float average = (gl_FragColor.r + gl_FragColor.g + gl_FragColor.b) / 3.0;",
" if (saturation > 0.0) {",
" gl_FragColor.rgb += (average - gl_FragColor.rgb) * (1.0 - 1.0 / (1.001 - saturation));",
" } else {",
" gl_FragColor.rgb += (average - gl_FragColor.rgb) * (-saturation);",
" }",
"}"
].join( "\n" )
};
export { HueSaturationShader };
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