three.js/examples/js/shaders/BleachBypassShader.js

( function () {

	/**
 * Bleach bypass shader [http://en.wikipedia.org/wiki/Bleach_bypass]
 * - based on Nvidia example
 * http://developer.download.nvidia.com/shaderlibrary/webpages/shader_library.html#post_bleach_bypass
 */
	var BleachBypassShader = {
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'opacity': {
				value: 1.0
			}
		},
		vertexShader: [ 'varying vec2 vUv;', 'void main() {', '	vUv = uv;', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ 'uniform float opacity;', 'uniform sampler2D tDiffuse;', 'varying vec2 vUv;', 'void main() {', '	vec4 base = texture2D( tDiffuse, vUv );', '	vec3 lumCoeff = vec3( 0.25, 0.65, 0.1 );', '	float lum = dot( lumCoeff, base.rgb );', '	vec3 blend = vec3( lum );', '	float L = min( 1.0, max( 0.0, 10.0 * ( lum - 0.45 ) ) );', '	vec3 result1 = 2.0 * base.rgb * blend;', '	vec3 result2 = 1.0 - 2.0 * ( 1.0 - blend ) * ( 1.0 - base.rgb );', '	vec3 newColor = mix( result1, result2, L );', '	float A2 = opacity * base.a;', '	vec3 mixRGB = A2 * newColor.rgb;', '	mixRGB += ( ( 1.0 - A2 ) * base.rgb );', '	gl_FragColor = vec4( mixRGB, base.a );', '}' ].join( '\n' )
	};

	THREE.BleachBypassShader = BleachBypassShader;

} )();