three.js/examples/js/shaders/ToneMapShader.js

( function () {

	/**
 * Full-screen tone-mapping shader based on http://www.cis.rit.edu/people/faculty/ferwerda/publications/sig02_paper.pdf
 */
	var ToneMapShader = {
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'averageLuminance': {
				value: 1.0
			},
			'luminanceMap': {
				value: null
			},
			'maxLuminance': {
				value: 16.0
			},
			'minLuminance': {
				value: 0.01
			},
			'middleGrey': {
				value: 0.6
			}
		},
		vertexShader: [ 'varying vec2 vUv;', 'void main() {', '	vUv = uv;', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ '#include <common>', 'uniform sampler2D tDiffuse;', 'varying vec2 vUv;', 'uniform float middleGrey;', 'uniform float minLuminance;', 'uniform float maxLuminance;', '#ifdef ADAPTED_LUMINANCE', '	uniform sampler2D luminanceMap;', '#else', '	uniform float averageLuminance;', '#endif', 'vec3 ToneMap( vec3 vColor ) {', '	#ifdef ADAPTED_LUMINANCE', // Get the calculated average luminance
			'		float fLumAvg = texture2D(luminanceMap, vec2(0.5, 0.5)).r;', '	#else', '		float fLumAvg = averageLuminance;', '	#endif', // Calculate the luminance of the current pixel
			'	float fLumPixel = linearToRelativeLuminance( vColor );', // Apply the modified operator (Eq. 4)
			'	float fLumScaled = (fLumPixel * middleGrey) / max( minLuminance, fLumAvg );', '	float fLumCompressed = (fLumScaled * (1.0 + (fLumScaled / (maxLuminance * maxLuminance)))) / (1.0 + fLumScaled);', '	return fLumCompressed * vColor;', '}', 'void main() {', '	vec4 texel = texture2D( tDiffuse, vUv );', '	gl_FragColor = vec4( ToneMap( texel.xyz ), texel.w );', '}' ].join( '\n' )
	};

	THREE.ToneMapShader = ToneMapShader;

} )();