three.js/examples/js/shaders/GammaCorrectionShader.js

/**
 * @author WestLangley / http://github.com/WestLangley
 *
 * Gamma Correction Shader
 * http://en.wikipedia.org/wiki/gamma_correction
 */

THREE.GammaCorrectionShader = {

	uniforms: {

		"tDiffuse": { type: "t", value: null },

	},

	vertexShader: [

		"varying vec2 vUv;",

		"void main() {",

			"vUv = uv;",
			"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",

		"}"

	].join( "\n" ),

	fragmentShader: [

		"#define GAMMA_OUTPUT",
		"#define GAMMA_FACTOR 2",

		"uniform sampler2D tDiffuse;",

		"varying vec2 vUv;",

		THREE.ShaderChunk[ "common" ],

		"void main() {",

			"vec4 tex = texture2D( tDiffuse, vec2( vUv.x, vUv.y ) );",

			"gl_FragColor = vec4( linearToOutput( tex.rgb ), tex.a );",

		"}"

	].join( "\n" )

};