three.js/examples/js/shaders/LuminosityHighPassShader.js

( function () {

	/**
 * Luminosity
 * http://en.wikipedia.org/wiki/Luminosity
 */

	var LuminosityHighPassShader = {
		shaderID: 'luminosityHighPass',
		uniforms: {
			'tDiffuse': {
				value: null
			},
			'luminosityThreshold': {
				value: 1.0
			},
			'smoothWidth': {
				value: 1.0
			},
			'defaultColor': {
				value: new THREE.Color( 0x000000 )
			},
			'defaultOpacity': {
				value: 0.0
			}
		},
		vertexShader: [ 'varying vec2 vUv;', 'void main() {', '	vUv = uv;', '	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );', '}' ].join( '\n' ),
		fragmentShader: [ 'uniform sampler2D tDiffuse;', 'uniform vec3 defaultColor;', 'uniform float defaultOpacity;', 'uniform float luminosityThreshold;', 'uniform float smoothWidth;', 'varying vec2 vUv;', 'void main() {', '	vec4 texel = texture2D( tDiffuse, vUv );', '	vec3 luma = vec3( 0.299, 0.587, 0.114 );', '	float v = dot( texel.xyz, luma );', '	vec4 outputColor = vec4( defaultColor.rgb, defaultOpacity );', '	float alpha = smoothstep( luminosityThreshold, luminosityThreshold + smoothWidth, v );', '	gl_FragColor = mix( outputColor, texel, alpha );', '}' ].join( '\n' )
	};

	THREE.LuminosityHighPassShader = LuminosityHighPassShader;

} )();