three-shaders/shaders/LuminosityHighPassShader.js

three-shaders - a library of shaders included with Three.js library

/**
 * @author bhouston / http://clara.io/
 *
 * Luminosity
 * http://en.wikipedia.org/wiki/Luminosity
 */

var THREE = require('three');

function LuminosityHighPassShader() {

	return {

  	shaderID: 'luminosityHighPass',

	uniforms: {

		tDiffuse: { type: 't', value: null },
		luminosityThreshold: { type: 'f', value: 1.0 },
		smoothWidth: { type: 'f', value: 1.0 },
		defaultColor: { type: 'c', value: new THREE.Color( 0x000000 ) },
		defaultOpacity:  { type: 'f', value: 0.0 }

	},

	vertexShader: `

		varying vec2 vUv;

		void main() {

			vUv = uv;

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

		}

	`,

	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 );

		}

	`
	}

};

module.exports = LuminosityHighPassShader;