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

THREE.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")

};