node_modules/three/examples/js/shaders/FocusShader.js

/**
 * @author alteredq / http://alteredqualia.com/
 *
 * Focus shader
 * based on PaintEffect postprocess from ro.me
 * http://code.google.com/p/3-dreams-of-black/source/browse/deploy/js/effects/PaintEffect.js
 */

THREE.FocusShader = {

	uniforms : {

		"tDiffuse":       { value: null },
		"screenWidth":    { value: 1024 },
		"screenHeight":   { value: 1024 },
		"sampleDistance": { value: 0.94 },
		"waveFactor":     { value: 0.00125 }

	},

	vertexShader: [

		"varying vec2 vUv;",

		"void main() {",

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

		"}"

	].join( "\n" ),

	fragmentShader: [

		"uniform float screenWidth;",
		"uniform float screenHeight;",
		"uniform float sampleDistance;",
		"uniform float waveFactor;",

		"uniform sampler2D tDiffuse;",

		"varying vec2 vUv;",

		"void main() {",

			"vec4 color, org, tmp, add;",
			"float sample_dist, f;",
			"vec2 vin;",
			"vec2 uv = vUv;",

			"add = color = org = texture2D( tDiffuse, uv );",

			"vin = ( uv - vec2( 0.5 ) ) * vec2( 1.4 );",
			"sample_dist = dot( vin, vin ) * 2.0;",

			"f = ( waveFactor * 100.0 + sample_dist ) * sampleDistance * 4.0;",

			"vec2 sampleSize = vec2(  1.0 / screenWidth, 1.0 / screenHeight ) * vec2( f );",

			"add += tmp = texture2D( tDiffuse, uv + vec2( 0.111964, 0.993712 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( 0.846724, 0.532032 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( 0.943883, -0.330279 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( 0.330279, -0.943883 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( -0.532032, -0.846724 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( -0.993712, -0.111964 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"add += tmp = texture2D( tDiffuse, uv + vec2( -0.707107, 0.707107 ) * sampleSize );",
			"if( tmp.b < color.b ) color = tmp;",

			"color = color * vec4( 2.0 ) - ( add / vec4( 8.0 ) );",
			"color = color + ( add / vec4( 8.0 ) - color ) * ( vec4( 1.0 ) - vec4( sample_dist * 0.5 ) );",

			"gl_FragColor = vec4( color.rgb * color.rgb * vec3( 0.95 ) + color.rgb, 1.0 );",

		"}"


	].join( "\n" )
};