three-shaders/shaders/FXAAShader.js

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

/**
 * @author alteredq / http://alteredqualia.com/
 * @author davidedc / http://www.sketchpatch.net/
 *
 * NVIDIA FXAA by Timothy Lottes
 * http://timothylottes.blogspot.com/2011/06/fxaa3-source-released.html
 * - WebGL port by @supereggbert
 * http://www.glge.org/demos/fxaa/
 */

var THREE = require('three');

 function FXAAShader() {

	return {

	uniforms: {

		tDiffuse:   { value: null },
		resolution: { value: new THREE.Vector2( 1 / 1024, 1 / 512 ) }

	},

	vertexShader: `

		void main() {

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

		}

	`,

	fragmentShader: `

		uniform sampler2D tDiffuse;
		uniform vec2 resolution;

		#define FXAA_REDUCE_MIN   (1.0/128.0)
		#define FXAA_REDUCE_MUL   (1.0/8.0)
		#define FXAA_SPAN_MAX     8.0

		void main() {

			vec3 rgbNW = texture2D( tDiffuse, ( gl_FragCoord.xy + vec2( -1.0, -1.0 ) ) * resolution ).xyz;
			vec3 rgbNE = texture2D( tDiffuse, ( gl_FragCoord.xy + vec2( 1.0, -1.0 ) ) * resolution ).xyz;
			vec3 rgbSW = texture2D( tDiffuse, ( gl_FragCoord.xy + vec2( -1.0, 1.0 ) ) * resolution ).xyz;
			vec3 rgbSE = texture2D( tDiffuse, ( gl_FragCoord.xy + vec2( 1.0, 1.0 ) ) * resolution ).xyz;
			vec4 rgbaM  = texture2D( tDiffuse,  gl_FragCoord.xy  * resolution );
			vec3 rgbM  = rgbaM.xyz;
			vec3 luma = vec3( 0.299, 0.587, 0.114 );

			float lumaNW = dot( rgbNW, luma );
			float lumaNE = dot( rgbNE, luma );
			float lumaSW = dot( rgbSW, luma );
			float lumaSE = dot( rgbSE, luma );
			float lumaM  = dot( rgbM,  luma );
			float lumaMin = min( lumaM, min( min( lumaNW, lumaNE ), min( lumaSW, lumaSE ) ) );
			float lumaMax = max( lumaM, max( max( lumaNW, lumaNE) , max( lumaSW, lumaSE ) ) );

			vec2 dir;
			dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
			dir.y =  ((lumaNW + lumaSW) - (lumaNE + lumaSE));

			float dirReduce = max( ( lumaNW + lumaNE + lumaSW + lumaSE ) * ( 0.25 * FXAA_REDUCE_MUL ), FXAA_REDUCE_MIN );

			float rcpDirMin = 1.0 / ( min( abs( dir.x ), abs( dir.y ) ) + dirReduce );
			dir = min( vec2( FXAA_SPAN_MAX,  FXAA_SPAN_MAX),
				  max( vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),
						dir * rcpDirMin)) * resolution;
			vec4 rgbA = (1.0/2.0) * (
        	texture2D(tDiffuse,  gl_FragCoord.xy  * resolution + dir * (1.0/3.0 - 0.5)) +
			texture2D(tDiffuse,  gl_FragCoord.xy  * resolution + dir * (2.0/3.0 - 0.5)));
    		vec4 rgbB = rgbA * (1.0/2.0) + (1.0/4.0) * (
			texture2D(tDiffuse,  gl_FragCoord.xy  * resolution + dir * (0.0/3.0 - 0.5)) +
      		texture2D(tDiffuse,  gl_FragCoord.xy  * resolution + dir * (3.0/3.0 - 0.5)));
    		float lumaB = dot(rgbB, vec4(luma, 0.0));

			if ( ( lumaB < lumaMin ) || ( lumaB > lumaMax ) ) {

				gl_FragColor = rgbA;

			} else {
				gl_FragColor = rgbB;

			}

		}

	`
	}

};

module.exports = FXAAShader;