three.js/src/extras/renderers/AnaglyphWebGLRenderer.js

/**
 * @author mrdoob / http://mrdoob.com/
 */

THREE.AnaglyphWebGLRenderer = function ( parameters ) {

	THREE.WebGLRenderer.call( this, parameters );

	var _this = this, _setSize = this.setSize, _render = this.render;
	var _cameraL = new THREE.Camera(), _cameraR = new THREE.Camera();

	var params = { minFilter: THREE.LinearFilter, magFilter: THREE.NearestFilter, format: THREE.RGBAFormat };
	var _renderTargetL = new THREE.WebGLRenderTarget( 512, 512, params ), _renderTargetR = new THREE.WebGLRenderTarget( 512, 512, params );

	var _camera = new THREE.Camera( 53, 1, 1, 10000 );
	_camera.position.z = 2;

	_material = new THREE.MeshShaderMaterial( {

		uniforms: {

			"mapLeft": { type: "t", value: 0, texture: _renderTargetL },
			"mapRight": { type: "t", value: 1, texture: _renderTargetR }

		},
		vertexShader: [

			"varying vec2 vUv;",

			"void main() {",

				"vUv = vec2( uv.x, 1.0 - uv.y );",
				"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",

			"}"

		].join("\n"),
		fragmentShader: [

			"uniform sampler2D mapLeft;",
			"uniform sampler2D mapRight;",
			"varying vec2 vUv;",

			"void main() {",

				"vec4 colorL, colorR;",
				"vec2 uv = vUv;",

				"colorL = texture2D( mapLeft, uv );",
				"colorR = texture2D( mapRight, uv );",

				// http://3dtv.at/Knowhow/AnaglyphComparison_en.aspx

				"gl_FragColor = vec4( colorL.g * 0.7 + colorL.b * 0.3, colorR.g, colorR.b, colorL.a + colorR.a ) * 1.1;",

			"}"

			].join("\n")

	} );

	var _scene = new THREE.Scene();
	_scene.addObject( new THREE.Mesh( new THREE.Plane( 2, 2 ), _material ) );

	this.setSize = function ( width, height ) {

		_setSize.call( _this, width, height );

		_renderTargetL.width = width;
		_renderTargetL.height = height;

		_renderTargetR.width = width;
		_renderTargetR.height = height;

	};

	this.render = function ( scene, camera, renderTarget, forceClear ) {

		_cameraL.projectionMatrix = camera.projectionMatrix;
		_cameraL.position.copy( camera.position );
		_cameraL.target.position.copy( camera.target.position );
		_cameraL.translateX( - 10 );

		_cameraR.projectionMatrix = camera.projectionMatrix;
		_cameraR.position.copy( camera.position );
		_cameraR.target.position.copy( camera.target.position );
		_cameraR.translateX( 10 );

		_render.call( _this, scene, _cameraL, _renderTargetL, true );
		_render.call( _this, scene, _cameraR, _renderTargetR, true );

		_render.call( _this, _scene, _camera );

	};

};

THREE.AnaglyphWebGLRenderer.prototype = new THREE.WebGLRenderer();
THREE.AnaglyphWebGLRenderer.prototype.constructor = THREE.AnaglyphWebGLRenderer;