text: /**
   * @author Slayvin / http://slayvin.net
   */
  
  THREE.ShaderLib['mirror'] = {
  
  	uniforms: { "mirrorColor": { type: "c", value: new THREE.Color(0x7F7F7F) },
  				"mirrorSampler": { type: "t", value: null },
  				"textureMatrix" : { type: "m4", value: new THREE.Matrix4() }
  	},
  
  	vertexShader: [
  
  		"uniform mat4 textureMatrix;",
  
  		"varying vec4 mirrorCoord;",
  
  		"void main() {",
  
  			"vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );",
  			"vec4 worldPosition = modelMatrix * vec4( position, 1.0 );",
  			"mirrorCoord = textureMatrix * worldPosition;",
  
  			"gl_Position = projectionMatrix * mvPosition;",
  
  		"}"
  
  	].join("\n"),
  
  	fragmentShader: [
  
  		"uniform vec3 mirrorColor;",
  		"uniform sampler2D mirrorSampler;",
  
  		"varying vec4 mirrorCoord;",
  
  		"float blendOverlay(float base, float blend) {",
  			"return( base < 0.5 ? ( 2.0 * base * blend ) : (1.0 - 2.0 * ( 1.0 - base ) * ( 1.0 - blend ) ) );",
  		"}",
  		
  		"void main() {",
  
  			"vec4 color = texture2DProj(mirrorSampler, mirrorCoord);",
  			"color = vec4(blendOverlay(mirrorColor.r, color.r), blendOverlay(mirrorColor.g, color.g), blendOverlay(mirrorColor.b, color.b), 1.0);",
  
  			"gl_FragColor = color;",
  
  		"}"
  
  	].join("\n")
  
  };
  
  THREE.Mirror = function ( renderer, camera, options ) {
  
  	THREE.Object3D.call( this );
  
  	this.name = 'mirror_' + this.id;
  
  	options = options || {};
  
  	this.matrixNeedsUpdate = true;
  
  	var width = options.textureWidth !== undefined ? options.textureWidth : 512;
  	var height = options.textureHeight !== undefined ? options.textureHeight : 512;
  
  	this.clipBias = options.clipBias !== undefined ? options.clipBias : 0.0;
  
  	var mirrorColor = options.color !== undefined ? new THREE.Color(options.color) : new THREE.Color(0x7F7F7F);
  
  	this.renderer = renderer;
  	this.mirrorPlane = new THREE.Plane();
  	this.normal = new THREE.Vector3( 0, 0, 1 );
  	this.mirrorWorldPosition = new THREE.Vector3();
  	this.cameraWorldPosition = new THREE.Vector3();
  	this.rotationMatrix = new THREE.Matrix4();
  	this.lookAtPosition = new THREE.Vector3(0, 0, -1);
  	this.clipPlane = new THREE.Vector4();
  	
  	// For debug only, show the normal and plane of the mirror
  	var debugMode = options.debugMode !== undefined ? options.debugMode : false;
  
  	if ( debugMode ) {
  
  		var arrow = new THREE.ArrowHelper(new THREE.Vector3( 0, 0, 1 ), new THREE.Vector3( 0, 0, 0 ), 10, 0xffff80 );
  		var planeGeometry = new THREE.Geometry();
  		planeGeometry.vertices.push( new THREE.Vector3( -10, -10, 0 ) );
  		planeGeometry.vertices.push( new THREE.Vector3( 10, -10, 0 ) );
  		planeGeometry.vertices.push( new THREE.Vector3( 10, 10, 0 ) );
  		planeGeometry.vertices.push( new THREE.Vector3( -10, 10, 0 ) );
  		planeGeometry.vertices.push( planeGeometry.vertices[0] );
  		var plane = new THREE.Line( planeGeometry, new THREE.LineBasicMaterial( { color: 0xffff80 } ) );
  
  		this.add(arrow);
  		this.add(plane);
  
  	}
  
  	if ( camera instanceof THREE.PerspectiveCamera ) {
  
  		this.camera = camera;
  
  	} else {
  
  		this.camera = new THREE.PerspectiveCamera();
  		console.log( this.name + ': camera is not a Perspective Camera!' );
  
  	}
  
  	this.textureMatrix = new THREE.Matrix4();
  
  	this.mirrorCamera = this.camera.clone();
  
  	this.texture = new THREE.WebGLRenderTarget( width, height );
  	this.tempTexture = new THREE.WebGLRenderTarget( width, height );
  
  	var mirrorShader = THREE.ShaderLib[ "mirror" ];
  	var mirrorUniforms = THREE.UniformsUtils.clone( mirrorShader.uniforms );
  
  	this.material = new THREE.ShaderMaterial( {
  
  		fragmentShader: mirrorShader.fragmentShader,
  		vertexShader: mirrorShader.vertexShader,
  		uniforms: mirrorUniforms
  
  	} );
  
  	this.material.uniforms.mirrorSampler.value = this.texture;
  	this.material.uniforms.mirrorColor.value = mirrorColor;
  	this.material.uniforms.textureMatrix.value = this.textureMatrix;
  
  	if ( !THREE.Math.isPowerOfTwo(width) || !THREE.Math.isPowerOfTwo( height ) ) {
  
  		this.texture.generateMipmaps = false;
  		this.tempTexture.generateMipmaps = false;
  
  	}
  
  	this.updateTextureMatrix();
  	this.render();
  
  };
  
  THREE.Mirror.prototype = Object.create( THREE.Object3D.prototype );
  
  THREE.Mirror.prototype.renderWithMirror = function ( otherMirror ) {
  
  	// update the mirror matrix to mirror the current view
  	this.updateTextureMatrix();
  	this.matrixNeedsUpdate = false;
  
  	// set the camera of the other mirror so the mirrored view is the reference view
  	var tempCamera = otherMirror.camera;
  	otherMirror.camera = this.mirrorCamera;
  
  	// render the other mirror in temp texture
  	otherMirror.renderTemp();
  	otherMirror.material.uniforms.mirrorSampler.value = otherMirror.tempTexture;
  
  	// render the current mirror
  	this.render();
  	this.matrixNeedsUpdate = true;
  
  	// restore material and camera of other mirror
  	otherMirror.material.uniforms.mirrorSampler.value = otherMirror.texture;
  	otherMirror.camera = tempCamera;
  
  	// restore texture matrix of other mirror
  	otherMirror.updateTextureMatrix();
  };
  
  THREE.Mirror.prototype.updateTextureMatrix = function () {
  
  	this.updateMatrixWorld();
  	this.camera.updateMatrixWorld();
  
  	this.mirrorWorldPosition.setFromMatrixPosition( this.matrixWorld );
  	this.cameraWorldPosition.setFromMatrixPosition( this.camera.matrixWorld );
  
  	this.rotationMatrix.extractRotation( this.matrixWorld );
  
  	this.normal.set( 0, 0, 1 );
  	this.normal.applyMatrix4( this.rotationMatrix );
  
  	var view = this.mirrorWorldPosition.clone().sub( this.cameraWorldPosition );
  	view.reflect( this.normal ).negate();
  	view.add( this.mirrorWorldPosition );
  
  	this.rotationMatrix.extractRotation( this.camera.matrixWorld );
  
  	this.lookAtPosition.set(0, 0, -1);
  	this.lookAtPosition.applyMatrix4( this.rotationMatrix );
  	this.lookAtPosition.add( this.cameraWorldPosition );
  
  	var target = this.mirrorWorldPosition.clone().sub( this.lookAtPosition );
  	target.reflect( this.normal ).negate();
  	target.add( this.mirrorWorldPosition );
  
  	this.up.set( 0, -1, 0 );
  	this.up.applyMatrix4( this.rotationMatrix );
  	this.up.reflect( this.normal ).negate();
  
  	this.mirrorCamera.position.copy( view );
  	this.mirrorCamera.up = this.up;
  	this.mirrorCamera.lookAt( target );
  
  	this.mirrorCamera.updateProjectionMatrix();
  	this.mirrorCamera.updateMatrixWorld();
  	this.mirrorCamera.matrixWorldInverse.getInverse( this.mirrorCamera.matrixWorld );
  
  	// Update the texture matrix
  	this.textureMatrix.set( 0.5, 0.0, 0.0, 0.5,
  							0.0, 0.5, 0.0, 0.5,
  							0.0, 0.0, 0.5, 0.5,
  							0.0, 0.0, 0.0, 1.0 );
  	this.textureMatrix.multiply( this.mirrorCamera.projectionMatrix );
  	this.textureMatrix.multiply( this.mirrorCamera.matrixWorldInverse );
  
  	// Now update projection matrix with new clip plane, implementing code from: http://www.terathon.com/code/oblique.html
  	// Paper explaining this technique: http://www.terathon.com/lengyel/Lengyel-Oblique.pdf
  	this.mirrorPlane.setFromNormalAndCoplanarPoint( this.normal, this.mirrorWorldPosition );
  	this.mirrorPlane.applyMatrix4( this.mirrorCamera.matrixWorldInverse );
  
  	this.clipPlane.set( this.mirrorPlane.normal.x, this.mirrorPlane.normal.y, this.mirrorPlane.normal.z, this.mirrorPlane.constant );
  
  	var q = new THREE.Vector4();
  	var projectionMatrix = this.mirrorCamera.projectionMatrix;
  
  	q.x = ( Math.sign(this.clipPlane.x) + projectionMatrix.elements[8] ) / projectionMatrix.elements[0];
  	q.y = ( Math.sign(this.clipPlane.y) + projectionMatrix.elements[9] ) / projectionMatrix.elements[5];
  	q.z = - 1.0;
  	q.w = ( 1.0 + projectionMatrix.elements[10] ) / projectionMatrix.elements[14];
  
  	// Calculate the scaled plane vector
  	var c = new THREE.Vector4();
  	c = this.clipPlane.multiplyScalar( 2.0 / this.clipPlane.dot(q) );
  
  	// Replacing the third row of the projection matrix
  	projectionMatrix.elements[2] = c.x;
  	projectionMatrix.elements[6] = c.y;
  	projectionMatrix.elements[10] = c.z + 1.0 - this.clipBias;
  	projectionMatrix.elements[14] = c.w;
  
  };
  
  THREE.Mirror.prototype.render = function () {
  
  	if ( this.matrixNeedsUpdate ) this.updateTextureMatrix();
  
  	this.matrixNeedsUpdate = true;
  
  	// Render the mirrored view of the current scene into the target texture
  	var scene = this;
  
  	while ( scene.parent !== undefined ) {
  
  		scene = scene.parent;
  
  	}
  
  	if ( scene !== undefined && scene instanceof THREE.Scene) {
  
  		this.renderer.render( scene, this.mirrorCamera, this.texture, true );
  
  	}
  
  };
  
  THREE.Mirror.prototype.renderTemp = function () {
  
  	if ( this.matrixNeedsUpdate ) this.updateTextureMatrix();
  
  	this.matrixNeedsUpdate = true;
  
  	// Render the mirrored view of the current scene into the target texture
  	var scene = this;
  
  	while ( scene.parent !== undefined ) {
  
  		scene = scene.parent;
  
  	}
  
  	if ( scene !== undefined && scene instanceof THREE.Scene) {
  
  		this.renderer.render( scene, this.mirrorCamera, this.tempTexture, true );
  
  	}
  
  };
  