text: /**
   * @author mrdoob / http://mrdoob.com/
   * @author alteredq / http://alteredqualia.com/
   */
  
  THREE.DirectionalLight = function ( color, intensity ) {
  
  	THREE.Light.call( this, color );
  
  	this.position.set( 0, 1, 0 );
  	this.target = new THREE.Object3D();
  
  	this.intensity = ( intensity !== undefined ) ? intensity : 1;
  
  	this.castShadow = false;
  	this.onlyShadow = false;
  
  	//
  
  	this.shadowCameraNear = 50;
  	this.shadowCameraFar = 5000;
  
  	this.shadowCameraLeft = - 500;
  	this.shadowCameraRight = 500;
  	this.shadowCameraTop = 500;
  	this.shadowCameraBottom = - 500;
  
  	this.shadowCameraVisible = false;
  
  	this.shadowBias = 0;
  	this.shadowDarkness = 0.5;
  
  	this.shadowMapWidth = 512;
  	this.shadowMapHeight = 512;
  
  	//
  
  	this.shadowCascade = false;
  
  	this.shadowCascadeOffset = new THREE.Vector3( 0, 0, - 1000 );
  	this.shadowCascadeCount = 2;
  
  	this.shadowCascadeBias = [ 0, 0, 0 ];
  	this.shadowCascadeWidth = [ 512, 512, 512 ];
  	this.shadowCascadeHeight = [ 512, 512, 512 ];
  
  	this.shadowCascadeNearZ = [ - 1.000, 0.990, 0.998 ];
  	this.shadowCascadeFarZ  = [  0.990, 0.998, 1.000 ];
  
  	this.shadowCascadeArray = [];
  
  	//
  
  	this.shadowMap = null;
  	this.shadowMapSize = null;
  	this.shadowCamera = null;
  	this.shadowMatrix = null;
  
  };
  
  THREE.DirectionalLight.prototype = Object.create( THREE.Light.prototype );
  
  THREE.DirectionalLight.prototype.clone = function () {
  
  	var light = new THREE.DirectionalLight();
  
  	THREE.Light.prototype.clone.call( this, light );
  
  	light.target = this.target.clone();
  
  	light.intensity = this.intensity;
  
  	light.castShadow = this.castShadow;
  	light.onlyShadow = this.onlyShadow;
  
  	//
  
  	light.shadowCameraNear = this.shadowCameraNear;
  	light.shadowCameraFar = this.shadowCameraFar;
  
  	light.shadowCameraLeft = this.shadowCameraLeft;
  	light.shadowCameraRight = this.shadowCameraRight;
  	light.shadowCameraTop = this.shadowCameraTop;
  	light.shadowCameraBottom = this.shadowCameraBottom;
  
  	light.shadowCameraVisible = this.shadowCameraVisible;
  
  	light.shadowBias = this.shadowBias;
  	light.shadowDarkness = this.shadowDarkness;
  
  	light.shadowMapWidth = this.shadowMapWidth;
  	light.shadowMapHeight = this.shadowMapHeight;
  
  	//
  
  	light.shadowCascade = this.shadowCascade;
  
  	light.shadowCascadeOffset.copy( this.shadowCascadeOffset );
  	light.shadowCascadeCount = this.shadowCascadeCount;
  
  	light.shadowCascadeBias = this.shadowCascadeBias.slice( 0 );
  	light.shadowCascadeWidth = this.shadowCascadeWidth.slice( 0 );
  	light.shadowCascadeHeight = this.shadowCascadeHeight.slice( 0 );
  
  	light.shadowCascadeNearZ = this.shadowCascadeNearZ.slice( 0 );
  	light.shadowCascadeFarZ  = this.shadowCascadeFarZ.slice( 0 );
  
  	return light;
  
  };
  