/**
 * @author mikael emtinger / http://gomo.se/
 */

THREE.LOD = function() {

	THREE.Object3D.call( this );

	this.LODs = [];

};

THREE.LOD.prototype             = new THREE.Object3D();
THREE.LOD.prototype.constructor = THREE.LOD;
THREE.LOD.prototype.supr        = THREE.Object3D.prototype;

/*
 * Add
 */

THREE.LOD.prototype.add = function( object3D, visibleAtDistance ) {
	
	if( visibleAtDistance === undefined ) visibleAtDistance = 0;
	visibleAtDistance = Math.abs( visibleAtDistance );
	
	for( var l = 0; l < this.LODs.length; l++ ) {
		
		if( visibleAtDistance < this.LODs[ l ].visibleAtDistance )
			break;
	}
	
	this.LODs.splice( l, 0, { visibleAtDistance: visibleAtDistance, object3D: object3D } );
	this.addChild( object3D );

};


/*
 * Update
 */

THREE.LOD.prototype.update = function( parentGlobalMatrix, forceUpdate, camera, renderer ) {
	
	// update local
	
	if( this.autoUpdateMatrix )
		forceUpdate |= this.updateMatrix();


	// update global

	if( forceUpdate || this.matrixNeedsToUpdate ) {
		
		if( parentGlobalMatrix )
			this.globalMatrix.multiply( parentGlobalMatrix, this.localMatrix );
		else
			this.globalMatrix.copy( this.localMatrix );
		
		this.matrixNeedsToUpdate = false;
		forceUpdate              = true;

	}


	// update lods
		
	if( this.LODs.length > 1 ) {
		
		var distance = -camera.inverseMatrix.mulitplyVector3OnlyZ( this.position );

		this.LODs[ 0 ].object3D.visible = true;
		
		for( var l = 1; l < this.LODs.length; l++ ) {
			
			if( distance >= this.LODs[ l ].visibleAtDistance ) {
				
				this.LODs[ l - 1 ].object3D.visible = false;
				this.LODs[ l     ].object3D.visible = true;
			}
			else 
				break;

		}
		
		for( ; l < this.LODs.length; l++ ) 
			this.LODs[ l ].object3D.visible = false;

	}


	// update children

	for( var c = 0; c < this.children.length; c++ )
		this.children[ c ].update( this.globalMatrix, forceUpdate, camera, renderer );

};