code: function () {
  
  		var f, fl = this.lensFlares.length;
  		var flare;
  		var vecX = - this.positionScreen.x * 2;
  		var vecY = - this.positionScreen.y * 2;
  
  		for ( f = 0; f < fl; f ++ ) {
  
  			flare = this.lensFlares[ f ];
  
  			flare.x = this.positionScreen.x + vecX * flare.distance;
  			flare.y = this.positionScreen.y + vecY * flare.distance;
  
  			flare.wantedRotation = flare.x * Math.PI * 0.25;
  			flare.rotation += ( flare.wantedRotation - flare.rotation ) * 0.25;
  
  		}
  
  	}
docs: /*
  Update lens flares update positions on all flares based on the screen position
  Set myLensFlare.customUpdateCallback to alter the flares in your project specific way.