handleResize() {

		if ( this.domElement === document ) {

			this._viewHalfX = window.innerWidth / 2;
			this._viewHalfY = window.innerHeight / 2;

		} else {

			this._viewHalfX = this.domElement.offsetWidth / 2;
			this._viewHalfY = this.domElement.offsetHeight / 2;

		}

	}
Must be called if the application window is resized.