dispose() {

		this.renderer.domElement.removeEventListener( 'pointerdown', this._onPointerDown );
		this.renderer.domElement.removeEventListener( 'pointermove', this._onPointerMove );
		this.renderer.domElement.removeEventListener( 'pointerup', this._onPointerUp );

		this.element.remove(); // in case disposal happens while dragging

	}
Call this method if you no longer want use to the controls. It frees all internal
resources and removes all event listeners.