constructor(
    vrDisplay,
    innerRadius = 0.02,
    outerRadius = 0.05,
    color = 0xff0077,
    easing = 0.25
  ) {
    const geometry = new RingGeometry(innerRadius, outerRadius, 36, 64);
    const material = new MeshBasicMaterial({ color });

    // Orient the geometry so it's position is flat on a horizontal surface
    geometry.applyMatrix(new Matrix4().makeRotationX(Math3.degToRad(-90)));

    super(geometry, material);
    this.visible = false;

    this.easing = easing;
    this.applyOrientation = true;
    this.vrDisplay = vrDisplay;
    this._planeDir = new Vector3();
  }
@param {VRDisplay} vrDisplay
@param {number} innerRadius
@param {number} outerRadius
@param {number} color
@param {number} easing