docs: protected void init(GVRContext gvrContext) {
          /*
           * Create an object hierarchy
           *
           *             [camera rig object]
           *                     |
           *           [head transform object]
           *            /        |          \
           * [left cam obj] [right cam obj] [center cam obj]
           *
           * 1. camera rig object: used for camera rig moving and turning via
           *    CameraRig.getTransform()
           * 2. head transform object: used internally to do sensor-based rotation
           */
          setOwnerObject(new GVRSceneObject(gvrContext));
          getOwnerObject().attachCameraRig(this);
  
          headTransformObject = new GVRSceneObject(gvrContext);
          addHeadTransformObject();
  
          leftCameraObject = new GVRSceneObject(gvrContext);
          rightCameraObject = new GVRSceneObject(gvrContext);
          centerCameraObject = new GVRSceneObject(gvrContext);
  
          headTransformObject.addChildObject(leftCameraObject);
          headTransformObject.addChildObject(rightCameraObject);
          headTransformObject.addChildObject(centerCameraObject);
      }