code: public void setScene(GVRScene scene) {
          if (this.scene == scene) {
              //do nothing return
              return;
          }
  
          //cleanup on the currently set scene if there is one
          if (this.scene != null) {
              // false to remove
              updateCursorsInScene(this.scene, false);
          }
  
          this.scene = scene;
          if (objectCursorPicker != null) {
              objectCursorPicker.setScene(scene);
          }
          if (scene == null) {
              return;
          }
          // process the new scene, use true to add
          updateCursorsInScene(scene, true);
      }
docs: Use this method to set a {@link GVRScene}. This call replaces the currently set {@link
  GVRScene} (if one was set either using the constructor or a previous {@link
  CursorManager#setScene(GVRScene)} call).
  <br/>
  <br/>
  
  If the provided {@link GVRScene} matches the currently set {@link GVRScene} then this call
  has no effect. Calling this method with a <code>null</code> resets the scene currently set
  with the {@link CursorManager}.
  
  @param scene the {@link GVRScene} to be set, or <code>null</code>.