code: public GVRRenderPass getPass(int passIndex) {
          if (passIndex < mRenderPassList.size()) {
              return mRenderPassList.get(passIndex);
          } else {
              Log.e(TAG, "Trying to get invalid pass. Pass " + passIndex + " was not created.");
              return null;
          }
      }
docs: Get a Rendering {@link GVRRenderPass Pass} for this Mesh
  @param passIndex The index of the RenderPass to get.