message: gltf_viewer should not crash when there is no IBL.
diff: @@ -207,7 +207,10 @@ int main(int argc, char** argv) {
  // Add the renderables to the scene.
  app.viewer->setAsset(app.asset, app.names, !app.actualSize);
  - app.viewer->setIndirectLight(FilamentApp::get().getIBL()->getIndirectLight());
  + auto ibl = FilamentApp::get().getIBL();
  + if (ibl) {
  + app.viewer->setIndirectLight(ibl->getIndirectLight());
  + }
  };
  auto setup = [&](Engine* engine, View* view, Scene* scene) {
  