message: spp control not needed in this tutorial,
diff: @@ -213,12 +213,6 @@ int main(int argc, const char **argv)
  vec2i{1024, 768}, box3f(vec3f(-1.f), vec3f(1.f)), world, renderer));
  glfwOSPRayWindow->registerImGuiCallback([=]() {
  - static int spp = 1;
  - if (ImGui::SliderInt("spp", &spp, 1, 64)) {
  - ospSet1i(renderer, "spp", spp);
  - ospCommit(renderer);
  - }
  -
  static int tessellationLevel = 5;
  if (ImGui::SliderInt("tessellation level", &tessellationLevel, 1, 10)) {
  ospSet1f(subdivisionGeometry.geometry, "level", tessellationLevel);
  