Report the actual GPU framerate rather than the main thread submit rate when using the filament renderer.

PiperOrigin-RevId: 838775463
Change-Id: If66644d284a4a9e0263cf31bfbd1785b18e0209b

src/experimental/filament/filament/filament_context.cc

@@ -33,6 +33,7 @@
 #include <filament/Texture.h>
 #include <filament/View.h>
 #include <math/vec4.h>
+#include <utils/FixedCapacityVector.h>
 #include <mujoco/mjmodel.h>
 #include <mujoco/mjvisualize.h>
 #include <mujoco/mujoco.h>
@@ -310,4 +311,15 @@ void FilamentContext::UploadFont(const uint8_t* pixels, int width, int height,
                                  int id) {
   object_manager_->UploadFont(pixels, width, height, id);
 }
+
+double FilamentContext::GetFrameRate() const {
+  utils::FixedCapacityVector<filament::Renderer::FrameInfo> frame_info =
+      renderer_->getFrameInfoHistory(1);
+  if (frame_info.empty()) {
+    return 0;
+  }
+  const int64_t ns = frame_info[0].denoisedGpuFrameDuration;
+  return 1.0e9 / static_cast<double>(ns);
+}
+
 }  // namespace mujoco

src/experimental/filament/filament/filament_context.h

@@ -53,6 +53,8 @@ class FilamentContext {
 
   void UploadFont(const uint8_t* pixels, int width, int height, int id);
 
+  double GetFrameRate() const;
+
   FilamentContext(const FilamentContext&) = delete;
   FilamentContext& operator=(const FilamentContext&) = delete;
 

src/experimental/filament/render_context_filament.cc

@@ -146,4 +146,9 @@ void mjr_uploadFont(const unsigned char* pixels, int width, int height, int bpp,
   g_filament_context->UploadFont(pixels, width, height, id);
 }
 
+double mjr_getFrameRate(const mjrContext* con) {
+  CheckFilamentContext();
+  return g_filament_context->GetFrameRate();
+}
+
 }  // extern "C"

src/experimental/filament/render_context_filament.h

@@ -78,6 +78,8 @@ MJAPI void mjr_setBuffer(int framebuffer, mjrContext* con);
 MJAPI void mjr_readPixels(unsigned char* rgb, float* depth, mjrRect viewport,
                           const mjrContext* con);
 
+double mjr_getFrameRate(const mjrContext* con);
+
 #if defined(__cplusplus)
 }  // extern "C"
 #endif

src/experimental/platform/renderer.cc

@@ -57,17 +57,6 @@ void Renderer::Render(const mjModel* model, mjData* data,
 
   mjrRect main_viewport = {0, 0, width, height};
   mjr_render(main_viewport, data ? &scene_ : nullptr, &render_context_);
-
-  auto now = std::chrono::steady_clock::now();
-  auto delta_time = now - last_fps_update_;
-  const double interval = std::chrono::duration<double>(delta_time).count();
-
-  ++frames_;
-  if (interval > 0.2) {  // only update FPS stat at most 5 times per second
-    last_fps_update_ = now;
-    fps_ = frames_ / interval;
-    frames_ = 0;
-  }
 }
 
 void Renderer::SaveScreenshot(const std::string& filename, int width,

src/experimental/platform/renderer.h

@@ -54,15 +54,10 @@ class Renderer {
   // Rendering flags.
   mjtByte* GetRenderFlags() { return scene_.flags; }
 
-  // Returns the current, average frame rate.
-  double GetFrameRate() const { return fps_; }
-
   // Returns the render context.
   const mjrContext& GetContext() const { return render_context_; }
 
  private:
-  using TimePoint = std::chrono::time_point<std::chrono::steady_clock>;
-
   // Resets the renderer; no rendering will occur until Init() is called again.
   void Deinit();
 
@@ -70,10 +65,6 @@ class Renderer {
   mjrContext render_context_;
   mjvScene scene_;
   bool initialized_ = false;
-
-  int frames_ = 0;
-  TimePoint last_fps_update_;
-  double fps_ = 0;
 };
 
 }  // namespace mujoco::platform

src/experimental/studio/app.cc

@@ -16,6 +16,9 @@
 
 #include <algorithm>
 #include <array>
+#if defined(USE_CLASSIC_OPENGL)
+#include <chrono>
+#endif
 #include <cstddef>
 #include <cstdint>
 #include <cstdio>
@@ -369,6 +372,21 @@ void App::Render() {
       data_->timer[i].number = 0;
     }
   }
+
+#ifdef USE_CLASSIC_OPENGL
+  TimePoint now = std::chrono::steady_clock::now();
+  TimePoint::duration delta_time = now - last_fps_update_;
+  const double interval = std::chrono::duration<double>(delta_time).count();
+
+  ++frames_;
+  if (interval > 0.2) {  // only update FPS stat at most 5 times per second
+    last_fps_update_ = now;
+    fps_ = frames_ / interval;
+    frames_ = 0;
+  }
+#else
+  fps_ = mjr_getFrameRate(&renderer_->GetContext());
+#endif
 }
 
 void App::HandleMouseEvents() {
@@ -797,8 +815,7 @@ void App::BuildGui() {
     platform::ScopedStyle style;
     style.Var(ImGuiStyleVar_Alpha, 0.6f);
     if (ImGui::Begin("Info", &tmp_.info)) {
-      platform::InfoGui(model_, data_, step_control_.IsPaused(),
-                       renderer_->GetFrameRate());
+      platform::InfoGui(model_, data_, step_control_.IsPaused(), fps_);
     }
     ImGui::End();
   }

src/experimental/studio/app.h

@@ -182,6 +182,10 @@ class App {
 
   UiState ui_;
   UiTempState tmp_;
+
+  int frames_ = 0;
+  TimePoint last_fps_update_;
+  double fps_ = 0;
 };
 
 }  // namespace mujoco::studio