HostDisplay: Add GPU usage statistics

src/frontend-common/d3d11_host_display.h

@@ -65,6 +65,9 @@ public:
 
   bool GetHostRefreshRate(float* refresh_rate) override;
 
+  bool SetGPUTimingEnabled(bool enabled) override;
+  float GetAndResetAccumulatedGPUTime() override;
+
   void SetVSync(bool enabled) override;
 
   bool Render(bool skip_present) override;
@@ -75,6 +78,7 @@ public:
 
 protected:
   static constexpr u32 DISPLAY_UNIFORM_BUFFER_SIZE = 16;
+  static constexpr u8 NUM_TIMESTAMP_QUERIES = 3;
 
   static AdapterAndModeList GetAdapterAndModeList(IDXGIFactory* dxgi_factory);
 
@@ -111,6 +115,11 @@ protected:
                                 s32 texture_view_x, s32 texture_view_y, s32 texture_view_width, s32 texture_view_height,
                                 u32 target_width, u32 target_height);
 
+  bool CreateTimestampQueries();
+  void DestroyTimestampQueries();
+  void PopTimestampQuery();
+  void KickTimestampQuery();
+
   ComPtr<ID3D11Device> m_device;
   ComPtr<ID3D11DeviceContext> m_context;
 
@@ -140,6 +149,13 @@ protected:
   PostProcessingChain m_post_processing_chain;
   D3D11::Texture m_post_processing_input_texture;
   std::vector<PostProcessingStage> m_post_processing_stages;
+
+  std::array<std::array<ComPtr<ID3D11Query>, 3>, NUM_TIMESTAMP_QUERIES> m_timestamp_queries = {};
+  u8 m_read_timestamp_query = 0;
+  u8 m_write_timestamp_query = 0;
+  u8 m_waiting_timestamp_queries = 0;
+  bool m_timestamp_query_started = false;
+  float m_accumulated_gpu_time = 0.0f;
 };
 
 } // namespace FrontendCommon