GPU: Add virtual call when buffers are swapped

src/core/gpu.cpp

@@ -1211,6 +1211,7 @@ void GPU::WriteGP1(u32 value)
         SynchronizeCRTC();
         m_crtc_state.regs.display_address_start = new_value;
         UpdateCRTCDisplayParameters();
+        OnBufferSwapped();
       }
     }
     break;
@@ -2704,6 +2705,10 @@ void GPU::DrawRendererStats()
 {
 }
 
+void GPU::OnBufferSwapped()
+{
+}
+
 void GPU::GetStatsString(SmallStringBase& str)
 {
   if (IsHardwareRenderer())

src/core/gpu.h

@@ -317,6 +317,7 @@ protected:
   virtual void DispatchRenderCommand();
   virtual void UpdateDisplay();
   virtual void DrawRendererStats();
+  virtual void OnBufferSwapped();
 
   ALWAYS_INLINE void AddDrawTriangleTicks(s32 x1, s32 y1, s32 x2, s32 y2, s32 x3, s32 y3, bool shaded, bool textured,
                                           bool semitransparent)

src/core/gpu_hw.cpp

@@ -3251,6 +3251,11 @@ void GPU_HW::UpdateDisplay()
     RestoreDeviceContext();
 }
 
+void GPU_HW::OnBufferSwapped()
+{
+  GL_INS("OnBufferSwapped()");
+}
+
 void GPU_HW::DownsampleFramebuffer(GPUTexture* source, u32 left, u32 top, u32 width, u32 height)
 {
   if (m_downsample_mode == GPUDownsampleMode::Adaptive)

src/core/gpu_hw.h

@@ -176,6 +176,7 @@ private:
   void DispatchRenderCommand() override;
   void FlushRender() override;
   void DrawRendererStats() override;
+  void OnBufferSwapped() override;
 
   bool BlitVRAMReplacementTexture(const TextureReplacementTexture* tex, u32 dst_x, u32 dst_y, u32 width, u32 height);