GPU: Rewrite automatic resolution scaling

Make it play nice with rewind/runahead.

src/core/gpu.cpp

@@ -1018,9 +1018,9 @@ void GPU::UpdateCRTCDisplayParameters()
   }
 
   if ((cs.display_vram_width != old_vram_width || cs.display_vram_height != old_vram_height) &&
-      g_settings.gpu_resolution_scale == 0)
+      g_settings.gpu_automatic_resolution_scale)
   {
-    GPUBackend::QueueUpdateResolutionScale();
+    System::UpdateAutomaticResolutionScale();
   }
 }
 
@@ -1980,6 +1980,38 @@ void GPU::QueuePresentCurrentFrame()
   }
 }
 
+u8 GPU::CalculateAutomaticResolutionScale() const
+{
+  // Auto scaling.
+  // When the system is starting and all borders crop is enabled, the registers are zero, and
+  // display_height therefore is also zero. Keep the existing resolution until it updates.
+  u32 scale = 1;
+  if (const WindowInfo& main_window_info = GPUThread::GetRenderWindowInfo();
+      !main_window_info.IsSurfaceless() && m_crtc_state.display_width > 0 && m_crtc_state.display_height > 0 &&
+      m_crtc_state.display_vram_width > 0 && m_crtc_state.display_vram_height > 0)
+  {
+    GSVector4i display_rect, draw_rect;
+    CalculateDrawRect(main_window_info.surface_width, main_window_info.surface_height, m_crtc_state.display_width,
+                      m_crtc_state.display_height, m_crtc_state.display_origin_left, m_crtc_state.display_origin_top,
+                      m_crtc_state.display_vram_width, m_crtc_state.display_vram_height, g_settings.display_rotation,
+                      g_settings.display_alignment, g_settings.gpu_show_vram ? 1.0f : ComputePixelAspectRatio(),
+                      g_settings.IsUsingIntegerDisplayScaling(), &display_rect, &draw_rect);
+
+    // We use the draw rect to determine scaling. This way we match the resolution as best we can, regardless of the
+    // anamorphic aspect ratio.
+    const s32 draw_width = draw_rect.width();
+    const s32 draw_height = draw_rect.height();
+    scale = static_cast<u32>(
+      std::ceil(std::max(static_cast<float>(draw_width) / static_cast<float>(m_crtc_state.display_vram_width),
+                         static_cast<float>(draw_height) / static_cast<float>(m_crtc_state.display_vram_height))));
+    scale = std::min<u32>(scale, std::numeric_limits<decltype(g_settings.gpu_resolution_scale)>::max());
+    VERBOSE_LOG("Draw Size = {}x{}, VRAM Size = {}x{}, Preferred Scale = {}", draw_width, draw_height,
+                m_crtc_state.display_vram_width, m_crtc_state.display_vram_height, scale);
+  }
+
+  return Truncate8(scale);
+}
+
 bool GPU::DumpVRAMToFile(const char* filename)
 {
   ReadVRAM(0, 0, VRAM_WIDTH, VRAM_HEIGHT);

src/core/gpu.h

@@ -230,6 +230,9 @@ public:
   // Queues the current frame for presentation. Should only be used with runahead.
   void QueuePresentCurrentFrame();
 
+  /// Computes the effective resolution scale when it is set to automatic.
+  u8 CalculateAutomaticResolutionScale() const;
+
   /// Helper function for computing the draw rectangle in a larger window.
   static void CalculateDrawRect(u32 window_width, u32 window_height, u32 crtc_display_width, u32 crtc_display_height,
                                 s32 display_origin_left, s32 display_origin_top, u32 display_vram_width,

src/core/gpu_backend.cpp

@@ -398,20 +398,6 @@ bool GPUBackend::AllocateMemorySaveStates(std::span<System::MemorySaveState> sta
   return result;
 }
 
-void GPUBackend::QueueUpdateResolutionScale()
-{
-  DebugAssert(!GPUThread::IsOnThread());
-
-  GPUThread::RunOnBackend(
-    [](GPUBackend* backend) {
-      Error error;
-      if (!backend->UpdateResolutionScale(&error)) [[unlikely]]
-        GPUThread::ReportFatalErrorAndShutdown(
-          fmt::format("Failed to update resolution scale: {}", error.GetDescription()));
-    },
-    false, true);
-}
-
 void GPUBackend::HandleCommand(const GPUThreadCommand* cmd)
 {
   switch (cmd->type)
@@ -837,7 +823,6 @@ public:
   bool UpdateSettings(const GPUSettings& old_settings, Error* error) override;
 
   u32 GetResolutionScale() const override;
-  bool UpdateResolutionScale(Error* error) override;
 
   void RestoreDeviceContext() override;
   void FlushRender() override;
@@ -891,11 +876,6 @@ u32 GPUNullBackend::GetResolutionScale() const
   return 1;
 }
 
-bool GPUNullBackend::UpdateResolutionScale(Error* error)
-{
-  return true;
-}
-
 void GPUNullBackend::RestoreDeviceContext()
 {
 }

src/core/gpu_backend.h

@@ -69,8 +69,6 @@ public:
 
   static bool AllocateMemorySaveStates(std::span<System::MemorySaveState> states, Error* error);
 
-  static void QueueUpdateResolutionScale();
-
 public:
   GPUBackend(GPUPresenter& presenter);
   virtual ~GPUBackend();
@@ -86,9 +84,6 @@ public:
   /// Returns the current resolution scale.
   virtual u32 GetResolutionScale() const = 0;
 
-  /// Updates the resolution scale when it's set to automatic.
-  virtual bool UpdateResolutionScale(Error* error) = 0;
-
   // Graphics API state reset/restore - call when drawing the UI etc.
   // TODO: replace with "invalidate cached state"
   virtual void RestoreDeviceContext() = 0;

src/core/gpu_hw.cpp

@@ -726,40 +726,7 @@ void GPU_HW::CheckSettings()
 
 u32 GPU_HW::CalculateResolutionScale() const
 {
-  u32 scale;
-  if (g_gpu_settings.gpu_resolution_scale != 0)
-  {
-    scale = g_gpu_settings.gpu_resolution_scale;
-  }
-  else
-  {
-    // Auto scaling.
-    if (m_presenter.GetDisplayWidth() == 0 || m_presenter.GetDisplayHeight() == 0 ||
-        m_presenter.GetDisplayVRAMWidth() == 0 || m_presenter.GetDisplayVRAMHeight() == 0 ||
-        !m_presenter.HasDisplayTexture() || !g_gpu_device->HasMainSwapChain())
-    {
-      // When the system is starting and all borders crop is enabled, the registers are zero, and
-      // display_height therefore is also zero. Keep the existing resolution until it updates.
-      scale = m_resolution_scale;
-    }
-    else
-    {
-      GSVector4i display_rect, draw_rect;
-      m_presenter.CalculateDrawRect(g_gpu_device->GetMainSwapChain()->GetWidth(),
-                                    g_gpu_device->GetMainSwapChain()->GetHeight(), true, true, &display_rect,
-                                    &draw_rect);
-
-      // We use the draw rect to determine scaling. This way we match the resolution as best we can, regardless of the
-      // anamorphic aspect ratio.
-      const s32 draw_width = draw_rect.width();
-      const s32 draw_height = draw_rect.height();
-      scale = static_cast<u32>(
-        std::ceil(std::max(static_cast<float>(draw_width) / static_cast<float>(m_presenter.GetDisplayVRAMWidth()),
-                           static_cast<float>(draw_height) / static_cast<float>(m_presenter.GetDisplayVRAMHeight()))));
-      VERBOSE_LOG("Draw Size = {}x{}, VRAM Size = {}x{}, Preferred Scale = {}", draw_width, draw_height,
-                  m_presenter.GetDisplayVRAMWidth(), m_presenter.GetDisplayVRAMHeight(), scale);
-    }
-  }
+  u32 scale = g_gpu_settings.gpu_resolution_scale;
 
   if (g_gpu_settings.gpu_downsample_mode == GPUDownsampleMode::Adaptive && scale > 1 && !Common::IsPow2(scale))
   {
@@ -782,14 +749,6 @@ u32 GPU_HW::CalculateResolutionScale() const
   return std::clamp<u32>(scale, 1, GetMaxResolutionScale());
 }
 
-bool GPU_HW::UpdateResolutionScale(Error* error)
-{
-  if (CalculateResolutionScale() == m_resolution_scale)
-    return true;
-
-  return UpdateSettings(g_gpu_settings, error);
-}
-
 GPUDownsampleMode GPU_HW::GetDownsampleMode(u32 resolution_scale) const
 {
   return (resolution_scale == 1) ? GPUDownsampleMode::Disabled : g_gpu_settings.gpu_downsample_mode;

src/core/gpu_hw.h

@@ -74,8 +74,6 @@ public:
   bool UpdateSettings(const GPUSettings& old_settings, Error* error) override;
   void UpdatePostProcessingSettings(bool force_reload) override;
 
-  bool UpdateResolutionScale(Error* error) override;
-
   void FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color, bool interlaced_rendering, u8 active_line_lsb) override;
   void ReadVRAM(u32 x, u32 y, u32 width, u32 height) override;
   void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data, bool set_mask, bool check_mask) override;

src/core/gpu_presenter.cpp

@@ -1004,8 +1004,7 @@ bool GPUPresenter::ApplyChromaSmoothing()
 void GPUPresenter::CalculateDrawRect(s32 window_width, s32 window_height, bool apply_aspect_ratio, bool apply_alignment,
                                      GSVector4i* display_rect, GSVector4i* draw_rect) const
 {
-  const bool integer_scale = (g_gpu_settings.display_scaling == DisplayScalingMode::NearestInteger ||
-                              g_gpu_settings.display_scaling == DisplayScalingMode::BilinearInteger);
+  const bool integer_scale = g_gpu_settings.IsUsingIntegerDisplayScaling();
   const bool show_vram = g_gpu_settings.gpu_show_vram;
   const u32 display_width = show_vram ? VRAM_WIDTH : m_display_width;
   const u32 display_height = show_vram ? VRAM_HEIGHT : m_display_height;

src/core/gpu_sw.cpp

@@ -65,11 +65,6 @@ void GPU_SW::ClearVRAM()
   std::memset(g_gpu_clut, 0, sizeof(g_gpu_clut));
 }
 
-bool GPU_SW::UpdateResolutionScale(Error* error)
-{
-  return true;
-}
-
 void GPU_SW::LoadState(const GPUBackendLoadStateCommand* cmd)
 {
   std::memcpy(g_vram, cmd->vram_data, sizeof(g_vram));

src/core/gpu_sw.h

@@ -46,8 +46,6 @@ public:
 
   void ClearVRAM() override;
 
-  bool UpdateResolutionScale(Error* error) override;
-
   void LoadState(const GPUBackendLoadStateCommand* cmd) override;
 
   bool AllocateMemorySaveState(System::MemorySaveState& mss, Error* error) override;

src/core/gpu_thread.cpp

@@ -1287,13 +1287,6 @@ void GPUThread::DisplayWindowResizedOnThread()
       Internal::PresentFrameAndRestoreContext();
       Internal::PresentFrameAndRestoreContext();
     }
-
-    if (g_gpu_settings.gpu_resolution_scale == 0)
-    {
-      Error error;
-      if (!s_state.gpu_backend->UpdateResolutionScale(&error)) [[unlikely]]
-        ReportFatalErrorAndShutdown(fmt::format("Failed to update resolution scale: {}", error.GetDescription()));
-    }
   }
 }
 

src/core/settings.cpp

@@ -199,6 +199,7 @@ void Settings::Load(const SettingsInterface& si, const SettingsInterface& contro
                    .value_or(DEFAULT_GPU_RENDERER);
   gpu_adapter = si.GetStringValue("GPU", "Adapter", "");
   gpu_resolution_scale = static_cast<u8>(si.GetUIntValue("GPU", "ResolutionScale", 1u));
+  gpu_automatic_resolution_scale = (gpu_resolution_scale == 0);
   gpu_multisamples = static_cast<u8>(si.GetUIntValue("GPU", "Multisamples", 1u));
   gpu_use_debug_device = si.GetBoolValue("GPU", "UseDebugDevice", false);
   gpu_disable_shader_cache = si.GetBoolValue("GPU", "DisableShaderCache", false);
@@ -972,6 +973,7 @@ void Settings::FixIncompatibleSettings(const SettingsInterface& si, bool display
     g_settings.enable_8mb_ram = false;
     g_settings.gpu_resolution_scale = 1;
     g_settings.gpu_multisamples = 1;
+    g_settings.gpu_automatic_resolution_scale = false;
     g_settings.gpu_per_sample_shading = false;
     g_settings.gpu_true_color = false;
     g_settings.gpu_scaled_dithering = false;

src/core/settings.h

@@ -102,6 +102,7 @@ struct GPUSettings
   bool gpu_disable_raster_order_views : 1 = false;
   bool gpu_disable_compute_shaders : 1 = false;
   bool gpu_disable_compressed_textures : 1 = false;
+  bool gpu_automatic_resolution_scale : 1 = false;
   bool gpu_per_sample_shading : 1 = false;
   bool gpu_true_color : 1 = true;
   bool gpu_scaled_dithering : 1 = true;
@@ -210,6 +211,11 @@ struct GPUSettings
 
   ALWAYS_INLINE bool IsUsingSoftwareRenderer() const { return (gpu_renderer == GPURenderer::Software); }
   ALWAYS_INLINE bool IsUsingAccurateBlending() const { return (gpu_accurate_blending && !gpu_true_color); }
+  ALWAYS_INLINE bool IsUsingIntegerDisplayScaling() const
+  {
+    return (display_scaling == DisplayScalingMode::NearestInteger ||
+            display_scaling == DisplayScalingMode::BilinearInteger);
+  }
 
   ALWAYS_INLINE bool UsingPGXPCPUMode() const { return gpu_pgxp_enable && gpu_pgxp_cpu; }
   ALWAYS_INLINE bool UsingPGXPDepthBuffer() const { return gpu_pgxp_enable && gpu_pgxp_depth_buffer; }

src/core/system.cpp

@@ -1219,6 +1219,10 @@ void System::LoadSettings(bool display_osd_messages)
     (g_settings.disable_all_enhancements ||
      Host::Internal::GetBaseSettingsLayer()->GetBoolValue("Main", "DisableAllEnhancements", false));
 
+  // Fix up automatic resolution scale, yuck.
+  if (g_settings.gpu_automatic_resolution_scale && IsValid())
+    g_settings.gpu_resolution_scale = g_gpu.CalculateAutomaticResolutionScale();
+
   Settings::UpdateLogConfig(si);
   Host::LoadSettings(si, lock);
   InputManager::ReloadSources(controller_si, lock);
@@ -1934,6 +1938,7 @@ bool System::Initialize(std::unique_ptr<CDImage> disc, DiscRegion disc_region, b
   PCDrv::Initialize();
 
   UpdateGTEAspectRatio();
+  UpdateAutomaticResolutionScale();
   UpdateThrottlePeriod();
   UpdateMemorySaveStateSettings();
 
@@ -2592,7 +2597,7 @@ void System::ClearMemorySaveStates(bool reallocate_resources, bool recycle_textu
   }
 
   // immediately save a rewind state next frame
-  s_state.rewind_save_counter = (s_state.rewind_save_frequency > 0) ? 0 : -1;
+  s_state.rewind_save_counter = (s_state.rewind_save_frequency >= 0) ? 0 : -1;
 }
 
 void System::FreeMemoryStateStorage(bool release_memory, bool release_textures, bool recycle_textures)
@@ -4220,8 +4225,8 @@ void System::UpdateRunningGame(const std::string& path, CDImage* image, bool boo
 
   UpdateRichPresence(booting);
 
-  FullscreenUI::OnRunningGameChanged(s_state.running_game_path, s_state.running_game_serial,
-                                     s_state.running_game_title, s_state.running_game_hash);
+  FullscreenUI::OnRunningGameChanged(s_state.running_game_path, s_state.running_game_serial, s_state.running_game_title,
+                                     s_state.running_game_hash);
 
   Host::OnGameChanged(s_state.running_game_path, s_state.running_game_serial, s_state.running_game_title,
                       s_state.running_game_hash);
@@ -4508,7 +4513,8 @@ void System::CheckForSettingsChanges(const Settings& old_settings)
 
       // NOTE: Must come after the GPU thread settings update, otherwise it allocs the wrong size textures.
       const bool use_existing_textures = (g_settings.gpu_resolution_scale == old_settings.gpu_resolution_scale);
-      ClearMemorySaveStates(true, use_existing_textures);
+      FreeMemoryStateStorage(false, true, use_existing_textures);
+      ClearMemorySaveStates(true, true);
 
       if (IsPaused())
       {
@@ -5823,6 +5829,7 @@ void System::DisplayWindowResized()
     return;
 
   UpdateGTEAspectRatio();
+  UpdateAutomaticResolutionScale();
 }
 
 void System::UpdateGTEAspectRatio()
@@ -5866,6 +5873,28 @@ void System::UpdateGTEAspectRatio()
   GTE::SetAspectRatio(gte_ar, custom_num, custom_denom);
 }
 
+void System::UpdateAutomaticResolutionScale()
+{
+  if (!IsValidOrInitializing() || !g_settings.gpu_automatic_resolution_scale)
+    return;
+
+  const u32 new_scale = g_gpu.CalculateAutomaticResolutionScale();
+  if (g_settings.gpu_resolution_scale == new_scale)
+    return;
+
+  g_settings.gpu_resolution_scale = Truncate8(new_scale);
+  GPUThread::UpdateSettings(true, false, false);
+  FreeMemoryStateStorage(false, true, false);
+  ClearMemorySaveStates(true, false);
+
+  if (IsPaused())
+  {
+    // resolution change needs display updated
+    g_gpu.UpdateDisplay(false);
+    GPUThread::PresentCurrentFrame();
+  }
+}
+
 bool System::ChangeGPUDump(std::string new_path)
 {
   Error error;

src/core/system_private.h

@@ -50,6 +50,9 @@ void DisplayWindowResized();
 /// Updates the internal GTE aspect ratio. Use with "match display" aspect ratio setting.
 void UpdateGTEAspectRatio();
 
+/// Updates the resolution scale when it is set to automatic.
+void UpdateAutomaticResolutionScale();
+
 /// Called on card read/write, handles fast forwarding.
 void OnMemoryCardAccessed();