From 37e5e64ddc0bd129d8b272396be5c8657f7e3a1d Mon Sep 17 00:00:00 2001
From: Stenzek <stenzek@gmail.com>
Date: Wed, 1 Jan 2025 23:05:07 +1000
Subject: [PATCH] System: Move state display updates to call sites

Fixes black frames when changing settings with runahead/rewind enabled.
---
 src/core/gpu.cpp    | 14 ++------------
 src/core/gpu.h      |  8 +++++---
 src/core/system.cpp | 20 +++++++++++++++++---
 3 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/src/core/gpu.cpp b/src/core/gpu.cpp
index 356bc099a..86a295fda 100644
--- a/src/core/gpu.cpp
+++ b/src/core/gpu.cpp
@@ -243,7 +243,7 @@ void GPU::SoftReset()
   UpdateGPUIdle();
 }
 
-bool GPU::DoState(StateWrapper& sw, bool update_display)
+bool GPU::DoState(StateWrapper& sw)
 {
   if (sw.IsWriting())
   {
@@ -378,10 +378,6 @@ bool GPU::DoState(StateWrapper& sw, bool update_display)
     UpdateDMARequest();
     UpdateCRTCConfig();
     UpdateCommandTickEvent();
-
-    // If we're paused, need to update the display FB.
-    if (update_display)
-      UpdateDisplay(false);
   }
   else // if not memory state
   {
@@ -395,7 +391,7 @@ bool GPU::DoState(StateWrapper& sw, bool update_display)
   return !sw.HasError();
 }
 
-void GPU::DoMemoryState(StateWrapper& sw, System::MemorySaveState& mss, bool update_display)
+void GPU::DoMemoryState(StateWrapper& sw, System::MemorySaveState& mss)
 {
   sw.Do(&m_GPUSTAT.bits);
 
@@ -438,12 +434,6 @@ void GPU::DoMemoryState(StateWrapper& sw, System::MemorySaveState& mss, bool upd
     sizeof(GPUBackendDoMemoryStateCommand)));
   cmd->memory_save_state = &mss;
   GPUThread::PushCommandAndWakeThread(cmd);
-
-  if (update_display)
-  {
-    DebugAssert(sw.IsReading());
-    UpdateDisplay(false);
-  }
 }
 
 void GPU::UpdateDMARequest()
diff --git a/src/core/gpu.h b/src/core/gpu.h
index 595d9012a..e7a327865 100644
--- a/src/core/gpu.h
+++ b/src/core/gpu.h
@@ -97,8 +97,8 @@ public:
   void Initialize();
   void Shutdown();
   void Reset(bool clear_vram);
-  bool DoState(StateWrapper& sw, bool update_display);
-  void DoMemoryState(StateWrapper& sw, System::MemorySaveState& mss, bool update_display);
+  bool DoState(StateWrapper& sw);
+  void DoMemoryState(StateWrapper& sw, System::MemorySaveState& mss);
 
   // Render statistics debug window.
   void DrawDebugStateWindow(float scale);
@@ -216,6 +216,9 @@ public:
   // Dumps raw VRAM to a file.
   bool DumpVRAMToFile(const char* filename);
 
+  // Kicks the current frame to the backend for display.
+  void UpdateDisplay(bool submit_frame);
+
   // Queues the current frame for presentation. Should only be used with runahead.
   void QueuePresentCurrentFrame();
 
@@ -296,7 +299,6 @@ private:
 
   void ReadVRAM(u16 x, u16 y, u16 width, u16 height);
   void UpdateVRAM(u16 x, u16 y, u16 width, u16 height, const void* data, bool set_mask, bool check_mask);
-  void UpdateDisplay(bool submit_frame);
 
   void PrepareForDraw();
   void FinishPolyline();
diff --git a/src/core/system.cpp b/src/core/system.cpp
index 768f2e071..8ea4f1325 100644
--- a/src/core/system.cpp
+++ b/src/core/system.cpp
@@ -1178,6 +1178,10 @@ void System::RecreateGPU(GPURenderer renderer)
   }
 
   ClearMemorySaveStates(true, false);
+
+  g_gpu.UpdateDisplay(false);
+  if (IsPaused())
+    GPUThread::PresentCurrentFrame();
 }
 
 void System::LoadSettings(bool display_osd_messages)
@@ -2390,7 +2394,7 @@ bool System::DoState(StateWrapper& sw, bool update_display)
   if (!sw.DoMarker("InterruptController") || !InterruptController::DoState(sw))
     return false;
 
-  if (!sw.DoMarker("GPU") || !g_gpu.DoState(sw, update_display))
+  if (!sw.DoMarker("GPU") || !g_gpu.DoState(sw))
     return false;
 
   if (!sw.DoMarker("CDROM") || !CDROM::DoState(sw))
@@ -2459,7 +2463,14 @@ bool System::DoState(StateWrapper& sw, bool update_display)
     Achievements::ResetClient();
   }
 
-  return !sw.HasError();
+  if (sw.HasError())
+    return false;
+
+  // If we're paused, need to update the display FB.
+  if (update_display)
+    g_gpu.UpdateDisplay(false);
+
+  return true;
 }
 
 System::MemorySaveState& System::AllocateMemoryState()
@@ -2665,7 +2676,7 @@ void System::DoMemoryState(StateWrapper& sw, MemorySaveState& mss, bool update_d
   SAVE_COMPONENT("DMA", DMA::DoState(sw));
   SAVE_COMPONENT("InterruptController", InterruptController::DoState(sw));
 
-  g_gpu.DoMemoryState(sw, mss, update_display);
+  g_gpu.DoMemoryState(sw, mss);
 
   SAVE_COMPONENT("CDROM", CDROM::DoState(sw));
   SAVE_COMPONENT("Pad", Pad::DoState(sw, true));
@@ -2677,6 +2688,9 @@ void System::DoMemoryState(StateWrapper& sw, MemorySaveState& mss, bool update_d
   SAVE_COMPONENT("Achievements", Achievements::DoState(sw));
 
 #undef SAVE_COMPONENT
+
+  if (update_display)
+    g_gpu.UpdateDisplay(false);
 }
 
 bool System::LoadBIOS(Error* error)