System: Reuse existing texture/buffers for runahead/rewind

src/core/gpu_hw_d3d11.cpp

@@ -99,9 +99,9 @@ bool GPU_HW_D3D11::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
                              static_cast<LONG>(m_vram_texture.GetHeight()), 1);
     ComPtr<ID3D11Resource> resource;
 
+    HostDisplayTexture* tex = *host_texture;
     if (sw.IsReading())
     {
-      HostDisplayTexture* tex = *host_texture;
       if (tex->GetWidth() != m_vram_texture.GetWidth() || tex->GetHeight() != m_vram_texture.GetHeight() ||
           tex->GetSamples() != m_vram_texture.GetSamples())
       {
@@ -113,15 +113,22 @@ bool GPU_HW_D3D11::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
     }
     else
     {
-      std::unique_ptr<HostDisplayTexture> tex =
-        m_host_display->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
-                                      m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false);
-      if (!tex)
-        return false;
+      if (!tex || tex->GetWidth() != m_vram_texture.GetWidth() || tex->GetHeight() != m_vram_texture.GetHeight() ||
+          tex->GetSamples() != m_vram_texture.GetSamples())
+      {
+        delete tex;
+
+        tex = m_host_display
+                ->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
+                                m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false)
+                .release();
+        *host_texture = tex;
+        if (!tex)
+          return false;
+      }
 
       static_cast<ID3D11ShaderResourceView*>(tex->GetHandle())->GetResource(resource.GetAddressOf());
       m_context->CopySubresourceRegion(resource.Get(), 0, 0, 0, 0, m_vram_texture.GetD3DTexture(), 0, &src_box);
-      *host_texture = tex.release();
     }
   }
 

src/core/gpu_hw_opengl.cpp

@@ -108,9 +108,9 @@ bool GPU_HW_OpenGL::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
 {
   if (host_texture)
   {
+    HostDisplayTexture* tex = *host_texture;
     if (sw.IsReading())
     {
-      HostDisplayTexture* tex = *host_texture;
       if (tex->GetWidth() != m_vram_texture.GetWidth() || tex->GetHeight() != m_vram_texture.GetHeight() ||
           tex->GetSamples() != m_vram_texture.GetSamples())
       {
@@ -123,16 +123,23 @@ bool GPU_HW_OpenGL::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
     }
     else
     {
-      std::unique_ptr<HostDisplayTexture> tex =
-        m_host_display->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
-                                      m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false);
-      if (!tex)
-        return false;
+      if (!tex || tex->GetWidth() != m_vram_texture.GetWidth() || tex->GetHeight() != m_vram_texture.GetHeight() ||
+          tex->GetSamples() != m_vram_texture.GetSamples())
+      {
+        delete tex;
+
+        tex = m_host_display
+                ->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
+                                m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false)
+                .release();
+        *host_texture = tex;
+        if (!tex)
+          return false;
+      }
 
       CopyFramebufferForState(m_vram_texture.GetGLTarget(), m_vram_texture.GetGLId(), m_vram_fbo_id, 0, 0,
                               static_cast<GLuint>(reinterpret_cast<uintptr_t>(tex->GetHandle())), 0, 0, 0,
                               m_vram_texture.GetWidth(), m_vram_texture.GetHeight());
-      *host_texture = tex.release();
     }
   }
 

src/core/gpu_hw_vulkan.cpp

@@ -131,11 +131,20 @@ bool GPU_HW_Vulkan::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
     }
     else
     {
-      std::unique_ptr<HostDisplayTexture> htex =
-        m_host_display->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
-                                      m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false);
-      if (!htex)
-        return false;
+      HostDisplayTexture* htex = *host_texture;
+      if (!htex || htex->GetWidth() != m_vram_texture.GetWidth() || htex->GetHeight() != m_vram_texture.GetHeight() ||
+          htex->GetSamples() != m_vram_texture.GetSamples())
+      {
+        delete htex;
+
+        htex = m_host_display
+                 ->CreateTexture(m_vram_texture.GetWidth(), m_vram_texture.GetHeight(), 1, 1,
+                                 m_vram_texture.GetSamples(), HostDisplayPixelFormat::RGBA8, nullptr, 0, false)
+                 .release();
+        *host_texture = htex;
+        if (!htex)
+          return false;
+      }
 
       Vulkan::Texture* tex = static_cast<Vulkan::Texture*>(htex->GetHandle());
       if (tex->GetWidth() != m_vram_texture.GetWidth() || tex->GetHeight() != m_vram_texture.GetHeight() ||
@@ -152,7 +161,6 @@ bool GPU_HW_Vulkan::DoState(StateWrapper& sw, HostDisplayTexture** host_texture,
                      tex->GetImage(), tex->GetLayout(), 1, &ic);
       m_vram_texture.TransitionToLayout(buf, old_vram_layout);
       tex->TransitionToLayout(buf, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL);
-      *host_texture = htex.release();
     }
   }
 

src/core/system.cpp

@@ -2046,13 +2046,17 @@ bool LoadMemoryState(const MemorySaveState& mss)
 
 bool SaveMemoryState(MemorySaveState* mss)
 {
-  mss->state_stream = std::make_unique<GrowableMemoryByteStream>(nullptr, MAX_SAVE_STATE_SIZE);
+  if (!mss->state_stream)
+    mss->state_stream = std::make_unique<GrowableMemoryByteStream>(nullptr, MAX_SAVE_STATE_SIZE);
+  else
+    mss->state_stream->SeekAbsolute(0);
 
-  HostDisplayTexture* host_texture = nullptr;
+  HostDisplayTexture* host_texture = mss->vram_texture.release();
   StateWrapper sw(mss->state_stream.get(), StateWrapper::Mode::Write, SAVE_STATE_VERSION);
   if (!DoState(sw, &host_texture, false))
   {
     Log_ErrorPrint("Failed to create rewind state.");
+    delete host_texture;
     return false;
   }
 
@@ -2064,11 +2068,15 @@ bool SaveRewindState()
 {
   Common::Timer save_timer;
 
+  // try to reuse the frontmost slot
   const u32 save_slots = g_settings.rewind_save_slots;
+  MemorySaveState mss;
   while (s_rewind_states.size() >= save_slots)
+  {
+    mss = std::move(s_rewind_states.front());
     s_rewind_states.pop_front();
+  }
 
-  MemorySaveState mss;
   if (!SaveMemoryState(&mss))
     return false;
 
@@ -2141,10 +2149,14 @@ void DoRewind()
 
 void SaveRunaheadState()
 {
-  if (s_runahead_states.size() >= s_runahead_frames)
+  // try to reuse the frontmost slot
+  MemorySaveState mss;
+  while (s_runahead_states.size() >= s_runahead_frames)
+  {
+    mss = std::move(s_runahead_states.front());
     s_runahead_states.pop_front();
+  }
 
-  MemorySaveState mss;
   if (!SaveMemoryState(&mss))
   {
     Log_ErrorPrint("Failed to save runahead state.");