System: Fix incorrect rewind VRAM estimation

src/core/fullscreen_ui.cpp

@@ -3155,6 +3155,7 @@ void FullscreenUI::DrawEmulationSettingsPage()
   }
   else if (rewind_enabled)
   {
+    const u32 resolution_scale = GetEffectiveUIntSetting(bsi, "GPU", "ResolutionScale", 1);
     const float rewind_frequency = GetEffectiveFloatSetting(bsi, "Main", "RewindFrequency", 10.0f);
     const s32 rewind_save_slots = GetEffectiveIntSetting(bsi, "Main", "RewindSaveSlots", 10);
     const float duration =
@@ -3162,7 +3163,7 @@ void FullscreenUI::DrawEmulationSettingsPage()
       static_cast<float>(rewind_save_slots);
 
     u64 ram_usage, vram_usage;
-    System::CalculateRewindMemoryUsage(rewind_save_slots, &ram_usage, &vram_usage);
+    System::CalculateRewindMemoryUsage(rewind_save_slots, resolution_scale, &ram_usage, &vram_usage);
     rewind_summary.format(
       FSUI_FSTR("Rewind for {0} frames, lasting {1:.2f} seconds will require up to {2} MB of RAM and {3} MB of VRAM."),
       rewind_save_slots, duration, ram_usage / 1048576, vram_usage / 1048576);

src/core/system.cpp

@@ -3844,10 +3844,11 @@ void System::LogUnsafeSettingsToConsole(const std::string& messages)
   Log_WarningPrint(console_messages.c_str());
 }
 
-void System::CalculateRewindMemoryUsage(u32 num_saves, u64* ram_usage, u64* vram_usage)
+void System::CalculateRewindMemoryUsage(u32 num_saves, u32 resolution_scale, u64* ram_usage, u64* vram_usage)
 {
+  const u64 real_resolution_scale = static_cast<u64>(std::max(g_settings.gpu_resolution_scale, 1u));
   *ram_usage = MAX_SAVE_STATE_SIZE * static_cast<u64>(num_saves);
-  *vram_usage = (VRAM_WIDTH * VRAM_HEIGHT * 4) * static_cast<u64>(std::max(g_settings.gpu_resolution_scale, 1u)) *
+  *vram_usage = ((VRAM_WIDTH * real_resolution_scale) * (VRAM_HEIGHT * real_resolution_scale) * 4) *
                 static_cast<u64>(g_settings.gpu_multisamples) * static_cast<u64>(num_saves);
 }
 
@@ -3869,7 +3870,7 @@ void System::UpdateMemorySaveStateSettings()
     s_rewind_save_counter = 0;
 
     u64 ram_usage, vram_usage;
-    CalculateRewindMemoryUsage(g_settings.rewind_save_slots, &ram_usage, &vram_usage);
+    CalculateRewindMemoryUsage(g_settings.rewind_save_slots, g_settings.gpu_resolution_scale, &ram_usage, &vram_usage);
     Log_InfoPrintf(
       "Rewind is enabled, saving every %d frames, with %u slots and %" PRIu64 "MB RAM and %" PRIu64 "MB VRAM usage",
       std::max(s_rewind_save_frequency, 1), g_settings.rewind_save_slots, ram_usage / 1048576, vram_usage / 1048576);

src/core/system.h

@@ -472,7 +472,7 @@ void InvalidateDisplay();
 //////////////////////////////////////////////////////////////////////////
 // Memory Save States (Rewind and Runahead)
 //////////////////////////////////////////////////////////////////////////
-void CalculateRewindMemoryUsage(u32 num_saves, u64* ram_usage, u64* vram_usage);
+void CalculateRewindMemoryUsage(u32 num_saves, u32 resolution_scale, u64* ram_usage, u64* vram_usage);
 void ClearMemorySaveStates();
 void UpdateMemorySaveStateSettings();
 bool LoadRewindState(u32 skip_saves = 0, bool consume_state = true);

src/duckstation-qt/emulationsettingswidget.cpp

@@ -183,13 +183,14 @@ void EmulationSettingsWidget::updateRewind()
 
   if (!runahead_enabled && rewind_enabled)
   {
+    const u32 resolution_scale = static_cast<u32>(m_dialog->getEffectiveIntValue("GPU", "ResolutionScale", 1));
     const u32 frames = static_cast<u32>(m_ui.rewindSaveSlots->value());
     const float frequency = static_cast<float>(m_ui.rewindSaveFrequency->value());
     const float duration =
       ((frequency <= std::numeric_limits<float>::epsilon()) ? (1.0f / 60.0f) : frequency) * static_cast<float>(frames);
 
     u64 ram_usage, vram_usage;
-    System::CalculateRewindMemoryUsage(frames, &ram_usage, &vram_usage);
+    System::CalculateRewindMemoryUsage(frames, resolution_scale, &ram_usage, &vram_usage);
 
     m_ui.rewindSummary->setText(
       tr("Rewind for %n frame(s), lasting %1 second(s) will require up to %2MB of RAM and %3MB of VRAM.", "", frames)