Add support for target FPS frame pacing

src/common/settings.h

@@ -434,6 +434,13 @@ struct Values {
                                                             "accelerate_astc",
                                                             Category::RendererAdvanced};
 
+    SwitchableSetting<FramePacingMode, true> frame_pacing_mode{linkage,
+                                                               FramePacingMode::Default,
+                                                               FramePacingMode::Default,
+                                                               FramePacingMode::Target_120,
+                                                               "frame_pacing_mode",
+                                                               Category::RendererAdvanced};
+
     SwitchableSetting<AstcRecompression, true> astc_recompression{linkage,
                                                                   AstcRecompression::Uncompressed,
                                                                   "astc_recompression",

src/common/settings_enums.h

@@ -129,6 +129,7 @@ ENUM(TimeZone, Auto, Default, Cet, Cst6Cdt, Cuba, Eet, Egypt, Eire, Est, Est5Edt
 ENUM(AnisotropyMode, Automatic, Default, X2, X4, X8, X16, X32, X64, None);
 ENUM(AstcDecodeMode, Cpu, Gpu, CpuAsynchronous);
 ENUM(AstcRecompression, Uncompressed, Bc1, Bc3);
+ENUM(FramePacingMode, Default, Target_30, Target_60, Target_120);
 ENUM(VSyncMode, Immediate, Mailbox, Fifo, FifoRelaxed);
 ENUM(VramUsageMode, Conservative, Aggressive);
 ENUM(RendererBackend, OpenGL_GLSL, Vulkan, Null, OpenGL_GLASM, OpenGL_SPIRV);

src/qt_common/config/shared_translation.cpp

@@ -225,6 +225,8 @@ std::unique_ptr<TranslationMap> InitializeTranslations(QObject* parent)
             "intermediate format: RGBA8.\n"
             "BC1/BC3: The intermediate format will be recompressed to BC1 or BC3 format,\n"
             " saving VRAM but degrading image quality."));
+    INSERT(Settings, frame_pacing_mode, tr("Frame Pacing Mode (Vulkan only)"),
+           tr("Controls how the emulator manages frame pacing to reduce stuttering and make the frame rate smoother and more consistent."));
     INSERT(Settings,
            vram_usage_mode,
            tr("VRAM Usage Mode:"),
@@ -497,6 +499,13 @@ std::unique_ptr<ComboboxTranslationMap> ComboboxEnumeration(QObject* parent)
              PAIR(AstcRecompression, Bc1, tr("BC1 (Low quality)")),
              PAIR(AstcRecompression, Bc3, tr("BC3 (Medium quality)")),
          }});
+    translations->insert({Settings::EnumMetadata<Settings::FramePacingMode>::Index(),
+                          {
+                              PAIR(FramePacingMode, Default, tr("Default")),
+                              PAIR(FramePacingMode, Target_30, tr("30 FPS")),
+                              PAIR(FramePacingMode, Target_60, tr("60 FPS")),
+                              PAIR(FramePacingMode, Target_120, tr("120 FPS")),
+                          }});
     translations->insert({Settings::EnumMetadata<Settings::VramUsageMode>::Index(),
                           {
                               PAIR(VramUsageMode, Conservative, tr("Conservative")),

src/video_core/renderer_vulkan/vk_scheduler.h

@@ -120,6 +120,22 @@ public:
         master_semaphore->Wait(tick);
     }
 
+    /// Waits until the next game frame based on the current game FPS.
+    void WaitFPS(u64 tick, double target_fps) {
+        if (master_semaphore->CurrentTick() >= tick) {
+            return;
+        }
+        static auto next_frame_time = std::chrono::steady_clock::now();
+        auto frame_duration = std::chrono::duration<double>(1.0 / target_fps);
+        next_frame_time += std::chrono::duration_cast<std::chrono::steady_clock::duration>(frame_duration);
+        auto now = std::chrono::steady_clock::now();
+        if (next_frame_time > now) {
+            std::this_thread::sleep_until(next_frame_time);
+        } else {
+            next_frame_time = now;
+        }
+    }
+
     /// Returns the master timeline semaphore.
     [[nodiscard]] MasterSemaphore& GetMasterSemaphore() const noexcept {
         return *master_semaphore;

src/video_core/renderer_vulkan/vk_swapchain.cpp

@@ -194,7 +194,25 @@ bool Swapchain::AcquireNextImage() {
         break;
     }
 
-    scheduler.Wait(resource_ticks[image_index]);
+    if (!Settings::values.use_speed_limit.GetValue()) {
+        scheduler.Wait(resource_ticks[image_index]);
+    } else {
+        switch (Settings::values.frame_pacing_mode.GetValue()) {
+        case Settings::FramePacingMode::Default:
+            scheduler.Wait(resource_ticks[image_index]);
+            break;
+        case Settings::FramePacingMode::Target_30:
+            scheduler.WaitFPS(resource_ticks[image_index], 30.0);
+            break;
+        case Settings::FramePacingMode::Target_60:
+            scheduler.WaitFPS(resource_ticks[image_index], 60.0);
+            break;
+        case Settings::FramePacingMode::Target_120:
+            scheduler.WaitFPS(resource_ticks[image_index], 120.0);
+            break;
+        }
+    }
+
     resource_ticks[image_index] = scheduler.CurrentTick();
 
     return is_suboptimal || is_outdated;