[VK]: Support for frame interpolation on PC and improve it's logic

I also suspect that frame interpolation hasn't been ever working, as it needs frame_skip_threshold and it was only being initialized if frame_skipping was on (actually a disabled and useless option, thats why i also nuked it), and the toggle was very messy with jni.

src/android/app/src/main/java/org/yuzu/yuzu_emu/features/settings/model/BooleanSetting.kt

@@ -51,7 +51,6 @@ enum class BooleanSetting(override val key: String) : AbstractBooleanSetting {
 
     ENABLE_RAII("enable_raii"),
     FRAME_INTERPOLATION("frame_interpolation"),
-//    FRAME_SKIPPING("frame_skipping"),
 
     PERF_OVERLAY_BACKGROUND("perf_overlay_background"),
     SHOW_PERFORMANCE_OVERLAY("show_performance_overlay"),
@@ -68,8 +67,6 @@ enum class BooleanSetting(override val key: String) : AbstractBooleanSetting {
     USE_LRU_CACHE("use_lru_cache");
 
     external fun isRaiiEnabled(): Boolean
-//  external fun isFrameSkippingEnabled(): Boolean
-    external fun isFrameInterpolationEnabled(): Boolean
 
     override fun getBoolean(needsGlobal: Boolean): Boolean =
         NativeConfig.getBoolean(key, needsGlobal)

src/android/app/src/main/java/org/yuzu/yuzu_emu/features/settings/model/view/SettingsItem.kt

@@ -234,15 +234,6 @@ abstract class SettingsItem(
                     descriptionId = R.string.frame_interpolation_description
                 )
             )
-
-//            put(
-//                SwitchSetting(
-//                    BooleanSetting.FRAME_SKIPPING,
-//                    titleId = R.string.frame_skipping,
-//                    descriptionId = R.string.frame_skipping_description
-//                )
-//            )
-
             put(
                 SwitchSetting(
                     dockedModeSetting,

src/android/app/src/main/res/values/strings.xml

@@ -479,8 +479,6 @@
     <string name="display">Display</string>
     <string name="processing">Post-Processing</string>
 
-    <string name="frame_skipping">WIP: Frameskip</string>
-    <string name="frame_skipping_description">Toggle frame skipping to improve performance by reducing the number of rendered frames. This feature is still being worked on and will be enabled in future releases.</string>
     <string name="renderer_accuracy">Accuracy level</string>
     <string name="renderer_resolution">Resolution (Handheld/Docked)</string>
     <string name="renderer_vsync">VSync mode</string>

src/common/settings.h

@@ -322,12 +322,8 @@ struct Values {
     SwitchableSetting<int> vulkan_device{linkage, 0, "vulkan_device", Category::Renderer,
                                          Specialization::RuntimeList};
     SwitchableSetting<bool> enable_raii{linkage, false, "enable_raii", Category::Renderer};
-#ifdef __ANDROID__
     SwitchableSetting<bool> frame_interpolation{linkage, true, "frame_interpolation", Category::Renderer,
                                                 Specialization::RuntimeList};
-    SwitchableSetting<bool> frame_skipping{linkage, false, "frame_skipping", Category::Renderer,
-                                           Specialization::RuntimeList};
-#endif
     SwitchableSetting<bool> use_disk_shader_cache{linkage, true, "use_disk_shader_cache",
                                                   Category::Renderer};
     SwitchableSetting<SpirvOptimizeMode, true> optimize_spirv_output{linkage,

src/video_core/renderer_vulkan/renderer_vulkan.cpp

@@ -38,9 +38,7 @@
 #include "video_core/vulkan_common/vulkan_memory_allocator.h"
 #include "video_core/vulkan_common/vulkan_surface.h"
 #include "video_core/vulkan_common/vulkan_wrapper.h"
-#ifdef __ANDROID__
-#include <jni.h>
-#endif
+
 namespace Vulkan {
 namespace {
 
@@ -189,39 +187,6 @@ RendererVulkan::~RendererVulkan() {
     void(device.GetLogical().WaitIdle());
 }
 
-#ifdef __ANDROID__
-class BooleanSetting {
-    public:
-//        static BooleanSetting FRAME_SKIPPING;
-        static BooleanSetting FRAME_INTERPOLATION;
-        explicit BooleanSetting(bool initial_value = false) : value(initial_value) {}
-
-        [[nodiscard]] bool getBoolean() const {
-            return value;
-        }
-
-        void setBoolean(bool new_value) {
-            value = new_value;
-        }
-
-    private:
-        bool value;
-    };
-
-    // Initialize static members
-//    BooleanSetting BooleanSetting::FRAME_SKIPPING(false);
-    BooleanSetting BooleanSetting::FRAME_INTERPOLATION(false);
-
-//    extern "C" JNIEXPORT jboolean JNICALL
-//    Java_org_yuzu_yuzu_1emu_features_settings_model_BooleanSetting_isFrameSkippingEnabled(JNIEnv* env, jobject /* this */) {
-//        return static_cast<jboolean>(BooleanSetting::FRAME_SKIPPING.getBoolean());
-//    }
-
-    extern "C" JNIEXPORT jboolean JNICALL
-    Java_org_yuzu_yuzu_1emu_features_settings_model_BooleanSetting_isFrameInterpolationEnabled(JNIEnv* env, jobject /* this */) {
-        return static_cast<jboolean>(BooleanSetting::FRAME_INTERPOLATION.getBoolean());
-    }
-
 void RendererVulkan::InterpolateFrames(Frame* prev_frame, Frame* interpolated_frame) {
     if (!prev_frame || !interpolated_frame || !prev_frame->image || !interpolated_frame->image) {
         return;
@@ -292,30 +257,15 @@ class BooleanSetting {
         TransitionImageLayout(cmdbuf, *interpolated_frame->image, VK_IMAGE_LAYOUT_GENERAL);
     });
 }
-#endif
 
 void RendererVulkan::Composite(std::span<const Tegra::FramebufferConfig> framebuffers) {
-    #ifdef __ANDROID__
-    static int frame_counter = 0;
-    static int target_fps = 60; // Target FPS (30 or 60)
-    int frame_skip_threshold = 1;
-
-    bool frame_skipping = false; //BooleanSetting::FRAME_SKIPPING.getBoolean();
-    bool frame_interpolation = BooleanSetting::FRAME_INTERPOLATION.getBoolean();
-    #endif
-
     if (framebuffers.empty()) {
         return;
     }
 
-    #ifdef __ANDROID__
-    if (frame_skipping) {
-        frame_skip_threshold = (target_fps == 30) ? 2 : 2;
-    }
+    bool frame_interpolation_enabled = Settings::values.frame_interpolation.GetValue();
 
-    frame_counter++;
-    if (frame_counter % frame_skip_threshold != 0) {
-        if (frame_interpolation && previous_frame) {
+    if (frame_interpolation_enabled && previous_frame) {
         Frame* interpolated_frame = present_manager.GetRenderFrame();
         InterpolateFrames(previous_frame, interpolated_frame);
         blit_swapchain.DrawToFrame(rasterizer, interpolated_frame, framebuffers,
@@ -323,10 +273,11 @@ void RendererVulkan::Composite(std::span<const Tegra::FramebufferConfig> framebu
                                    swapchain.GetImageViewFormat());
         scheduler.Flush(*interpolated_frame->render_ready);
         present_manager.Present(interpolated_frame);
-        }
+
+        // Optionally, update previous_frame here if you want to chain interpolations
+        previous_frame = interpolated_frame;
         return;
     }
-    #endif
 
     SCOPE_EXIT {
         render_window.OnFrameDisplayed();
@@ -346,6 +297,11 @@ void RendererVulkan::Composite(std::span<const Tegra::FramebufferConfig> framebu
     scheduler.Flush(*frame->render_ready);
     present_manager.Present(frame);
 
+    // Store the current frame for interpolation on the next call
+    if (frame_interpolation_enabled) {
+        previous_frame = frame;
+    }
+
     gpu.RendererFrameEndNotify();
     rasterizer.TickFrame();
 }

src/yuzu/configuration/shared_translation.cpp

@@ -250,6 +250,12 @@ std::unique_ptr<TranslationMap> InitializeTranslations(QWidget* parent)
               "of available video memory for performance. Has no effect on integrated graphics. "
               "Aggressive mode may severely impact the performance of other applications such as "
               "recording software."));
+    INSERT(Settings,
+           frame_interpolation,
+           tr("Enhanced Frame Pacing"),
+           tr("Ensures smooth and consistent frame delivery by synchronizing the timing between frames, "
+              "reducing stuttering and uneven animation. Ideal for games that experience frame timing "
+              "instability or micro-stutters during gameplay."));
     INSERT(Settings,
            skip_cpu_inner_invalidation,
            tr("Skip CPU Inner Invalidation"),
@@ -333,14 +339,13 @@ std::unique_ptr<TranslationMap> InitializeTranslations(QWidget* parent)
            barrier_feedback_loops,
            tr("Barrier feedback loops"),
            tr("Improves rendering of transparency effects in specific games."));
-
-    // Renderer (Extensions)
     INSERT(Settings,
            enable_raii,
            tr("RAII"),
            tr("A method of automatic resource management in Vulkan "
               "that ensures proper release of resources "
               "when they are no longer needed, but may cause crashes in bundled games."));
+    // Renderer (Extensions)
     INSERT(Settings,
            dyna_state,
            tr("Extended Dynamic State"),