Run Guest on Main Emulator Thread + Remove Mutex/GroupMutex + Introduce PresentationEngine

app/src/main/cpp/skyline/gpu/presentation_engine.h

@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#pragma once
+
+#include <kernel/types/KEvent.h>
+#include "texture.h"
+
+struct ANativeWindow;
+
+namespace skyline::gpu {
+    class PresentationEngine {
+      private:
+        const DeviceState &state;
+        std::mutex windowMutex;
+        std::condition_variable windowConditional;
+        jobject surface; //!< The Surface object backing the ANativeWindow
+        u64 frameTimestamp{}; //!< The timestamp of the last frame being shown
+
+      public:
+        texture::Dimensions resolution{};
+        i32 format{};
+        std::shared_ptr<kernel::type::KEvent> vsyncEvent; //!< Signalled every time a frame is drawn
+        std::shared_ptr<kernel::type::KEvent> bufferEvent; //!< Signalled every time a buffer is freed
+
+        PresentationEngine(const DeviceState &state);
+
+        ~PresentationEngine();
+
+        void UpdateSurface(jobject newSurface);
+
+        void Present(const std::shared_ptr<Texture>& texture);
+
+        ANativeWindow *window{};
+    };
+}