GPU: Split software to frontend/backend

src/core/gpu_backend.h

@@ -0,0 +1,91 @@
+#pragma once
+#include "common/event.h"
+#include "common/heap_array.h"
+#include "gpu_types.h"
+#include <atomic>
+#include <condition_variable>
+#include <memory>
+#include <mutex>
+#include <thread>
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4324) // warning C4324: 'GPUBackend': structure was padded due to alignment specifier
+#endif
+
+class GPUBackend
+{
+public:
+  GPUBackend();
+  virtual ~GPUBackend();
+
+  ALWAYS_INLINE u16* GetVRAM() const { return m_vram_ptr; }
+
+  virtual bool Initialize();
+  virtual void UpdateSettings();
+  virtual void Reset();
+  virtual void Shutdown();
+
+  GPUBackendFillVRAMCommand* NewFillVRAMCommand();
+  GPUBackendUpdateVRAMCommand* NewUpdateVRAMCommand(u32 num_words);
+  GPUBackendCopyVRAMCommand* NewCopyVRAMCommand();
+  GPUBackendSetDrawingAreaCommand* NewSetDrawingAreaCommand();
+  GPUBackendDrawPolygonCommand* NewDrawPolygonCommand(u32 num_vertices);
+  GPUBackendDrawRectangleCommand* NewDrawRectangleCommand();
+  GPUBackendDrawLineCommand* NewDrawLineCommand(u32 num_vertices);
+
+  void PushCommand(GPUBackendCommand* cmd);
+  void Sync();
+
+  /// Processes all pending GPU commands.
+  void RunGPULoop();
+
+protected:
+  void* AllocateCommand(u32 size);
+  u32 GetPendingCommandSize() const;
+  void WakeGPUThread();
+  void StartGPUThread();
+  void StopGPUThread();
+
+  virtual void FillVRAM(u32 x, u32 y, u32 width, u32 height, u32 color, GPUBackendCommandParameters params) = 0;
+  virtual void UpdateVRAM(u32 x, u32 y, u32 width, u32 height, const void* data,
+                          GPUBackendCommandParameters params) = 0;
+  virtual void CopyVRAM(u32 src_x, u32 src_y, u32 dst_x, u32 dst_y, u32 width, u32 height,
+                        GPUBackendCommandParameters params) = 0;
+  virtual void DrawPolygon(const GPUBackendDrawPolygonCommand* cmd) = 0;
+  virtual void DrawRectangle(const GPUBackendDrawRectangleCommand* cmd) = 0;
+  virtual void DrawLine(const GPUBackendDrawLineCommand* cmd) = 0;
+  virtual void FlushRender() = 0;
+  virtual void DrawingAreaChanged() = 0;
+
+  void HandleCommand(const GPUBackendCommand* cmd);
+
+  u16* m_vram_ptr = nullptr;
+
+  Common::Rectangle<u32> m_drawing_area{};
+
+  Common::Event m_sync_event;
+  std::atomic_bool m_gpu_thread_sleeping{false};
+  std::atomic_bool m_gpu_loop_done{false};
+  std::thread m_gpu_thread;
+  bool m_use_gpu_thread = false;
+
+  std::mutex m_sync_mutex;
+  std::condition_variable m_sync_cpu_thread_cv;
+  std::condition_variable m_wake_gpu_thread_cv;
+  bool m_sync_done = false;
+
+  enum : u32
+  {
+    COMMAND_QUEUE_SIZE = 4 * 1024 * 1024,
+    THRESHOLD_TO_WAKE_GPU = 256
+  };
+
+  HeapArray<u8, COMMAND_QUEUE_SIZE> m_command_fifo_data;
+  alignas(64) std::atomic<u32> m_command_fifo_read_ptr{0};
+  alignas(64) std::atomic<u32> m_command_fifo_write_ptr{0};
+};
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif