Implement D3D12 backend

Source/Core/VideoBackends/D3D12/SwapChain.h

@@ -0,0 +1,55 @@
+// Copyright 2019 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <d3d12.h>
+#include <dxgi.h>
+#include <memory>
+#include <vector>
+
+#include "Common/CommonTypes.h"
+#include "Common/WindowSystemInfo.h"
+#include "VideoBackends/D3D12/Common.h"
+#include "VideoBackends/D3DCommon/SwapChain.h"
+#include "VideoCommon/TextureConfig.h"
+
+namespace DX12
+{
+class DXTexture;
+class DXFramebuffer;
+
+class SwapChain : public D3DCommon::SwapChain
+{
+public:
+  SwapChain(const WindowSystemInfo& wsi, IDXGIFactory2* dxgi_factory,
+            ID3D12CommandQueue* d3d_command_queue);
+  ~SwapChain();
+
+  static std::unique_ptr<SwapChain> Create(const WindowSystemInfo& wsi);
+
+  bool Present() override;
+
+  DXTexture* GetCurrentTexture() const { return m_buffers[m_current_buffer].texture.get(); }
+  DXFramebuffer* GetCurrentFramebuffer() const
+  {
+    return m_buffers[m_current_buffer].framebuffer.get();
+  }
+
+protected:
+  bool CreateSwapChainBuffers() override;
+  void DestroySwapChainBuffers() override;
+
+private:
+  struct BufferResources
+  {
+    std::unique_ptr<DXTexture> texture;
+    std::unique_ptr<DXFramebuffer> framebuffer;
+  };
+
+  std::vector<BufferResources> m_buffers;
+  u32 m_current_buffer = 0;
+};
+
+}  // namespace DX12