D3D12: Initial commit for D3D12 backend implementation.

Source/Core/VideoBackends/D3D12/VertexManager.h

@@ -0,0 +1,47 @@
+// Copyright 2008 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "VideoCommon/VertexManagerBase.h"
+
+namespace DX12
+{
+
+class D3DStreamBuffer;
+
+class VertexManager final : public VertexManagerBase
+{
+public:
+	VertexManager();
+	~VertexManager();
+
+	NativeVertexFormat* CreateNativeVertexFormat(const PortableVertexDeclaration& vtx_decl) override;
+	void CreateDeviceObjects() override;
+	void DestroyDeviceObjects() override;
+
+	void SetIndexBuffer();
+
+protected:
+	void ResetBuffer(u32 stride) override;
+
+private:
+	void PrepareDrawBuffers(u32 stride);
+	void Draw(u32 stride);
+	void vFlush(bool use_dst_alpha) override;
+
+	u32 m_vertex_draw_offset;
+	u32 m_index_draw_offset;
+
+	D3DStreamBuffer* m_vertex_stream_buffer = nullptr;
+	D3DStreamBuffer* m_index_stream_buffer = nullptr;
+
+	bool m_vertex_stream_buffer_reallocated = false;
+	bool m_index_stream_buffer_reallocated = false;
+
+	std::vector<u8> m_index_cpu_buffer;
+	std::vector<u8> m_vertex_cpu_buffer;
+};
+
+}  // namespace