D3D12: Initial commit for D3D12 backend implementation.

Source/Core/VideoBackends/D3D12/D3DStreamBuffer.h

@@ -0,0 +1,70 @@
+// Copyright 2016 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <queue>
+
+struct ID3D12Resource;
+
+namespace DX12
+{
+
+class D3DStreamBuffer
+{
+public:
+	D3DStreamBuffer(unsigned int initial_size, unsigned int max_size, bool* buffer_reallocation_notification);
+	~D3DStreamBuffer();
+
+	bool AllocateSpaceInBuffer(unsigned int allocation_size, unsigned int alignment);
+	void OverrideSizeOfPreviousAllocation(unsigned int override_allocation_size);
+
+	void*                     GetBaseCPUAddress() const;
+	D3D12_GPU_VIRTUAL_ADDRESS GetBaseGPUAddress() const;
+	ID3D12Resource*           GetBuffer() const;
+	void*                     GetCPUAddressOfCurrentAllocation() const;
+	D3D12_GPU_VIRTUAL_ADDRESS GetGPUAddressOfCurrentAllocation() const;
+	unsigned int              GetOffsetOfCurrentAllocation() const;
+	unsigned int              GetSize() const;
+
+	static void QueueFenceCallback(void* owning_object, UINT64 fence_value);
+
+private:
+	void AllocateBuffer(unsigned int size);
+	bool AttemptBufferResizeOrElseStall(unsigned int new_size);
+
+	bool AttemptToAllocateOutOfExistingUnusedSpaceInBuffer(unsigned int allocation_size);
+
+	bool AttemptToFindExistingFenceToStallOn(unsigned int allocation_size);
+
+	void UpdateGPUProgress();
+	void QueueFence(UINT64 fence_value);
+
+	struct FenceTrackingInformation
+	{
+		UINT64 fence_value;
+		unsigned int buffer_offset;
+	};
+
+	std::queue<FenceTrackingInformation> m_queued_fences;
+
+	ID3D12Fence* m_buffer_tracking_fence = nullptr;
+
+	ID3D12Resource* m_buffer = nullptr;
+
+	void* m_buffer_cpu_address = nullptr;
+	D3D12_GPU_VIRTUAL_ADDRESS m_buffer_gpu_address = {};
+
+	unsigned int m_buffer_current_allocation_offset = 0;
+	unsigned int m_buffer_offset = 0;
+	unsigned int m_buffer_size = 0;
+
+	const unsigned int m_buffer_max_size = 0;
+
+	unsigned int m_buffer_gpu_completion_offset = 0;
+
+	bool* m_buffer_reallocation_notification = nullptr;
+};
+
+}