D3D: Moved render state cache into separate source files.

Refactored  StateCache::Get() to early out for narrower indentation.
Added comments to clarify ownership of objects returned by  StateCache::Get().

Source/Core/VideoBackends/D3D/StateCache.h

@@ -0,0 +1,82 @@
+// Copyright 2013 Dolphin Emulator Project
+// Licensed under GPLv2
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <unordered_map>
+
+#include "Common/CommonTypes.h"
+#include "VideoBackends/D3D/D3DBase.h"
+#include "VideoCommon/BPMemory.h"
+
+namespace DX11
+{
+
+union RasterizerState
+{
+	struct
+	{
+		u32 cull_mode : 2;
+		u32 wireframe : 1;
+	};
+
+	u32 packed;
+};
+
+union BlendState
+{
+	struct
+	{
+		u32 blend_enable : 1;
+		u32 blend_op : 3;
+		u32 write_mask : 4;
+		u32 src_blend : 5;
+		u32 dst_blend : 5;
+		u32 use_dst_alpha : 1;
+	};
+
+	u32 packed;
+};
+
+union SamplerState
+{
+	struct
+	{
+		u64 min_filter : 3;
+		u64 mag_filter : 1;
+		u64 min_lod : 8;
+		u64 max_lod : 8;
+		s64 lod_bias : 8;
+		u64 wrap_s : 2;
+		u64 wrap_t : 2;
+		u64 max_anisotropy : 5;
+	};
+
+	u64 packed;
+};
+
+class StateCache
+{
+public:
+
+	// Get existing or create new render state.
+	// Returned objects is owned by the cache and does not need to be released.
+	ID3D11SamplerState* Get(SamplerState state);
+	ID3D11BlendState* Get(BlendState state);
+	ID3D11RasterizerState* Get(RasterizerState state);
+	ID3D11DepthStencilState* Get(ZMode state);
+
+	// Release all cached states and clear hash tables.
+	void Clear();
+
+private:
+
+	std::unordered_map<u32, ID3D11DepthStencilState*> m_depth;
+	std::unordered_map<u32, ID3D11RasterizerState*> m_raster;
+	std::unordered_map<u32, ID3D11BlendState*> m_blend;
+	std::unordered_map<u64, ID3D11SamplerState*> m_sampler;
+
+};
+
+}