VideoCommon: Add class for quickly transforming and culling vertices on the CPU

Source/Core/VideoCommon/CPUCull.h

@@ -0,0 +1,38 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "VideoCommon/BPMemory.h"
+#include "VideoCommon/DataReader.h"
+#include "VideoCommon/OpcodeDecoding.h"
+
+class CPUCull
+{
+public:
+  ~CPUCull();
+  void Init();
+  bool AreAllVerticesCulled(VertexLoaderBase* loader, OpcodeDecoder::Primitive primitive,
+                            const u8* src, u32 count);
+
+  struct alignas(16) TransformedVertex
+  {
+    float x, y, z, w;
+  };
+
+  using TransformFunction = void (*)(void*, const void*, u32, int);
+  using CullFunction = bool (*)(const CPUCull::TransformedVertex*, int);
+
+private:
+  template <typename T>
+  struct BufferDeleter
+  {
+    void operator()(T* ptr);
+  };
+  std::unique_ptr<TransformedVertex[], BufferDeleter<TransformedVertex>> m_transform_buffer;
+  u32 m_transform_buffer_size = 0;
+  std::array<std::array<TransformFunction, 2>, 2> m_transform_table;
+  Common::EnumMap<Common::EnumMap<CullFunction, CullMode::All>,
+                  OpcodeDecoder::Primitive::GX_DRAW_TRIANGLE_FAN>
+      m_cull_table;
+};