[D3D12] Triangle fan conversion (untested, only indexed and without cache)

src/xenia/gpu/d3d12/primitive_converter.h

@@ -0,0 +1,108 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2018 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_GPU_D3D12_PRIMITIVE_CONVERTER_H_
+#define XENIA_GPU_D3D12_PRIMITIVE_CONVERTER_H_
+
+#include <atomic>
+#include <memory>
+#include <unordered_map>
+
+#include "xenia/gpu/d3d12/shared_memory.h"
+#include "xenia/gpu/register_file.h"
+#include "xenia/gpu/xenos.h"
+#include "xenia/memory.h"
+#include "xenia/ui/d3d12/d3d12_context.h"
+
+namespace xe {
+namespace gpu {
+namespace d3d12 {
+
+// Index buffer cache for primitive types not natively supported by Direct3D 12:
+// - Triangle and line strips with non-0xFFFF/0xFFFFFFFF reset index.
+// - Triangle fans.
+// - Line loops (only indexed ones - non-indexed are better handled in vertex
+//   shaders, otherwise a whole index buffer would have to be created for every
+//   vertex count value).
+class PrimitiveConverter {
+ public:
+  PrimitiveConverter(ui::d3d12::D3D12Context* context,
+                     RegisterFile* register_file, Memory* memory,
+                     SharedMemory* shared_memory);
+  ~PrimitiveConverter();
+
+  void Initialize();
+  void Shutdown();
+  void ClearCache();
+
+  void BeginFrame(ID3D12GraphicsCommandList* command_list);
+  void EndFrame();
+
+  // Returns the primitive type that the original type will be converted to.
+  static PrimitiveType GetReplacementPrimitiveType(PrimitiveType type);
+
+  enum class ConversionResult {
+    // Converted to a transient buffer.
+    kConverted,
+    // Conversion not required - use the index buffer in shared memory.
+    kConversionNotNeeded,
+    // No errors, but nothing to render.
+    kPrimitiveEmpty,
+    // Total failure of the draw call.
+    kFailed
+  };
+
+  // Converts an index buffer to the primitive type returned by
+  // GetReplacementPrimitiveType. If conversion has been performed, the returned
+  // buffer will be in the GENERIC_READ state (it's in an upload heap). Only
+  // writing to the outputs if returning kConverted. The restart index will be
+  // handled internally from the register values.
+  ConversionResult ConvertPrimitives(PrimitiveType source_type,
+                                     uint32_t address, uint32_t index_count,
+                                     IndexFormat index_format,
+                                     Endian index_endianness,
+                                     D3D12_GPU_VIRTUAL_ADDRESS& gpu_address_out,
+                                     uint32_t& index_count_out);
+
+  // TODO(Triang3l): A function that returns a static index buffer for
+  // non-indexed drawing of unsupported primitives
+
+ private:
+  // simd_offset is source address & 15 - if SIMD is used, the source and the
+  // target must have the same alignment within one register. 0 is optimal when
+  // not using SIMD.
+  void* AllocateIndices(IndexFormat format, uint32_t count,
+                        uint32_t simd_offset,
+                        D3D12_GPU_VIRTUAL_ADDRESS& gpu_address_out);
+
+  ui::d3d12::D3D12Context* context_;
+  RegisterFile* register_file_;
+  Memory* memory_;
+  SharedMemory* shared_memory_;
+
+  std::unique_ptr<ui::d3d12::UploadBufferPool> buffer_pool_ = nullptr;
+
+  struct ConvertedIndices {
+    D3D12_GPU_VIRTUAL_ADDRESS gpu_address;
+    PrimitiveType primitive_type;
+    uint32_t index_count;
+    IndexFormat index_format;
+    // Index pre-swapped - in guest storage endian.
+    uint32_t reset_index;
+    bool reset;
+  };
+  // Cache for a single frame.
+  std::unordered_multimap<uint32_t, ConvertedIndices> converted_indices_;
+};
+
+}  // namespace d3d12
+}  // namespace gpu
+}  // namespace xe
+
+#endif  // XENIA_GPU_D3D12_PRIMITIVE_CONVERTER_H_