VideoCommon: add gpu skinning logic to dump the data required to rebuild skinning

Source/Core/VideoCommon/GraphicsModEditor/GpuSkinningDataDumper.cpp

@@ -0,0 +1,86 @@
+// Copyright 2025 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "VideoCommon/GraphicsModEditor/GpuSkinningDataDumper.h"
+
+#include "Common/JsonUtil.h"
+
+namespace GraphicsModEditor
+{
+void GpuSkinningDataDumper::SetOutputPath(std::string path)
+{
+  m_path = std::move(path);
+}
+
+void GpuSkinningDataDumper::WriteToFile()
+{
+  if (m_gpu_skinning_data.m_draw_call_to_gpu_skinning.empty())
+    return;
+
+  JsonToFile(m_path, picojson::value{ToJsonObject(m_gpu_skinning_data)}, true);
+}
+
+void GpuSkinningDataDumper::AddData(GraphicsModSystem::DrawCallID draw_call_id,
+                                    const GraphicsModSystem::DrawDataView& draw_data,
+                                    bool apply_gpu_skinning, std::span<const u16> index_data)
+{
+  const auto& declaration = draw_data.vertex_format->GetVertexDeclaration();
+  if (!declaration.position.enable || !declaration.posmtx.enable)
+  {
+    return;
+  }
+
+  auto& gpu_skinning_data = m_gpu_skinning_data.m_draw_call_to_gpu_skinning[draw_call_id];
+  gpu_skinning_data.positions.clear();
+  gpu_skinning_data.view_to_object_transforms.clear();
+
+  // TODO: remove, this is debugging
+  gpu_skinning_data.indices.clear();
+  gpu_skinning_data.indices.reserve(index_data.size());
+  gpu_skinning_data.indices.assign(index_data.begin(), index_data.end());
+
+  const auto byte_offset = declaration.position.offset;
+  auto vert_ptr = reinterpret_cast<const u8*>(draw_data.vertex_data.data());
+  for (std::size_t vert_index = 0; vert_index < draw_data.vertex_data.size(); vert_index++)
+  {
+    u32 gpu_skin_index;
+    std::memcpy(&gpu_skin_index, vert_ptr + declaration.posmtx.offset, sizeof(u32));
+
+    Common::Matrix44 position_transform = Common::Matrix44::Identity();
+    if (apply_gpu_skinning)
+    {
+      for (std::size_t i = 0; i < 3; i++)
+      {
+        position_transform.data[i * 4 + 0] =
+            draw_data.gpu_skinning_position_transform[gpu_skin_index + i][0];
+        position_transform.data[i * 4 + 1] =
+            draw_data.gpu_skinning_position_transform[gpu_skin_index + i][1];
+        position_transform.data[i * 4 + 2] =
+            draw_data.gpu_skinning_position_transform[gpu_skin_index + i][2];
+        position_transform.data[i * 4 + 3] =
+            draw_data.gpu_skinning_position_transform[gpu_skin_index + i][3];
+      }
+      position_transform.data[12] = 0;
+      position_transform.data[13] = 0;
+      position_transform.data[14] = 0;
+      position_transform.data[15] = 1;
+    }
+
+    Common::Vec3 vertex_position;
+    std::memcpy(&vertex_position.x, vert_ptr + byte_offset, sizeof(float));
+    std::memcpy(&vertex_position.y, vert_ptr + sizeof(float) + byte_offset, sizeof(float));
+    std::memcpy(&vertex_position.z, vert_ptr + sizeof(float) * 2 + byte_offset, sizeof(float));
+    gpu_skinning_data.positions.push_back(position_transform.Transform(vertex_position, 1));
+
+    if (apply_gpu_skinning)
+    {
+      position_transform = position_transform.Inverted();
+    }
+
+    gpu_skinning_data.view_to_object_transforms.push_back(std::move(position_transform));
+    gpu_skinning_data.skinning_index_per_vertex.push_back(gpu_skin_index);
+
+    vert_ptr += draw_data.vertex_format->GetVertexStride();
+  }
+}
+}  // namespace GraphicsModEditor

Source/Core/VideoCommon/GraphicsModEditor/GpuSkinningDataDumper.h

@@ -0,0 +1,27 @@
+// Copyright 2025 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <span>
+#include <string>
+
+#include "VideoCommon/GraphicsModEditor/GpuSkinningDataUtils.h"
+#include "VideoCommon/GraphicsModSystem/Types.h"
+
+namespace GraphicsModEditor
+{
+class GpuSkinningDataDumper
+{
+public:
+  void SetOutputPath(std::string path);
+  void WriteToFile();
+  void AddData(GraphicsModSystem::DrawCallID draw_call_id,
+               const GraphicsModSystem::DrawDataView& draw_data, bool apply_gpu_skinning,
+               std::span<const u16> index_data);
+
+private:
+  std::string m_path;
+  GpuSkinningData m_gpu_skinning_data;
+};
+}  // namespace GraphicsModEditor