VideoBackends / VideoCommon: add support for specifying include files in shader code

Source/Core/VideoCommon/ShaderCompileUtils.cpp

@@ -0,0 +1,93 @@
+// Copyright 2025 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "VideoCommon/ShaderCompileUtils.h"
+
+#include <fstream>
+#include <ranges>
+
+#include "Common/FileUtil.h"
+#include "Common/StringUtil.h"
+
+namespace VideoCommon
+{
+ShaderIncluder::ShaderIncluder(const std::string& user_path, const std::string& system_path)
+    : m_root_user_path(user_path), m_root_system_path(system_path)
+{
+}
+
+std::vector<std::string> ShaderIncluder::GetIncludes() const
+{
+  const auto keys = std::views::keys(m_include_results);
+  return {keys.begin(), keys.end()};
+}
+
+ShaderIncluder::IncludeResult*
+ShaderIncluder::includeLocal(const char* header_name, const char* includer_name, std::size_t depth)
+{
+  return ProcessInclude(m_root_user_path, header_name, includer_name, depth);
+}
+
+ShaderIncluder::IncludeResult*
+ShaderIncluder::includeSystem(const char* header_name, const char* includer_name, std::size_t depth)
+{
+  return ProcessInclude(m_root_system_path, header_name, includer_name, depth);
+}
+
+void ShaderIncluder::releaseInclude(IncludeResult* result)
+{
+  m_include_results.erase(result->headerName);
+}
+
+ShaderIncluder::IncludeResult* ShaderIncluder::ProcessInclude(const std::string& root,
+                                                              const char* header_name,
+                                                              const char* includer_name,
+                                                              std::size_t depth)
+{
+  m_dirs.resize(depth);
+  if (depth == 1)
+  {
+    const auto includer_dir = GetDirectory(includer_name);
+    if (includer_dir == ".")
+    {
+      m_dirs.push_back(root);
+    }
+    else
+    {
+      m_dirs.push_back(std::string{includer_dir});
+    }
+  }
+
+  // Search through directories back to front
+  for (auto iter = m_dirs.rbegin(); iter != m_dirs.rend(); iter++)
+  {
+    const std::string full_path = WithUnifiedPathSeparators(*iter + '/' + header_name);
+
+    std::string file_data;
+    if (File::ReadFileToString(full_path, file_data))
+    {
+      m_dirs.push_back(std::string{GetDirectory(full_path)});
+
+      const char* file_bytes = file_data.data();
+      const std::size_t file_size = file_data.size();
+      IncludeResultData result_data{
+          .result = std::make_unique<IncludeResult>(full_path, file_bytes, file_size, nullptr),
+          .file_data = std::move(file_data)};
+
+      auto ptr = result_data.result.get();
+      m_include_results[full_path] = std::move(result_data);
+      return ptr;
+    }
+  }
+  return nullptr;
+}
+
+std::string_view ShaderIncluder::GetDirectory(std::string_view path) const
+{
+  const auto last_pos = path.find_last_of('/');
+  if (last_pos == std::string_view::npos)
+    return ".";
+
+  return path.substr(0, last_pos);
+}
+}  // namespace VideoCommon