EngineBug4.25
lipengzha
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UE4.25 Mac 字符转换 bug

在 4.26+ 中已修复。

Mac 用的是 2 字节的宽字符，但却按 4 字节的去转，当材质里参数有中文时，就会出现不一致的 bug：

Runtime/Core/Private/Serialization/MemoryImage.cpp
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FHashedName::FHashedName(const FName& InName)
{
  if (!InName.IsNone())
  {
    const FNameEntry* Entry = InName.GetComparisonNameEntry();
    const int32 InternalNumber = InName.GetNumber();
    if (Entry->IsWide())
    {
      WIDECHAR WideNameBuffer[NAME_SIZE];
      Entry->GetWideName(WideNameBuffer);
      for (int32 i = 0; i < Entry->GetNameLength(); ++i)
      {
        WideNameBuffer[i] = FCharWide::ToUpper(WideNameBuffer[i]);
      }
      // Bug
      // const FTCHARToUTF8 NameUTF8(WCHAR_TO_TCHAR(WideNameBuffer));
      // Hash = CityHash64WithSeed(NameUTF8.Get(), NameUTF8.Length(), InternalNumber);
          
      // WChar conversion bug in Mac
      if (sizeof(WIDECHAR) != sizeof(TCHAR))
      {
        const FTCHARToUTF8 NameUTF8(WCHAR_TO_TCHAR(WideNameBuffer));
        Hash = CityHash64WithSeed(NameUTF8.Get(), NameUTF8.Length(), InternalNumber);
      }
      else
      {
        const FTCHARToUTF8 NameUTF8((TCHAR*)WideNameBuffer);
        Hash = CityHash64WithSeed(NameUTF8.Get(), NameUTF8.Length(), InternalNumber);
      }
      //
    }
    else
    {
      ANSICHAR AnsiNameBuffer[NAME_SIZE];
      Entry->GetAnsiName(AnsiNameBuffer);
      for (int32 i = 0; i < Entry->GetNameLength(); ++i)
      {
        AnsiNameBuffer[i] = FCharAnsi::ToUpper(AnsiNameBuffer[i]);
      }
      Hash = CityHash64WithSeed(AnsiNameBuffer, Entry->GetNameLength(), InternalNumber);
    }
  }
  else
  {
    Hash = 0u;
  }
}