How to mount a pak file at Game Content Directory?

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1

For now, I can mount a pak file at Engine Content Directory and then load asset from it. (path is “/Engine/AssetName.AssetName”)

When I change the mount point to Game Content Directory (FPaths::GameContentDir()), the mount method return success, but I just can not load asset.

The Error logs are something like:

LogLinker:Warning: Can't find file '/Game/AssetName'
LogLinker:Warning: Can't find file '/Game/AssetName'
LogUObjectGlobals:Warning: Failed to find object 'Object /Game/AssetName.AssetName'

Can anybody tell me how to mount a pak file at Game Content Directory?
Or is there a way to let the engine auto load and mount my pak file at start ? (I use UnrealPak.exe to generate pak file)

Any help will be appreciate!

2

This is the code I’m using. Please note since 4.15 I’m having a crash on Un mount, but the mount is working still.

bool DLCDownloadManager::MountPak(const FString &rPakFileName, DLCMountPointInfo &rMPI)
{
 	//Load and mount pak file
	if (mp_DLCPakFiles == nullptr)
	{
		mp_DLCPakFiles = new FPakPlatformFile;
		if (!mp_DLCPakFiles->Initialize(&FPlatformFileManager::Get().GetPlatformFile(), TEXT("")))
		{
  			return false;
		}

		FPlatformFileManager::Get().SetPlatformFile(*mp_DLCPakFiles);
	}

	FString StandardFilename(rPakFileName);
	FPaths::MakeStandardFilename(StandardFilename);
	StandardFilename = FPaths::GetPath(StandardFilename);
	
	if (!mp_DLCPakFiles->Mount(*rPakFileName, 0, *StandardFilename))
	{
 		return false;
	}

	static int siMountIndex = 0;
	rMPI.m_Directory = StandardFilename;
	rMPI.m_MountPoint = FString::Printf(_T("/DLC%d/"), siMountIndex++);
	FPackageName::RegisterMountPoint(rMPI.m_MountPoint, StandardFilename);

#if 0 //Enable to dump files and directories while debugging
	struct Dump : public IPlatformFile::FDirectoryVisitor
	{
		virtual bool Visit(const TCHAR* FilenameOrDirectory, bool bIsDirectory)
		{
		        SysOutputf(DownloadManager, bIsDirectory ? _T("Directory: %s") : _T("File: %s"), FilenameOrDirectory);
			return true;
		}
	};
	Dump visitor;
    mp_DLCPakFiles->IterateDirectoryRecursively(*StandardFilename, visitor);
#endif

	return true;
}

The important bit for you is probably here:

rMPI.m_MountPoint = FString::Printf(_T("/DLC%d/"), siMountIndex++);
FPackageName::RegisterMountPoint(rMPI.m_MountPoint, StandardFilename);
3

The unmount crash was fixed by calling:

mp_DLCPakFiles->InitializeNewAsyncIO();

Prior to:

FPlatformFileManager::Get().SetPlatformFile(*mp_DLCPakFiles);
4

Can ths be made as a C++ class for blueprnt users? Been lookng for a mountng system but cant fnd one.