Unreal Engine 5.2 on Wayland

TheSunCat · 2023-09-13 22:13:25

I've been using Unreal Engine 5.1 for a while as required by a university course, and it ran with many bugs in Xwayland. When started with SDL_VIDEODRIVER=wayland, the mouse would not work (keyboard input still allowed opening projects fine). I read that 5.2 fixes the issue, so I upgraded today using the unreal-engine-bin AUR package.
However, it seems UE5.2 was not built with Wayland support, as this user points out: https://forums.unrealengine.com/t/ue-5- … rt/1208088
I tried using SDL_DYNAMIC_API=/usr/lib/libSDL2.so to force it to use a Wayland-enabled SDL2 version, but shortly after opening the dashboard it crashes with the following backtrace:

[2023.09.13-21.42.06:895][  1]LogTurnkeySupport: Turnkey Device: Linux@apg: (Name=apg, Type=Computer, Status=Valid, , Flags="Device_InstallSoftwareValid")
[2023.09.13-21.42.07:062][  2]LogCore: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to read memory at address 0x00000000000000d8

[2023.09.13-21.42.07:062][  2]LogCore: Fatal error!

0x00007f4cf420085e libSDL2.so!UnknownFunction(0x12085e)
0x00007f4cf41b722f libSDL2.so!UnknownFunction(0xd722e)
0x00007f4cf41ba26a libSDL2.so!UnknownFunction(0xda269)
0x00007f4d6ab08e01 libUnrealEditor-ApplicationCore.so!FLinuxWindow::Initialize(FLinuxApplication*, TSharedRef<FGenericWindowDefinition, (ESPMode)1> const&, TSharedPtr<FLinuxWindow, (ESPMode)1> const&, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/ApplicationCore/Private/Linux/LinuxWindow.cpp:238]
0x00007f4d6ab085ad libUnrealEditor-ApplicationCore.so!FLinuxApplication::InitializeWindow(TSharedRef<FGenericWindow, (ESPMode)1> const&, TSharedRef<FGenericWindowDefinition, (ESPMode)1> const&, TSharedPtr<FGenericWindow, (ESPMode)1> const&, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/ApplicationCore/Private/Linux/LinuxApplication.cpp:150]
0x00007f4d6a47d08e libUnrealEditor-Slate.so!FSlateApplication::MakeWindow(TSharedRef<SWindow, (ESPMode)1>, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateApplication.cpp:1880]
0x00007f4d6a47c990 libUnrealEditor-Slate.so!FSlateApplication::AddWindow(TSharedRef<SWindow, (ESPMode)1>, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateApplication.cpp:1796]
0x00007f4d6a4ea930 libUnrealEditor-Slate.so!FSlateUser::GetOrCreateTooltipWindow() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateUser.cpp:998]
0x00007f4d6a4ea242 libUnrealEditor-Slate.so!FSlateUser::ShowTooltip(TSharedRef<IToolTip, (ESPMode)1> const&, UE::Slate::FDeprecateVector2DParameter const&) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateUser.cpp:541]
0x00007f4d6a4f1af1 libUnrealEditor-Slate.so!FSlateUser::UpdateTooltip(FMenuStack const&, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateUser.cpp:1375]
0x00007f4d6a47ae81 libUnrealEditor-Slate.so!FSlateApplication::TickPlatform(float) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateApplication.cpp:1565]
0x00007f4d6a479f91 libUnrealEditor-Slate.so!FSlateApplication::Tick(ESlateTickType) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Slate/Private/Framework/Application/SlateApplication.cpp:1503]
0x000000000023dda4 UnrealEditor!FEngineLoop::Tick() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Launch/Private/LaunchEngineLoop.cpp:5867]
0x000000000024a20a UnrealEditor!GuardedMain(char16_t const*) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Launch/Private/Launch.cpp:190]
0x00007f4d727eb9ba libUnrealEditor-UnixCommonStartup.so!CommonUnixMain(int, char**, int (*)(char16_t const*), void (*)()) [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Unix/UnixCommonStartup/Private/UnixCommonStartup.cpp:269]
0x00007f4d66627cd0 libc.so.6!UnknownFunction(0x27ccf)
0x00007f4d66627d8a libc.so.6!__libc_start_main(+0x89)
0x0000000000236749 UnrealEditor!_start()

[2023.09.13-21.42.07:072][  2]LogExit: Executing StaticShutdownAfterError

This looks like a null pointer dereference somewhere in SDL2. What am I doing wrong? I'd like to re-enable the Wayland backend as for the brief time it is open before crashing, the mouse input seems to actually work.

Lone_Wolf · 2023-09-14 09:22:22

Last Updated: 	2023-09-14 04:30 (UTC)

Aur unreal-engine-bin was updated to UE 5.3 a few hours ago, have you tried with that ?

TheSunCat · 2023-09-14 09:31:02

Hmm no, I did see it was flagged out of date yesterday but I don't think it was available. I could try it, but unfortunately my course requires 5.2.1 specifically (teachers cannot open project files made in newer versions, so they want all students on the same version).

Lone_Wolf · 2023-09-14 09:53:53

You can try the aur unreal-engine that builds from source as it appears to use system librairies instead of bundled ones and may not have the issue.

https://aur.archlinux.org/cgit/aur.git/ … a4da25abb3 has the files for the final UE 5.2.1 version of that package

You can retrieve those exact files like this :

$ git clone https://aur.archlinux.org/unreal-engine.git
$ cd unreal-engine
$ git reset --hard e77e955e2d8b7e76031689676f5ce7a4da25abb3

TheSunCat · 2023-09-14 09:57:56

Oh, that's a good idea! I will try this (Unreal is famous for taking a while to build, but I hope it will be worth it!). I copied the commands to get that version and am now running makepkg. ?

TheSunCat · 2023-09-16 08:54:18

It seems that the built version still lacks Wayland compatibility... If I run it with SDL_VIDEODRIVER=wayland, it says that Wayland is not available.

Lone_Wolf · 2023-09-16 09:53:32

Does it run better on xwayland then unreal-engine-bin ?
If not, you'll have to setup an X environment for your course.

Arch Linux

#1 2023-09-13 22:13:25

Unreal Engine 5.2 on Wayland

#2 2023-09-14 09:22:22

Re: Unreal Engine 5.2 on Wayland

#3 2023-09-14 09:31:02

Re: Unreal Engine 5.2 on Wayland

#4 2023-09-14 09:53:53

Re: Unreal Engine 5.2 on Wayland

#5 2023-09-14 09:57:56

Re: Unreal Engine 5.2 on Wayland

#6 2023-09-16 08:54:18

Re: Unreal Engine 5.2 on Wayland

#7 2023-09-16 09:53:32

Re: Unreal Engine 5.2 on Wayland

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