Tabet movement inputs are completely dropped if built-in tablet support is disabled under Linux/Wayland.

[timschumi]

Type

Game behaviour

Bug description

When disabling built-in tablet support (the intention being that I want to use the input events provided by my external instance of OpenTabletDriver), the game apparently stops processing movement events that are received from the tablet.

Button/Touch inputs continue to be processed, which are visible in the video through a jumping cursor, as the pen moved between me disabling tablet support and re-enabling it.

The issue can be mitigated temporarily by moving the cursor outside the window once, after which the game starts handling tablet movement inputs even with tablet support disabled. However, it breaks again once actual gameplay starts (as visible in the video, where the cursor suddenly stops shortly before the first hit objects show up). I haven't been able to confirm whether this also works on fullscreen mode, as the cursor isn't movable outside the window there. Simply tabbing out and tabbing back in doesn't appear to have the same effect, the cursor will stay frozen.

Note that this doesn't appear to affect setups that use X11, only Wayland.

The recorded video shows my OSes cursor above the in-game cursor. Note that this is not how it actually shows on screen, it's just how my OBS was configured and I figured it might be useful to see.

Screenshots or videos

osu-notablet.mp4

Version

2022.1228.0

Logs

input.log
network.log
performance.log
runtime.log

[SupDos]

This is a known issue on Wayland with lazer, and it's listed on the OpenTabletDriver Linux FAQ page: https://opentabletdriver.net/Wiki/FAQ/Linux#osu-lazer-broken-input-wayland

To fix it, you need to set the enviroment variable SDL_VIDEODRIVER=wayland

[timschumi]

Whoops, that's on me then. I believed that SDL switched their default from X11 to Wayland some time ago, but apparently they reverted that change shortly after.

If I'm following the discussion in libsdl-org/SDL#5527 correctly, most of the issues surrounding the Wayland videodriver appear to have been fixed, but the defaults change will not roll out until SDL 3.0.

Is there a possibility that we can just hint SDL to use Wayland over X11 (via SDL_SetHint(SDL_HINT_VIDEODRIVER, ...)) ourselves instead of relying on whatever default is hardcoded into SDL? Maybe I'll look into creating a PR for that to have it available for discussion/testing.

[fxzzi]

im having something similar but not quite, which happens even when im using sdl wayland backend.

otd set up and working perfectly

in game, cursor is stuck in the middle of the screen.

I have confirmed that osu!lazer is running in wayland native.

[44Neki]

This happens to me too

[LucasGGamerM]

Tablet input for me only works properly if I have the OpenTabletDriver installed, wacom kernel module disabled (so that the kde settings are disabled), and the OpenTabletDriver daemon also disabled. Somehow that allows for osu to work properly without either not seeing the tablet at all (that happens when using the stock kde (6.3.3) tablet settings), or having the on screen keyboard pop up all the time (that happens either with using OpenTabletDriver for tablet settings or the kde tablet settings). It's really weird

[LucasGGamerM]

And I can confirm that using the x11 through XWayland (instead of native wayland) fixes the issues I was having. I am happy to provide more testing data if there is anything I missed or that I might need to clarify

[taep96]

Running on GNOME Wayland with SDL_VIDEODRIVER=wayland,x11. As long as I don't change the fullscreen setting (f11) it works perfectly. Otherwise I have to set it back to fullscreen and restart which is a little annoying because sometimes osu starts in windowed mode all by itself, or without a window at all. I think this worked with SDL3 before it got reverted.

[umuod]

As long as I don't change the fullscreen setting (f11) it works perfectly. Otherwise I have to set it back to fullscreen and restart

I have this on SDL2 too, you can add OSU_SDL3=1 to your launch env var to launch lazer with SDL3, that fixed it for me

[LucasGGamerM]

Turns out using OSU_SDL3=1 fixed some of my issues (except the tablet not showing up, but maybe that's a different issue?)

[umuod]

Besides switching between SDL versions and screen modes, I can only suggest messing around with 'high precision mouse' and 'confine mouse cursor to window' in the in-game settings. My external tablet driver issues were caused by those. If that falls too consider using the built-in tablet driver.

[LucasGGamerM]

My main issue is that the built in tablet driver straight up does not work if I don't disable the wacom kernel driver, which is weird