Bug 463841 - Mouse pointer offset in Unreal Engine
Summary: Mouse pointer offset in Unreal Engine
Status: CLOSED NOT A BUG
Alias: None
Product: kwin
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 5.26.4
Platform: Fedora RPMs Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-01-04 16:29 UTC by Andrea
Modified: 2023-01-12 08:32 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Image showing the gap between the cursor texture and the highlight button (11.93 KB, image/webp)
2023-01-04 16:29 UTC, Andrea
Details

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Description Andrea 2023-01-04 16:29:19 UTC
Created attachment 155026 [details]
Image showing the gap between the cursor texture and the highlight button

SUMMARY
I'm on KDE 5.26.4 [Fedora], and I've a weird issue with Unreal Engine. The mouse pointer has an offset between the mouse texture and the actual mouse hover/click point.

This bug only show in Unreal Engine Editor, and does occurs with both Wayland and X11. I've a 4k display, and I tried already to change the scaling back to 100%, but this doesn't solve the issue.

Beware that this is a fresh KDE installation, no exotic widgets installed that can mess the mouse pointer.

Notice that the Unreal Engine Editor works perfectly on the exact same Machine/OS using Gnome.

STEPS TO REPRODUCE
1. Compile unreal engine
2. Open unreal engine editor
3. Open an asset in a new window
4. Try to hove something

OBSERVED RESULT
You will notice that you need to offset your cursor to properly hover that menu.

EXPECTED RESULT
The button should highlight when the cursor texture is visually hover the button.

SOFTWARE/OS VERSIONS
OS: Fedora: 37
Kernel Version: 6.0.15-300.fc37.x86_64
KDE Plasma Version: 5.26.4
KDE Frameworks Version: 5.101.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
GPU: AMD 6800M
CPU: 6900HX
RAM: 64GB
Comment 1 David Edmundson 2023-01-11 13:11:13 UTC
Given this only affects one client, this doesn't seem to be an issue our side.
It might work on gnome but maybe unreal engine explicitly tests for that - or runs with CSDs and forgets the offset.

A good test would be in the X11 session run "openbox --replace" and confirm the issue persists. I strongly suspect it will.
Comment 2 Andrea 2023-01-11 15:12:36 UTC
(In reply to David Edmundson from comment #1)
> Given this only affects one client, this doesn't seem to be an issue our
> side.
> It might work on gnome but maybe unreal engine explicitly tests for that -
> or runs with CSDs and forgets the offset.
> 
> A good test would be in the X11 session run "openbox --replace" and confirm
> the issue persists. I strongly suspect it will.

I'm not the only having this issue, see another person reporting the same under my post on reddit: https://www.reddit.com/r/kde/comments/1037hwu/comment/j3vahpu/?context=3

As mention on the issue report, I've already tried with X11 and the issue persist. However, pretend this is not an issue just because it's just me reporting it, it's not great. Still it's fine if no one fix it immediately, but at least don't close this issue or pretend it doesn't exist.
Comment 3 David Edmundson 2023-01-11 15:42:04 UTC
Please take this to Unreal Engine Editor developers.
Comment 4 Andrea 2023-01-12 08:32:43 UTC
According to a message on reddit, the issue seems caused by the AMD gpu. It doesn't occur with KDE + Fedora + NVidia gpu.