Linux: Artifacts around text

[Jonta]

https://user-images.githubusercontent.com/359397/167219073-1b9ceb71-1105-4b83-9b07-d9fe91431bdc.mp4

(Video scaled down to fit into GitHub's current limit of 10MB. Video has cuts)

Ubuntu 21.10

Either running on Intel i5-4670K or NVidia GeForce GTX 770

I can investigate which of these two if there's interest/nobody else can reproduce in a timely manner

Yes: I don't know whether I'm running on integrated or dedicated, and yes, the monitor is plugged into the GPU instead of the motherboard

Just throwing this up here instead of procrastinating it for who knows how long. =)

The artifacts around text get even worse than in these short clips, the longer I play

[SebLague]

Hm, mysterious. Seems to have something to do with the gradients I'm drawing at top and bottom of screen, but I have no idea why/how to fix at the moment.