Show software rasterizer warning in title bar

[Wumpf]

It's easy to accidentally run on Linux into a situation where Rerun is rendered using the software rasterizer, quickly leading to abyssmal performance. We log a warning on commandline but it's easy to miss.

Simply style it like our "Debug Build" warning and have it link to the troubleshoot guide.

(The troubleshoot guide is not always helping out with this right now, but that's a separate issue we (and wgpu) have to work on)

[emilk]

Even better would be to show all logged warnings and errors in an easily visible way, i.e. as a "notification" bar in the top bar. We used to have an issue for this, but now I can't find it.

[Wumpf]

agreed, our log notification system needs an overhaul. But let's stick with the simple thing here :)

[Wumpf]

Separate issue for that here:

• Log notification system that makes logged errors & warnings more visible #5601

EDIT: Found the original now which was better:

• Panel with recent log/notification messages #4304