For the last year I've been playing lots of classic DOOM. DOOM has one feature that I started to appreciate ever since I learned about it, which is the ability to roll up brightness very high. This is what doom looks like when I play it:
I miss this thing in lots of other games. Recently I've been trying to get into Deus Ex (2000) via wine but it was so dark I couldn't see shit. Maybe it's my monitor that's not very powerful or my environment that's pretty bright by itself, but I feel just the simple ability to gamma correct any game or the whole desktop would solve this problem for me.
Do you know any such util that works on wayland?
Ah. Guess the steam deck must still run X11? That's currently my primary computer, so I haven't had to learn about/deal with X11 vs Wayland quite just yet.
Yes, the desktop mode uses Plasma on X11 by default. It can be changed, but X11 is still perfectly functional and Wayland doesn't have a lot of advantages in that particular use case.
Big Picture (and the games launched from it) uses an entirely different compositor called GameScope, which is developed by Valve and is meant specifically for games or other single-window applications. It can also be used in a nested setup inside another compositor.