# gamescope

## Preface

I'm using endeavourOS, KDE Plasma 6.1, a RTX 3080, Wayland, and my main monitor is a Samsung Odyssey Neo G7 (3840x2160 165hz "HDR10")
  
---
  
Ideally, these are my launch options for each game:

```sh
gamemoderun gamescope -W 3840 -H 2160 -r 165 --hdr-enabled --hdr-itm-enable --hdr-itm-sdr-nits 300 -f -e --mangoapp -- %command%
```

There are some issues with it:

- Steam overlay and input won't work (`-e` flag is broken)
- `--mangoapp` won't show GPU and gamemode info
- Game might freeze randomly
- Performance is incredibly low after a while
- `-W -H -w -h -f -b` don't do anything

## and the workarounds...

### Steam overlay and input

[GitHub issue](https://github.com/ValveSoftware/gamescope/issues/835)

Creating a gamescope window on the terminal and attaching the game to it will work.

First I run this on a terminal:

```sh
gamescope -W 3840 -H 2160 -r 165 --hdr-enabled --hdr-itm-enable --hdr-itm-sdr-nits 300 -f --mangoapp
```

Then set the game's launch options:

```sh
DISPLAY=:x gamemoderun %command%
```

Where `x` is the display number, shown on the gamescope terminal output, example:
  
`wlserver: [xwayland/server.c:107] Starting Xwayland on :2`
  
In this case, the launch option would be `DISPLAY=:2`
  
The game might take a while to open up and also to completely exit, but it works just fine.

### mangohud and --mangoapp

Running it as `mangohud` before `%command%` will show GPU info but not gamemode, and apparently there are issues running it this way.

I have to investigate if I have these supposed issues, and if they are related to any config about vsync and/or framerate locks on mangohud.

### Game freezing

Possibly due to HDR flags but I'm not certain. Needs a reboot for the game to open again.

I haven't had this issue in a while, might've been fixed in an update, might've been something I did.

### Performance

Have to set the niceness of gamescope. Run:

```sh
sudo setcap 'CAP_SYS_NICE=eip' $(which gamescope)`
```
  
It seems that after a while it loses its niceness, so I made a systemd service that runs on login
  
checking if the niceness is set, and setting it if it's not. Check the [gamescope-niceness.service](gamescope-niceness.service) gist

### Placebo flags

`-W -H -w -h -f -b` don't have any effect. I can freely change my resolution and fullscreen settings ingame and it'll work just fine.

Reading gamescope's readme, it mentions:

> You can spoof a virtual screen with a desired resolution and refresh rate as the only thing the game sees, and control/resize the output as needed.
>
> This can be useful in exotic display configurations like ultrawide or multi-monitor setups that involve rotation.

Probably I can run the game on a lower resolution without impacting my desktop's resolution and use the FSR flags to upscale it. Maybe I can even downscale the game?

`-r` seems funky though. Sometimes not setting it will lock the game to 60FPS, sometimes it has no effect at all.

There's also a flag to limit the max FPS but it doesn't do anything, or a setting on mangohud might be conflicting with both flags.