Adding Proton, GE and Steam Linux runtime as engines

[Jpxe]

It would be nice to have the option to set Luxtorpeda as the default Steam Play option for all games. That way you could use if for all the supported games without having to set it up manually for each of them. However this would require adding Proton, GE and the Linux runtime as Default engines so you can also use it for unsupported games.

It would also be possible to expand this feature further down the line with things like: automatic selection of default engines, ie DOSBox for DOS games, ScummVM, and maybe even Proton GE.

[d10sfan]

The way luxtorpeda currently works is that one the client is launched, it is already running under the sniper runtime. That could be changed so that the client (the UI part mainly) is running under the system's libraries, to allow for different runtimes to be run, but that could cause some support problems.

For most games, it seems like proton launching could be done with mimicking the same thing that steam does to launch games, as you can see in the script launches if you look at steam when it's running. I'm not sure if that would work for some of the special cases, like games that use eac, or games that have third party launchers, so not sure if you'd get 100% compatibility.

I'm not sure how it could work for various custom versions like ge, that'd require looking through the different compatibility tool areas to see what would be available.

What would be the useful use case of this compared to using the features inside steam for this? Steam normally handles saving what compat tool is in use, although that does not seem to be synced, so if we figured out a cloud sync thing, that could be one useful thing. It's also difficult to tell as a whole what games are using what compat tool, and lux could provide an interface for that (although protonup already has some of those features).

[Jpxe]

So the usecase, as I imagine it, is to set Luxturpeda as default and then never having to make custom settings for a game. It picks the best engine, compatibility layer and patches for each game automatically. This saves the user time and research.

I imagine it working like this:

1. Looking up the game in a database. A database containing the best engine/compat layer/patches for each game
2. Applying the best option. Ie Dosbox for DOS games, ScummVM for supported games, custom engines, Protom GE for games that work better with it, etc
3. Loading game with the default option (best option for most use cases) in five seconds unless the users press a button, in that case they can select another option