Which environments support multiplayer control?

[jkterry1]

In the multiplayer documentation (https://retro.readthedocs.io/en/latest/python.html#multiplayer-environments), you say that multiplayer is supported "in a small number of environments." Other than pong, which environments are those? Most games that support multiplayer environments don't have support in ALE.

[christopherhesse]

It looks like only "Pong-Atari2600" and "FishingDerby-Atari2600" have 2player states defined.

There are other games, for instance I believe "Sonic The Hedgehog" has a 2 player mode, but for those games you'll have to define the 2 player start state, as well as update the various json files for the game to enable that mode. See the Pong data files for a reference of what that should look like.

If you end up adding any of those, please link to your changes from this issue so people can find them.

[djsu-andy]

"FishingDerby-Atari2600

@christopherhesse , so does it mean that it doesn't support Boxing-atari2600 for two players?

[jkterry1]

So there's a PR adding proper multiplayer game support to the ALE:

Farama-Foundation/Arcade-Learning-Environment#350

It also has a gym-styled wrapper in Python https://www.pettingzoo.ml/atari

[christopher-hesse]

@andysu2008 without modification, yes that looks to be the case.