Multiplayer

Status: experimental.

What it is

This API lets your mod build online features on top of Steam. It has five parts. Steam tells you who the local player is on Steam and who their friends are. Lobby hosts or joins a lobby, a group of players who are connected to each other. Net sends short text messages between the players in a lobby, on a channel (a name) that you choose. Presence shares where each player is and which area they are in. NetBlob sends larger data to one player. Nothing runs until a mod uses it. Every player in a lobby needs Steam and the same mods.

When to use it

  • Host a lobby for friends, or join one when the player accepts a Steam invite.
  • Send small messages between players, such as chat lines or game events.
  • Show other players’ positions in your own world.
  • Send a file or a save-sized piece of data from one player to another.

Quick example

This mod hosts a lobby for up to four players once a save is loaded, joins a lobby when the player accepts an invite, and sends a hello to each player who joins. Messages that arrive on the ping channel are written to the log.

using ObenseuerCore;

[ModInfo("example.pingpong", "Ping Pong", "0.1.0")]
[ModDependency("obenseuer.moddingframework", "0.11.0")]
public sealed class PingPong : FrameworkMod
{
    protected override void OnLoad()
    {
        Net.Register(Mod.Id, "ping", (peer, text) => Log.Info(Lobby.MemberName(peer) + " says: " + text));
        Lobby.JoinRequested += lobby => Lobby.Join(lobby, "pingpong", "0.1.0");
        Lobby.MemberJoined += peer => Net.Send(peer, "ping", "Hello from " + Steam.Name(Net.Me), true);

        Events.WhenReady(() =>
        {
            if (Steam.IsReady && Lobby.Status == LobbyStatus.Offline)
                Lobby.Host("pingpong", "0.1.0", 4, true);
        });
    }
}

Register gives the framework a piece of your code to run each time a message arrives on a channel. JoinRequested and MemberJoined are events: the framework calls your code each time they happen. WhenReady waits until a save is loaded before it runs your code. See Using events for more on events and WhenReady.

Table of contents