ModNet

Lets mods send messages to the other modded players in a multiplayer game, through the game's own network. Other mods use it to share what only they know about, such as a player's emote or custom model, and to check that everyone has the same mod version.

ModNet is a library. On its own it does nothing you can see in play. Every player who wants a mod's shared features needs ModNet and that mod.

• Hello handshake. Each modded player announces their installed mods and versions when they join.
• Players card. With Mods Menu installed, Options → Mods has a ModNet card listing who runs which mods, with version differences highlighted.

A game where some players don't have ModNet hasn't been tested yet.

Settings

The file is BepInEx\config\com.helvetica.modnet.cfg.

How it works

Each message is a string passed to the game's replicated Root.SetAnimationTrigger(Character, string). The host relays it to every client. On a modded player, a Harmony prefix catches the string before it reaches the Animator.

For mod developers

1. Add a soft dependency, so your mod still loads without ModNet:

   [BepInDependency("com.helvetica.modnet", BepInDependency.DependencyFlags.SoftDependency)]
   

2. Reference ModNet.dll with Private="false", so it isn't copied next to your mod.
3. Put every ModNet call in one nested class, and only call into it after checking that ModNet is installed: the runtime loads ModNet's types only when that class's code runs.

   internal static class MySync
   {
       static bool _available;
       internal static void Init() { _available = true; Bridge.Hook(); }        // from OnModLoaded, if installed
       internal static void Tell(Character c, string what) { if (_available) Bridge.Send(c, what); }
   
       static class Bridge
       {
           internal static void Send(Character c, string p) => ModNetApi.Send("mymod", p, c);
           internal static void Hook()
           {
               ModNetApi.Register("mymod", m => Handle(m.Character, m.Payload));
               ModNetApi.PlayerHello += _ => ResendState();                      // late joiners
           }
       }
   }
   // OnModLoaded: if (Chainloader.PluginInfos.ContainsKey("com.helvetica.modnet")) MySync.Init();
   

API (ModNetApi)

Rules

• Events only. Send events, never per-frame data.
• Size and rate. Payloads up to 1000 characters. Sending is throttled to 10 per second, with bursts of 20.
• Sending from a handler is fine. A message sent while another one is being received (from a handler, or from PlayerHello) is queued and goes out on the next frame.
• Separator. Use | inside payloads. Channel names can't contain it.
• Don't trust the sender. A message's Character is the sender's own character. Ignore messages that would change your own characters.
• Protocol version. ModNetApi.Protocol is part of the wire marker. Players on another protocol version ignore each other.