SplituxFacepunch

BepInEx plugin for splitux that enables local split-screen multiplayer in games using Facepunch.Steamworks.

Features

• Identity Spoofing: Each instance gets a unique Steam ID and display name
• Facepunch Library Patches: Patches SteamClient.SteamId, SteamClient.Name, IsValid, IsLoggedOn
• Photon Auth Bypass: Sets AuthType=255 (None) for games using Photon networking
• Runtime Patches: Apply game-specific patches via config (no recompilation needed)

How It Works

Splitux generates a BepInEx/config/splitux.cfg for each game instance. The plugin reads this config and applies:

1. Facepunch Settings - Toggle switches for known library patches
2. Runtime Patches - Game-specific class/method patches using Harmony

Configuration Format

[Identity]
player_index=0
account_name=Player 1
steam_id=76561198000000001

[Facepunch]
spoof_identity=true
force_valid=true
photon_bypass=true

[RuntimePatches]
patch.0.class=SteamManager
patch.0.method=DoSteam
patch.0.action=force_steam_loaded

patch.1.class=GameManager
patch.1.property=DisableSteamAuthorizationForPhoton
patch.1.action=force_true

Available Actions

Action	Description
force_true	Force bool return to true
force_false	Force bool return to false
skip	Skip original method entirely
force_steam_loaded	Set steamLoaded=true, steamId/steamName to spoofed values
fake_auth_ticket	Return fake Steam auth ticket string
photon_auth_none	Set Photon AuthType=255, random UserId
log_call	Log method calls (debug)

Splitux Handler Example

name: "Across The Obelisk"
steam_appid: 1385380
exec: "AcrossTheObelisk.exe"

facepunch_settings:
  spoof_identity: true
  force_valid: true
  photon_bypass: true

runtime_patches:
  - class: "SteamManager"
    method: "DoSteam"
    action: "force_steam_loaded"
  - class: "GameManager"
    property: "DisableSteamAuthorizationForPhoton"
    action: "force_true"
  - class: "NetworkManager"
    method: "GetSteamAuthTicket"
    action: "fake_auth_ticket"
  - class: "GameManager"
    method: "SteamNotConnected"
    action: "skip"

Supported Games

Games using Facepunch.Steamworks:

• Across The Obelisk
• (more as tested)

Building

dotnet build src/SplituxFacepunch.csproj -c Release

Output: src/bin/Release/net472/SplituxFacepunch.dll

License

MIT