Example Enemy

This repository contains the full source code for the Example Enemy for Lethal Company, including the Unity project which can be used to build its asset bundle. The guide part of this project can be found at https://lethal.wiki/dev/apis/lethallib/custom-enemies/overview.

Note

The wiki page might be slightly out of date regarding how the Example Enemy prefab is constructed.

Setting Up The Project For Development

Setup Script

After copying this repo for yourself, run SETUP-PROJECT.py from the command-line like this: python SETUP-PROJECT.py (Or you can run it from your file manager on Linux). Note that you will have to have Python installed.

• First, the setup project will copy DLL files over to UnityProject/Assets/Plugins directory so we can build our Asset Bundles without any errors.
  • Make sure have HookGenPatcher installed and have run the game at least once! This is needed for MMHOOK dll files.
• Second, it will run dotnet tool restore in the Plugin folder to locally install Unity Netcode Patcher & Thunderstore CLI.
• Third, it will ask you to paste a path to where it will copy over your mod files when you build your project. This is done by generating a csproj.user file with the path you inputted. After this, the setup process is done.
• If the script closes instantly after opening it, it means it crashed. This is actually the reason why I told to run it from the command-line. If you use Windows and can make this work, please open a pull request to fix this, thanks!
  • If the script still crashes after running from command-line, try making sure you are running Python 3.

Example csproj.user template which is also generated by the setup script:

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="Current" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <GameDirectory>%programfiles(x86)%/Steam/steamapps/Common/Lethal Company/</GameDirectory>
        <!-- Paste a path to where your mod files get copied to when building.  Include the last slash '/' -->
        <PluginsDirectory>/my/path/to/BepInEx/plugins/</PluginsDirectory>
    </PropertyGroup>

    <!-- Game Directories - Do Not Modify -->
    <PropertyGroup>
        <ManagedDirectory>$(GameDirectory)Lethal Company_Data/Managed/</ManagedDirectory>
    </PropertyGroup>

    <!-- Our mod files get copied over after NetcodePatcher has processed our DLL -->
    <Target Name="CopyToTestProfile" DependsOnTargets="NetcodePatch" AfterTargets="PostBuildEvent">
        <MakeDir
            Directories="$(PluginsDirectory)$(AssemblyName)-DEV/"
            Condition="!Exists('$(PluginsDirectory)$(AssemblyName)-DEV/')"
        />
        <Copy SourceFiles="$(TargetPath)" DestinationFolder="$(PluginsDirectory)$(AssemblyName)-DEV/"/>
        <!-- We will copy the asset bundle named "modassets" over -->
        <Copy SourceFiles="../UnityProject/AssetBundles/StandaloneWindows/modassets" DestinationFolder="$(PluginsDirectory)$(AssemblyName)-DEV/"/>
        <Exec Command="echo '[csproj.user] Mod files copied to $(PluginsDirectory)$(AssemblyName)-DEV/'" />
    </Target>
</Project>

You might also want to add this to the csproj.user file to also copy it over to our Unity project:

<!-- Copy the dll to our Unity project -->
<Copy SourceFiles="$(TargetPath)" DestinationFolder="../UnityProject/Assets/Plugins/"/>    

Dependencies

You need to install the following dependencies for this mod to work in the game (these are not installed by the setup script):

• LethalLib for registering and adding our enemy.
  • LethalLib depends on HookGenPatcher.

If you didn't run the setup script you will also need to, in the Plugin directory where our plugin code is, run dotnet tool restore on the command-line to install the rest of the dependencies.

That should be all the required setup for this project, and now you can move to coding AI or making your own 3D models for your custom enemy. Good luck!

Making The Mod Yours

Thunderstore Packages

We have configured ExampleEnemy.csproj to build a Thunderstore package to /Plugin/Thunderstore/Packages/ using tcli each time we make a release build of our mod. A release build can be done for example from the command-line like this: dotnet build -c release. This will use configuration options from thunderstore.toml, so configure it for your own mod! Do note that we have not included a way to upload your mod to thunderstore via tcli in this project.

Renaming The Mod

Renaming a mod can easily break things if you don't update every instance of it. If you want to rename your mod, these are some of the things you need to worry about:

• rename csproj files
• rename solution file, with its references to your new csproj filename
• When renaming ExampleEnemyAI.cs and its class, make sure to compile your mod DLL and place it in ./UnityProject/Assets/Plugins and add your new AI class as a component to your enemy prefab. If the class doesn't appear as an option, make sure your mod DLL doesn't have any errors in the Unity editor console. If your mod depends on other mods, also add their DLL files to the Plugins folder.
  • You might have to reapply all your configuration settings for the AI script. You need to be very careful to not miss a configuration option, as missing something can break the enemy's behavior or lead to errors.
• If your IDE complains about invalid references, try restarting it. If this does not fix it, you probably have forgotten to rename something.

Tip

You can use Ctrl + Shift+ F to search every file in both Visual Studio and Visual Studio Code. This can for example help you find every instance of ExampleEnemy inside files in the whole project. Do note however that this does not apply to filenames.
In Visual Studio, you can use Ctrl + , to search files by name. In Visual Studio Code you can use Ctrl + P to do the same.

Credits

EvaisaDev - LethalLib
Lordfirespeed - reference tcli usage in LethalLib
Xilophor - csproj files taken from Xilo's mod templates
XuuXiao - porting LC-ExampleEnemy for LC v50
nomnomab - Lethal Company Project Patcher - used for the Unity Project
AlbinoGeek - issue template
Melavex - suggestions and feedback on this project
...and everyone who has helped with this project!