Making Mods: Getting Started

Ever wanted to make a mod for the game? Here’s how to get you started.

Creating your mod

There is no standard template for making a mod (yet), so here’s a step-by-step guide on making your mod.

Prerequisites

Obviously, modding requires you know how to code in C#. It is highly recommended you have experience with Reflection in C# before making your first mod. Although it is not a hard requirement, Reflection is one of the core principles of C# that makes modding possible.

To make a mod, you will need:

• A .NET SDK installed that compiles .NET Framework or .NET Standard
  • If you are on Windows, you can get away with using .NET Framework
  • If you are on Linux, install any recent .NET SDK and make your mod using .NET Standard 2.0 or 2.1
• A C# IDE
  • If you are on Windows, you can choose between Visual Studio or Rider.
  • If you are on Linux, we recommend you use Rider.

Making your project

Open your IDE of choice and create a new class library targeting either .NET Framework 4.7.2 or 4.8, or .NET Standard 2.0 or 2.1.

Before writing any code, you will need to add references to these files from your game directory:

• DirectoryBepInEx

  • Directorycore

    • 0Harmony.dll
    • BepInEx.dll
• DirectorySpinRhythm_Data

  • DirectoryManaged

    • Assembly-CSharp.dll
    • UnityEngine.CoreModule.dll
    • UnityEngine.dll

Every plugin needs a main plugin class. Rename Class1.cs to something like Plugin.cs or Main.cs, then have your main class look like this:

using BepInEx;

namespace YourMod
{
    [BepInPlugin(Guid, Name, Version)]
    internal class Plugin : BaseUnityPlugin             // Plugin or Main, whatever you named your file.
    {
        private const string Guid = "your.mod.guid";    // Globally Unique Identifier, usually follows the convention com.yourwebsite.yourmod
        private const string Name = "Your Mod Name";    // Your mod name
        private const string Version = "0.1.0";         // Mod version, follows semantic versioning https://semver.org/

        private void Awake()
        {
            Logger.LogInfo("Hello from ${Name}!");
        }
    }
}

Build your mod, then go in your build files and copy YourMod.dll into the game’s BepInEx plugins directory. Launch the game and you should see “Hello form Your Mod Name!” in the console. Congratulations, you made your first mod!

Automatically copy your mod when building

You probably don’t want to copy your mod to the game’s directory everytime, and that’s very understandable. But what if I told you that you can tell the compiler to automatically copy your mod every time it is rebuilt?

Open your project’s .csproj file, and add these lines before the closing </Project> tag:

    <Target Name="PostBuildScript" AfterTargets="AfterBuild">
        <Copy SourceFiles="$(TargetPath)" DestinationFolder="<path to srxd>\BepInEx\plugins" SkipUnchangedFiles="false" OverwriteReadOnlyFiles="true" />
    </Target>

    <Target Name="CopyPdbFile" AfterTargets="AfterBuild" Condition="'$(Configuration)' == 'Debug' And '$(OS)' == 'Unix'">
        <Copy SourceFiles="$(TargetDir)\$(ProjectName).pdb" DestinationFolder="<path to srxd>\BepInEx\plugins" SkipUnchangedFiles="false" OverwriteReadOnlyFiles="true" />
    </Target>

These 2 targets will copy your mod to the plugins directory every time it is rebuilt, and when you build your mod in debug mode, the associated pdb file will also be copied to the plugins directory to use when debugging.

Note: the second MSBuild target will only work if your project name matches the name of your mod. If it doesn’t work, try modifying $(ProjectName).pdb to the actual name of the file.

Where to go next?

You made your first mod. Well done! From here on out, you have the freedom to do pretty much anything you want.