R2Wiki: Risk of Rain 2 Modding Documentation

The Data Oriented Technology Stack (DOTS) is a development philosophy for creating high-performance code using data-oriented programming. In the context of Risk of Rain 2 modding via ThunderKit, two pillars are accessible:

1. Burst Compiler: Translates IL/.Net bytecode into native CPU code using the LLVM compiler for improved performance.
2. C# Jobs: Allows for multithreaded code execution for performance-intensive tasks (e.g., complex math, transform modifications) with built-in safety guard rails.

While the Entity Component System (ECS) is a core part of DOTS, its availability for modding is currently unknown.

A ContentPack (found in the RoR2.ContentManagement namespace) is a class that represents a package of content for Risk of Rain 2. It is used by the game's catalog systems to load and manage various assets.

Common assets included in a ContentPack:

• ItemDef, EquipmentDef, BuffDef, EffectDef, etc.
• Body Prefabs
• Master Prefabs
• Projectile Prefabs

Precautions:

• Unique Naming: Every asset in a ContentPack must have a unique name.
• No Duplicates: You cannot have duplicate assets (e.g., two identical ItemDefs); doing so will cause the game to crash.

UNetWeaver is a utility that patches NetworkBehaviour components to ensure proper serialization and deserialization of data across the network. It allows developers to use standard Unity Networking (UNet) features outside of the Unity Editor in Risk of Rain 2 mods.

Key benefits:

• No user-side dependencies: Users only need your plugin DLL.
• Native Unity integration: Uses standard using UnityEngine.Networking; syntax.

Hooking and Patching are techniques used to modify the behavior of .NET assemblies, such as the Risk of Rain 2 codebase, other mods, or Unity's C# components.

There are two primary frameworks used for this:

• MonoMod: Uses generated files (e.g., MMHOOK_RoR2.dll) to provide IL and On namespaces, enabling easy method referencing and autocompletion.
• Harmony: Uses attributes to mark patching code. It does not require generated files and has fewer dependency issues, but requires manual writing of patching signatures as it lacks the autocompletion provided by MonoMod.

Common Intermediate Language (CIL) is the intermediate form produced when C# code is compiled. It is processed by the runtime and converted into machine code.

CIL operates using a Stack. In this model:

• Instructions push values onto the stack or pop values off to perform operations.
• Only the value at the very top of the stack can be popped.
• Stack Balance: At the point of method termination (ret), the stack must be empty. If instructions or values remain on the stack, the process will terminate with an Invalid ILCode error.

Reflection provides Type objects that describe assemblies, modules, and types. TypeInfo acts as a unique signature for a type (classes, interfaces, arrays, etc.). You can use typeof() to perform comparisons to ensure an object conforms to a specific type before attempting to invoke methods or access fields.

    var obj = "asdf";
    if(typeof(obj) == typeof(string)) {//true}

Expansion icons appear in the lobby to indicate content from a specific mod or expansion.

Technical Specifications:

• Canvas Size: 512 x 512.
• Unity Import: Because of the larger canvas, you must set Pixels Per Unit to 200.
• Visual Structure:
  • A primary foreground shape.
  • A translucent detailed background.
  • A transparent background.
  • No canvas border, but an outline around the central shape.

Design Tips:

• Maintain color consistency (e.g., if the theme is blue, use blue for the foreground and translucent blue for background details).
• Translucency: For background details, use an Alpha value between 63 and 186:
  • Brighter colors (Yellow/Blue): Higher Alpha (closer to 186).
  • Bolder colors (Red/Green): Lower Alpha (closer to 63).