X157 Dev Notes

One simulant attempts to share insight with others.

>> X157 / UE5 / Modular Gameplay

Modular Gameplay Plugin Overview

A Modular Gameplay Plugin is a plugin whose base classes implement the Modular Gameplay pattern, which allows Lyra (and your project!) to inject components into actors at runtime.

This pattern gives the game support for GameFeature Plugins.

The ModularGameplayActors Plugin is a specific implementation of Modular Gameplay, distributed in Lyra.

You can either (like LyraStarterGame) actually base your classes on the ModularGameplayActors classes, or you can implement the same patterns in your own existing base classes.

Game Framework Component Manager

UGameFrameworkComponentManager « UGameInstanceSubsystem

This Game Instance Subsystem is what allows Lyra to inject components into Actors at runtime.

Actors must explicitly opt-in to this behavior. Epic publishes the ModularGameplayActors plugin with LyraStarterGame as an easy set of base classes to automate this opt-in process, but you don’t necessarily have to base your classes on those. You can duplicate the procedure in your own classes if you prefer.

For example take a look at this code from LyraStarterGame:

Debugging Tip

Execute Log LogModularGameplay Verbose in the console to see verbose logging for this module.

Execute ModularGameplay.DumpGameFrameworkComponentManagers in the console to dump debugging info to help understand which components are being injected into which actors.

Game Framework Init State Interface

IGameFrameworkInitStateInterface must be implemented by any Component that needs to initialize based on dependencies that themselves are other Components with their own dependent initialization steps.

TLDR every component in the Game Framework spams Init() until everything has successfully initialized or has finally failed initialization.

Implementation in Lyra 5.1: Pawn Extension

To implement the Modular Gameplay Plugin, take a look at Lyra as an example. Lyra implements this module by:

For more information, see:

The above links will hopefully help illustrate how the various components in Lyra’s ShooterGame Mannequin are able to initialize in an appropriate order when they have dependencies on one another.