Marooned

I wanted to create an ability system that was easy to extend and easy to edit using built in inspectors. I was heavily inspired by the Unreal Gameplay Ability System and was able to implement an ability system that incorporates many of the same elements. Like GAS it is built around assets that define Abilities, Effects, and Cues. # Ability assets define the behavior of an ability, what effects to apply, animations to play etc. Abilities typically use Tasks to handle behavior over time like playing an animation and waiting for an animation event to check for collision and apply an effect. Tasks are wrappers for C# async tasks that respond to events.

Effect assets are used to modify the value of a Stat such as health or stamina. this can be a simple addition/subtraction or a custom calculation. Effects can also trigger cues via tags.

Cue assets define a visual or auditory response to an action such as playing particles or sounds. Cues are triggered via tag rather than directly. This means an actor can define what cue it wants to activate in response to a particular tag or fallback to a default cue. For example, trees and rocks can each have their own particle effect to play in response to a melee hit or play a default dust effect.

The first iteration of the ability system was built around polymorphic plain C# classes using Serialize Reference. While this was functional it required me to write custom editors and inspectors to allow authoring abilities in the unity editor. This ended up being more brittle than desired and I eventually switched to a system based on Scriptable Objects. In Unity, Scriptable Objects are first class citizens with respect to serialization and editor support, allowing references to be assigned through drag and drop or the asset search box. The ability Scriptable Objects are not instantiated on a per instance basis but rather have a single instance per unique ability and are treated as read only. Individual ability instances are still plain C# class objects passed to the ability operation functions.