SO Game Events Architecture

Event system for communication between objects in a Unity scene, based on the use of Scriptable Objects, avoiding classes dependencies. Inspired by Ryan Hipple's talk Unite Austin 2017 - Game Architecture with Scriptable Objects

You can try a demo from this itch.io page, where all the objects from the scene interact with each other without referring to other scripts.

Table of contents

• How to install
• How to use
  • Events creation
  • Triggering events
  • Events debugging
  • Adding listeners
  • Listener response from code
  • Create new events types
• License

How to install

• Download the Unity Package from the Releases section or from the itch.io page
• From the Unity project editor, drag and drop the Unity Package into the Assets folder
• Click Import in the displayed window

How to use

Events creation

In the Project window, right click and nagivate to Create -> Game Events, and select the event type you want.

The event type indicates the type of data you will send to the listeners subscirbed to it.

Triggering events

To trigger an event, you'll first requiere a reference to the event in your code. Then, you can use the Raise function. This method requires an argument containing the information you want to send to the listeners.

using GameEvents;
using UnityEngine;

public class TestClass : MonoBehaviour
{
    [SerializeField]
    private IntEvent _myIntEvent;

    ...

    private void InvokeMyEvent()
    {
        int value = GetValue();

        if (_myIntEvent != null)
            _myIntEvent.Raise(value);
    }
}

Events debugging

You can trigger an event selecting the scriptable object, setting a Debug Value in the insepctor and clicking on the Raise button. This will help in debugging whether the listeners are responding correctly to the event, whitout requiring to execute the code needed to trigger it.

Adding listeners

With a GameObject selected, click on Add Component and search for a listener of the same type of the event you want to be suscribed.

In the component, there is an Game Event attribute, where you must assing the scriptable object of the event, and a UnityEvent for the Response.

Listener response from code

You can add a response to an event from code. Just take a reference to the listener and use the AddAction function to add a new response, or the RemoveAction and RemoveAllActions functions to remove responses.

using GameEvents;
using UnityEngine;

public class TestClass : MonoBehaviour
{
    private IntListener _listener;

    private void Awake()
    {
        _listener = GetComponent<IntListener>();
    }

    private void OnEnable() => _listener.AddAction(DoSomething);

    private void OnDisable() => _listener.RemoveAction(DoSomething);

    private void DoSomething(int value)
    {
        ...
    }
}

Create new events types

Navigate to Game Events -> Create New Type Event, from the top bar. In the new menu displayed, you will have to indicate the namespace of the class (if it belongs to one), and the class name.

All the code genereted from this menu will be located in the CODE_GENERATION folder inside Assets.

License

This project is released under the MIT License by Diego Ruiz Gil (2024)