UnityEcsEvents

An event system package for Unity's data-oriented design framework.

What is it?

Events in ECS are a convenient way to communicate short-lived information between systems. An event is just an Entity with a few components on it and this project makes it faster and easier to create them!

Check out the example project here

Installation:

Download by clicking the "Clone or Download" button on the GitHub repo then copy the folders into your "/packages/" folder.

There are two separate packages included:

• Entities.Unlocked - Provides access to various internal features of Unity.Entities
• UnityEcsEvents - The core events system.

Getting Started:

Here's an example of routing ECS events through to a MonoBehavior:

using Unity.Collections;
using Unity.Entities;
using UnityEngine;
using Vella.Events;

public class HelloWorld : MonoBehaviour, IEventObserver<MyHelloEvent>
{
    public EventRouter EventSource;

    private void Start() => EventSource.Subscribe<MyHelloEvent>(this);

    public void OnEvent(MyHelloEvent e)
    {
        Debug.Log($"Event Triggered in GameObject. Message={e.Message}, Value={e.SomeValue}");
    }
}

public class TestSystem : SystemBase
{
    private EntityEventSystem _eventSystem;

    protected override void OnCreate()
    {
        _eventSystem = World.GetOrCreateSystem<EntityEventSystem>();

        _eventSystem.Enqueue(new MyHelloEvent
        {
            Message = "Hello World",
            SomeValue = 41
        });
    }

    protected override void OnUpdate()
    {
        Entities.ForEach((in MyHelloEvent e) =>
        {
            Debug.Log($"Event Triggered in System. Message={e.Message}, Value={e.SomeValue}");

        }).Run();
    }
}

public struct MyHelloEvent : IComponentData
{
    public NativeString64 Message;
    public int SomeValue;
}

In general you can also:

• Create events anywhere with the same syntax - ForEach, Jobs, Managed, in parallel.
• Attach DynamicBuffers and Arrays to events.
• Cache and re-use an event queue per system.

For more advanced examples have a look at the test project

Package Dependencies:

"com.unity.burst": "1.3.3",
"com.unity.collections": "0.9.0-preview.6",
"com.unity.entities": "0.11.1-preview.4",
"com.unity.test-framework": "1.1.11",
"com.unity.test-framework.performance": "1.3.3-preview",
"com.vella.entities.unlocked": "0.0.3"

Supported Editors:

• 2020.1.0b14+

Troubleshooting

• Unity still has some issues with ASMREF in certain situations, if Unity.Entities doesnt have the Unlocked package compiled with it properly then the usual fix is to go into preferences >> External tools and click 'regenerate project files'.

Acknowledgements

Consider checking out the project that inspired this work here: com.bovinelabs.entities and the Unity forums thread on event systems: here.