PlayerLoopHelper

Single file helper class for registering/unregistering systems in Unity's PlayerLoop.

How to install

Either:

• In the Package Manager Window, install using this repository's Git URL:
  https://github.com/gilzoide/unity-playerloophelper.git
• Copy the PlayerLoopHelper.cs file anywhere inside your project.

Usage example

using System;
using System.Collections.Concurrent;
using PlayerLoopHelper;

// Class for scheduling tasks that will run in Unity's Main Thread.
// 
// Using a PlayerLoopSystem avoids needing a living singleton GameObject
// with a MonoBehaviour that overrides `Update`, which is the usual way
// of implementing such functionality in Unity.
//
// Usage:
//     MainThreadDispatcher.Dispatch(() =>
//     {
//         Debug.Log("Some action that runs on Unity's Main Thread"));
//     }
public static class MainThreadDispatcher
{
    static readonly ConcurrentQueue<Action> _taskQueue;
    static MainThreadDispatcher()
    {
        _taskQueue = new ConcurrentQueue<Action>();
        Enable(); 
    }

    public static bool Enable()
    {
        return PlayerLoopSystemHelper.Register(
            // PlayerLoop systems are identified by their Type
            typeof(MainThreadDispatcher),
            // "FirstChildOf Update": this system will run as the first step
            // in the Update phase, before other components
            // For more phases, check out UnityEngine.PlayerLoop subclasses
            // (e.g.: https://docs.unity3d.com/ScriptReference/PlayerLoop.Update.html)
            InsertPosition.FirstChildOf,
            typeof(UnityEngine.PlayerLoop.Update),
            // Callback that will run once per frame
            UpdateCallback
        );
    }

    public static bool Disable()
    {
        return PlayerLoopSystemHelper.Unregister(typeof(MainThreadDispatcher));
    }

    public static void Dispatch(Action action)
    {
        _taskQueue.Enqueue(action);
    }

    static void UpdateCallback()
    {
        while (_taskQueue.TryDequeue(out Action task))
        {
            task();
        }
    }
}

API

enum InsertPosition

• Before: insert new system before specified one, as its sibling
• After: insert new system after specified one, as its sibling
• FirstChildOf: insert new system as the first child of specified one
• LastChildOf: insert new system as the last child of specified one

class PlayerLoopSystemHelper

• static bool Register(Type type, InsertPosition position, Type anchorType, PlayerLoopSystem.UpdateFunction action)

  Registers a PlayerLoopSystem with the given type and action in the specified position relative to anchorType.

  Returns whether anchorType was found and system was inserted successfully.

• static bool Unregister(Type type)

  Unregisters a PlayerLoopSystem.

  Returns whether type was found and removed successfully.

• static bool IsRegistered(Type type)

  Returns whether a PlayerLoopSystem with type is registered.

Other projects for injecting callbacks in Unity's PlayerLoop

• https://github.com/Refsa/PlayerLoopInjector
• https://github.com/sotanmochi/PlayerLooper