Callbacks

This project implements a modular callback system for Unity that provides easy-to-use MonoBehaviour lifecycle event hooks. It's designed to be lightweight, reusable, and easily integrated into any Unity project.

Table of Contents

1. Overview
2. Scripts
   • Core
     • MonoBehaviourCallback.cs
   • Callbacks
     • AwakeCallback.cs
     • StartCallback.cs
     • UpdateCallback.cs
     • FixedUpdateCallback.cs
3. Getting Started
4. Usage
5. License

---

Overview

The Unity Callback System provides a unified way to handle MonoBehaviour lifecycle events through UnityEvents. It offers:

• Clean separation of concerns for event handling
• Easy integration with Unity's Inspector
• Type-safe callback registration
• Minimal overhead and memory allocation

---

Scripts

Core

MonoBehaviourCallback.cs

The MonoBehaviourCallback.cs script serves as the base class for all callback components.

public class MonoBehaviourCallback : MonoBehaviour
{
    public CallbackEvent Callback = new();
}

[System.Serializable]
public class CallbackEvent : UnityEvent<MonoBehaviourCallback> { }

Key Features:

• Base functionality for all callback types
• Serializable UnityEvent for Inspector integration
• Type-safe callback handling

---

Callbacks

AwakeCallback.cs

The AwakeCallback.cs script handles the Awake event in the Unity lifecycle.

public class AwakeCallback : MonoBehaviourCallback
{
    private void Awake()
    {
        Callback?.Invoke(this);
    }
}

Key Features:

• Triggered once when the script instance is being loaded
• Ideal for component initialization
• Executes before Start

---

StartCallback.cs

The StartCallback.cs script manages the Start event callback.

public class StartCallback : MonoBehaviourCallback
{
    private void Start()
    {
        Callback?.Invoke(this);
    }
}

Key Features:

• Triggered once before the first frame update
• Useful for initialization that requires other components to be ready
• Executes after all Awake calls are completed

---

UpdateCallback.cs

The UpdateCallback.cs script provides frame-by-frame update callbacks.

public class UpdateCallback : MonoBehaviourCallback
{
    private void Update()
    {
        Callback?.Invoke(this);
    }
}

Key Features:

• Called every frame
• Ideal for input handling and regular updates
• Frame-rate dependent

---

FixedUpdateCallback.cs

The FixedUpdateCallback.cs script handles physics-based update callbacks.

public class FixedUpdateCallback : MonoBehaviourCallback
{
    private void FixedUpdate()
    {
        Callback?.Invoke(this);
    }
}

Key Features:

• Called at fixed time intervals
• Perfect for physics calculations
• Frame-rate independent

---

Getting Started

1. Add the desired callback component to your GameObject
2. In the Inspector, set up your callback events using UnityEvents
3. Create methods that accept a MonoBehaviourCallback parameter to handle the events

---

Usage

Basic Setup

1. Add a callback component (e.g., UpdateCallback) to your GameObject
2. In the Inspector, click the '+' button under the Callback event
3. Drag your target component to the event slot
4. Select your handling method from the dropdown

Example Code

public class ExampleHandler : MonoBehaviour
{
    public void HandleCallback(MonoBehaviourCallback callback)
    {
        // Handle the callback event
        Debug.Log($"Received callback from {callback.GetType().Name}");
    }
}

Best Practices

• Use AwakeCallback for component initialization
• Use StartCallback for inter-component setup
• Use UpdateCallback for frame-based logic
• Use FixedUpdateCallback for physics calculations

License

This project is licensed under the MIT License. See the LICENSE file for details.