GlobalObject.cs

GlobalObject.cs

using UnityEngine;

/**
 * Singleton-esque inter-Scene GameObject loader.
 * 
 * Ever wanted a singleton or global sort of GameObject that still allowed for editing properties in the Unity Editor? 
 * I sure did, for things like background music, a game controller, etc. So, I made this simple system of creating a global or "inter-scene" GameObject. It's not a true singleton, but it does a good job at ensuring there's only GameObject with this script attached. I don't like the approach of creating a persistent, additively-loaded scene -- not to mention the other approaches to making true Singleton objects -- so I've opted for a pre-fabbable GameObject approach.
 * 
 * HowTo, in the Unity Editor (tested with 2017.3.1f1):
 * 1. Attach this script to an empty GameObject in the current scene.
 * 2. Add any other global game objects as children of this one.
 * 3. Create a prefab of this object.
 * 4. Go to Edit > Project Settings > Script Execution Order
 * 5. Add this script to the list by clicking the "+" button
 * 6. In the numeric field, enter -1 or below so this runs before any other script you might have. Save this setting.
 * 7. Add the prefab to all scenes & every new scene you create.
 * 
 * If other scripts run before this one, and there's inter-dependencies between those scripts, then it's possible that the scripts will get the wrong object when calling, e.g., FindObjectOfType<>(). This is why you need to set a low number in the Script Execution Order list.
 */

public class GlobalObject : MonoBehaviour {
    private static GlobalObject instance;

    private void Awake() {
        if (!instance) {
            Debug.Log(gameObject.name + " Awake, becoming global");
            DontDestroyOnLoad(gameObject);
            instance = this;
        } else {
            Debug.Log(gameObject.name + " Awake, self-destructing");
            DestroyImmediate(gameObject);
        }
    }
}