RPG Menu Notes

Here’s notes from several videos, indicating stuff I want to do or try. Rather than link to each video, let alone an embed, let me shout out EngiGames and Jason Weiman.

• I want to stick my interface in a separate scene. This is contraindicated by EngiGames for small games, but for my RPG, I think it makes sense to have it be its own thing that sits over the top of everything else going on.
  • using UnityEngine.SceneManagement;
  • if (SceneManager.GetSceneByName("UI").IsLoaded == false) SceneManager.LoadSceneAsync("UI", LoadSceneMode.Additive);
• Consider, instead, having the menu call Don'tDestroyOnLoad() and then swapping immediately to a gameplay scene, rather than monkeying around with additive scenes, though.
• If I don’t want to hook up events to buttons using the Unity Button delegates, I can create scripts that handle the button directly. E.g.
  • // In Start(), using UnityEngine.UI...
  • button = GetComponent<Button>();
  • button.onClick.AddListener(YourClickFunctionHere);
• Obviously, I’ll want to be able to grab an instance of some access point to my menu from any other scene. I should be aware that just putting a reference in a public static field in Awake() is considered a Very Bad Plan. This is because it is a sloppy singleton that doesn’t do the first part of a singleton’s job — ensure that one, and only one instance of the class exists. This video details a singleton generic that will allow you to turn a Monobehavior into a proper singleton merely by inheriting from it.

Here’s a singleton implementation that is more or less identical to the EngiGames one linked above. Only the names have been changed to protect the record. (By that I mean I read it, I grokked, it, I typed it in myself to ensure I understood what I was doing and why). I use a property instead of a getter method because for some reason I hate methods, even when I’m replacing them with what are secretly just methods.

using UnityEngine;

public abstract class singleton<T> : MonoBehaviour 
    where T: MonoBehaviour
{
    static T instance;
    static bool quitting = false;

    public static T Instance
    { 
        get
        {
            if (quitting) return null;
            if (instance == null)
            {
                GameObject go = new GameObject();
                go.name = typeof(T).Name;
                instance = go.AddComponent<T>();
            }
            return instance;
        }
    }

    protected virtual void Awake()
    {
        if (instance == null)
        {
            instance = this as T;
            DontDestroyOnLoad(gameObject);
        }
        else if (instance != this as T)
        {
            Destroy(gameObject);
        }
        else DontDestroyOnLoad(gameObject);
    }

    private void OnApplicationQuit()
    {
        quitting = true;
    }
}