SINGLETON DECLARATION

OBJECTIVE: Create a GameManager Class with the use of the Singleton Design Pattern

When you declare a singleton class, you are telling that class that you are going to have a reference among all classes --> The entire program will know that this class exists --> There will never be a duplicate of this class

public class GameManager: MonoBehaviour
{
    private static GameManager _instance;
    public static GameManager Instance
    {
        get
        {
            if(_instance == null)
                Debug.LogError("The GameManager is NULL.")
            
            return _instance;
        }
    }
    
    private void Awake()
    {
        _instance = this;
    }
}

CODE BREAKDOWN

• LINE 3 --> Creates a private static instance of the current class

  • _instance is going to define the instance of THIS GameManager and there never can be more than ONE instance of a single class

• LINE 4 --> Creates a public static instance of this class

  • Needed for script communication

  • Needs to be a property that other classes GET but cannot SET

• LINE 6-12 --> Defines the GET property for the Instance property

  • when another script calls upon the Instance property the following happens...

    • FIRST: program checks that _instance is not NULL (I.E. that the class exists within the hierarchy)

    • SECOND: If not NULL the property returns the instance of itself, allowing the other script access

• LINE 15-18 --> Initialized the singleton while the program initially loads

  • This is where the program assigns _instance to this script