Useful Components for Unity3D engine. You probably have a component somewhere where you only want one of them and you probably want to get access to it from everywhere for some reason. So we added SingletonComponent. from http://garry.tv/2015/06/14/unity-tips/

SingletonComponent.cs

using UnityEngine;

public abstract class SingletonComponent<T> : SingletonComponent where T : MonoBehaviour
{
	public static T Instance
	{
		get { return instance; }
	}

	private static T instance = default( T );

	public override void Setup()
	{
		if (instance != this) instance = this as T;
	}

	public override void Clear()
	{
		if (instance == this) instance = null;
	}
}

public abstract class SingletonComponent : MonoBehaviour
{
	public abstract void Setup();
	public abstract void Clear();

	protected virtual void Awake()
	{
		Setup();
	}

	protected virtual void OnDestroy()
	{
		Clear();
	}
}