Unity Script: Fade Orthello sprite in or out

FadeSprite.cs

using UnityEngine;
using System.Collections;

public class FadeSprite : MonoBehaviour {

  public enum FadeDirection { FadeOut, FadeIn }

  public FadeDirection Direction = FadeDirection.FadeOut;

  public float Speed = 0.0f;

  public bool Loop;

  private OTSprite sprite;

  private float CurrentDirection 
  {
    get { return Direction == FadeDirection.FadeOut ? -1.0f : 1.0f; }
  }

  void Start () 
  {
    sprite = gameObject.GetComponent<OTSprite>();

    if(sprite == null)
    {
      Debug.LogWarning("FadeSprite script only works with orthello sprites");
    }
  }

  void Update () 
  {
    if (sprite == null) 
    {
      return;
    }
		
    ChangeAlpha ();
    CheckLoopCondition ();
  }

  private void ChangeAlpha ()
  {
    sprite.alpha += Time.deltaTime * Speed * CurrentDirection;
  }

  void CheckLoopCondition ()
  {
    var fadeOutCompleted = sprite.alpha < 0.0f;
    bool fadeInCompleted = sprite.alpha > 1.0f;
	
    if( Loop && ( fadeOutCompleted || fadeInCompleted ) )
    {
      ToggleFadeDirection();
    }

    if( !Loop && fadeOutCompleted )
    {
      Destroy(gameObject);
    }
  }

  private void ToggleFadeDirection()
  {
    Direction = Direction == FadeDirection.FadeOut 
      ? FadeDirection.FadeIn : FadeDirection.FadeOut;
  }
}