Fliping The Code Backwards?

See this is the script I got and when enabled it fades in, if someone could flip it to fade out or even show me I would be very grateful. Here is the code, its in java in case you were wondering. -

 #pragma strict
  
  // FadeInOut
  
  var fadeTexture : Texture2D;
  var fadeSpeed = 0.2;
  var drawDepth = -1000;
  
  private var alpha = 1.0; 
  private var fadeDir = -1;
  
  function OnGUI(){
      
      alpha += fadeDir * fadeSpeed * Time.deltaTime;  
      alpha = Mathf.Clamp01(alpha);   
      
      GUI.color.a = alpha;
      
      GUI.depth = drawDepth;
      
      GUI.DrawTexture(Rect(0, 0, Screen.width, Screen.height), fadeTexture);
  }