public void SetKeys (CCGradientColorKey[] colorKeys, CCGradientAlphaKey[] alphaKeys)
 	{
         this.colorKeys = (CCGradientColorKey[])colorKeys.Clone();
         Array.Sort<CCGradientColorKey>(this.colorKeys, (x, y) => y.time.CompareTo(x.time));
         this.alphaKeys = (CCGradientAlphaKey[])alphaKeys.Clone();
         Array.Sort<CCGradientAlphaKey>(this.alphaKeys, (x, y) => y.time.CompareTo(x.time));
 		
         if (this.alphaKeys == null || this.alphaKeys.Length == 0) {
             this.alphaKeys = new CCGradientAlphaKey[]{
                 new CCGradientAlphaKey (1f, 0f),
                 new CCGradientAlphaKey (1f, 1f)
             };			
 		}	
 		
 		UpdateHash ();
 	}