public AnimatedSprite(IGameObject gameObject, SpriteAtlas atlas, List <Rectangle> sourceRects, float frameTime, Vector2?scale = null)
     : base(gameObject, atlas, new MultipleSource(sourceRects), scale)
 {
     this.frameTime = frameTime;
 }
 public FixedSprite(IGameObject gameObject, SpriteAtlas atlas, Rectangle sourceRect, Vector2?scale = null)
     : base(gameObject, atlas, new SingleSource(sourceRect), scale)
 {
 }