title: Any ideas to implement a simple 2D sky?
body: <p>I need a very simple sky with simple day/night cycle. In my implementation
  the 'sky' is just a simple dynamically created gradient background, based on two colors.</p>
  
  <p><a href="http://img14.deviantart.net/ff6c/i/2012/009/1/a/sky_gradient_stock_by_nikhilmoh-d4lt15o.jpg" rel="nofollow">For example</a></p>
  
  <p>My question is: There is a simple formula or any other solution to dynamically 'change' the rgb colors of gradient by the angle of 'sun', or by the actual gametime?</p>