title: Light generation algorithm for clouds on the iOS platform
body: <p>I'd like to fill the background of my app with animated clouds. I did some research and stumbled upon the perlin noise algorithm which seems to be fitting. However even in the first test it was extremely expensive to generate a 512x512 (2D) cloud map. I tried simplex noise but it didn't fix it. </p>
  
  <p>According to <a href="http://freespace.virgin.net/hugo.elias/models/m_clouds.htm" rel="nofollow">http://freespace.virgin.net/hugo.elias/models/m_clouds.htm</a> generating clouds is done by adding some perlin/simplex noise maps together. Impossible to do it on a iPhone in my app: I need fluid graphics (my optimistic expectation is 60 FPS on an A4).</p>
  
  <p>So my question: Is there a lighter algorithm to generate animated clouds that does not make my frame rate drop too much?</p>
  
  <p>Thanks in advance!</p>
  
  <p>Paul</p>