title: box2d on separate thread
body: <p>I am creating a box2d game on android. </p>
  
  <ul>
  <li>When I place world.step() in a separate thread from the opengl render thread and have the camera follow a body, the player jitters terribly. </li>
  <li>If I place world.step on the render thread before the draw commands, it renders perfectly even with camera following the body. But I cant use the extra power of multi-threading.</li>
  </ul>
  
  <p>I am guessing this is a sync problem between threads? Any tips or source code examples?</p>