title: NSTimer vs CACurrentMediaTime()
body: <p>So I'm amidst my first iOS game and am struggling with how to go about the best way to integrate object movement. </p>
  
  <p>The game relies heavily on fast moving objects and constant, fast user input changes. As such, I'm trying to have object integration and the constraint solver run as quickly and accurately as possible (to minimize user input change in between successive game loop calls). </p>
  
  <p>More specifically, I'm unsure of the capabilities of the NSTimer class and CACurrentMediaTime() function. It's hard to test empirically because I'm not sure which have the larger error. For example, using an NSTimer with a repeating interval of 0.008 (~2updates/screen refresh) and calling CACurrentMediaTime() on successive calls, I find the time interval between calls varies from 0.0075 - 0.009. Hard to say which is responsible for the (small) inconsistency. So for determining the time step should I be:</p>
  
  <ol>
  <li><p>Assume NSTimer is accurate enough to use the NSTimer time interval as the game loop time step</p></li>
  <li><p>Use CACurrentMediaTime() to determine the time interval between successive game loop calls. </p></li>
  </ol>
  
  <p>Student and new to all of this - please be nice :) Any advice is greatly appreciated. Thanks for your time.</p>