title: iPhone 5S - Possible Depth Buffer issue
body: <p>In my application, I render plane over plane. Lower plane has Z = 0, second one has Z = 0.5. If I render them (lower first), I got missing part of render, as shown on picture </p>
  
  <p><img src="https://i.stack.imgur.com/PtqAq.png" alt="enter image description here"></p>
  
  <p>On iPhone 4 and desktop (using ES emulator), there is everything correct and no problem. What could cause this bevaiour ?</p>
  
  <p>Same problem occurs also for other parts of scene, like tracks, tubes (green and blue on this picture). Problem occurs, when I move camera</p>