title: glsl shader working differently on different devices
body: <p>I am trying this below shader on my Nexus 7 and I see that it does not work as expected.</p>
  
  <p><a href="http://www.iquilezles.org/apps/shadertoy/index2.html?p=flower" rel="nofollow">http://www.iquilezles.org/apps/shadertoy/index2.html?p=flower</a></p>
  
  <p>The green rotating background is just missing in nexus 7 ( and also some other devices with GPUs like Adreno 300 series)</p>
  
  <p>Can any one can give any hint as to why this is happening?</p>