title: Differences between GLSL and GLSL ES 2
body: <p>Two questions really... </p>
  
  <ol>
  <li>Is GLSL ES 2 a totally separate language, or a special version of GLSL?</li>
  <li>What are the differences between them, in terms of "standard library" functions, syntax and capabilities?</li>
  </ol>
  
  <p>I am writing shaders for an application targeted at Windows, Mac and iPad and I would prefer not to have to add more versions of each shader - well simpler shaders anyway.</p>