title: How to ensure that a plane perfectly fills the viewport in OpenGL ES
body: <p>I'm trying to create a flat plane such that it perfectly fills the viewport in an OpenGL ES application. I can achieve this effect by creating the plane and then experimentally moving it forwards and backwards until I get the right effect, but I'm certain that it must be possible to work out exactly how far away from the camera it should be. I would welcome any pointers!</p>
  
  <p>I need to be accurate because the plane has a texture applied to it, which I want to fill the window and not be clipped at all.</p>
  
  <p>Thanks!</p>