title: openGL pixel coordinate
body: <p>I am trying to work with textures in openGL to do parallel computation (openCL is not an option). I understand that the domain is 0.0 to 1.0 on each axis from the bottom left. However, is the coordinate of a pixel during rendering map to the pixel's upper left corner, or the middle of the pixel?</p>
  
  <p>Ex. If I have a texture that is 100x100px. Is the coordinate of the upper left most pixel (0.0,1.0) or is it (0.005,0.995)? I assumed it was the former, but have been getting some unexpected results. I am wondering if I am accessing data on "pixel boundaries" and openGL is interpolating to a value that is averaging the two neighboring pixels.</p>