Calculating normalized patch coords from pixel coords?

[James C. W. <jfc...@ya...>]

Hi all,
 
In order to have a patch work across 3d space, and not be hindered by the seperate cube faces, I wondered if there was a way to calculate, with the 2D coords(e.g. face 1, 342, 567) the equivilent in 3D coords?
 
Thanks,
  James CW