[TopazFrost]

I am having trouble location the frustum method used for stereoscopic rendering for a HMD and projection screen.

I need to know if the HMD stereo uses the roll angle when determining the eye locations (e.g. 45 degree roll would make the left eye lower than the right) or if it just takes the position and moves the viewpoint parallel to the floor along the current horizontal axis.

Same question for a projections screen, and I need to know if it uses an oblique frustum or the the perpendicular version.

E.g.
(oblique)

 
      *|
    *  |
  *    |
x      |
    *  |

where X is the view point and | is the rendering plane and screen


versus
(perpendicular)

 
       *|
     *  |\
  *     | \
x       |  \
    *   |  \

where X is the view point and | is the screen and \ rendering plane