[AySz88]

As an update for anyone else stumbling across this needing to set up a single-wall orthographic "cave", it appears that, instead of a cave, a solution is to set up an orthographic projection like this (example down the world z axis):

<window>.ortho(coordinates of screen in world x and y)
<window>.screenDistance(coordinate of screen in world z)

I'm not sure if head tracking does anything useful in an orthographic projection context - since it's a projection onto the screen that explicitly ignores the viewpoint, it seems like it'd be inappropriate to update the projection matrices using the head position. But I think IPD still needs to be updated somehow from head orientation, for correct stereo - still looking at the best way to do that.