  Virtual reality (VR) renderers driving CAVEs and similar immersive
environments use the off-axis stereo camera model so that a tracked user can
move freely in front of the projection plane. Geometrically, off-axis
projection results in asymmetric viewing frusta and generalizes the ubiquitous
perspective camera model to support positioning off the center of the
projection plane. VR renderers often integrate with larger visualization
systems that rely on libraries for position tracking and pose estimates, for
ray tracing-based rendering, and for user interaction. We demonstrate different
strategies to implement off-axis stereo projection within the constraints of
given VR applications and ray tracing libraries. We aim for minimal to no
adjustments required to the internal camera representation of such libraries.
We include host and shader code with the article that can be directly
integrated in custom applications.
