Perspective camera at (0,0,1) looking down −Z, for the behind-camera guard cases. A point at world z=3 lands at view-space z=+2 (behind the camera), so the perspective-only guard (view z >= 0 under a perspective projection) fires.
Perspective camera at (0,0,1) looking down −Z, for the behind-camera guard cases. A point at world z=3 lands at view-space z=+2 (behind the camera), so the perspective-only guard (view z >= 0 under a perspective projection) fires.