VR and AR test cases, where a dropped frame is a safety issue

Every other platform treats frame rate as a quality measure. In a headset it is a physiological one. Sustained drops below the platform comfort target cause nausea and disorientation, so a scene that stutters under load is a high severity defect rather than an optimisation task, and it needs measuring in the heaviest scene over several minutes rather than in a quick pass. Thermal throttling belongs in the same category, because a long session heats the device and the resulting slowdown arrives exactly when the user is most immersed and least able to disengage comfortably.

Involuntary motion is the second comfort category and it is a design problem more than a code one. Camera movement the user did not initiate, a horizon that tilts, acceleration effects, forced cutscene movement: each is a strong trigger for simulator sickness and each is easy to introduce without realising. Smooth locomotion needs an alternative, usually teleport and snap turn, and on most platforms the comfortable option should be the default rather than something the user discovers after feeling ill.

Tracking is the input, the camera and the interface all at once, so losing it removes the user ability to do anything while they are still wearing the device. Covering the sensors, moving into darkness or standing in a featureless white space all cause it, and the correct behaviour is to freeze safely with a clear message rather than letting the scene drift. Controller disconnection has the same shape: no phantom input at the moment of disconnect, and a clean resume when it comes back.

AR adds an environmental dependency that no test lab reproduces on its own. Plane detection behaves differently on a patterned floor, a plain surface, a reflective one and glass. Lighting changes tracking quality, and content anchored in one visit needs to be in the same place on the next. And spatial mapping is a detailed scan of somebody private space, so what is stored and what leaves the device is a privacy question that deserves the same scrutiny as any other personal data.