We can't help but experience a little déjà vu as we unmask our latest subject.

Pulling back the outer shell on the Vive reveals a number of sensors—32 in total, according to HTC.

These photodiodes take in IR light from the two Lighthouse base stations as they flash and sweep light across the room. This enables a connected PC to calculate the headset's position and orientation in space as a function of the time between receiving the flash and the following IR laser sweep.

This method is the exact opposite of the head-tracking technique found in the Oculus Rift. In the Rift, the desk-mounted camera tracked the IR emitters in the headset, whereas in the Vive, the headset sees light from the mounted IR emitters without actually "tracking" its location.