This funky little camera was the heart of Valve's first foray into virtual reality. Head-mounted machine vision cameras were aimed at markers that sort of look like QR codes. This would help figure out a user's physical orientation. This style of tracking -- better known as the AprilTags system -- is rather popular for things like augmented reality.
This display prototype also used fiducial-based tracking, and served as a kind of telescope for peering into a virtual space. Valve describes the experience as akin to "looking through an empty tube at a different three-dimensional space." Most importantly, latency was pretty low: Valve claims that the lag in this unit was about 4 milliseconds, which would make for a smooth (if awkward) experience.
The telescope proved a success, which meant it was time to figure out a display someone would actually want to use. AMOLED panels offered fast switching times, but weren't quite right for what Valve was hoping to achieve.
This prototype was one of the first to combine panels Valve was satisfied with and fiducial-based positional tracking. It would also be one of the models used to convince hardware and software developers to get on board.
There was a glaring problem with fiducial-based tracking: you'd need to cover your walls or playspace with those funky, QR-like tags, which probably wouldn't fly in the average household. Valve had other designs in mind, and settled on a laser-tracking system. This prototype was cobbled together from a pair of hard drives.
The desktop dot tracking system allowed Valve to experiment with controllers: this prototype features a dot pattern attached to a Steam Machine controller. A little unwieldy, but an interesting way to get an input device in on the action.
This laser-tracked prototype headset integrates laser-tracking sensors for a cleaner look, and was the prototype that most of the developers creating content for GDC have worked with. It's called the V Minus-1 because the HTC prototype is known as the V Zero. That little box on the right is an evolved version of the base station.
And here's what the Steam VR's input devices look like at the moment. You'll use a pair of them to poke and prod things in virtual worlds, with buttons and triggers arrayed along the body handling interaction.
This is one of the latest versions of the laser base station that'll beam lasers at your face, and close to the models that'll ship with the Steam VR developer kits. There's no word on when Steam VR will be available, but it's been phenomenal ride thus far.