Two former Valve employees are continuing their work on a pair of augmented reality glasses and have demoed a protoytpe for the first time.  

Former Valve employees unveil virtual reality glasses
A protoype of the CastAR glasses as demoed at the Maker's Faire in San Francisco. (Credit: The Verge)

The glasses, called CastAR, are unlike the Oculus Rift in that they physically beam the image from a connected PC onto a special screen in front of you using two mini-projectors built into the frame. The image is then reflected back into the lenses of the glasses and rendered in 3D by active shutters.

Cameras on the glasses then track infrared LEDs positioned around the special projection screen, meaning you can physically move your head around the projected image to view from different angles, all in 3D.

The glasses can also be used in multiplayer games. Even if two people are looking at the same projection screen, only the image from their glasses will be beamed back to them.

The CastAR glasses are currently in the prototype phase, but were demoed last week at the 2013 Maker Faire held in San Francisco.

They were originally being developed by Jerri Ellsworth and Rick Johnson while they both worked for Valve. However, after being fired as part of a mass restructuring at the company in February, the two engineers managed to negotiate with Valve president Gabe Newell to be allowed to continue development on the glasses independently.

A model demonstrated to The Verge had exposed wires and chips on the frame and was held together by tape. Ellsworth and Johnson, working under the company name Technical Illusions, are now planning to launch a Kickstarter campaign to gather funding for a consumer model, though no potential release date has been set.

"This is what I'm going to build come hell or high water," Ellsworth said. "It was just a no-brainer that when we were not at Valve... we just had to do it.  I talked to Gabe, and he talked to the lawyers, and he's like, 'It's theirs, make it happen,' because he could see we were passionate about it."

Despite differences between the two devices, CastAR will face competition from the Oculus Rift which is already in the hands of game developers. A heavier, bulkier pair of VR goggles, it beams the image from a game directly into player's eyes and makes it possible to control a character's head movement by physically turning your own head.

A consumer model of the Rift does not have a release date either, though development kits are now available costing $300 (£200.)