Here is something that looks very promising and might be able to provide good virtual reality-like gaming experience when playing video games on larger displays such as an HDTV or a projector, especially for FPS games. And although it is not specifically designed for stereo 3D support, it could turn out to be a great addition to a 3D HDTV, by making the experience even more immersive. What the company called IMMERSIX is offering is a solution providing immersive experience with 6 degrees of freedom by being able to track independently markers on your gun and your head movement and this translates into realistic motion inside the game world. What makes this seem very realistic is the use of a phenomenon called moving parallax to render the virtual game world in a way that creates a more realistic feeling of depth even when you are using a 2D display devices.
IMMERSIX claims that they already have plugins for several game engines in order for game developers to quickly implement the required support, however the problem is the hardware that will provide the tracking – the infrared camera along with the gun and glasses with IR markers (passive or active markers?) that will be providing the tracking. The company developing this does not provide much information besides the embedded promo video above, but I get the impression that they are more of a software development company looking to license their technology to hardware manufacturers and this will make it harder for game developers to be convinced to add support. On the other hand if you are a user that is interested in taking advantage of this technology, before buying the hardware you would want to see some good games that are able to support it well. So, IMMERSIX development kits anyone? Anyway this does look promising and is worth keeping a track on their development if you find it interesting.