Depth Charges

Three main branches of 3D technology are proposed for home usage. One of them involves a special screen which actually has two layers of display, each pointing in a slightly different direction and showing a slightly different picture. Sit in the right place in front of the screen, and you get a stereoscopic image - proper 3D. The downside is that no existing TV sets support this technology, and there are question marks over whether it'll ever work effectively with more than one or two viewers in the room.

The second approach copies the present cinema technology into a living room. The screen displays two stereoscopic images, with the light from each image being polarised. A cheap pair of viewing glasses (which look like normal lightly-tinted sunglasses rather than horrible red and green 3D glasses of old) then separates out the polarised light, so each eye sees the appropriate stereoscopic image. This technology works remarkably well in cinemas, and would be great in the home - however, it also requires a new screen technology which no homes possess as yet.

The final approach is the one favoured by game makers at present, and has actually been around for some time. It displays the image for the left eye, then the right eye, in quick succession on screen - while the glasses you wear close LCD "shutters" over your eyes so that each eye only sees the appropriate image. If this is done fast enough, the brain sees no flicker - just a continuous, steady 3D image.

The best thing about this final approach is that some televisions already exist which could, in theory, support it. No new display technology is required, but what you do need is a TV screen which can display twice the number of frames per second as a normal screen - since you now need one frame for each eye, where previously you had one frame for both eyes. You also need LCD glasses synched to the television's refresh rate for each viewer.

All of this lies in the realms of being moderately plausible. Many consumers won't upgrade their TVs again for a few years, having only just entered the HD era, but very high-end consumers will be willing to upgrade for 3D - and a handful of consumers already have somewhat 3D-capable sets, without even knowing it (although this in itself is likely to be a source of huge confusion as the technology starts to roll out).

An even bigger problem, however, is content. Game consoles can output 3D signals to a television screen if required, certainly - in theory, if a standard for 3D display emerged today, the PS3 and Xbox 360 could support it by tomorrow. Blu-ray players, DVD players and television receivers, however, are mostly stuck in the 2D era. Their standards aren't designed for 3D, and nor is the content they display. Where games could possibly make a bold leap into 3D, movies and TV are only equipped to take faint-hearted, faltering steps.

In some regards, this is an opportunity for games - but it is also a ball and chain around the ankle of the much-desired 3D revolution. Games will drive some uptake of the technology, but the leap into the third dimension won't really happen until the rest of the entertainment media is ready as well. For now, it's fantastic to see game companies laying the foundations of the future, but I don't expect to see 3D making a major impact on the wider market for several years. It's not a gimmick - but its time has not yet come.