I'm working on a new project suggested to me by my friend Alex. The idea is to present a split-screen multiplayer experience without having to worry about "screen-watching", when you're friends try to get an advantage by looking at your screen. An added benefit of this is that instead of having your screen crammed in the corner, it fills up the whole TV. To be clear, this technique is not presenting a "3-D" image to a viewer, but it is taking advantage of the same science and technology that 3-D uses. Here are two separate screenshots from Halo 2. Some astute observers may note they are not from the same gameplay session, but they will still serve our purpose.
Screenshot 1 of Halo 2 (courtesy of IGN)
Screenshot 2 of Halo 2 (courtesy of Team Xbox)
Now, we're going to combine the two images into one anaglyph, or red/cyan image you may be familiar with from 3-D movies or images. The red/cyan filters will result in a loss of color quality, but this is just a proof of concept. To appropriately view the image below, you'll need a pair of old-school 3-D glasses (red/cyan). Put them on and look at the picture, first closing the left eye, then the right. You'll be able to see each screenshot isolated.
Screenshots 1 and 2 combined to form the red/cyan anaglyph
In order for this to be implemented in a game, Player A would wear glasses with two red lenses and Player B would wear glasses with two cyan lenses. This way, neither player could see the others screen. Using red/cyan, only 2 players can play at a time, but this technique could also be done using polarized lenses, which you see used in 3-D movies these days. Using polarized lenses, more than 2 players could play at one time.
This technique is not perfect. One problem is the loss of color quality mentioned above. Polarized lenses would solve this, but they require a screen or projector capable of presenting polarized images; red/cyan only requires the user to have special glasses. Players can still cheat using polarized lenses by rotating their head to look at an opponent's screen.