Remember a year or so ago, when everyone was arguing over whether the LCD TV or the plasma TV was the next big thing? And then after that, when everyone was arguing over whether HD DVD or Blu-ray was the future of home entertainment? Remember how dumb you felt when you sat down with your HD DVD player in front of your DLP TV and realized you’d backed the wrong horse both times? Well, guess what? You have a chance to redeem yourself, because the new format debate is starting, and it’s aaaalll about the 3D.

As the technology behind “stereoscopic” 3D imaging progresses (real pop-out-of-the-screen 3D, not just polygons or Wolfenstein 3D), companies are coming up with more and more ingenious ways to trick your eyes into seeing depth. Our guide will tell you how it all works, as well as which untested gizmos to start saving your pennies for. And just in case you didn’t think this was relevant to gaming today, guess what? Invincible Tiger: The Legend of Han Tao comes out for XBLA and PSN later this month, and aside from being one of the most fun beat-em-ups we’ve played for a while, it also features support for nearly all of the 3D modes we’re about to explain to you.

The basic premise

It’s time to learn about your body, class! To sum it all up in a single sentence: 3D images work because your brain is really advanced, but also really gullible. As you may have noticed, humans have two eyes on their heads.

Above: Fact 

That means when you’re looking at something - say the hot girl above - you’re really seeing two nearly identical images simultaneously. (You lucky dog!)  We say identical because – hopefully – your eyes are positioned an inch or so apart. (If your eyes are not an inch or so apart, you may want to stop reading this article and contact a doctor.)

What your eyes are actually seeing:

Your brain, supercomputer that it is, sees two identical hot girls, figures out how far apart they are, and says, “Oh! That image is actually one hot girl, and it is x distance away from me.” Your brain is good at this little trick, and it rarely messes up, which is good, because otherwise you might think everyone was twins. But with a little ingenuity, you can find a way to break your brain.

Above: Pretty much what we’re going for 

All you need to do to create the illusion of depth is take two identical images, place them side by side, and find a way to prevent each eye from seeing both images. Simple, right? If your left eye can’t see the right-eye image and vice-versa, your brain decides it’s seeing one image that it then deduces is closer than it actually is. That’s the core concept behind all the 3D you see in TV, movies and games.

But that’s also the million-dollar dilemma. How do you get your left or right eye to see only the image it’s supposed to, and not see the image it’s not supposed to see? This is where the folks behind today’s 3D effects work their magic.

Anaglyph 3D

Or, How it used to be done

Back when dinosaurs roamed the Earth, this was the way to do 3D. So archaic that a GR editor could produce a 3D image with virtually no effort or special tools beyond colored plastic, anaglyph 3D relies on the concept of color filters to prevent one of your eyes from seeing the other eye’s image and vice-versa. The colored lenses in anaglyph 3D glasses keep you from seeing anything with the corresponding color in the film – the red lens removes the red, and the blue lens removes the blue.

Don’t get how the filters work? Here’s an experiment that might help. See if you can see the hidden message in this image:

Oh, you saw it, didn’t you. OK, try it now:

Above: Suck on that 

The message is still there, but you can’t see it because it’s no longer distinguished from the background. The same concept is at work within the red plastic lens – by making everything red, any red image disappears. By filtering out images based on color, you can control what each eye sees. All you have to do to create “convincing” 3D is take two nearly identical images, set them a fixed distance apart, make one eye image red and the other blue, and strap on some glasses. Voila: you’ve got anaglyph 3D.

Above: GamesRadar’s not-so-hidden message 

How it looks on Han Tao:

Above: if you have any old-fashioned red/blue 3D glasses at home, they’ll work on this image. Try it out! 

We put “convincing” in scare quotes up there because anaglyph 3D is really the bottom of the barrel in terms of modern 3D effects. The images do “pop,” sure, but if you’re using colored filters on your eyes, everything you see will be a disgusting soup of reds and blues. Simply put, you don’t want to play games in anaglyph 3D. It’s dizzying, ugly, and will give you serious eyestrain. Be extra careful when buying “3D” games like G-Force or new 3D DVDs like Coraline - the box will try to sell you anaglyph 3D and pass it off as the real thing. It’s not. Watching a current movie in outdated anaglyph 3D will make you miserable and a little bit queasy. Don’t say Uncle GamesRadar didn’t warn you.

Parallax 3D

Or, “Virtual Boy” 3D

The Virtual Boy took the most obvious approach to 3D gaming we could have come up with. Each eye needs to see a unique image? Okay, we’ll jam a screen up in front of each eye so close that they can’t see the other eye’s screen (or anything else, for that matter). Hmm… Where has that been done before?

Above: Images from modojo and Born-again redneck.com 

There’s nothing inherently wrong with this 3D technique, even if it means only one person can view the effect at a time. In fact, many 3D VR displays operate using the parallax principle. No, the real problem with the Virtual Boy is that Nintendo decided the best way to process its 3D effects was with Oh-God-My-Eyes cheap Red LED lights, like the kind you buy at hardware stores.

Above: Seems like a good idea to rub this up against your face 

Eyestrain was a big issue for the Virtual Boy (not to mention the fact that it was about as big as an original Xbox) and it was unceremoniously dumped into the bottomless pile of Nintendo junk within a year of launch. So much for the new age of 3D gaming.

How it looks on Han Tao:

If you have the means to split up your display onto two separate monitors, Invincible Tiger’s side-by-side 3D mode produces pretty convincing effects using parallax. You’ll have to play the game with the displays pretty darn close to your eyes, though, and we’re pretty sure you can only pull that off with a specialized VR helmet. You’ll probably feel sick and look like a complete dork, just like you did when you played Virtual Boy.

Next up: 3D that actually looks good!