1993's 'Doom' Wasn't the 3D Game We Think It Was

The new Doom is out, and as you may have already learned today, Motherboard editor Emanuel Maiberg and I rather like it. This is a good opportunity to talk about the legacy of the original game, which has long been heralded as one of the key pioneers in 3D gaming. But the truth, at least from a technical standpoint, is a little more complicated. As Ronnie Oni Edwards relates on his YouTube show "Digressing and Sidequesting," the original Doom from 1993 was actually little more than a cleverly disguised 2D top-down shooter.

Part of the problem was working with the technology at the time. Both

Doom

and its similarly innovative 1992 predecessor

Wolfenstein 3D—

both programmed by John Carmack and John Romero—would eventually make it to the Super Nintendo Entertainment System, for instance, and the SNES just wasn't capable of rendering the type of "true" 3D we know today. Edwards points out that this limitation was even true of 1991's

The Legend of Zelda: A Link to the Past

, which appears to have depth and multiple layers, but which in reality merely has specific tiles that restrict movement to a single direction in order to create the illusion of dropping down.

This smoke-and-mirrors approach, fascinatingly enough, was also applied in

Wolfenstein 3D

. Through a process known as raycasting, Edwards points out,

Wolfenstein 3D

was simply making distant tiles appear to be a particular size "every fraction of a fraction of a second" depending on how far away they were from the player. This is why the walls in

Wolfenstein

were all the same size and why all the maps only had one floor.

"All of

Wolfenstein

's maps are essentially 2D maps you could sketch on a piece of graph paper," Edwards says.

Doom

, however, had things like stairs and walls with different heights, but it still used a much more complicated version of the same approach called binary space partitioning. The big difference is that multiple, smaller compartments of the map were being processed at once, which resulted in the illusion of three dimensions. You can still find ghosts of Wolfenstein 3D's raycasting approach, though, in little quirks such as the way the Doomguy's gun hits enemies above and below him even though the gun itself never moves.

"The processor [in Doom] is just thinking of everything as being in a 2D plane, but drawing it in such a way that it looks like it's calculating three-dimensional space," Edwards says. "If it were actually calculating three-dimensional space, you would be able to stack rooms on top of one another, but you can't in Doom." It wasn't until 1996, with the release of Quake, that Carmack would deliver the "proper" 3D technology that led to the foundations of many if not most games today. But considering that he and Romero showed us what dreams may come a few years before with technically incompatible technology only serves to enhance the games' legendary status.