It was early 1993 and Id Software was at the top of the PC gaming industry. Wolfenstein 3D had established the First Person Shooter genre and sales of its sequel Spear of Destiny were skyrocketing. The technology and tools Id had taken years to develop were no match for their many competitors. It would have been easy for Id to coast on their success, but instead they made the audacious decision to throw away everything they had built and start from scratch. Game Engine Black Book: Doom is the story of how they did it. This is a book about history and engineering. Don’t expect much prose (the author’s English has improved since the first book but is still broken). Instead you will find inside extensive descriptions and drawings to better understand all the challenges Id Software had to overcome. From the hardware (the Intel 486 CPU, the Motorola 68040 CPU, and the NeXT workstations) to the game engine’s revolutionary design, open up to learn how Doom changed the gaming industry and became a legend among video games.
Foreword by John Carmack:
In many ways, DOOM was almost a “perfect” game.
With hindsight and two decades more skill building, I can think of better ways to implement almost everything, but even if I could time machine back and make all the changes, it wouldn’t have really mattered. DOOM hit a saturation level of success, and the legacy wouldn’t be any different if it was 25% faster and had a few more features.
The giant aliased pixels make it hard to look at from a modern perspective, but Doom felt “solid” in a way that few 3D games of the time did, largely due to perspective correct, subpixel accurate texture mapping, and a generally high level of robustness.
Moving to a fully textured and lit world with arbitrary 2D geometry let designers do meaningful things with the levels. Wolfenstein 3D could still be thought of as a “maze game”, but DOOM had architecture, and there were hints of grandeur in some of the compositions.
Sound effects were actually processed, with attenuation and spatialization, instead of simply being played back, and many of them were iconic enough that people still recognize them decades later.
The engine was built for user modification from the ground up, and the synergy of shareware distribution, public tool source release, and early online communities led to the original game being only a tiny fraction of the content created for it. Many careers in the gaming industry started with someone hacking on DOOM.
Blasting through the game in cooperative mode with a friend was a lot of fun, but competitive FPS deathmatch is one of the greatest legacies of the game. Seeing another player running across your screen, converging with the path of the rocket that you just launched, is something that still makes millions of gamers grin today.
There was a lot of clever smoke and mirrors involved in making DOOM look and feel as good as it did, and it is a testament to the quality of the decisions that so many people thought it was doing more than it actually was. This remains the key lesson that still matters today: there are often tradeoffs that can be made that gets you a significant advantage in exchange for limitations that you can successfully cover up with good design.