People

John Carmack

The engine architect

John Carmack's programming genius powered id Software's revolutionary shooters, from Commander Keen's smooth scrolling to Doom's 3D carnage.

C64 programmerspioneers 1970–

Overview

John Carmack is programming as competitive sport. His engines powered Commander Keen, Wolfenstein 3D, Doom, and Quake—each a technical leap that competitors spent years catching up to. He open-sourced his code, shared his techniques, and pushed real-time 3D forward almost single-handedly.

Fast facts

  • Born: August 1970 in Roeland Park, Kansas.
  • Early work: Apple II games, freelance programming.
  • id Software: Co-founded 1991 with John Romero, Tom Hall, Adrian Carmack.
  • Engine innovations: Adaptive tile refresh, raycasting, BSP trees, client-server networking.
  • Later work: CTO of Oculus VR (2013-2019), now AGI research.
  • Philosophy: Technical purity, open source, relentless optimisation.

Commander Keen’s trick

Before id, Carmack solved a problem:

  • IBM PCs couldn’t scroll smoothly like NES games.
  • Carmack invented “adaptive tile refresh”—only redraw what changed.
  • Suddenly, PCs could do platformers.

This technique became Commander Keen (1990), proving Carmack could make hardware do what it “couldn’t.”

The 3D revolution

Carmack’s engines defined eras:

  • Wolfenstein 3D (1992): Raycasting created fast pseudo-3D corridors.
  • Doom (1993): Variable height, lighting, non-orthogonal walls—still not true 3D but looked like it.
  • Quake (1996): True 3D polygons, internet multiplayer, revolutionary.

Each engine’s source code was eventually released, educating generations of programmers.

Open source philosophy

Carmack shared freely:

  • Released engine source code after commercial relevance faded.
  • Wrote detailed technical articles.
  • Gave GDC talks explaining his methods.
  • Believed in advancing the field, not hoarding secrets.

Beyond games

Carmack’s interests expanded:

  • Armadillo Aerospace (rocket company).
  • Oculus VR (helped make consumer VR viable).
  • AGI research (current focus at his startup).

Each pursuit applied the same relentless technical focus.

Legacy

Carmack proved that one exceptional programmer could move an entire industry. His engines weren’t just fast—they were studied, imitated, and built upon. The modern games industry runs on techniques he pioneered and shared.

See also