id Software · 1993 · 1990s · C
The Doom engine introduced binary space partitioning to real-time rendering, producing the illusion of a 3D world from a 2D map that ran fluidly on 1993 consumer hardware.
id Tech 1, developed by John Carmack and released with Doom in December 1993, used a technique called binary space partitioning (BSP) to subdivide the game world into a tree structure that allowed the renderer to draw only the visible geometry in the correct order without a Z-buffer. The engine could not render true 3D spaces — floors and ceilings were always horizontal and rooms could not be stacked — but its use of variable-height sectors, textured walls, and dynamic lighting via diminished lighting created a convincing illusion of depth. The engine was licensed to dozens of studios and used as the basis for Heretic, Hexen, Strife, and many more; id Software released the source code under the GPL in 1997, spawning a community of source ports including PrBoom and GZDoom that remain in active development today.