A First-Person Engine in 265 Lines
Hunter Loftis (via Hacker News):
In this article, we’ll compose a first-person exploration from scratch, quickly and without difficult math, using a technique called raycasting. You may have seen it before in games like Daggerfall and Duke Nukem 3D, or more recently in Notch Persson’s ludum dare entries.
Raycasting feels like cheating, and as a lazy programmer, I love it. You get the immersion of a 3D environment without many of the complexities of “real 3D” to slow you down. For example, raycasts run in constant time, so you can load up a massive world and it will just work, without optimization, as quickly as a tiny world. Levels are defined as simple grids rather than as trees of polygon meshes, so you can dive right in without a 3D modeling background or mathematics PhD.