doom-regex v1.0 - interactive demo

The playable demo of DOOM computed by find-and-replace. Unzip, double-click doomregex_demo.exe (Windows, no dependencies), and you are looking at the real machine: a 96.6 MB string being rewritten by a fixed set of 544 regex rules, with a live view of the frame taking shape and a feed of every substitution as it fires.

Two modes when it starts:

• Watch one frame render: the machine paints a frame from black and halts. A "frame painted %" counter climbs as the substitutions fill in the picture. A frame takes a few minutes.
• Play: send keys (WASD/arrows, Ctrl fire, Space use) that the machine reads with its own GETC instruction out of the state string.

The window: resize it freely, click the FEED / RULES / MAP tabs (FEED is the scrolling substitution history, RULES is which rules fire most, MAP shows the whole 96 MB string as a bar with a marker where the last substitution landed), P pauses the telemetry, F12 saves the frame as a BMP.

Nothing in the driver ever parses the state or does arithmetic on it. Every change you see was produced by a regex substitution and nothing else.