ZenConsoleProc

Jun 2001 – Jul 2001 · age 19

What it was

A two-week prototype of the in-game console Jeff wanted for a future engine, built as a plain Win32 console program in C++. A processor class held two fixed tables: commands, each a name and a function pointer, and variables, each a name, pointers aimed at live engine values, and an optional callback that fired on change. After registration both tables were quicksorted by name and searched with a home-made jump search. Typing a name ran the command or echoed the variable; typing a name and a value assigned it and fired the callback. Underneath sat a wrapping buffer of 80 lines, meant to be drawn in OpenGL someday. The demo registered two commands and two variables, one of them sv_gravity, and looped until Escape. It never met an engine.

Wins, for the age

At nineteen, Jeff rediscovered the Quake cvar model of 1996: variables as pointers into the running engine plus a callback, so typing sv_gravity 800 would change the game. The shape was right, found by an ape who wanted a console and simply built one.
Sorted once at startup so every lookup was sublinear, the right instinct for something meant to run every frame, even if four names hardly needed it.
Chose fixed capacities on purpose and said so in a comment: "I don't really like dynamic data." A decision, written down.

What it taught

The boring parts, registration, lookup and echo, are most of a console.
A sort and a search over a handful of strings is more machinery than the problem deserves. Enjoying writing it anyway is allowed, once.
Polling the keyboard in a tight loop burns a core. A real console has to be driven by the game's input system.
A text surface that writes through raw pointers into engine memory needs bounds and type checks, and that matters more once something other than a human is typing.

Genealogy

Ancestors: none on record. The first data-driven command surface. Descendants: Adama Tooling: a devbox REPL poking at live state, twenty-odd years on.

Epitaph

Here lies ZenConsoleProc, which sorted four names so it could find them faster, and knew how to change gravity in a game that did not exist.