ascii-city

A walkable — and drivable — ASCII cyberpunk city. By default it's an ambient stroll: traffic cruises the avenues, pedestrians wander the sidewalks, and you can hop into any car (E) just to drive around. Set engine.game: true in js/config.js for GTA mode: missions, money, wanted stars, and cops. Three layers:

• The base — js/citygen.js, a seeded city generator: spec in, deterministic city model out. Pure data, no rendering, strictly printable ASCII (0x20–0x7E). The city is INFINITE: roads sit on a jittered lattice and every block is a pure function of (seed, coordinates), so generateRegion() can materialize any window of it; js/world.js slides a 160×160 window around the player (regen ~3ms, bit-identical overlap, so recentring is invisible).
• The sim — js/sim.js, the shared gameplay core: player (on foot or driving), civilian traffic, pedestrians, police + wanted stars, delivery missions + money, radio stations, and BFS GPS routing.
• The renderers — js/walker.js (browser) and js/tui.js (terminal), the same first-person raycaster drawing the same sim as glyphs.

js/config.js is the single input: city goes straight into generateCity(), engine tunes the renderer. City specs land there.

Run — browser

python3 serve.py 8670

http://localhost:8670 — click to walk. WASD move, mouse look, shift run, F or left-click shoots, E enters/exits cars, V toggles third person, M minimap, N new seed, 1-4 glyph size. Police respond to crimes by default (engine.police: false for a peaceful city; engine.missions: true adds deliveries and money).

Run — terminal

npx . # from the repo, or: npm i -g . && ascii-city

Same city, same raycaster, rendered as ANSI truecolor cells. V toggles a third-person chase cam, F fires (hold in kitty terminals), E jacks cars, and the HUD shows a speedometer while driving. In terminals with the kitty keyboard protocol (iTerm2, Ghostty, kitty, WezTerm) you get real hold-to-move: hold WASD, shift to run, hold arrows or drag the mouse to look. Elsewhere (e.g. Terminal.app, which never reports key releases) it falls back to latched movement: w walks and keeps going, s stops then reverses, space stops, a/d/arrows turn in eased steps, r toggles run. n new city, q quits, either way. Flags: --seed, --palette neon|terminal|amber|rust|ice, --size WxD, --fov, --dist, and --frame to print a single frame and exit. Needs Node 18+ and a truecolor terminal. js/tui.js mirrors js/walker.js — change the projection or ramps in one, mirror it in the other.

The generator

import { generateCity } from './js/citygen.js';
const model = generateCity({ seed: 'ghost-harbor-412', size: { width: 200, depth: 160 } });

Any subset of DEFAULT_CONFIG (see js/citygen.js) can be passed: road spacing/widths/jitter, per-district weight/centerBias/heights/parcels/window style/wall glyph (custom district types are kept), building tiers and antennas, plazas, trees, every glyph. Each stage pulls from its own named RNG stream and per-cell effects are coordinate hashes, so changing one parameter never reshuffles unrelated parts of the city.

Model output: cells (road/sidewalk/building/park/plaza/tree), roadAxis (lane markings), heightMap (per-cell height — what the raycaster marches), bIndex (cell → building), buildings (footprint, tiers, district, window style), plus blocks/trees/fountains/stats.

The walker

Per screen column: DDA front-to-back through the grid. Each cell contributes a wall face and a top-surface strip, clipped against yCur (lowest unpainted row) so occlusion is free. Window lattices are per-building coordinate hashes — stable across frames. Distance fog is quantized so the glyph atlas stays small.

Debug page

http://localhost:8670/debug.html — slider playground over the generator (plan view + skyline probe). Diagnostic tool only, not the product.

Roadmap

• traffic + pedestrians (roads/sidewalks already in the model)
• interiors, lifts, elevation
• signs, rain, audio