# 🏙️ PolyCity — 3D City Builder

**PolyCity** is a full-featured, free, open-source city-building simulation that runs
entirely in your browser. Zone districts, wire up power, keep citizens happy, fight
fires, balance the budget — and grow a tiny island outpost into a glittering megalopolis.

Built with **Three.js + Vite**, zero runtime dependencies beyond the engine,
procedural graphics (no asset downloads), and a simulation modeled on the classics.

![gameplay](docs/screenshot.png)

## ✨ Features

| | |
|---|---|
| 🗺️ **Procedural islands** | Every new map is unique — winding rivers, beaches, forests |
| 🏘️ **RCI zoning** | Residential / commercial / industrial with demand-driven growth |
| ⚡ **Power grid** | Coal, solar & wind plants; brownouts when demand exceeds supply; wind turbines get +50 % on the coast |
| 📈 **Land value & upgrades** | Parks, plazas, services and waterfronts raise land value; buildings grow through 3 density tiers |
| 🚓 **City services** | Police, fire stations, hospitals and schools shape happiness and value |
| 🔥 **Disasters** | Pollution-driven fires spread and are contained by fire coverage; mature cities face tornadoes that flatten whole streets (toggle in settings) |
| 💰 **Budget & taxes** | Live tax slider, itemized income/upkeep ledger, debt warnings |
| 🚗 **Traffic** | Animated cars flow along your road network |
| 🌗 **Day/night cycle** | Windows light up as the sun sets |
| 🎯 **Goals & milestones** | From *Outpost* to *Megalopolis*, with an onboarding quest list |
| 💾 **Saves** | Autosave, 3 manual slots, JSON export/import |
| 📱 **Touch support** | Paint with one finger, pinch-zoom, two-finger rotate |
| 🔌 **PWA** | Installable, offline-capable via service worker |

## 🎮 Controls

| Action | Input |
|---|---|
| Use tool / paint | **Left-drag** or one finger |
| Orbit camera | **Right-drag** or two fingers |
| Pan | **Middle-drag**, or `WASD` / arrow keys (`Shift` = faster) |
| Zoom | Mouse wheel / pinch |
| Pause · speed | `Space` · `1` `2` `3` |
| Tools | `Q` inspect · `B` bulldoze · `R` road · `Z/X/C` zones |
| Close / cancel | `Esc` · Help: `H` |

### How to play in 30 seconds
1. Drag an **L-shaped road** from the coast inland.
2. Paint **homes** beside it, then some **shops** and **industry**.
3. Drop a **coal plant** anywhere — power is a city-wide grid.
4. Press ▶▶ and watch the neighborhood fill in.
5. Add police/fire/parks to push land value past the upgrade thresholds.

## 🚀 Run it locally

```bash
pnpm install
pnpm dev        # dev server → http://localhost:5173
```

## 📦 Production build

```bash
pnpm build      # outputs static site to dist/
pnpm preview    # serve dist/ locally
```

The build is fully static and relative-path based — drop `dist/` on any host.

## 🌍 Publish it

**GitHub Pages** — this repo ships `.github/workflows/deploy.yml`; push to `main`
and enable Pages (*Settings → Pages → Source: GitHub Actions*).

**Netlify / Vercel / Cloudflare Pages** — import the repo, build command
`pnpm build`, publish directory `dist`. A ready-made [`netlify.toml`](netlify.toml)
is included.

**itch.io** — zip the contents of `dist/` (keep `index.html` at the zip root),
upload as an HTML5 game, check *sharedarraybuffer is not needed* and any
resolution; the game auto-fits.

## 🧪 Tests

```bash
node tests/engine.mjs   # 40-assertion simulation suite (pure Node)
node tests/soak.mjs     # 40-year economy/growth/power soak test
node tests/smoke.mjs    # headless-browser end-to-end run
node tests/capture.mjs  # renders promo screenshots into shots/
```

## 🛠️ Tech notes

- One shared `MeshStandardMaterial` + instanced meshes draw the entire city in a
  handful of draw calls; geometry is merged & vertex-colored at load time.
- Simulation runs on typed arrays (64×64 tiles) with monthly ticks decoupled
  from rendering; speeds pause / 1× / 2× / 3×.
- Adaptive resolution keeps frame times sane on weak GPUs.
- All audio is synthesized WebAudio — no assets, no tracking, no network calls.

## License

[MIT](LICENSE) — build, remix, ship it. 🏗️
