Torus Chess

A browser chess variant on an 8×8 torus (edges wrap in both directions), with a custom start (Black on ranks 5–6; pawns move toward decreasing rank, as in the in-app blurb). Built with React, TypeScript, Vite, Chessground, and a small torus rules engine (legal moves, castling state, check detection).

Run locally

npm install
npm run dev

Open the URL Vite prints (default http://localhost:5173/). The app redirects into a game path under /fen/….

Production build and preview (uses base path /torus-chess/ for GitHub Pages):

npm run build
npm run preview

GitHub Pages

The repo includes a workflow that builds and deploys the dist output. Set Settings → Pages → Source: GitHub Actions. The site expects to live at https://<user>.github.io/torus-chess/ (see vite.config.ts base if your repo slug differs).

Game URL (current encoding)

The shareable path is a single format:

/fen/{w|b}/{KQkq or -}/{lastMove or -}/{eight rank strings}

Example: turn, castling rights, last move (- if none), then eight board ranks using a FEN-like piece alphabet. Invalid paths fall back to the default start position.

What works today

• Torus geometry — Wrapping moves; four repeating Chessground tiles in a panning viewport so you can scroll the torus without hitting a hard edge.
• Rules — Legal move generation, king-in-check filtering, castling rights in state and URL, last-move in URL.
• Modes — Vs human (URL + localStorage in this browser; share the link), vs bot (you are White; Black plays a uniform random legal move after a short delay).
• Pawn promotion — When a pawn hits its promotion rank, a modal offers queen, rook, bishop, knight (not auto-queen only).
• UI — Dark chrome, check highlighting, multi-board selection highlight, drag-to-pan on empty squares; layout uses a square viewport with min(100%, min(96vw, 900px)) and container-query-based cell sizing so the grid tracks the clipped board area.

Roadmap (planned work)

Roughly in line with current priorities:

Area	Status / intent
Reactive design — fit to view & polish UI	Layout is usable on desktop and narrow viewports, but typography, spacing, safe areas, and touch UX still need a deliberate responsive pass.
Colour promotion ranks	Engine knows promotion ranks; the board does not yet visually distinguish those squares (e.g. tint or marker).
Bots	A minimal random Black bot exists; stronger or configurable opponents are open work.
Pawn promotions	Done for interactive play (including underpromotion). Further work might be bot promotion policy, animation, or URL details if extended encodings are added.
Alternative game encoding URLs	Only the segmented /fen/… scheme exists today; shorter or alternate encodings (e.g. compressed state) are planned.
Fix viewport container thing	CSS already works around Chessground bounds vs tile size and cqmin vs max-width clamps; remaining edge cases (alignment, resize, very small screens) are tracked for cleanup.
Undo	Not implemented; needs a move stack (and policy for URL + bot + human mode).
Help menu	No in-app rules or controls reference yet.
Rotation?	Board orientation is fixed to White’s view everywhere; optional flip / rotate is exploratory.

License

Add a LICENSE file when you choose one.