curltastic

A multiplayer 2D curling game for mobile browser. Any number of clients can join a room, pick Red or Yellow freely, and throw when it is that team's turn (solo pass-and-play or remote opponents).

• Backend — Rust, Axum, WebSocket, Rapier2D physics (server-authoritative, 120 Hz).
• Frontend — TypeScript, Vite, Canvas2D, portrait-first touch UI.

Run locally

1. Install Rust via rustup (if not already installed).
2. Start the backend:

   cd backend
   cargo run --release
   # listens on 0.0.0.0:3000
   

3. Start the frontend dev server:

   cd frontend
   npm install
   npm run dev
   # opens on 0.0.0.0:5173 by default
   

4. Open one or more browser tabs to the same room URL, e.g.:

   http://localhost:5173/?room=DEMO1
   

   Use the team dropdown in the top-right to switch between Red and Yellow — this enables local pass-and-play on one device. Use the Copy share link button to invite an opponent on another device.

Mobile devices

The frontend binds to 0.0.0.0 via --host. Find your machine's LAN IP and open http://<ip>:5173/?room=CODE on the phone. Both devices must be on the same Wi-Fi and able to reach the backend on port 3000. The default view is zoomed in on the house; drag the sheet vertically to scroll up to the hog line.

Controls

• When it is your team's turn, drag on the sheet to place the broom (aim point) — aim is not limited to the house.
• When it is not your turn, drag to pan the ice (default framing shows the house with sidelines; pan up toward the hog line).
• Use the team dropdown to choose which team's stone you are throwing; switch any time (including mid-end for solo play).
• Use the left/right curl buttons and the weight/friction controls; friction is a local scalar.
• Tap THROW. Anyone identifying as the turn team may throw.
• The server runs physics for every stone and streams multi-stone paths; the client animates them on one clock so collisions move together.

Architecture

• WebSocket JSON protocol with tagged messages.
• Server simulates each throw at 120 Hz and sends a subset of (x, y, t) path points at 40 Hz.
• All game state, scoring, end management, and hammer rules live on the server.
• Disconnects are tolerated: the room and turn remain in memory.

E2E tests

With the backend and frontend dev server running:

cd e2e
npm install -g ws   # or npm install ws locally in the project
node e2e_test.cjs              # room lifecycle, throw, trajectory
node e2e_score.cjs             # alternate turns / stones in play
node e2e_persistence.cjs       # multi-throw stone persistence
node e2e_multi_client.cjs      # 3 clients share state (no room-full)
node e2e_end_score.cjs         # full end → end_scored + next end
node collision_trajectory_qa.cjs  # multi-stone trajectory on collision

Limitations / known simplifications

• No accounts, persistence, anti-cheat, replay log, or turn timer.
• Curl is fixed as a function of release speed (more curl at lower speed); sweeping is not implemented.
• Stones that pass the back line or leave the sheet are removed from play.