curltastic/README.md

curltastic

A 1v1 async multiplayer 2D curling game for mobile browser.

• 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

• Drag inside the house to place the broom (aim point).
• Use the team dropdown to choose which team's stone you are throwing.
• Use the left/right arrow buttons to select curl; the arrow points the direction the stone will curve.
• Tap THROW.
• The server runs the physics for every stone and streams their paths; the frontend interpolates the animation, so collisions animate smoothly for all stones.
• Drag anywhere outside the house (or when it's not your turn) to scroll up toward the hog line.

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, out-of-play removal
node e2e_score.cjs  # stones remain in play and alternate turns
node collision_trajectory_qa.cjs  # verifies every stone gets a trajectory during a 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.