Sim Drive

Sim Drive is a multiplayer browser racing game where a shared display hosts the race and phones become tilt-steering controllers.

Status

Playable prototype in active development. The core room flow, phone controller, server-authoritative race loop, split-screen display, vehicle selection, procedural tracks, audio, and optional haptics are working.

Run locally

npm install
npm run dev

Open the display at http://localhost:5173/. The dev server also prints a LAN URL, which is useful for joining from a real phone on the same network. Phone motion sensors require a secure origin in Chrome/Chromium and iOS Safari/WebKit, so use the HTTPS Codespaces/forwarded URL, production HTTPS URL, or an HTTPS tunnel when testing tilt steering; plain LAN http:// may only work in Firefox.

In GitHub Codespaces, open the forwarded 5173 port URL. The app proxies WebSockets through the same forwarded origin, so you do not need to separately open port 8787 for normal dev use.

Current playable slice

Room flow

• Create a room from a display browser.
• Join from a phone controller by QR code or room code.
• Phone controller refreshes and same-phone QR rescans auto-resume the saved driver when possible.
• First joined controller becomes VIP.
• Lobby shows the QR code, race settings, selected track, driver lineup, each driver's vehicle, setup, and cockpit style.
• The home screen shows a live active-driver count only when at least one driver is online.
• One-player practice works.

Race settings

• VIP can choose track, laps, pre-race tutorial, warm-up/flying start, ghost cars, rain, gentle stability assist, and reset mode.

Vehicles and driver options

• Each driver can choose a vehicle: Formula Prototype, KZ Kart, Stock Truck, or Tuk-Tuk.
• Formula Prototype and Stock Truck offer Balanced, High Grip, and High Speed setups; KZ Kart and Tuk-Tuk use a fixed setup.
• Each driver can choose a personal cockpit style: None, Hands, or Paws; new players default to None.
• Each driver can choose a personal rear-view mirror mode: Auto, On, or Off; new players default to Auto, which shows it when other active cars exist.

Race display

• Display landing/lobby/tutorial/results screens support System, Light, and Dark themes.
• Five tracks are available: Sakura Sprint, Alpine Grand Prix, Fjord Loop, Keys Causeway, and Cloudline Ascent.
• Race view renders a cockpit-style 3D scene with smooth procedural track ribbons, raised curbs, rubber/skid road detail, generated terrain support for elevated tracks, vehicle-specific cockpit silhouettes, countdown lights, and a short first-place banner.
• Race view includes a minimap, live global leaderboard, rear-view mirror, and display-side auto-spectate for finished racers while others are still active.
• Results include podium-style placement, total time, and best lap.

Phone controller

• Phone controller supports tilt steering with iOS/WebKit motion permission prompts, Chrome-friendly devicemotion/Generic Sensor fallbacks, countdown-time steering centering, 1-10 motion sensitivity, saved motion-steering inversion, fallback touch steering, touch brake/throttle zones, first-tap pedal preferences, motion/audio/haptic tests, quick countdown control hints, vehicle-specific/nearby-rival audio, and vibration where supported.
• Controller setup/lobby screens show a recommended-browser notice when the phone is not on the preferred Android Chromium-style browser path.
• Web vibration depends on browser support. Android Chromium/Samsung-style browsers are the main target; iOS Safari does not support it; Firefox Android may expose partial/no-op support.

Server behavior

• Server owns room state, race phase, vehicle-specific velocity-based movement, per-driver setup multipliers, warm-up/flying start timing, downforce-style speed-building grip, elevation/grade effects, tuk-tuk rollover risk, optional crash/off-track reset, checkpoint-gated lap completion, directional collisions, DNF handling, and results.
• If every display/host browser disconnects, the room stays resumable for a 20-second grace window. If no display reconnects in that window, the room closes and controllers are sent back out of the game.

Project docs

• SPEC_detailed.md: canonical product and technical spec.
• FEATURES.md: product-facing feature summary.
• HUMAN_CHECKS.md: real-device phone playtest checklist.
• PLAYTEST_AUTOMATION.md: automated full-lap and visual capture workflow.
• DRIVER_FEEDBACK.md: phone-side audio and haptic mapping.
• CARS.md: current vehicle and handling notes.
• PERFORMANCE.md: race performance, networking, rendering, and new-track engineering notes.
• REMINDERS.md: follow-up ideas.

Useful commands

npm run typecheck
npm run build
npm start

npm start serves the production build and WebSocket server from one Node process on port 8787.

Contributing

Issues and pull requests are welcome. Keep changes scoped, update the relevant docs when behavior changes, and run npm run typecheck plus npm run build before opening larger changes.