A realistic sailing simulation built with LLMs, Go and Ebitengine, playable both as a desktop application and in web browsers via WebAssembly.

• Realistic sailing physics with polar diagrams
• Complete race system with countdown timer and race finishing
• OCS detection (On Course Side) rule enforcement
• Mark rounding detection with proper sailing rules
• Race timing with finish time display
• VMG calculations (Velocity Made Good)
• Interactive starting line with pin flag and committee boat
• Infinite sailing world without boundaries
• Cross-platform - Desktop and Web/WASM support

make run

make web

This will:

1. Build the WASM version
2. Start a local web server on http://localhost:8080
3. Automatically open your browser
4. Serve the game with proper WASM headers

1. Pre-start: Position your boat behind the starting line
2. Countdown: Watch the timer count down from 1 minute
3. OCS Warning: Red banner appears if you cross the line early
4. Race Start: Green starting line when timer reaches zero
5. Starting: Cross the starting line from south to north (bow must cross)
6. Mark Rounding: Sail to upwind mark and round it properly:
   • Sail past the mark (south to north)
   • Pass to the left side (east to west while north of mark)
   • Sail below the mark (north to south)
7. Finishing: Cross the finish line from north to south after rounding
8. Race Complete: Timer stops and "RACE FINISHED" banner displays your time

• Wind: Constant 15 knots from North (0°)
• Boat Speed: Determined by realistic polar curves
• VMG: Velocity Made Good towards/away from wind
• Starting Line: 400 meter line with pin flag and committee boat
• Mark Laylines: Visual aids showing optimal sailing angles to the upwind mark
• Infinite World: Sail in any direction without boundaries

• Engine: Ebitengine v2
• Language: Go 1.21+
• Web Support: WebAssembly (WASM)
• Coordinates: Meter-based world coordinates
• Graphics: 2D pixel-perfect rendering

cmd/
  gosailing/     - Desktop version main
  wasm_server/   - Web server for WASM version
pkg/
  game/          - Core game logic
  coordinates/   - World coordinate system
  dashboard/     - UI and instrumentation
  geometry/      - Mathematical utilities
  polars/        - Boat performance curves
web/             - Generated WASM build output

Desktop (native):

go build ./cmd/gosailing

Web (WASM):

GOOS=js GOARCH=wasm go build -o sailing.wasm ./cmd/gosailing

Web Server:

go run ./cmd/wasm_server

The web version works in all modern browsers that support:

• WebAssembly
• Canvas API
• Keyboard input

Tested on:

• Chrome 90+
• Firefox 89+
• Safari 14+
• Edge 90+

• Desktop: 60 FPS, native performance
• Web/WASM: ~45-60 FPS, depending on browser
• Memory: Low memory usage with efficient rendering
• Network: Initial WASM download ~2-5MB

Enjoy sailing! ⛵