# hear-on-out

A generative ambient music application that transforms real-time weather and air quality data into dynamic soundscapes.

## Overview

hear-on-out uses your geolocation to fetch current weather and air quality data, then generates unique ambient music that responds to environmental conditions in real-time. Every parameter of the audio - from tempo to reverb to note patterns - is affected by the weather around you.

## Features

### Weather-Reactive Generative Music

**Chord Progressions**
- 6 distinct mood-based progressions (bright, dreamy, melancholic, tense, warm, ethereal)
- Intelligent selection based on weather comfort scoring
- Smooth transitions between progressions

**Instruments**
- **Ambient Pad**: Lush detuned fat oscillator (3 voices, 30 cent spread) with day/night reactive envelopes for rich, warm soundscapes
- **Main Arpeggio**: Temperature-reactive note patterns with variable speed (1n → 8n) and volume, bypasses filter for clarity
- **Ping Arpeggio**: High-pitched reverse arpeggios that intensify with weather extremity, speed scales with temperature (1n → 16n)
- **Bass Synth**: Root note foundation with randomized release times for subtle variation

**Dynamic Audio Parameters**
- **BPM**: Scales linearly with temperature (5 BPM at 0°C → 30 BPM at 30°C)
- **Reverb**: Wet signal responds to humidity (more humid = more reverb)
- **Delay**: Time and feedback react to wind speed (faster wind = shorter delay, more feedback)
- **Filter**: Applied only to ambient pad, cutoff frequency brightens with temperature (0°C = 400Hz dark, 30°C = 8000Hz bright)
- **Resonance**: Increases with wind speed for sharper filtering

### Air Quality Monitor

- Geiger-counter style noise bursts that trigger based on pollution levels
- Higher pollution = more frequent bursts (6s intervals for clean air → 0.3s for heavy pollution)
- Spacious reverb (30s decay) for atmospheric depth
- Monitors PM2.5, PM10, and dust particles

### Audio Visualization

- Real-time particle system using p5.js
  - **Desktop**: 40 particles at 30fps with connection lines
  - **Mobile**: 15 particles at 20fps, no connections (performance optimized)
- FFT analysis for bass, mid, and treble frequency detection
- Particles react to audio levels with dynamic size and movement
- Adaptive sizing: 400x400px (desktop) or 280x280px (mobile)
- Automatic pause during scrolling to prevent audio interference on mobile

## Technologies

- **SvelteKit** - Web framework with Svelte 5 runes
- **Tone.js** - Web Audio API wrapper for synthesis and effects
- **p5.js** - Creative coding for visualizations
- **Tailwind CSS v4** - Styling with black/white monochrome theme
- **Open-Meteo API** - Weather and air quality data

## Performance Optimizations

The application includes several optimizations for smooth performance:

**Desktop Optimizations:**
- 40 particles with 30fps rendering
- Audio-reactive displacement updates every 3rd frame
- Particle connections drawn every other frame with limited neighbor checking
- Tab visibility detection: Visualization pauses when tab is not focused
- Efficient audio routing: Arpeggios bypass filter for cleaner CPU usage

**Mobile-Specific Optimizations:**
- **Reduced particle count**: 15 particles (vs 40 on desktop)
- **Lower framerate**: 20fps (vs 30fps on desktop)
- **Disabled connection lines**: Removes expensive O(n²) calculations
- **Smaller canvas**: 280x280px visualizations (vs 400x400px on desktop)
- **Scroll handling**: Visualization pauses during scrolling to prevent audio stuttering
- **Less frequent updates**: Displacement updates every 5th frame (vs 3rd on desktop)
- **Screen sleep recovery**: Audio context automatically resumes after device wakes up
- **Visibility API**: Properly handles audio context suspension/resumption

**Mobile Performance Note:**
Running both generators simultaneously on mobile devices may cause performance issues. For optimal experience on mobile, consider running one generator at a time.

## Setup

```bash
# Install dependencies
npm install

# Run development server
npm run dev

# Build for production
npm run build
```

## How It Works

1. **Location Input**: User can either:
   - Grant browser geolocation permissions (automatic location detection)
   - Manually enter latitude/longitude coordinates
2. **Data Fetch**: Current weather and air quality data retrieved from Open-Meteo API
3. **Weather Comfort Scoring**: Algorithm calculates comfort based on temperature, humidity, cloud cover, wind, and precipitation
4. **Progression Selection**: Chooses appropriate chord progression based on weather mood
5. **Audio Generation**: All instruments and effects dynamically adjust to conditions
6. **Real-time Updates**: Audio parameters smoothly transition as weather changes

## Geolocation & Browser Compatibility

The app supports two methods for location input:

**Automatic Geolocation:**
- Requires HTTPS in production (localhost works without HTTPS)
- User must grant browser permission when prompted
- May not work on some mobile browsers or restrictive browser settings

**Manual Coordinate Entry:**
- Fallback option for when geolocation is unavailable
- Accepts latitude (-90 to 90) and longitude (-180 to 180)
- Works on all devices and browsers
- Useful for exploring weather from different locations

**Production Requirements:**
- Must be served over HTTPS for geolocation to work
- Development server uses `@vitejs/plugin-basic-ssl` for local HTTPS

## Mobile Experience

The application is optimized for mobile devices with several performance enhancements:

**Audio Playback:**
- Automatic audio context recovery after screen sleep/wake
- Handles browser audio suspension gracefully
- Transport automatically restarts when app becomes visible

**Visual Performance:**
- Adaptive particle count and framerate based on device
- Visualization pauses during scrolling to prevent stuttering
- Smaller canvas size for reduced GPU load

**Known Limitations:**
- Running both generators simultaneously may impact performance on lower-end devices
- Some mobile browsers may require user interaction to start audio playback
- Audio may briefly pause during heavy scrolling or multitasking

## Project Structure

```
src/
├── lib/
│   ├── audio/
│   │   ├── instruments/        # Modular synth instruments
│   │   ├── audio-effects.ts    # Shared audio effects
│   │   ├── chord-progressions.ts
│   │   └── weather-mood.ts     # Comfort scoring & progression selection
│   ├── components/
│   │   └── AudioVisualization.svelte
│   └── generators/
│       ├── weather/WeatherGen.svelte
│       └── air-quality/AirQualityGen.svelte
└── routes/
    ├── +page.svelte           # Geolocation entry point
    └── on-out/+page.svelte    # Audio generators
```

## Weather Mood Mapping

| Conditions | Progression | Characteristics |
|------------|-------------|-----------------|
| Stormy/Extreme | Tense | Dissonant, unsettling |
| Very Hot (30°C+) | Warm | Energetic, bright |
| Cold/Rainy | Melancholic | Somber, introspective |
| Foggy/Misty | Ethereal | Spacious, mysterious |
| Pleasant Day | Bright | Uplifting, major tonality |
| Pleasant Night | Dreamy | Calm, flowing |

## License

MIT