A procedural rain and thunderstorm simulator built with Python, Pygame, NumPy, and SciPy. Features multi-layer parallax rainfall, particle splash physics, fractal branching lightning strikes, and real-time procedural audio synthesis.

• Parallax Rainfall: Multi-depth rain layers with independent velocities, lengths, opacities, and wind deflection angles.
• Particle Splashes & Ripples: Water droplets eject upward on surface collision with expanding ground ripples.
• Fractal Branching Lightning: Midpoint displacement generation producing branching lightning bolts, multi-phase sky illumination, and camera trauma shake.
• Procedural Sound Synthesis:
  • Real-time lowpass filtered rain ambiance.
  • Granular droplet impact synthesis using decaying sinusoids.
  • Modulated wind noise responsive to current wind velocity.
  • Realistic thunder playback with optional distance delay (speed of sound physics).
• Interactive Controls & Audio Mixer:
  • Live volume sliders for Master, Thunder, Rain Ambiance, Droplet Patters, and Wind.
  • Five weather presets: Drizzle, Steady Rain, Thunderstorm, Gale Storm, and Window Rain.
  • Auto-hiding HUD for uncluttered ambient viewing.
• Resolution & Fullscreen Support: Dynamic layout recalculation supporting window resizing and seamless fullscreen toggling.

1. Clone the repository:

   git clone https://github.com/azuletto/rain_generator.git
   cd rain_generator

2. Install dependencies:

   pip install -r requirements.txt

3. (Optional) Install in editable mode:

   pip install -e .

Run via the main launcher:

python thunderstorm_simulator.py

Or via module execution:

python -m rain_generator

python -m rain_generator --preset thunderstorm --fullscreen
python -m rain_generator --preset drizzle --mute -W 1280 -H 720

Available options:

• -p, --preset: Weather preset (drizzle, steady, thunderstorm, gale, cozy)
• -i, --intensity: Intensity level (Low, Medium, High, Extreme)
• -f, --fullscreen: Launch in fullscreen mode
• -m, --mute: Launch with audio muted
• -W, --width: Window width in pixels (default: 1080)
• -H, --height: Window height in pixels (default: 720)
• --fps: Target framerate (default: 60)
• --no-shake: Disable camera shake on lightning
• -d, --duration: Audio export duration in seconds (default: 60)
• -o, --export: Output filepath to generate and export audio directly without GUI

Generate an ambient audio file of any custom length (e.g. 2 minutes of thunderstorm audio):

python thunderstorm_simulator.py --duration 120 --export thunderstorm_2m.wav --preset thunderstorm

You can also click the Export Audio button in the top HUD (or press G) while running the simulator to open the interactive generator dialog.

Run the test suite using pytest:

pytest

This project is licensed under the MIT License. See LICENSE for details.