Orbital Mechanics Simulation

A 3D orbital mechanics simulation using a 2-body gravitational model with sphere of influence (SOI) transitions. Features real-time visualization of celestial bodies using raylib.

Features

• 2-body gravitational physics with Euler integration
• Eccentric orbit support - circular and elliptical orbits using vis-viva equation
• Sphere of influence (SOI) transitions between gravitational parents
• 3D real-time visualization using raylib
• Configurable star systems via simple text files
• Interactive camera controls (rotate, zoom)
• Simulation controls (pause, resume, speed adjustment)
• Solar system and binary star example configurations

Getting Started

Cloning the Project

This project includes raylib as a git submodule. Clone with submodules:

git clone --recursive https://github.com/yourusername/claudes_game.git
cd claudes_game

If you already cloned without --recursive, initialize the submodule:

git submodule update --init --recursive

Dependencies (Debian 13)

Install the required system packages:

sudo apt-get update
sudo apt-get install -y \
    build-essential \
    g++ \
    make \
    libx11-dev \
    libxcursor-dev \
    libxrandr-dev \
    libxinerama-dev \
    libxi-dev \
    libgl1-mesa-dev \
    libglu1-mesa-dev

Note: You don't need to install raylib separately - it's included as a git submodule and will be built automatically by the Makefile.

Building

make

This will:

1. Build raylib from the submodule (first time only)
2. Compile all source files
3. Create the orbit_sim executable in the project directory

To clean and rebuild:

make rebuild

To clean everything including raylib:

make clean-all

Running

Run with the default solar system configuration:

./orbit_sim

Run with a custom configuration file:

./orbit_sim configs/example_binary_star.txt

Controls

• Arrow Keys: Rotate and zoom camera
• Space: Pause/Resume simulation
• +/-: Speed up/slow down simulation
• I: Toggle info display
• ESC: Quit

Configuration File Format

Configuration files define celestial bodies in a simple text format:

# Comments start with #
# Format: name mass(kg) radius(m) x(m) y(m) z(m) parent_index r g b eccentricity semi_major_axis(m)

# Sun at origin
Sun 1.989e30 6.96e8 0 0 0 -1 1.0 1.0 0.0 0 0

# Earth - circular orbit (e=0)
Earth 5.972e24 6.371e6 1.496e11 0 0 0 0.0 0.5 1.0 0 1.496e11

# Comet - eccentric orbit (e=0.7)
Comet 1e14 5e3 1.122e11 0 0 0 0.5 0.8 1.0 0.7 3.74e11

Fields:

• name: Body name (string, no spaces)
• mass: Mass in kilograms
• radius: Radius in meters
• x, y, z: Initial position in meters (absolute coordinates)
• parent_index: Index of gravitational parent (-1 for root bodies like stars)
• r, g, b: RGB color values (0.0 to 1.0)
• eccentricity: Orbital eccentricity (0 = circular, >0 = elliptical)
• semi_major_axis: Semi-major axis in meters (for e=0, use orbital radius)

Velocities are calculated automatically using the vis-viva equation based on position and orbital parameters.

Technical Details

• Physics: 2-body gravitational model using Newton's law of gravitation
• Integration: Euler method with configurable time step (default: 60 seconds)
• SOI Detection: Hill sphere approximation for sphere of influence
• Rendering: Logarithmic distance scaling and exponential size scaling for visualization
• Language: C-style C++ (structs and functions, no classes or templates)

License

This project is provided as-is for educational and research purposes.