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:

Build raylib from the submodule (first time only)
Compile all source files
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.

3.6 KiB Raw Blame History