# 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
- **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:

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

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

```bash
git submodule update --init --recursive
```

### Dependencies (Debian 13)

Install the required system packages:

```bash
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

```bash
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:
```bash
make rebuild
```

To clean everything including raylib:
```bash
make clean-all
```

## Running

Run with the default solar system configuration:

```bash
./orbit_sim
```

Run with a custom configuration file:

```bash
./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

Sun 1.989e30 6.96e8 0 0 0 -1 1.0 1.0 0.0
Earth 5.972e24 6.371e6 1.496e11 0 0 0 0.0 0.5 1.0
Moon 7.342e22 1.737e6 1.500e11 0 0 1 0.7 0.7 0.7
```

Fields:
- **name**: Body name (string, no spaces)
- **mass**: Mass in kilograms
- **radius**: Radius in meters
- **x, y, z**: Initial position in meters
- **parent_index**: Index of gravitational parent (-1 for root bodies like stars)
- **r, g, b**: RGB color values (0.0 to 1.0)

Velocities are calculated automatically for circular orbits.

## Project Structure

```
claudes_game/
├── src/
│   ├── main.cpp           - Main program loop
│   ├── physics.cpp/h      - Vector math and physics
│   ├── bodies.cpp/h       - Celestial bodies and simulation
│   ├── config_loader.cpp/h - Configuration file parser
│   └── renderer.cpp/h     - 3D rendering with raylib
├── configs/
│   ├── solar_system.txt   - Solar system configuration
│   └── example_binary_star.txt - Binary star example
├── docs/
│   └── implementation_plan.md - Detailed implementation plan
├── Makefile
└── README.md
```

## 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)

## Future Enhancements

- Quaternion-based rotations for realistic body orientation
- Orbit trail rendering
- N-body simulation mode
- More accurate integration methods (RK4, Verlet)
- Save/load simulation state
- Interactive body selection and information display
- Multiple reference frames

## License

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