Simple gravity

A N body simulation with several tiny particles, painted all in gradients of red/pink in honor of the Petrova Line from Project Hail Mary. They orbit a comparatively massive body in the center.

Quick start

On a desktop Linux machine with a graphical display:

git clone git@github.com:bodoque-01/nbody.git gravity
cd gravity
./setup.sh

That's it. setup.sh detects your package manager (apt or dnf), installs a C++ toolchain and raylib (building raylib from source if your distro doesn't package a new enough version), compiles the program, and launches it.

To install and build without launching:

./setup.sh --no-run

Controls

Key	Action
Space	Pause/resume
Esc	Quit

Local development (make)

For fast iteration while hacking on the code, use the Makefile. It builds against the raylib already on your system (from setup.sh or your distro's package), so there's no per-build raylib fetch/compile:

make run     # build (if needed) and run
make build   # just build
make clean   # remove the binary
make benchmark-compare # Runs benchmarking comparing a simple run of the heavy physics for loop without OpenMP (single-threaded) and one with OpenMP parallelization.
make watch   # auto-rebuild on save

Building it yourself with CMake (recommended, no raylib install)

The most portable way to build is the included CMakeLists.txt. It fetches and builds a pinned raylib from source as part of the build, so you never install raylib system-wide and every build gets a known-good version. The commands are identical on every distro.

First install the build tools and the OpenGL/X11 development libraries raylib needs to compile:

Distro	Command
Debian / Ubuntu	sudo apt update && sudo apt install -y build-essential git cmake libgl1-mesa-dev libx11-dev libxrandr-dev libxi-dev libxcursor-dev libxinerama-dev
Fedora / RHEL	sudo dnf install -y gcc-c++ make git cmake mesa-libGL-devel libX11-devel libXrandr-devel libXi-devel libXcursor-devel libXinerama-devel

Then build and run:

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j
./build/main                                    # run the demo
cmake --build build --target benchmark-compare  # run the benchmarks

The first configure downloads and compiles raylib, so it takes a couple of minutes; later builds are incremental. Nothing is installed globally, everything just lands in build/.

Requirements

• A desktop Linux environment with OpenGL and an X11 display.
• A C++17 compiler (g++), plus either make + a system raylib, or cmake + git for the self-contained CMake build above.

Note: this project needs raylib 5.0 or newer (it uses ColorLerp and FLAG_BORDERLESS_WINDOWED_MODE, both added in 5.0). The CMake build handles this for you. If you install raylib yourself, watch the version: some distro packages are older, for example Ubuntu 24.04's libraylib-dev is 4.5.0 and will fail to compile this program.

Using a system-wide raylib

If you'd rather manage raylib yourself instead of using setup.sh or the CMake build, install it system-wide by following raylib's official guide:

• https://github.com/raysan5/raylib/wiki/Working-on-GNU-Linux

Make sure the version you install is 5.0 or newer (on recent Fedora sudo dnf install raylib-devel is new enough; Ubuntu's apt package is not, so build from source or just use the CMake build above). Once raylib is available, build and run with make run.