box2d

# Box2D 

Box2D is a 2D physics engine for games.

![Box2D Logo](https://box2d.org/images/logo.svg)

[![Box2D Version 3.0 Release
Demo](https://img.youtube.com/vi/dAoM-xjOWtA/0.jpg)](https://www.youtube.com/watch?v=dAoM-xjOWtA)

## Build Status

[![Build
Status](https://github.com/erincatto/box2d/actions/workflows/build.yml/badge.svg)](https://github.com/erincatto/box2d/actions)

## Features

### Collision

- Continuous collision detection
- Contact events
- Convex polygons, capsules, circles, rounded polygons, segments, and chains
- Multiple shapes per body
- Collision filtering
- Ray casts, shape casts, and overlap queries
- Sensor system

### Physics

- Robust _Soft Step_ rigid body solver
- Continuous physics for fast translations and rotations
- Island based sleep
- Revolute, prismatic, distance, motor, weld, and wheel joints
- Joint limits, motors, springs, and friction
- Joint and contact forces
- Body movement events and sleep notification

### Character movement

- Geometric mover with robust plane solver
- Dynamic mover with custom joint support

### System

- Data-oriented design
- Written in portable C17
- Extensive multithreading and SIMD
- Optimized for large piles of bodies
- Low cost double-precision support for large worlds
- Recording and replay
- Cross platform determinism
- Snapshot and restore

### Samples

- OpenGL with GLFW
- Graphical user interface with imgui
- Many samples to demonstrate features and performance

## Building All Platforms

- Install [CMake](https://cmake.org/)
- Install [git](https://git-scm.com/)
- Ensure these run from the command line

## Building with CMake presets

The presets in `CMakePresets.json` give one build flow on every platform and are picked up
automatically by Visual Studio, VS Code, and CLion (open the folder and choose a preset). From the
command line:

- Windows: `cmake --preset windows` then `cmake --build --preset windows-release`
- Linux: `cmake --preset linux-release` then `cmake --build --preset linux-release`
- macOS: `cmake --preset macos` then `cmake --build --preset macos-release`

Use the `*-debug` build presets for a debug build (not recommended for the replay viewer). The
presets use the default native toolchain (the installed Visual Studio on Windows, Make on Linux,
Xcode on macOS), so no specific compiler version is required.

## Building for Visual Studio

- Install [Visual Studio](https://visualstudio.microsoft.com/)
- Run `build_vs2026.bat` for Visual Studio 2026, or use the `windows` preset above for other
  versions
- Open and build the generated solution in the `build` folder

## Building for Linux

- Run `build.sh` from a bash shell
- Results are in the build sub-folder

## Building for Xcode

- mkdir build
- cd build
- cmake -G Xcode ..
- Open `box2d.xcodeproj`
- Select the samples scheme
- Build and run the samples

## Building and installing

- mkdir build
- cd build
- cmake ..
- cmake --build . --config Release
- cmake --install . (might need sudo)

Installing