# Matter.js
> *Matter.js* is a JavaScript 2D rigid body physics engine for the web
[brm.io/matter-js](http://brm.io/matter-js)
[Features](#features) - [Status](#status) - [Install](#install) - [Usage](#usage) - [Docs](http://brm.io/matter-js-docs/) - [Implementation](#implementation) - [References](#references) - [License](#license)
[](https://travis-ci.org/liabru/matter-js)
### Demos
- [Mixed Shapes](http://brm.io/matter-js-demo#mixed)
- [Solid Shapes](http://brm.io/matter-js-demo#mixedSolid)
- [Newton's Cradle](http://brm.io/matter-js-demo#newtonsCradle)
- [Wrecking Ball](http://brm.io/matter-js-demo#wreckingBall)
- [Slingshot Game](http://brm.io/matter-js-demo#slingshot)
- [Rounded Corners (Chamfering)](http://brm.io/matter-js-demo#rounded)
- [Views](http://brm.io/matter-js-demo/#views)
- [Time Scaling](http://brm.io/matter-js-demo/#timescale)
- [Raycasting](http://brm.io/matter-js-demo/#raycasting)
- [Sprites](http://brm.io/matter-js-demo/#sprites)
- [Pyramid](http://brm.io/matter-js-demo#pyramid)
- [Car](http://brm.io/matter-js-demo#car)
- [Catapult](http://brm.io/matter-js-demo#catapult)
- [Reverse Gravity](http://brm.io/matter-js-demo#gravity)
- [Bridge](http://brm.io/matter-js-demo#bridge)
- [Avalanche](http://brm.io/matter-js-demo#avalanche)
- [Basic Soft Bodies](http://brm.io/matter-js-demo#softBody)
- [Cloth](http://brm.io/matter-js-demo#cloth)
- [Events](http://brm.io/matter-js-demo/#events)
- [Chains](http://brm.io/matter-js-demo#chains)
- [Ball Pool](http://brm.io/matter-js-demo#ballPool)
- [Stack](http://brm.io/matter-js-demo#stack)
- [Circle Stack](http://brm.io/matter-js-demo#circleStack)
- [Restitution](http://brm.io/matter-js-demo#restitution)
- [Friction](http://brm.io/matter-js-demo#friction)
- [Air Friction](http://brm.io/matter-js-demo#airFriction)
- [Sleeping](http://brm.io/matter-js-demo#sleeping)
- [Grid Broadphase](http://brm.io/matter-js-demo#broadphase)
- [Beach Balls](http://brm.io/matter-js-demo#beachBalls)
- [Stress 1](http://brm.io/matter-js-demo#stress)
- [Stress 2](http://brm.io/matter-js-demo#stress2)
### Features
- Physical properties (mass, area, density etc.)
- Rigid bodies of any convex polygon
- Stable stacking and resting
- Collisions (broad-phase, mid-phase and narrow-phase)
- Restitution (elastic and inelastic collisions)
- Conservation of momentum
- Friction and resistance
- Constraints
- Gravity
- Composite bodies
- Sleeping and static bodies
- Events
- Rounded corners (chamfering)
- Views (translate, zoom)
- Collision queries (raycasting, region tests)
- Time scaling (slow-mo, speed-up)
- Canvas renderer (supports vectors and textures)
- WebGL renderer (requires [pixi.js](https://github.com/GoodBoyDigital/pixi.js/))
- [MatterTools](https://github.com/liabru/matter-tools) for creating, testing and debugging worlds
- World state serialisation (requires [resurrect.js](https://github.com/skeeto/resurrect-js))
- Cross-browser (Chrome, Firefox, Safari, IE8+)
- Mobile-compatible (touch, responsive)
- An original JavaScript physics implementation (not a port)
### Install
Download the [latest release](https://github.com/liabru/matter-js/releases) and include the script in your web page:
For the latest features try the [edge version (master)](https://raw.github.com/liabru/matter-js/master/build/matter.js), but it may not be fully stable.
You can also install using the package managers [Bower](http://bower.io/search/?q=matter-js) and [NPM](https://www.npmjs.org/package/matter-js).
bower install matter-js
npm install matter-js
### Usage
See the [Getting started](https://github.com/liabru/matter-js/wiki/Getting-started) wiki page for a minimal usage example.
Check out the [demo page](http://brm.io/matter-js-demo/) for more examples and then refer to [Demo.js](https://github.com/liabru/matter-js/blob/master/demo/js/Demo.js) to see how they work. Some of the demos are also available on [codepen](http://codepen.io/collection/Fuagy/), where you can easily experiment with them.
### Documentation
See the [Matter.js API Docs (v0.8.0)](http://brm.io/matter-js-docs/).
If you're using the [edge version (master)](https://raw2.github.com/liabru/matter-js/master/build/matter.js) then see the [API Docs (master)](http://brm.io/matter-js-docs-master/).
### Status
Matter.js is currently in *alpha* status, meaning the API is still in development and may change occasionally.
The library is reasonably stable as-is, but it is not yet feature complete.
### Building and Contributing
To build you must first install [node.js](http://nodejs.org/) and [grunt](http://gruntjs.com/), then run
npm install
This will install the required build dependencies, then run
grunt dev
which is a task that builds the `matter-dev.js` file, spawns a `connect` and `watch` server, then opens `demo/dev.html` in your browser. Any changes you make to the source will automatically rebuild `matter-dev.js` and reload your browser for quick and easy testing.
Contributions are welcome, please ensure they follow the same style and architecture as the rest of the code. You should run `grunt test` to ensure `jshint` gives no errors. Please do not include any changes to the files in the `build` directory.
If you'd like to contribute but not sure what to work on, feel free to message me. Thanks!
### Changelog
To see what's new or changed in the latest version, see the [changelog](https://github.com/liabru/matter-js/blob/master/CHANGELOG.md).
### Implementation
The technical details for physics nerds and game devs.
This engine is using the following techniques:
- Time-corrected position Verlet integrator
- Adaptive grid broad-phase detection
- AABB mid-phase detection
- SAT narrow-phase detection
- Iterative sequential impulse solver and position solver
- Resting collisions with resting constraints ala Erin Catto's method
(GDC08)
- Temporal coherence impulse caching and warming
- Collision pairs, contacts and impulses maintained with a pair
manager
- Approximate Coulomb friction model using friction constraints
- Constraints solved with the Gauss-Siedel method
- Semi-variable time step, synced with rendering
- A basic sleeping strategy
- HTML5 Canvas / WebGL renderer
### References
See my post on [Game physics for beginners](http://brm.io/game-physics-for-beginners/).
### License
Matter.js is licensed under [The MIT License (MIT)](http://opensource.org/licenses/MIT)
Copyright (c) 2014 Liam Brummitt
This license is also supplied with the release and source code.
As stated in the license, absolutely no warranty is provided.