lucy-b2

Lucy b2

Box2D by Erin Catto with google's particle simulation liquidfun for node.js.

This fork

Fork from box2d.js.

Due to the fact that we are not creating sub-classes of C++ classes, we do not need to use 'b2' prefix to separate namespaces so this prefix has been removed.

// Instead of writing box2d.b2Vec2
// Write this:
const b2 = require ( 'lucy-b2' )
let gravity = new b2.Vec2  ( 0, -9.8 )
let world   = new b2.World ( gravity )
// ...
let shape = new b2.PolygonShape

Documentation

• Programmer's guide
• liquidfun API

Example

Here is a falling ball simulation.

'use strict'
const b2 = require ( 'lucy-b2' )

// Create world
let gravity = new b2.Vec2  ( 0, -9.8 )
let world   = new b2.World ( gravity )

// Define body
let bodyDef = new b2.BodyDef
bodyDef.type = b2.BodyType.dynamicBody

// Create body with definition
let body = world.CreateBody ( bodyDef )

// Define fixture
let fixDef = new b2.FixtureDef
fixDef.density     = 1.0
fixDef.friction    = 0.2
fixDef.restitution = 0.8

let shape = new b2.PolygonShape
shape.SetAsBox ( 0.1, 0.1 )

fixDef.shape = shape

// Create fixture
body.CreateFixture ( fixDef )

// Move body into initial position ( and rotation )
body.SetTransform ( 0, 2, 0 )

// Run simulation
for ( let i = 0; i < 10; i++ )
{ world.Step ( 1/60, 10, 10 )
  console.log ( body.GetPosition ().y )
}

Installation

npm install lucy-b2 --save

Tests

npm test

Contributing

Please see box2d.js for contributions. The port from this library is just a few Regexp executed on the minified JS version and a wrapper for node.js.

Please use 'jessy style' if you want to write some unit tests for lucy-b2...

Release History

• 1.0.1 (2015-09-22) Fixed readme.
• 1.0.0 (2015-09-09) Initial release.