A tiny 2D/3D verlet physics system.
var Point = require('verlet-point')
var array = require('array-range')
var random = require('randf')
//create a world where points stay within window bounds
var world = require('verlet-system')({
gravity: [0, 500],
min: [0, 0],
max: [width, height]
})
//create 500 points scattered around page
var points = array(500).map(function() {
return Point({
position: [ random(0, width), random(0, height) ]
})
})
//draw our scene
fuction render() {
//step the physics
world.integrate(points, dt)
drawPoints(points)
}
Typically used alongside verlet-constraint and verlet-point.
By default, assumes 2D and points with [x, y]
. You can require an explicit dimension like so:
var World2D = require('verlet-system/2d') //points [x, y]
var World3D = require('verlet-system/3d') //points [x, y, z]
PRs for fixes/improvements welcome.
See the demos folder. The demos are run with beefy.
You can use verlet-point, or just bare objects with the following structure:
var point = {
position: [x, y], //required
previous: [x, y], //required
acceleration: [x, y], //required
mass: 1 //optional, will default to 1.0
radius: 25 //optional, will default to 0.0
}
Points with a mass of 0 are considered "unmovable". radius
is used for collision testing against min
and max
, but different applications may choose to ignore this.
Collisions are ignored unless you set a min
and/or max
vector on the system (with the same number of components as the rest of your points). This will lead to particles 'bouncing' off the collision box. If a component is not a number, it will be ignored (i.e. act as infinity). For example, to allow particles to flow freely horizontally, but restrict them to the 2D window vertically, you might do this:
world.min = [null, 0]
world.max = [null, height]
You can also specify a radius
on points which will get used in the collision testing. See demo/bounce.js. By default, min
and max
are null objects, and no collisions are computed.
system = require('verlet-system')([opt])
Creates a new system with the specified options.
gravity
a vector describing the gravity of this system, defaults to a zero vectormin
the minimum bounds vector, defaults to null (i.e. negative infinity)max
the maximum bounds vector, defaults to null (i.e. positive infinity)friction
the air friction, defaults to 0.98bounce
the friction with collision edges, i.e. "bounciness", defaults to 1.0system.integrate(points, step)
Integrates the list of "points" with the given step (typically in seconds).
system.integratePoint(point, step)
Integrates a single "point".
git clone https://github.com/mattdesl/verlet-system.git
cd verlet-system
npm install
# if you haven't got these tools,
# install them globally
npm install browserify beefy uglify-js -g
# now run or build any of the demos
npm run line
npm run triangulate
npm run build-line
npm run build-triangulate
Should work with any tool that consumes CommonJS (i.e. jspm, DuoJS, browserify, webpack).
This is not meant to be as feature-complete as choices like verlet-js, PhysicsJS, or matter-js. Some novel goals of this project:
triangulate
demo)MIT, see LICENSE.md for details.