Random Spherical

Generate a random uniformly distributed (x,y,z) point on a sphere. Returns either an array or an object with an optional constructor.

Basic Usage

Array

var random = require('random-spherical/array')()

random() // returns [  0.20921503109744416,  0.5193212554924722, -0.8285737772562065 ]
random() // returns [ -0.23002829130722735, -0.061082054576348306, -0.971265137749219 ]
random() // returns [  0.5578066492160378,   0.0729061655774499, -0.826762621984793 ]

Object

var random = require('random-spherical/object')()

random() // returns { x: 0.20921503109744416, y: 0.5193212554924722, z: -0.8285737772562065 }
random() // returns { x: -0.23002829130722735, y: -0.061082054576348306, z: -0.971265137749219 }
random() // returns { x: 0.5578066492160378, y: 0.0729061655774499, z: -0.826762621984793 }

Live Example

Spinning dots on a sphere

Initializing

Works as an array or object. All parameters are optional. If no random number generator is provided then Math.random is used. If no constructor is provided for the object then it will create a bare {}.

var randomSpherical = require('random-spherical/array')( randomGenerator )
var randomSpherical = require('random-spherical/object')( randomGenerator, constructor )

It can also be initialized this way, but includes more source code if used with browserify.

var random = require('random-spherical')
var randomArray = random.array()
var randomObject = random.object()

Interface

The radius is a number, offset is a 3d array/object vector, and the target is an optional array/object target to avoid garbage collection.

var randomSpherical = require('random-spherical/array')()

randomSpherical()
randomSpherical( radius, offset )
randomSpherical( target, radius, offset )

Usage configured with a PRNG and three.js vectors

var randomGenerator = SeededRandom("my-seed")
var randomSpherical = require('random-spherical/object')( randomGenerator, THREE.Vector3 )

var planetRadius = 10
var planetPosition = new THREE.Vector( 134, 352, 135 )

var pointOnSurface = randomSpherical( planetRadius, planetPosition )
var pointInsidePlanet = randomSpherical( randomGenerator(), planetPosition )
var directionalVector = randomSpherical()