A grab bag of vector utility functions for 2D and 3D vectors that operate on plain arrays
npm install vectorsA grab bag of vector utility functions for 2D and 3D vectors that
operate on plain arrays. Much like cog,
each method can be required individually to limit the amount of
bloat you get from using the module on the client with
browserify.
`` bash`
npm install vectors
Each method is requireable from vectors/${dims}d/${method},
e.g.:
` javascript`
var mag2d = require('vectors/2d/mag')
var add2d = require('vectors/2d/add')
var copy2d = require('vectors/2d/copy')
Each method takes a vec vector, which if returning a new
vector will almost always do so by modifying it directly:
` javascript
var spd = [+1, 0]
var acc = [-1, 0]
var cop = copy2d(spd)
mag2d(spd) // 1
add2d(spd, acc) // spd === [0, 0]
mag2d(spd) // 0
mag2d(cop) // 1
`
Working on this one...
Adds the other vector to vec:
` javascript
var add = require('vectors/2d/add')
var pos = [0, 0]
var spd = [1, 1.5]
add(pos, spd)
add(pos, spd)
console.log(pos) // [2, 3]
`
Returns a copy of the vector vec:
` javascript
var copy = require('vectors/2d/copy')
var spd = [5, 5]
var cop = copy(spd)
mult(spd, 100) === [100, 100]
cop === [5, 5]
`
Returns the cross product of vectors vec and other:
` javascript
var cross = require('vectors/2d/cross')
var a = [1, 2]
var b = [8, 4]
cross(a, b) === -12
`
Returns the distance between vectors vec and other:
` javascript
var dist = require('vectors/2d/dist')
var pos1 = [2, 4]
var pos2 = [4, 4]
dist(pos1, pos2) === 2
`
Divides the vector vec by a scalar value:
` javascript
var div = require('vectors/2d/div')
var spd = [5, 5]
div(spd, 2) === [2.5, 2.5]
`
Returns the dot product of vectors vec and other:
` javascript
var dot = require('vectors/2d/dot')
var vecA = [15, 5]
var vecB = [10, 8]
dot(vecA, vecB) === 190
`
Mutliplies the vector vec by a scalar value:
` javascript
var heading = require('vectors/2d/heading')
var a = [5, 0]
var b = [0, 5]
heading(a, b) * 180 / Math.PI === 45 // degrees
`
Set vec to the linear interpolation between vectors start
and :
` javascript
var lerp = require('vectors/2d/lerp')
var start = [0, 0]
var finish = [100, 100]
lerp([], start, finish, 0.75) === [75, 75]
`
Limits the vector vec to a magintude of scalar units.
` javascript
var limit = require('vectors/2d/limit')
limit([3, 0], 2) === [2, 0]
limit([3, 4], 1) === [0.6, 0.8]
limit([5, 5], 24) === [5, 5]
`
Returns the magnitude of the vector:
` javascript
var mag = require('vectors/2d/mag')
var spd = [2, 4]
mag(spd) === 4.47213595499958
`
Mutliplies the vector vec by a scalar value:
` javascript
var mult = require('vectors/2d/mult')
var spd = [5, 5]
mult(spd, 2) === [10, 10]
`
Normalizes the vector (i.e. scales it to make its
distance 1 unit).
` javascript
var normalize = require('vectors/2d/normalize')
normalize([3, 0]) === [1, 0]
normalize([4, 3]) === [0.8, 0.6]
`
Subtracts the other vector from vec:
` javascript
var sub = require('vectors/2d/sub')
var pos = [0, 0]
var spd = [1, 1.5]
sub(pos, spd)
sub(pos, spd)
console.log(pos) // [-2, -3]
``