vectors
A grab bag of vector utility functions for 2D and 3D vectors that operate on plain arrays
npm install vectors
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Version | 0.1.0 last updated 8 months ago |
License | MIT |
Keywords | vectors, math, utility, browserify |
Repository | git://github.com/hughsk/vectors.git (git) |
Dependencies | None |
Dependents | click-boards |
vectors
A 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.
Installation
npm install vectors
Contributors
Usage
Each method is requireable from vectors/${method}
,
followed by calling the returned generator function
with the number of dimensions you want your vectors to be.
e.g.:
var mag = require('vectors/mag')(2)
var add = require('vectors/add')(3)
var sub = require('vectors/sub')(3)
If you want something totally generic, you can assume
in most cases that appending -nd
to your require
will return a less performant but more flexible function:
var mag = require('vectors/mag-nd')
var add = require('vectors/add-nd')
var sub = require('vectors/sub-nd')
Most of the methods in this module support vectors of arbitrary dimensions, but the ones that don't will throw an error to let you know.
Each method takes a vec
vector, which if returning a new
vector will almost always do so by modifying it directly:
var spd = [+1, 0]
var acc = [-1, 0]
var cop = copy(spd)
mag(spd) // 1
add(spd, acc) // spd === [0, 0]
mag(spd) // 0
mag(cop) // 1
add(vec, other[, ...])
Adds the other
vector to vec
:
var add = require('vectors/add')(2)
var pos = [0, 0]
var spd = [1, 1.5]
add(pos, spd)
add(pos, spd)
console.log(pos) // [2, 3]
Or add a scalar to the entire array:
var res = add([1, 1, 1], 6)
console.log(res) // [7, 7, 7]
You can disable this by passing scalars: false
to
the generator function for faster results:
var add = require('vectors/add')(2, { scalars: false })
copy(vec)
Returns a copy of the vector vec
:
var copy = require('vectors/copy')(2)
var spd = [5, 5]
var cop = copy(spd)
mult(spd, 100) === [100, 100]
cop === [5, 5]
cross(vec, other)
Returns the cross product of vectors vec
and other
:
var cross = require('vectors/cross')(2)
var a = [1, 2]
var b = [8, 4]
cross(a, b) === -12
This method only works in 2 and 3 dimensions.
dist(vec, other)
Returns the distance between vectors vec
and other
:
var dist = require('vectors/dist')(2)
var pos1 = [2, 4]
var pos2 = [4, 4]
dist(pos1, pos2) === 2
div(vec, other[, ...])
Divides the vector vec
by a other
value:
var div = require('vectors/div')(2)
var spd = [5, 5]
div(spd, 2) === [2.5, 2.5]
Or divide multiple arrays from each other:
var res = div([6, 6, 6], [2, 2, 2])
console.log(res) // [3, 3, 3]
You can disable this by passing vectors: false
to
the generator function for faster results:
var sub = require('vectors/div')(2, { vectors: false })
dot(vec, other)
Returns the dot product of vectors vec
and other
:
var dot = require('vectors/dot')(2)
var vecA = [15, 5]
var vecB = [10, 8]
dot(vecA, vecB) === 190
heading(vec, other)
Mutliplies the vector vec
by a scalar
value:
var heading = require('vectors/heading')(2)
var a = [5, 0]
var b = [0, 5]
heading(a, b) * 180 / Math.PI === 45 // degrees
lerp(vec, start, finish, scalar)
Set vec
to the linear interpolation between vectors start
and finish
:
var lerp = require('vectors/lerp')(2)
var start = [0, 0]
var finish = [100, 100]
lerp([], start, finish, 0.75) === [75, 75]
limit(vec, scalar)
Limits the vector vec
to a magnitude of scalar
units.
var limit = require('vectors/limit')(2)
limit([3, 0], 2) === [2, 0]
limit([3, 4], 1) === [0.6, 0.8]
limit([5, 5], 24) === [5, 5]
mag(vec)
Returns the magnitude of the vector:
var mag = require('vectors/mag')(2)
var spd = [2, 4]
mag(spd) === 4.47213595499958
mult(vec, other[, ...])
Mutliplies the vector vec
by a other
value:
var mult = require('vectors/mult')(2)
var spd = [5, 5]
mult(spd, 2) === [10, 10]
Or multiply multiple arrays:
var res = mult([2, 2, 2], [4, 4, 4])
console.log(res) // [8, 8, 8]
You can disable this by passing vectors: false
to
the generator function for faster results:
var sub = require('vectors/mult')(2, { vectors: false })
normalize(vec, scalar)
Normalizes the vector (i.e. scales it to make its distance 1 unit).
var normalize = require('vectors/normalize')(2)
normalize([3, 0]) === [1, 0]
normalize([4, 3]) === [0.8, 0.6]
sub(vec, other[, ...])
Subtracts the other
vector from vec
:
var sub = require('vectors/sub')(2)
var pos = [0, 0]
var spd = [1, 1.5]
sub(pos, spd)
sub(pos, spd)
console.log(pos) // [-2, -3]
Or subtract a scalar from the entire array:
var res = sub([9, 8, 7], 6)
console.log(res) // [3, 2, 1]
You can disable this by passing scalars: false
to
the generator function for faster results:
var sub = require('vectors/sub')(2, { scalars: false })