mxd

MXD Linear math library for JS

Goals: 1. Readable 2. Fast

Conventions: - Vectors are 1d JS Arrays - Matrices are 2d JS Arrays - Everything is immutable - Functions are pure unless otherwise noted

Usage:

var mxd = require('mxd')

Vectors:

var V = mxd.Vector;

Basics:
    V.copy(v)
    V.eq(a, b)
    V.floor(v)
    V.ceil(v)
    V.dot(a, b)
    V.invert(v)
    V.rotate(radians)

Part-wise arithmetic (v, v) -> v:
    V.add(a, b)
    V.sub(a, b)
    V.mul(a, b)
    V.div(a, b)
    V.mod(a, b) -- uses mxd.Util.mod

Magnitude functions:
    V.magSq(v)
    V.mag(v)
    V.norm(v) -- normalize v, except [0, 0] -> [0, 0]
    V.withMag(v, f)

Scaling:
    V.scale(v, f)
    V.rscale(f, v)
    V.scaleInverse(v, f)
    V.rscaleInverse(f, v)

Utilities:
    V.transform(v, m) [2D Vectors only]
        Transforms by six-element Canvas matrix

    V.iterect(a, b, cb) [2D Integer Vectors only] [impure]
        for (a[0] <= i < b[0], a[1] <= j < b[1]) cb([i, j])

    V.perpendicular(v) [2D Vectors only]
        [x, y] -> [y, -x] or [-y, x]

Matrices:

var M = mxd.Matrix;

M.mul(
    [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]],
    [[1, 0, 0],
     [0, 1, 0],
     [0, 0, 1]]);

M.eq(a, b)

M.apply(m, v)

M.scaling(v)
M.rotation(a) -> [[cos(a), -sin(a)]
                  [sin(a), cos(a)]]

Util:

var U = mxd.Util;

U.mod(a, b) -- modulo, properly handling negative args

DSL:

mxd.math('a + (b * f)')([1, 2], [3, 4], 1.5)
    -> V.add([1, 2]. V.scale([3, 4], 1.5))

This is still pretty basic. Supports: precedence, grouping, type
overloading (vec * vec != vec * num)

mxd.math(expr) -> function(args...)

    args are mapped to variables appearing in 'expr' in the order
    they appear. Repeated variables correspond to the same argument.