first commit

2d/add.js

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+/**
+
+### `add(vec, other)`
+
+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]
+```
+
+**/
+
+module.exports = add
+
+function add(vec, other) {
+  vec[0] += other[0]
+  vec[1] += other[1]
+  return vec
+}

2d/copy.js

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+/**
+
+### `copy(vec)`
+
+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]
+```
+
+**/
+
+module.exports = copy
+
+function copy(vec) {
+  return [vec[0], vec[1]]
+}

2d/cross.js

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+/**
+
+### `cross(vec, other)`
+
+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
+```
+
+**/
+
+module.exports = cross
+
+function cross(vec, other) {
+  return (
+    vec[0] * other[1] -
+    vec[1] * other[0]
+  )
+}

2d/dist.js

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+/**
+
+### `dist(vec, other)`
+
+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
+```
+
+**/
+
+module.exports = dist
+
+function dist(vec, other) {
+  var x = other[0] - vec[0]
+  var y = other[1] - vec[1]
+  return Math.sqrt(x*x + y*y)
+}

2d/div.js

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+/**
+
+### `div(vec, scalar)`
+
+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]
+```
+
+**/
+
+module.exports = div
+
+function div(vec, scalar) {
+  vec[0] /= scalar
+  vec[1] /= scalar
+  return vec
+}

2d/dot.js

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+/**
+
+### `dot(vec, other)`
+
+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
+```
+
+**/
+
+module.exports = dot
+
+function dot(vec, other) {
+  return vec[0] * other[0] + vec[1] * other[1]
+}

2d/heading.js

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+/**
+
+### `heading(vec, other)`
+
+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
+```
+
+**/
+
+module.exports = heading
+
+function heading(vec, other) {
+  return Math.atan2(vec[1] - other[1], vec[0] - other[0])
+}

2d/index.js

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+/**
+## 2D Vector API
+**/
+
+module.exports = {
+    add: require('./add')
+  , sub: require('./sub')
+  , mag: require('./mag')
+  , div: require('./div')
+  , dot: require('./dot')
+  , mult: require('./mult')
+  , dist: require('./dist')
+  , lerp: require('./lerp')
+  , copy: require('./copy')
+  , cross: require('./cross')
+  , limit: require('./limit')
+  , heading: require('./heading')
+  , normalize: require('./normalize')
+}

2d/lerp.js

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+/**
+
+### `lerp(vec, start, finish, scalar)`
+
+Set `vec` to the linear interpolation between vectors `start`
+and `finish`:
+
+``` javascript
+var lerp = require('vectors/2d/lerp')
+var start = [0, 0]
+var finish = [100, 100]
+
+lerp([], start, finish, 0.75) === [75, 75]
+```
+
+**/
+
+module.exports = lerp
+
+function lerp(vec, a, b, scalar) {
+  vec[0] = a[0] + (b[0] - a[0]) * scalar
+  vec[1] = a[1] + (b[1] - a[1]) * scalar
+  return vec
+}

2d/limit.js

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+/**
+
+### `limit(vec, scalar)`
+
+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]
+```
+
+**/
+
+module.exports = limit
+
+function limit(vec, scalar) {
+  var mag = vec[0]*vec[0] + vec[1]*vec[1]
+
+  if (mag > scalar*scalar) {
+    mag = Math.sqrt(mag)
+    vec[0] = vec[0] * scalar / mag
+    vec[1] = vec[1] * scalar / mag
+  }
+
+  return vec
+}

2d/mag.js

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+/**
+
+### `mag(vec)`
+
+Returns the magnitude of the vector:
+
+``` javascript
+var mag = require('vectors/2d/mag')
+var spd = [2, 4]
+
+mag(spd) === 4.47213595499958
+```
+
+**/
+
+module.exports = mag
+
+function mag(vec) {
+  return Math.sqrt(vec[0]*vec[0] + vec[1]*vec[1])
+}

2d/mult.js

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+/**
+
+### `mult(vec, scalar)`
+
+Mutliplies the vector `vec` by a `scalar` value:
+
+``` javascript
+var mult = require('vectors/2d/mult')
+var spd = [5, 5]
+
+mult(spd, 2) === [10, 10]
+```
+
+**/
+
+module.exports = mult
+
+function mult(vec, scalar) {
+  vec[0] *= scalar
+  vec[1] *= scalar
+  return vec
+}

2d/normalize.js

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+/**
+
+### `normalize(vec, scalar)`
+
+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]
+```
+
+**/
+
+module.exports = normalize
+
+function normalize(vec, scalar) {
+  var mag = Math.sqrt(vec[0]*vec[0] + vec[1]*vec[1])
+
+  vec[0] /= mag
+  vec[1] /= mag
+
+  return vec
+}

2d/sub.js

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+/**
+
+### `sub(vec, other)`
+
+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]
+```
+
+**/
+
+module.exports = sub
+
+function sub(vec, other) {
+  vec[0] -= other[0]
+  vec[1] -= other[1]
+  return vec
+}

3d/index.js

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+/**
+## 3D Vector API
+
+Working on this one...
+**/
+module.exports = {
+  // soon...
+}

LICENSE.md

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+This software is released under the MIT license:
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.