basics - vector


!main action pipeline
!beta action pipeline


This library provides 3D Vector in js including arithmetic operator overloading (+ - / % *).

Normally vector implementations in javascript handle arithmetic operation by methods aVec.multiply(bVec).substract(dVec).
Other languages provide operator overloading, that coders can create Vector class which can handle operation similar to number handling aVec * bVec - dVec.

This library gives javascript coders a way to handle operators with a single statement () => aVec * bVec - dVec.
The calculation can be combined with numbers () => aVec bVec 4 - dVec - 1.5.
Vector objects can be create with number new Vector(5, 6, 7) or directly with assigned statement new Vector(() => 5 * 30 + 2).

Implementation details

``javascript
// typical implementation of vector in js
const vec = aVec.multiply(bVec).multiply(4).substract(dVec).substract(1.5);

⇓

// better readable, but much more complicated
const vec = new Vec(aVec.x bVec.x 4 - dVec.x - 1.5,
aVec.y bVec.y 4 - dVec.y - 1.5,
aVec.z bVec.z 4 - dVec.z - 1.5);

⇓

// inspired by smart array handling
// first version of calling assigned function three times
const vec = oldCalc( aVec, bVec, dVec,
( aVec, bVec, dVec) => aVec bVec 4 - dVec - 1.5
);

⇓

// final version with overwritten valueOf() method
const vec = calc(() => aVec bVec 4 - dVec - 1.5);
`

Javascript has this one peculiarity called valueOf() this method is designed for primitive handling (numbers and strings) when handling arithmetic operations.
Every class can overwrite this method to give it special behavior. This Vector class calls the assigned statement three times for x, y and z.
Comparable to trigger arithmetic operation manually for every axis.

Internally the valueOf() implementation returns x in first call, y in second call and z in last call, these results are put into an new Vector object and can be reused further.

Usage

$3

`html
type="text/javascript"
src="https://unpkg.com/@js-basics/vector/build/iife"
>
`

`javascript
const { calc, vector, victor, point, ipoint } = basics.vector;
`

$3

\$ npm i @js-basics/vector

`javascript
import { calc, vector, victor, point, ipoint } from "@js-basics/vector";
`

working with Vector classes

$3

`javascript
const pos = vector(5, 6, 7);
const dir = vector(1, 0, 0);
console.log(debugpos:${pos}, dir: ${dir});
// pos: { x: 5, y: 6, z: 7 } dir: { x: 1, y: 0, z: 0 }
`

$3

`javascript
const offsetA = vector(() => dir * 30 + pos);
console.log(debugoffsetA: ${offsetA});
// offsetA: { x: 35, y: 6, z: 7 }
`

$3

`javascript
const dir1 = vector(0, 1, 0);
const dir2 = vector(-1, 0, 1);
const cross = dir1.cross(dir2);

console.log(debugcross: ${cross});
// cross: { x: 1, y: 0, z: 1 }
`

$3

`javascript
const crossNorm = dir1.crossNormalize(dir2);

console.log(debugcrossNorm: ${crossNorm});
// crossNorm: { x: 0.7071, y: 0, z: 0.7071 }
`

$3

`javascript
const crossNormCalc = vector(() => dir1.crossNormalize(dir2) * 50);

console.log(debugcrossNormCalc: ${crossNormCalc});
// crossNormCalc: { x: 35.36, y: 0, z: 35.36 }
`

$3

`javascript
const norm = vector(() => offsetA / offsetA.length);
console.log(debugnorm: ${norm});
// norm: { x: 0.967, y: 0.1658, z: 0.1934 }
`

$3

`javascript
const v1 = vector(5, 6, 7);

v1.x = 27;
console.log(debugv1: ${v1});
// v1: { x: 27, y: 6, z: 7 }

v1.calc(p => (p + 1) * 12);
console.log(debugv1: ${v1});
// v1: { x: 336, y: 84, z: 96 }
`

$3

behaves exactly like Vector but code cant change its x, y and z axes.

`javascript
const v2 = victor(5, 6, 7);

try {
v2.x = 27;
} catch (error) {
console.log(error: ${error});
// error: Error: set x() not implemented
}
`

$3

`javascript
const p1 = point(5, 6);

p1.x = 27;
console.log(debugp1: ${p1});
// p1: { x: 27, y: 6 }

p1.calc(p => (p + 1) * 12);
console.log(debugv1: ${v1});
// p1: { x: 336, y: 84 }
`

$3

behaves exactly like Point but code cant change its x and y axes.

`javascript
const p2 = ipoint(5, 6);

try {
p2.x = 27;
} catch (error) {
console.log('error:', error.toString());
// error: Error: set x() not implemented
}
`

$3

works fine thanks to caching in factory function.

`javascript
// creating vector inside calculation works fine,
// thanks to caching in factory function
const inlineVec = victor(() => victor(25, 30, 0) / 2);
console.log(debuginlineVec: ${inlineVec});
// inlineVec: { x: 12.5, y: 15, z: 0 }
`

$3

`javascript
// mix 2D and 3D space
const from2d = victor(() => point(25, 30) / 2);
const from3d = ipoint(() => from2d.xy * 2);
console.log(debugfrom2d: ${from2d});
console.log(debugfrom3d: ${from3d});
// from2d: { x: 12.5, y: 15, z: 0 }
// from3d: { x: 25, y: 30 }
`

Not another vector lib

You are happy with your current vector library and definitely don’t want to change 1000 lines of code already written in your projects. Then you can only use the valueOf extension and the calc function.

working with Operator class

$3

`html
type="text/javascript"
src="https://unpkg.com/@js-basics/vector/build/iife/operator.js"
>
`

`javascript
const { cachedValueOf, cachedFactory, operatorCalc } = basics.vector.operator;
`

$3

\$ npm i @js-basics/vector

`javascript
import {
cachedValueOf,
cachedFactory,
operatorCalc
} from "@js-basics/vector/operator";
`

$3

`javascript
class Tuple {
constructor(x, y, z) {
this.x = x;
this.y = y;
this.z = z;
}
}
cachedValueOf(Tuple);
`

$3

`javascript
const tuple = (() => {
const tupleFactory = cachedFactory(Tuple);
return (x, y, z) => {
if (typeof x === 'function') {
return operatorCalc(x, new Tuple());
}
return tupleFactory(x, y, z);
};
})();

const t1 = tuple(3, 4, 5);
const t2 = tuple(6, 7, 8);
const t = tuple(() => t1 + t2 * 2);

console.log(t: ${JSON.stringify(t)});
// t: {"x":15,"y":18,"z":21}
``

Predefined adapters

existing operator overloading for game engines or other vector libraries

- playcanvas