"use strict";
/******************************************************
************** Simple ES6 Vector Class **************
******************************************************
* Author: Starbeamrainbowlabs
* Twitter: @SBRLabs
* Email: feedback at starbeamrainbowlabs dot com
*
* From https://gist.github.com/sbrl/69a8fa588865cacef9c0
******************************************************
* Originally written for my 2D Graphics ACW at Hull
* University.
******************************************************
* Changelog
******************************************************
* 19th December 2015:
* Added this changelog.
* 28th December 2015:
* Rewrite tests with klud.js + Node.js
* 30th January 2016:
* Tweak angleFrom function to make it work properly.
* 31st January 2016:
* Add the moveTowards function.
* Add the minComponent getter.
* Add the maxComponent getter.
* Add the equalTo function.
* Tests still need to be written for all of the above.
* 19th September 2016:
* Added Vector support to the multiply method.
* 10th June 2017:
* Fixed a grammatical mistake in a comment.
* Added Vector.fromBearing static method.
* 21st October 2017:
* Converted to ES6 module.
* Added Vector.zero and Vector.one constants. Remember to clone them!
* 4th August 2018: (#LOWREZJAM!)
* Optimised equalTo()
* 6th August 2018: (#LOWREZJAM again!)
* Added round(), floor(), and ceil()
* 7th August 2018: (moar #LOWREZJAM :D)
* Added area() and snapTo(grid_size)
* 10th August 2018: (even more #LOWREZJAM!)
* Added Vector support to divide()
*/
class Vector {
// Constructor
constructor(inX, inY) {
if(typeof inX != "number")
throw new Error("Invalid x value.");
if(typeof inY != "number")
throw new Error("Invalid y value.");
// Store the (x, y) coordinates
this.x = inX;
this.y = inY;
}
/**
* Add another vector to this vector.
* @param {Vector} v The vector to add.
* @return {Vector} The current vector. useful for daisy-chaining calls.
*/
add(v) {
this.x += v.x;
this.y += v.y;
return this;
}
/**
* Take another vector from this vector.
* @param {Vector} v The vector to subtrace from this one.
* @return {Vector} The current vector. useful for daisy-chaining calls.
*/
subtract(v) {
this.x -= v.x;
this.y -= v.y;
return this;
}
/**
* Divide the current vector by a given value.
* @param {Number|Vector} value The number (or Vector) to divide by.
* @return {Vector} The current vector. Useful for daisy-chaining calls.
*/
divide(value) {
if(value instanceof Vector)
{
this.x /= value.x;
this.y /= value.y;
}
else if(typeof value == "number")
{
this.x /= value;
this.y /= value;
}
else
throw new Error("Can't divide by non-number value.");
return this;
}
/**
* Multiply the current vector by a given value.
* @param {Number|Vector} value The number (or Vector) to multiply the current vector by.
* @return {Vector} The current vector. useful for daisy-chaining calls.
*/
multiply(value) {
if(value instanceof Vector)
{
this.x *= value.x;
this.y *= value.y;
}
else if(typeof value == "number")
{
this.x *= value;
this.y *= value;
}
else
throw new Error("Can't multiply by non-number value.");
return this;
}
/**
* Move the vector towards the given vector by the given amount.
* @param {Vector} v The vector to move towards.
* @param {Number} amount The distance to move towards the given vector.
*/
moveTowards(v, amount)
{
// From http://stackoverflow.com/a/2625107/1460422
var dir = new Vector(
v.x - this.x,
v.y - this.y
).limitTo(amount);
this.x += dir.x;
this.y += dir.y;
return this;
}
/**
* Rounds the x and y components of this vector down to the next integer.
* @return {Vector} This vector - useful for diasy-chaining.
*/
floor() {
this.x = Math.floor(this.x);
this.y = Math.floor(this.y);
return this;
}
/**
* Rounds the x and y components of this vector up to the next integer.
* @return {Vector} This vector - useful for diasy-chaining.
*/
ceil() {
this.x = Math.ceil(this.x);
this.y = Math.ceil(this.y);
return this;
}
/**
* Rounds the x and y components of this vector to the nearest integer.
* @return {Vector} This vector - useful for diasy-chaining.
*/
round() {
this.x = Math.round(this.x);
this.y = Math.round(this.y);
return this;
}
/**
* Calculates the 'area' of this vector and returns the result.
* In other words, returns x * y. Useful if you're using a Vector to store
* a size.
* @return {Number} The 'area' of this vector.
*/
area() {
return this.x * this.y;
}
/**
* Snaps this vector to an imaginary square grid with the specified sized
* squares.
* @param {Number} grid_size The size of the squares on the imaginary grid to which to snap.
* @return {Vector} The current vector - useful for daisy-chaining.
*/
snapTo(grid_size) {
this.x = Math.floor(this.x / grid_size) * grid_size;
this.y = Math.floor(this.y / grid_size) * grid_size;
return this;
}
/**
* Limit the length of the current vector to value without changing the
* direction in which the vector is pointing.
* @param {Number} value The number to limit the current vector's length to.
* @return {Vector} The current vector. useful for daisy-chaining calls.
*/
limitTo(value) {
if(typeof value != "number")
throw new Error("Can't limit to non-number value.");
this.divide(this.length);
this.multiply(value);
return this;
}
/**
* Return the dot product of the current vector and another vector.
* @param {Vector} v The other vector we should calculate the dot product with.
* @return {Vector} The current vector. Useful for daisy-chaining calls.
*/
dotProduct(v) {
return (this.x * v.x) + (this.y * v.y);
}
/**
* Calculate the angle, in radians, from north to another vector.
* @param {Vector} v The other vector to which to calculate the angle.
* @return {Vector} The current vector. useful for daisy-chaining calls.
*/
angleFrom(v) {
// From http://stackoverflow.com/a/16340752/1460422
var angle = Math.atan2(v.y - this.y, v.x - this.x) - (Math.PI / 2);
angle += Math.PI/2;
if(angle < 0) angle += Math.PI * 2;
return angle;
}
/**
* Clones the current vector.
* @return {Vector} A clone of the current vector. Very useful for passing around copies of a vector if you don't want the original to be altered.
*/
clone() {
return new Vector(this.x, this.y);
}
/*
* Returns a representation of the current vector as a string.
* @returns {string} A representation of the current vector as a string.
*/
toString() {
return `(${this.x}, ${this.y})`;
}
/**
* Whether the vector is equal to another vector.
* @param {Vector} v The vector to compare to.
* @return {boolean} Whether the current vector is equal to the given vector.
*/
equalTo(v)
{
return this.x == v.x && this.y == v.y;
}
/**
* Get the unit vector of the current vector - that is a vector poiting in the same direction with a length of 1. Note that this does *not* alter the original vector.
* @return {Vector} The current vector's unit form.
*/
get unitVector() {
var length = this.length;
return new Vector(
this.x / length,
this.y / length);
}
/**
* Get the length of the current vector.
* @return {Number} The length of the current vector.
*/
get length() {
return Math.sqrt((this.x * this.x) + (this.y * this.y));
}
/**
* Get the value of the minimum component of the vector.
* @return {Number} The minimum component of the vector.
*/
get minComponent() {
return Math.min(this.x, this.y);
}
/**
* Get the value of the maximum component of the vector.
* @return {Number} The maximum component of the vector.
*/
get maxComponent() {
return Math.min(this.x, this.y);
}
}
/**
* Returns a new vector based on an angle and a length.
* @param {Number} angle The angle, in radians.
* @param {Number} length The length.
* @return {Vector} A new vector that represents the (x, y) of the specified angle and length.
*/
Vector.fromBearing = function(angle, length) {
return new Vector(
length * Math.cos(angle),
length * Math.sin(angle)
);
}
Vector.zero = new Vector(0, 0);
Vector.one = new Vector(1, 1);
export default Vector;