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Updated Vector2 docs

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This commit is contained in:
Mitchell McCaffrey 2020-10-10 11:10:45 +11:00
parent 718713b036
commit b6531507a5
1 changed files with 158 additions and 16 deletions
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174
src/helpers/vector2.js
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@ -4,14 +4,33 @@ import {
lerp as lerpNumber,
} from "./shared";
/**
* Vector class with x and y
* @typedef {Object} Vector2
* @property {number} x - X component of the vector
* @property {number} y - Y component of the vector
*/
/**
* @param {Vector2} p
* @returns {number} Length squared of `p`
*/
export function lengthSquared(p) {
return p.x * p.x + p.y * p.y;
}
/**
* @param {Vector2} p
* @returns {number} Length of `p`
*/
export function length(p) {
return Math.sqrt(lengthSquared(p));
}
/**
* @param {Vector2} p
* @returns {Vector2} `p` normalized, if length of `p` is 0 `{x: 0, y: 0}` is returned
*/
export function normalize(p) {
const l = length(p);
if (l === 0) {
@ -20,10 +39,20 @@ export function normalize(p) {
return divide(p, l);
}
/**
* @param {Vector2} a
* @param {Vector2} b
* @returns {number} Dot product between `a` and `b`
*/
export function dot(a, b) {
return a.x * b.x + a.y * b.y;
}
/**
* @param {Vector2} a
* @param {(Vector2 | number)} b
* @returns {Vector2} a - b
*/
export function subtract(a, b) {
if (typeof b === "number") {
return { x: a.x - b, y: a.y - b };
@ -32,6 +61,11 @@ export function subtract(a, b) {
}
}
/**
* @param {Vector2} a
* @param {(Vector2 | number)} b
* @returns {Vector2} a + b
*/
export function add(a, b) {
if (typeof b === "number") {
return { x: a.x + b, y: a.y + b };
@ -40,6 +74,11 @@ export function add(a, b) {
}
}
/**
* @param {Vector2} a
* @param {(Vector2 | number)} b
* @returns {Vector2} a * b
*/
export function multiply(a, b) {
if (typeof b === "number") {
return { x: a.x * b, y: a.y * b };
@ -48,6 +87,11 @@ export function multiply(a, b) {
}
}
/**
* @param {Vector2} a
* @param {(Vector2 | number)} b
* @returns {Vector2} a / b
*/
export function divide(a, b) {
if (typeof b === "number") {
return { x: a.x / b, y: a.y / b };
@ -56,6 +100,13 @@ export function divide(a, b) {
}
}
/**
* Rotates a point around a given origin by an angle in degrees
* @param {Vector2} point Point to rotate
* @param {Vector2} origin Origin of the rotation
* @param {number} angle Angle of rotation in degrees
* @returns {Vector2} Rotated point
*/
export function rotate(point, origin, angle) {
const cos = Math.cos(toRadians(angle));
const sin = Math.sin(toRadians(angle));
@ -66,18 +117,53 @@ export function rotate(point, origin, angle) {
};
}
/**
* Rotates a direction by a given angle in degrees
* @param {Vector2} direction Direction to rotate
* @param {number} angle Angle of rotation in degrees
* @returns {Vector2} Rotated direction
*/
export function rotateDirection(direction, angle) {
return rotate(direction, { x: 0, y: 0 }, angle);
}
export function min(a) {
return a.x < a.y ? a.x : a.y;
}
export function max(a) {
return a.x > a.y ? a.x : a.y;
/**
* Returns the min of `value` and `minimum`, if `minimum` is undefined component wise min is returned instead
* @param {Vector2} a
* @param {(Vector2 | number)} [minimum] Value to compare
* @returns {(Vector2 | number)}
*/
export function min(a, minimum) {
if (minimum === undefined) {
return a.x < a.y ? a.x : a.y;
} else if (typeof minimum === "number") {
return { x: Math.min(a.x, minimum), y: Math.min(a.y, minimum) };
} else {
return { x: Math.min(a.x, minimum.x), y: Math.min(a.y, minimum.y) };
}
}
/**
* Returns the max of `a` and `maximum`, if `maximum` is undefined component wise max is returned instead
* @param {Vector2} a
* @param {(Vector2 | number)} [maximum] Value to compare
* @returns {(Vector2 | number)}
*/
export function max(a, maximum) {
if (maximum === undefined) {
return a.x > a.y ? a.x : a.y;
} else if (typeof maximum === "number") {
return { x: Math.max(a.x, maximum), y: Math.max(a.y, maximum) };
} else {
return { x: Math.max(a.x, maximum.x), y: Math.max(a.y, maximum.y) };
}
}
/**
* Rounds `p` to the nearest value of `to`
* @param {Vector2} p
* @param {Vector2} to
* @returns {Vector2}
*/
export function roundTo(p, to) {
return {
x: roundToNumber(p.x, to.x),
@ -85,14 +171,27 @@ export function roundTo(p, to) {
};
}
/**
* @param {Vector2} a
* @returns {Vector2} The component wise sign of `a`
*/
export function sign(a) {
return { x: Math.sign(a.x), y: Math.sign(a.y) };
}
/**
* @param {Vector2} a
* @returns {Vector2} The component wise absolute of `a`
*/
export function abs(a) {
return { x: Math.abs(a.x), y: Math.abs(a.y) };
}
/**
* @param {Vector2} a
* @param {(Vector2 | number)} b
* @returns {Vector2} `a` to the power of `b`
*/
export function pow(a, b) {
if (typeof b === "number") {
return { x: Math.pow(a.x, b), y: Math.pow(a.y, b) };
@ -101,10 +200,21 @@ export function pow(a, b) {
}
}
/**
* @param {Vector2} a
* @returns {number} The dot product between `a` and `a`
*/
export function dot2(a) {
return dot(a, a);
}
/**
* Clamps `a` between `min` and `max`
* @param {Vector2} a
* @param {number} min
* @param {number} max
* @returns {Vector2}
*/
export function clamp(a, min, max) {
return {
x: Math.min(Math.max(a.x, min), max),
@ -112,7 +222,14 @@ export function clamp(a, min, max) {
};
}
// https://iquilezles.org/www/articles/distfunctions2d/distfunctions2d
/**
* Calculates the distance between a point and a line segment
* See more at {@link https://www.iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm}
* @param {Vector2} p Point
* @param {Vector2} a Start of the line
* @param {Vector2} b End of the line
* @returns {Object} The distance to and the closest point on the line segment
*/
export function distanceToLine(p, a, b) {
const pa = subtract(p, a);
const ba = subtract(b, a);
@ -122,8 +239,16 @@ export function distanceToLine(p, a, b) {
return { distance, point };
}
// TODO: Fix the robustness of this to allow smoothing on fog layers
// https://www.shadertoy.com/view/MlKcDD
/**
* Calculates the distance between a point and a quadratic bezier curve
* See more at {@link https://www.shadertoy.com/view/MlKcDD}
* @todo Fix the robustness of this to allow smoothing on fog layers
* @param {Vector2} pos Position
* @param {Vector2} A Start of the curve
* @param {Vector2} B Control point of the curve
* @param {Vector2} C End of the curve
* @returns {Object} The distance to and the closest point on the curve
*/
export function distanceToQuadraticBezier(pos, A, B, C) {
let distance = 0;
let point = { x: pos.x, y: pos.y };
@ -174,6 +299,11 @@ export function distanceToQuadraticBezier(pos, A, B, C) {
return { distance: Math.sqrt(distance), point: point };
}
/**
* Calculates an axis-aligned bounding box around an array of point
* @param {Vector2[]} points
* @returns {Object}
*/
export function getBounds(points) {
let minX = Number.MAX_VALUE;
let maxX = Number.MIN_VALUE;
@ -188,9 +318,14 @@ export function getBounds(points) {
return { minX, maxX, minY, maxY };
}
// Check bounds then use ray casting algorithm
// https://en.wikipedia.org/wiki/Point_in_polygon#Ray_casting_algorithm
// https://stackoverflow.com/questions/217578/how-can-i-determine-whether-a-2d-point-is-within-a-polygon/2922778
/**
* Checks to see if a point is in a polygon using ray casting
* See more at {@link https://en.wikipedia.org/wiki/Point_in_polygon#Ray_casting_algorithm}
* and {@link https://stackoverflow.com/questions/217578/how-can-i-determine-whether-a-2d-point-is-within-a-polygon/2922778}
* @param {Vector2} p
* @param {Vector2[]} points
* @returns {boolean}
*/
export function pointInPolygon(p, points) {
const { minX, maxX, minY, maxY } = getBounds(points);
if (p.x < minX || p.x > maxX || p.y < minY || p.y > maxY) {
@ -215,7 +350,7 @@ export function pointInPolygon(p, points) {
}
/**
* Returns true if a the distance between a and b is under threshold
* Returns true if a the distance between `a` and `b` is under `threshold`
* @param {Vector2} a
* @param {Vector2} b
* @param {number} threshold
@ -228,7 +363,7 @@ export function compare(a, b, threshold) {
* Returns the distance between two vectors
* @param {Vector2} a
* @param {Vector2} b
* @param {string} type - "chebyshev" | "euclidean" | "manhattan"
* @param {string} type - `chebyshev | euclidean | manhattan`
*/
export function distance(a, b, type) {
switch (type) {
@ -243,13 +378,20 @@ export function distance(a, b, type) {
}
}
/**
* Linear interpolate between `a` and `b` by `alpha`
* @param {Vector2} a
* @param {Vector2} b
* @param {number} alpha
* @returns {Vector2}
*/
export function lerp(a, b, alpha) {
return { x: lerpNumber(a.x, b.x, alpha), y: lerpNumber(a.y, b.y, alpha) };
}
/**
* Returns total length of a an array of points treated as a path
* @param {Array} points the array of points in the path
* @param {Vector2[]} points the array of points in the path
*/
export function pathLength(points) {
let l = 0;
@ -262,7 +404,7 @@ export function pathLength(points) {
/**
* Resample a path to n number of evenly distributed points
* based off of http://depts.washington.edu/acelab/proj/dollar/index.html
* @param {Array} points the points to resample
* @param {Vector2[]} points the points to resample
* @param {number} n the number of new points
*/
export function resample(points, n) {