arcade-physics/lib/geom/triangle/Random.js

Use Arcade Physics without Phaser.

"use strict";
/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const Point_1 = __importDefault(require("../point/Point"));
/**
 * Returns a random Point from within the area of the given Triangle.
 *
 * @function Phaser.Geom.Triangle.Random
 * @since 3.0.0
 *
 * @generic {Phaser.Geom.Point} O - [out,$return]
 *
 * @param {Phaser.Geom.Triangle} triangle - The Triangle to get a random point from.
 * @param {Phaser.Geom.Point} [out] - The Point object to store the position in. If not given, a new Point instance is created.
 *
 * @return {Phaser.Geom.Point} A Point object holding the coordinates of a random position within the Triangle.
 */
const Random = (triangle, out) => {
    if (out === undefined) {
        out = new Point_1.default();
    }
    //  Basis vectors
    const ux = triangle.x2 - triangle.x1;
    const uy = triangle.y2 - triangle.y1;
    const vx = triangle.x3 - triangle.x1;
    const vy = triangle.y3 - triangle.y1;
    //  Random point within the unit square
    let r = Math.random();
    let s = Math.random();
    //  Point outside the triangle? Remap it.
    if (r + s >= 1) {
        r = 1 - r;
        s = 1 - s;
    }
    out.x = triangle.x1 + (ux * r + vx * s);
    out.y = triangle.y1 + (uy * r + vy * s);
    return out;
};
exports.default = Random;
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