arcade-physics/lib/geom/triangle/InCenter.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"));
// The three angle bisectors of a triangle meet in one point called the incenter.
// It is the center of the incircle, the circle inscribed in the triangle.
function getLength(x1, y1, x2, y2) {
    const x = x1 - x2;
    const y = y1 - y2;
    const magnitude = x * x + y * y;
    return Math.sqrt(magnitude);
}
/**
 * Calculates the position of the incenter of a Triangle object. This is the point where its three angle bisectors meet and it's also the center of the incircle, which is the circle inscribed in the triangle.
 *
 * @function Phaser.Geom.Triangle.InCenter
 * @since 3.0.0
 *
 * @generic {Phaser.Geom.Point} O - [out,$return]
 *
 * @param {Phaser.Geom.Triangle} triangle - The Triangle to find the incenter of.
 * @param {Phaser.Geom.Point} [out] - An optional Point in which to store the coordinates.
 *
 * @return {Phaser.Geom.Point} Point (x, y) of the center pixel of the triangle.
 */
const InCenter = (triangle, out) => {
    if (out === undefined) {
        out = new Point_1.default();
    }
    const x1 = triangle.x1;
    const y1 = triangle.y1;
    const x2 = triangle.x2;
    const y2 = triangle.y2;
    const x3 = triangle.x3;
    const y3 = triangle.y3;
    const d1 = getLength(x3, y3, x2, y2);
    const d2 = getLength(x1, y1, x3, y3);
    const d3 = getLength(x2, y2, x1, y1);
    const p = d1 + d2 + d3;
    out.x = (x1 * d1 + x2 * d2 + x3 * d3) / p;
    out.y = (y1 * d1 + y2 * d2 + y3 * d3) / p;
    return out;
};
exports.default = InCenter;
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