arcade-physics
Version:
Use Arcade Physics without Phaser.
69 lines • 2.37 kB
JavaScript
;
/**
* @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 Circle_1 = __importDefault(require("../circle/Circle"));
// Adapted from https://gist.github.com/mutoo/5617691
/**
* Finds the circumscribed circle (circumcircle) of a Triangle object. The circumcircle is the circle which touches all of the triangle's vertices.
*
* @function Phaser.Geom.Triangle.CircumCircle
* @since 3.0.0
*
* @generic {Phaser.Geom.Circle} O - [out,$return]
*
* @param {Phaser.Geom.Triangle} triangle - The Triangle to use as input.
* @param {Phaser.Geom.Circle} [out] - An optional Circle to store the result in.
*
* @return {Phaser.Geom.Circle} The updated `out` Circle, or a new Circle if none was provided.
*/
const CircumCircle = (triangle, out) => {
if (out === undefined) {
out = new Circle_1.default();
}
// A
const x1 = triangle.x1;
const y1 = triangle.y1;
// B
const x2 = triangle.x2;
const y2 = triangle.y2;
// C
const x3 = triangle.x3;
const y3 = triangle.y3;
const A = x2 - x1;
const B = y2 - y1;
const C = x3 - x1;
const D = y3 - y1;
const E = A * (x1 + x2) + B * (y1 + y2);
const F = C * (x1 + x3) + D * (y1 + y3);
const G = 2 * (A * (y3 - y2) - B * (x3 - x2));
let dx;
let dy;
// If the points of the triangle are collinear, then just find the
// extremes and use the midpoint as the center of the circumcircle.
if (Math.abs(G) < 0.000001) {
const minX = Math.min(x1, x2, x3);
const minY = Math.min(y1, y2, y3);
dx = (Math.max(x1, x2, x3) - minX) * 0.5;
dy = (Math.max(y1, y2, y3) - minY) * 0.5;
out.x = minX + dx;
out.y = minY + dy;
out.radius = Math.sqrt(dx * dx + dy * dy);
}
else {
out.x = (D * E - B * F) / G;
out.y = (A * F - C * E) / G;
dx = out.x - x1;
dy = out.y - y1;
out.radius = Math.sqrt(dx * dx + dy * dy);
}
return out;
};
exports.default = CircumCircle;
//# sourceMappingURL=CircumCircle.js.map