arcade-physics
Version:
Use Arcade Physics without Phaser.
60 lines • 2.64 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 Point_1 = __importDefault(require("../point/Point"));
// This is based off an explanation and expanded math presented by Paul Bourke:
// See http:'local.wasp.uwa.edu.au/~pbourke/geometry/lineline2d/
/**
* Checks if two Lines intersect. If the Lines are identical, they will be treated as parallel and thus non-intersecting.
*
* @function Phaser.Geom.Intersects.LineToLine
* @since 3.0.0
*
* @param {Phaser.Geom.Line} line1 - The first Line to check.
* @param {Phaser.Geom.Line} line2 - The second Line to check.
* @param {Phaser.Geom.Point} [out] - A Point in which to optionally store the point of intersection.
*
* @return {boolean} `true` if the two Lines intersect, and the `out` object will be populated, if given. Otherwise, `false`.
*/
const LineToLine = (line1, line2, out) => {
if (out === undefined) {
out = new Point_1.default();
}
const x1 = line1.x1;
const y1 = line1.y1;
const x2 = line1.x2;
const y2 = line1.y2;
const x3 = line2.x1;
const y3 = line2.y1;
const x4 = line2.x2;
const y4 = line2.y2;
const numA = (x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3);
const numB = (x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3);
const deNom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);
// Make sure there is not a division by zero - this also indicates that the lines are parallel.
// If numA and numB were both equal to zero the lines would be on top of each other (coincidental).
// This check is not done because it is not necessary for this implementation (the parallel check accounts for this).
if (deNom === 0) {
return false;
}
// Calculate the intermediate fractional point that the lines potentially intersect.
const uA = numA / deNom;
const uB = numB / deNom;
// The fractional point will be between 0 and 1 inclusive if the lines intersect.
// If the fractional calculation is larger than 1 or smaller than 0 the lines would need to be longer to intersect.
if (uA >= 0 && uA <= 1 && uB >= 0 && uB <= 1) {
out.x = x1 + uA * (x2 - x1);
out.y = y1 + uA * (y2 - y1);
return true;
}
return false;
};
exports.default = LineToLine;
//# sourceMappingURL=LineToLine.js.map