phaser/src/geom/line/GetPoints.js

A fast, free and fun HTML5 Game Framework for Desktop and Mobile web browsers.

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

var Length = require('./Length');
var Point = require('../point/Point');

/**
 * [description]
 *
 * @function Phaser.Geom.Line.GetPoints
 * @since 3.0.0
 *
 * @generic {Phaser.Geom.Point[]} O - [out,$return]
 *
 * @param {Phaser.Geom.Line} line - [description]
 * @param {integer} quantity - [description]
 * @param {integer} [stepRate] - [description]
 * @param {(array|Phaser.Geom.Point[])} [out] - [description]
 *
 * @return {(array|Phaser.Geom.Point[])} [description]
 */
var GetPoints = function (line, quantity, stepRate, out)
{
    if (out === undefined) { out = []; }

    //  If quantity is a falsey value (false, null, 0, undefined, etc) then we calculate it based on the stepRate instead.
    if (!quantity)
    {
        quantity = Length(line) / stepRate;
    }

    var x1 = line.x1;
    var y1 = line.y1;

    var x2 = line.x2;
    var y2 = line.y2;

    for (var i = 0; i < quantity; i++)
    {
        var position = i / quantity;

        var x = x1 + (x2 - x1) * position;
        var y = y1 + (y2 - y1) * position;

        out.push(new Point(x, y));
    }

    return out;
};

module.exports = GetPoints;