/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2013 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
/**
* Phaser.RandomDataGenerator constructor.
*
* @class Phaser.RandomDataGenerator
* @classdesc An extremely useful repeatable random data generator. Access it via Phaser.Game.rnd
* Based on Nonsense by Josh Faul https://github.com/jocafa/Nonsense.
* Random number generator from http://baagoe.org/en/wiki/Better_random_numbers_for_javascript
*
* @constructor
* @param {array} seeds
*/
Phaser.RandomDataGenerator = function (seeds) {
if (typeof seeds === "undefined") { seeds = []; }
this.sow(seeds);
};
Phaser.RandomDataGenerator.prototype = {
/**
* @property {number} c
* @private
*/
c: 1,
/**
* @property {number} s0
* @private
*/
s0: 0,
/**
* @property {number} s1
* @private
*/
s1: 0,
/**
* @property {number} s2
* @private
*/
s2: 0,
/**
* Private random helper.
* @method Phaser.RandomDataGenerator#rnd
* @private
* @return {number} Description.
*/
rnd: function () {
var t = 2091639 * this.s0 + this.c * 2.3283064365386963e-10; // 2^-32
this.c = t | 0;
this.s0 = this.s1;
this.s1 = this.s2;
this.s2 = t - this.c;
return this.s2;
},
/**
* Reset the seed of the random data generator.
*
* @method Phaser.RandomDataGenerator#sow
* @param {array} seeds
*/
sow: function (seeds) {
if (typeof seeds === "undefined") { seeds = []; }
this.s0 = this.hash(' ');
this.s1 = this.hash(this.s0);
this.s2 = this.hash(this.s1);
this.c = 1;
var seed;
for (var i = 0; seed = seeds[i++]; )
{
this.s0 -= this.hash(seed);
this.s0 += ~~(this.s0 < 0);
this.s1 -= this.hash(seed);
this.s1 += ~~(this.s1 < 0);
this.s2 -= this.hash(seed);
this.s2 += ~~(this.s2 < 0);
}
},
/**
* Description.
* @method Phaser.RandomDataGenerator#hash
* @param {Any} data
* @private
* @return {number} Description.
*/
hash: function (data) {
var h, i, n;
n = 0xefc8249d;
data = data.toString();
for (i = 0; i < data.length; i++) {
n += data.charCodeAt(i);
h = 0.02519603282416938 * n;
n = h >>> 0;
h -= n;
h *= n;
n = h >>> 0;
h -= n;
n += h * 0x100000000;// 2^32
}
return (n >>> 0) * 2.3283064365386963e-10;// 2^-32
},
/**
* Returns a random integer between 0 and 2^32.
* @method Phaser.RandomDataGenerator#integer
* @return {number}
*/
integer: function() {
return this.rnd.apply(this) * 0x100000000;// 2^32
},
/**
* Returns a random real number between 0 and 1.
* @method Phaser.RandomDataGenerator#frac
* @return {number}
*/
frac: function() {
return this.rnd.apply(this) + (this.rnd.apply(this) * 0x200000 | 0) * 1.1102230246251565e-16;// 2^-53
},
/**
* Returns a random real number between 0 and 2^32.
* @method Phaser.RandomDataGenerator#real
* @return {number}
*/
real: function() {
return this.integer() + this.frac();
},
/**
* Returns a random integer between min and max.
* @method Phaser.RandomDataGenerator#integerInRange
* @param {number} min
* @param {number} max
* @return {number}
*/
integerInRange: function (min, max) {
return Math.floor(this.realInRange(min, max));
},
/**
* Returns a random real number between min and max.
* @method Phaser.RandomDataGenerator#realInRange
* @param {number} min
* @param {number} max
* @return {number}
*/
realInRange: function (min, max) {
return this.frac() * (max - min) + min;
},
/**
* Returns a random real number between -1 and 1.
* @method Phaser.RandomDataGenerator#normal
* @return {number}
*/
normal: function () {
return 1 - 2 * this.frac();
},
/**
* Returns a valid RFC4122 version4 ID hex string from https://gist.github.com/1308368
* @method Phaser.RandomDataGenerator#uuid
* @return {string}
*/
uuid: function () {
var a, b;
for (
b=a='';
a++<36;
b+=~a%5|a*3&4?(a^15?8^this.frac()*(a^20?16:4):4).toString(16):'-'
);
return b;
},
/**
* Returns a random member of `array`.
* @method Phaser.RandomDataGenerator#pick
* @param {Any} ary
* @return {number}
*/
pick: function (ary) {
return ary[this.integerInRange(0, ary.length)];
},
/**
* Returns a random member of `array`, favoring the earlier entries.
* @method Phaser.RandomDataGenerator#weightedPick
* @param {Any} ary
* @return {number}
*/
weightedPick: function (ary) {
return ary[~~(Math.pow(this.frac(), 2) * ary.length)];
},
/**
* Returns a random timestamp between min and max, or between the beginning of 2000 and the end of 2020 if min and max aren't specified.
* @method Phaser.RandomDataGenerator#timestamp
* @param {number} min
* @param {number} max
* @return {number}
*/
timestamp: function (a, b) {
return this.realInRange(a || 946684800000, b || 1577862000000);
},
/**
* Returns a random angle between -180 and 180.
* @method Phaser.RandomDataGenerator#angle
* @return {number}
*/
angle: function() {
return this.integerInRange(-180, 180);
}
};