/* jshint noempty: false */
/**
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2015 Photon Storm Ltd.
* @license {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
*/
/**
* An extremely useful repeatable random data generator.
*
* Based on Nonsense by Josh Faul https://github.com/jocafa/Nonsense.
*
* The random number genererator is based on the Alea PRNG, but is modified.
* - https://github.com/coverslide/node-alea
* - https://github.com/nquinlan/better-random-numbers-for-javascript-mirror
* - http://baagoe.org/en/wiki/Better_random_numbers_for_javascript (original, perm. 404)
*
* @class Phaser.RandomDataGenerator
* @constructor
* @param {any[]|string} [seeds] - An array of values to use as the seed, or a generator state (from {#state}).
*/
Phaser.RandomDataGenerator = function (seeds) {
if (seeds === undefined) { seeds = []; }
/**
* @property {number} c - Internal var.
* @private
*/
this.c = 1;
/**
* @property {number} s0 - Internal var.
* @private
*/
this.s0 = 0;
/**
* @property {number} s1 - Internal var.
* @private
*/
this.s1 = 0;
/**
* @property {number} s2 - Internal var.
* @private
*/
this.s2 = 0;
if (typeof seeds === 'string')
{
this.state(seeds);
}
else
{
this.sow(seeds);
}
};
Phaser.RandomDataGenerator.prototype = {
/**
* Private random helper.
*
* @method Phaser.RandomDataGenerator#rnd
* @private
* @return {number}
*/
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.
*
* _Note_: the seed array is only processed up to the first `undefined` (or `null`) value, should such be present.
*
* @method Phaser.RandomDataGenerator#sow
* @param {any[]} seeds - The array of seeds: the `toString()` of each value is used.
*/
sow: function (seeds) {
// Always reset to default seed
this.s0 = this.hash(' ');
this.s1 = this.hash(this.s0);
this.s2 = this.hash(this.s1);
this.c = 1;
if (!seeds)
{
return;
}
// Apply any seeds
for (var i = 0; i < seeds.length && (seeds[i] != null); i++)
{
var 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);
}
},
/**
* Internal method that creates a seed hash.
*
* @method Phaser.RandomDataGenerator#hash
* @private
* @param {any} data
* @return {number} hashed value.
*/
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} A random integer between 0 and 2^32.
*/
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} A random real number between 0 and 1.
*/
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} A random real number between 0 and 2^32.
*/
real: function() {
return this.integer() + this.frac();
},
/**
* Returns a random integer between and including min and max.
*
* @method Phaser.RandomDataGenerator#integerInRange
* @param {number} min - The minimum value in the range.
* @param {number} max - The maximum value in the range.
* @return {number} A random number between min and max.
*/
integerInRange: function (min, max) {
return Math.floor(this.realInRange(0, max - min + 1) + min);
},
/**
* Returns a random integer between and including min and max.
* This method is an alias for RandomDataGenerator.integerInRange.
*
* @method Phaser.RandomDataGenerator#between
* @param {number} min - The minimum value in the range.
* @param {number} max - The maximum value in the range.
* @return {number} A random number between min and max.
*/
between: function (min, max) {
return this.integerInRange(min, max);
},
/**
* Returns a random real number between min and max.
*
* @method Phaser.RandomDataGenerator#realInRange
* @param {number} min - The minimum value in the range.
* @param {number} max - The maximum value in the range.
* @return {number} A random number between min and max.
*/
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} A random real number between -1 and 1.
*/
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} A valid RFC4122 version4 ID hex string
*/
uuid: function () {
var a = '';
var 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 {Array} ary - An Array to pick a random member of.
* @return {any} A random member of the array.
*/
pick: function (ary) {
return ary[this.integerInRange(0, ary.length - 1)];
},
/**
* Returns a sign to be used with multiplication operator.
*
* @method Phaser.RandomDataGenerator#sign
* @return {number} -1 or +1.
*/
sign: function () {
return this.pick([-1, 1]);
},
/**
* Returns a random member of `array`, favoring the earlier entries.
*
* @method Phaser.RandomDataGenerator#weightedPick
* @param {Array} ary - An Array to pick a random member of.
* @return {any} A random member of the array.
*/
weightedPick: function (ary) {
return ary[~~(Math.pow(this.frac(), 2) * (ary.length - 1) + 0.5)];
},
/**
* 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 - The minimum value in the range.
* @param {number} max - The maximum value in the range.
* @return {number} A random timestamp between min and max.
*/
timestamp: function (min, max) {
return this.realInRange(min || 946684800000, max || 1577862000000);
},
/**
* Returns a random angle between -180 and 180.
*
* @method Phaser.RandomDataGenerator#angle
* @return {number} A random number between -180 and 180.
*/
angle: function() {
return this.integerInRange(-180, 180);
},
/**
* Gets or Sets the state of the generator. This allows you to retain the values
* that the generator is using between games, i.e. in a game save file.
*
* To seed this generator with a previously saved state you can pass it as the
* `seed` value in your game config, or call this method directly after Phaser has booted.
*
* Call this method with no parameters to return the current state.
*
* If providing a state it should match the same format that this method
* returns, which is a string with a header `!rnd` followed by the `c`,
* `s0`, `s1` and `s2` values respectively, each comma-delimited.
*
* @method Phaser.RandomDataGenerator#state
* @param {string} [state] - Generator state to be set.
* @return {string} The current state of the generator.
*/
state: function (state) {
if (typeof state === 'string' && state.match(/^!rnd/))
{
state = state.split(',');
this.c = parseFloat(state[1]);
this.s0 = parseFloat(state[2]);
this.s1 = parseFloat(state[3]);
this.s2 = parseFloat(state[4]);
}
return ['!rnd', this.c, this.s0, this.s1, this.s2].join(',');
}
};
Phaser.RandomDataGenerator.prototype.constructor = Phaser.RandomDataGenerator;
