RPG Maker MV
CXJ Core - Random v1.0.0

/******************************************************************************
 * CXJ_CXJCoreRandom.js                                                       *
 ******************************************************************************
 * CXJ Core - Random v1.0.0                                                   *
 * By G.A.M. Kertopermono, a.k.a. GaryCXJk                                    *
 ******************************************************************************
 * License: ISC                                                               *
 ******************************************************************************
 * Copyright (c) 2017, G.A.M. Kertopermono                                    *
 *                                                                            *
 * Permission to use, copy, modify, and/or distribute this software for any   *
 * purpose with or without fee is hereby granted, provided that the above     *
 * copyright notice and this permission notice appear in all copies.          *
 *                                                                            *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES   *
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF           *
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR    *
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES     *
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN      *
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR *
 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.                *
 ******************************************************************************/
 
/*:
 * @plugindesc A random number generator
 * @author G.A.M. Kertopermono
 *
 * @help
 * ============================================================================
 * = About                                                                    =
 * ============================================================================
 *
 * Well, crap. Apparently JavaScript doesn't have a Random class. Sure, I could
 * just grab a random number generator from somewhere, but screw that, let's
 * make one myself!
 *
 * Now I'm pretty sure this one isn't as random or even psuedo-random as you
 * might want, but it's meant for those who want a simple random number
 * generator that doesn't use the Math.random() function. It also has the
 * ability to set your own random seeds, so there's that.
 * 
 * The Random object is now part of the CXJCore line of scripts. Even though
 * it is part of it, it's still a stand-alone script, and can even be used
 * outside of RPG Maker MV.
 *
 * ============================================================================
 * = Usage                                                                    =
 * ============================================================================
 * 
 * This is a simple helper plugin, meant for those with a little bit more
 * programming experience. As such, the end-user is supposed to place this as
 * high as possible. As it doesn't touch any JavaScript class, you can freely
 * use it as you want.
 *
 * Of course, developers are fully authorized to integrate the code into their
 * own scripts, no strings attached. It is adviseable though to alter the
 * _next function so that it generates better random numbers.
 * 
 * You can use this Random object by creating a new CXJScripts.CXJCore.Random
 * instance. If CXJCore is installed and the Namespace parameter is set, you
 * can also call this object from the chosen namespace.
 *
 * When creating a Random object instance, you can leave out any parameters,
 * which will pick the random seed based on the current time in milliseconds.
 * Otherwise, the first argument is the random seed. The next four determine
 * the numbers with which it modifies the number. In the code, they're called
 * _bigInt1, _bigInt2 and _bigIntMod, and the formula to generate the next
 * number is:
 *
 * this._seed = (this._seed * this._bigInt1 + this._bigInt2) % this._bigIntMod;
 *
 * To actually get a number, you can use one of two instance methods, nextInt
 * and nextRandom.
 *
 * nextInt returns an integer. When no arguments are passed, it just returns
 * the current seed after a new one is generated. If one argument is given,
 * it generates a number between 0 and the given number. If a second argument
 * is given, it generates a number between the lowest number and the highest
 * number.
 *
 * nextRandom returns a floating point value between 0 and 1.
 * 
 * ----------------------------------------------------------------------------
 * - Methods                                                                  -
 * ----------------------------------------------------------------------------
 * 
 * CXJScripts.CXJCore.Random(seed, bigInt1, bigInt2, bigIntMod)
 * 
 * Constructor.
 * This initializes the Random object. You can optionally set the random seed
 * for this object.
 * 
 * The purpose of this Random object is to allow you to store and reuse random
 * number generators, for example, when used in replays and save states. This
 * allows your game to be consistent throughout the entire run of the game for
 * each seed when programmed correctly.
 * 
 * Arguments:
 * 
 * seed      - (optional) A random seed
 * bigInt1   - (optional) An integer, preferably a prime number
 * bigInt2   - (optional) An integer, preferably a prime number
 * bigIntMod - (optional) An integer, preferably a prime number, and at least
 *             bigger than (the multiplication of) the previous two integers
 *
 * ---
 *
 * CXJScripts.CXJCore.Random.prototype.setSeed(seed)
 * 
 * Sets the seed of a Random object
 * 
 * Arguments:
 * 
 * seed      - A random seed
 * 
 * ---
 * 
 * CXJScripts.CXJCore.Random.prototype.getSeed()
 * 
 * Gets the current seed of a Random object
 * 
 * Returns: The current seed as an integer
 * 
 * ---
 * 
 * CXJScripts.CXJCore.Random.prototype.nextInt(num1, num2)
 * 
 * Generates a random integer. Optionally, you can define a range, between the
 * lowest number (inclusive) and the highest (exclusive).
 * 
 * Arguments:
 * 
 * num1      - (optional) A minimum number
 * num2      - (optional) A maximum number
 * 
 * Returns: An integer
 * 
 * ---
 * 
 * CXJScripts.CXJCore.Random.prototype.nextRandom()
 * 
 * Generates a random float between 0 (inclusive) and 1 (inclusive)
 * 
 * Returns: A float between 0 and 1
 * 
 * ============================================================================
 * = Compatibility                                                            =
 * ============================================================================
 * 
 * This plugin does not overwrite default functionality.
 *
 * ============================================================================
 * = Changelog                                                                =
 * ============================================================================
 *
 * 1.0.0 (2017-07-15)
 * ------------------
 *
 * * Initial release
 *
 * ============================================================================
 * = License                                                                  =
 * ============================================================================
 *
 * Copyright (c) 2017, G.A.M. Kertopermono
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * ============================================================================
 */
 
// If it doesn't already exist, create a new CXJScripts object.
/** @namespace */
var CXJScripts = CXJScripts || {};

+function(_) {
    // Creates the CXJCore object and attaches it to the main CXJScripts object
    var CXJCore = {};
    _.CXJCore = CXJCore;
    
    /**
     * @constructor
     * This initializes the Random object. You can optionally set the random
     * seed for this object.
     * 
     * The purpose of this Random object is to allow you to store and reuse
     * random number generators, for example, when used in replays and save
     * states. This allows your game to be consistent throughout the entire
     * run of the game for each seed when programmed correctly.
     * @param {int} seed
     * @param {int} bigInt1
     * @param {int} bigInt2
     * @param {int} bigIntMod
     * @returns {CXJScripts.CXJCore.Random}
     */
    CXJCore.Random = function(seed, bigInt1, bigInt2, bigIntMod) {
        if(!seed && seed !== 0) {
            seed = (new Date()).getTime();
        }
        this._bigInt1 = 13;
        this._bigInt2 = 271;
        this._bigIntMod = 0x5A1ADDAD;
        if(bigInt1 || bigInt1 === 0) {
            this._bigInt1 = bigInt1;
        }
        if(bigInt2 || bigInt2 === 0) {
            this._bigInt2 = bigInt2;
        }
        if(bigIntMod || bigIntMod === 0) {
            this._bigIntMod = bigIntMod;
        }
        this.setSeed(seed);
    }

    /**
     * Sets the seed of a Random object
     * @param {type} seed
     */
    CXJCore.Random.prototype.setSeed = function(seed) {
        this._seed = seed;
    }

    /**
     * Gets the current seed of a Random object
     * @returns {int}
     */
    CXJCore.Random.prototype.getSeed = function() {
        return this._seed;
    }

    /**
     * Sets a new random seed
     * @private
     */
    CXJCore.Random.prototype._next = function() {
        this._seed = (this._seed * this._bigInt1 + this._bigInt2) % this._bigIntMod;
    }

    /**
     * Generates a random integer. Optionally, you can define a range, between
     * the lowest number (inclusive) and the highest (exclusive).
     * @param {int} num1
     * @param {int} num2
     * @returns {int}
     */
    CXJCore.Random.prototype.nextInt = function(num1, num2) {
        this._next();
        var num = this._seed;
        if(num1 !== null && num1 !== undefined && ((num2 !== null && num2 !== undefined) || num1 > 0)) {
            if(num2 === null || num2 === undefined) {
                num2 = 0;
            }
            if(num2 > num1) {
                var num3 = num2;
                num2 = num1;
                num1 = num3;
            }
            num = (num % (num1 - num2)) + num2;
        }
        return num;
    }

    /**
     * Generates a random float between 0 (inclusive) and 1 (inclusive)
     * @returns {float}
     */
    CXJCore.Random.prototype.nextRandom = function() {
        this._next();
        return this._seed / (this._bigIntMod - 1);
    }
}(CXJScripts);