83 lines
1.8 KiB
Haxe
83 lines
1.8 KiB
Haxe
package kha.math;
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// Small Fast Counter 32 (sfc32) PRNG implementation
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// sfc32 is public domain: http://pracrand.sourceforge.net/license.txt
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// Implementation derived from: https://github.com/bryc/code/blob/master/jshash/PRNGs.md
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// which is also public domain
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/**
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Random number generator
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Please use this one instead of the native Haxe one to
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keep consistency between different platforms.
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**/
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class Random {
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var a: Int;
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var b: Int;
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var c: Int;
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var d: Int;
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public function new(seed: Int): Void {
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d = seed;
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a = 0x36aef51a;
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b = 0x21d4b3eb;
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c = 0xf2517abf;
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// Immediately skip a few possibly poor results the easy way
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for (i in 0...15) {
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this.Get();
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}
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}
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public function Get(): Int {
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var t = (a + b | 0) + d | 0;
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d = d + 1 | 0;
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a = b ^ b >>> 9;
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b = c + (c << 3) | 0;
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c = c << 21 | c >>> 11;
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c = c + t | 0;
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return t & 0x7fffffff;
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}
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public function GetFloat(): Float {
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return Get() / 0x7fffffff;
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}
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public function GetUpTo(max: Int): Int {
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return Get() % (max + 1);
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}
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public function GetIn(min: Int, max: Int): Int {
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return Get() % (max + 1 - min) + min;
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}
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public function GetFloatIn(min: Float, max: Float): Float {
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return min + GetFloat() * (max - min);
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}
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public static var Default: Random;
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public static function init(seed: Int): Void {
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Default = new Random(seed);
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}
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public static function get(): Int {
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return Default.Get();
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}
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public static function getFloat(): Float {
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return Default.GetFloat();
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}
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public static function getUpTo(max: Int): Int {
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return Default.GetUpTo(max);
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}
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public static function getIn(min: Int, max: Int): Int {
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return Default.GetIn(min, max);
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}
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public static function getFloatIn(min: Float, max: Float): Float {
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return min + Default.GetFloat() * (max - min);
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}
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}
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