PKHeX/PKHeX.Core/Util/RandUtil.cs
Kurt ff2e890e69 Revise Overworld8a application of PIDIV
Instantiating from template now follows group seed -> spawn 1 correlation, including alpha move.
Differentiates static encounters that don't follow the ow8a correlation, scrambles EC to disassociate.
Adds rand64 to get initial seeds
Set correct level range to match slotSeed; not respecting the slot roll being valid, but whatever.
2022-04-22 21:11:11 -07:00

48 lines
1.9 KiB
C#

using System;
using System.Threading;
namespace PKHeX.Core
{
public static partial class Util
{
// Multithread safe rand, ha
public static Random Rand => _local.Value;
private static int randomSeed = Environment.TickCount;
private static readonly ThreadLocal<Random> _local = new(() =>
{
// threads should never really step on each other when starting, but we'll play it safe.
var seed = Interlocked.Increment(ref randomSeed);
var mix = (0x41C64E6D * seed) + 0x00006073; // why not
return new Random(mix);
});
public static uint Rand32() => Rand32(Rand);
public static uint Rand32(this Random rnd) => (uint)rnd.Next(1 << 30) << 2 | (uint)rnd.Next(1 << 2);
public static ulong Rand64(this Random rnd) => rnd.Rand32() | (ulong)rnd.Rand32() << 32;
/// <summary>
/// Shuffles the order of items within a collection of items.
/// </summary>
/// <typeparam name="T">Item type</typeparam>
/// <param name="items">Item collection</param>
public static void Shuffle<T>(Span<T> items) => Shuffle(items, 0, items.Length, Rand);
/// <summary>
/// Shuffles the order of items within a collection of items.
/// </summary>
/// <typeparam name="T">Item type</typeparam>
/// <param name="items">Item collection</param>
/// <param name="start">Starting position</param>
/// <param name="end">Ending position</param>
/// <param name="rnd">RNG object to use</param>
public static void Shuffle<T>(Span<T> items, int start, int end, Random rnd)
{
for (int i = start; i < end; i++)
{
int index = i + rnd.Next(end - i);
(items[index], items[i]) = (items[i], items[index]);
}
}
}
}