PKHeX/PKHeX.Core/Legality/RNG/Overworld8aRNG.cs
2022-02-21 16:11:58 -08:00

286 lines
8.4 KiB
C#

using System;
using System.Runtime.CompilerServices;
namespace PKHeX.Core;
/// <summary>
/// Contains logic for the Generation 8 (Legends: Arceus) overworld spawns that walk around the overworld.
/// </summary>
public static class Overworld8aRNG
{
public static uint AdaptPID(PKM pk, Shiny shiny, uint pid)
{
if (shiny == Shiny.Never)
{
if (GetIsShiny(pk.TID, pk.SID, pid))
pid ^= 0x1000_0000;
}
else if (shiny != Shiny.Random)
{
if (!GetIsShiny(pk.TID, pk.SID, pid))
pid = GetShinyPID(pk.TID, pk.SID, pid, 0);
}
return pid;
}
private static uint GetShinyPID(int tid, int sid, uint pid, int type)
{
return (uint)(((tid ^ sid ^ (pid & 0xFFFF) ^ type) << 16) | (pid & 0xFFFF));
}
private static bool GetIsShiny(int tid, int sid, uint pid)
{
return GetShinyXor(pid, (uint)((sid << 16) | tid)) < 16;
}
private static uint GetShinyXor(uint pid, uint oid)
{
var xor = pid ^ oid;
return (xor ^ (xor >> 16)) & 0xFFFF;
}
private const int UNSET = -1;
public static void ApplyDetails(PKM pk, EncounterCriteria criteria, in OverworldParam8a para)
{
int ctr = 0;
const int maxAttempts = 50_000;
var rnd = Util.Rand;
do
{
ulong s0 = Util.Rand32(rnd) | (ulong)Util.Rand32(rnd) << 32;
ulong s1 = Util.Rand32(rnd) | (ulong)Util.Rand32(rnd) << 32;
var rand = new Xoroshiro128Plus(s0, s1);
if (TryApplyFromSeed(pk, criteria, para, rand))
return;
} while (++ctr != maxAttempts);
{
ulong s0 = Util.Rand32(rnd) | (ulong)Util.Rand32(rnd) << 32;
ulong s1 = Util.Rand32(rnd) | (ulong)Util.Rand32(rnd) << 32;
var rand = new Xoroshiro128Plus(s0, s1);
TryApplyFromSeed(pk, EncounterCriteria.Unrestricted, para, rand);
}
}
public static bool TryApplyFromSeed(PKM pk, EncounterCriteria criteria, in OverworldParam8a para, Xoroshiro128Plus rand)
{
// Encryption Constant
pk.EncryptionConstant = (uint)rand.NextInt();
// PID
var fakeTID = (uint)rand.NextInt();
uint pid = (uint)rand.NextInt();
bool isShiny = false;
if (para.Shiny == Shiny.Random) // let's decide if it's shiny or not!
{
for (int i = 1; i < para.RollCount; i++)
{
isShiny = GetShinyXor(pid, fakeTID) < 16;
if (isShiny)
break;
pid = (uint)rand.NextInt();
}
}
else
{
// no need to calculate a fake trainer
isShiny = para.Shiny == Shiny.Always;
}
ForceShinyState(pk, isShiny, ref pid);
if (para.Shiny == Shiny.Never)
{
if (GetIsShiny(pk.TID, pk.SID, pid))
return false;
}
else if (para.Shiny != Shiny.Random)
{
if (!GetIsShiny(pk.TID, pk.SID, pid))
return false;
if (para.Shiny == Shiny.AlwaysSquare && pk.ShinyXor != 0)
return false;
if (para.Shiny == Shiny.AlwaysStar && pk.ShinyXor == 0)
return false;
}
pk.PID = pid;
Span<int> ivs = stackalloc[] { UNSET, UNSET, UNSET, UNSET, UNSET, UNSET };
const int MAX = 31;
for (int i = 0; i < para.FlawlessIVs; i++)
{
int index;
do { index = (int)rand.NextInt(6); }
while (ivs[index] != UNSET);
ivs[index] = MAX;
}
for (int i = 0; i < ivs.Length; i++)
{
if (ivs[i] == UNSET)
ivs[i] = (int)rand.NextInt(32);
}
if (!criteria.IsIVsCompatible(ivs, 8))
return false;
pk.IV_HP = ivs[0];
pk.IV_ATK = ivs[1];
pk.IV_DEF = ivs[2];
pk.IV_SPA = ivs[3];
pk.IV_SPD = ivs[4];
pk.IV_SPE = ivs[5];
pk.RefreshAbility((int)rand.NextInt(2));
int gender = para.GenderRatio switch
{
PersonalInfo.RatioMagicGenderless => 2,
PersonalInfo.RatioMagicFemale => 1,
PersonalInfo.RatioMagicMale => 0,
_ => (int)rand.NextInt(252) + 1 < para.GenderRatio ? 1 : 0,
};
if (gender != criteria.Gender && criteria.Gender != -1)
return false;
pk.Gender = gender;
int nature = (int)rand.NextInt(25);
pk.StatNature = pk.Nature = nature;
var (height, weight) = para.IsAlpha
? (byte.MaxValue, byte.MaxValue)
: ((byte)((int)rand.NextInt(0x81) + (int)rand.NextInt(0x80)),
(byte)((int)rand.NextInt(0x81) + (int)rand.NextInt(0x80)));
if (pk is IScaledSize s)
{
s.HeightScalar = height;
s.WeightScalar = weight;
if (pk is IScaledSizeValue a)
{
a.ResetHeight();
a.ResetWeight();
}
}
return true;
}
public static bool Verify(PKM pk, ulong seed, in OverworldParam8a para)
{
var rand = new Xoroshiro128Plus(seed);
var ec = (uint)rand.NextInt();
if (ec != pk.EncryptionConstant)
return false;
var fakeTID = (uint)rand.NextInt();
uint pid = (uint)rand.NextInt();
bool isShiny = false;
if (para.Shiny == Shiny.Random) // let's decide if it's shiny or not!
{
for (int i = 1; i < para.RollCount; i++)
{
isShiny = GetShinyXor(pid, fakeTID) < 16;
if (isShiny)
break;
pid = (uint)rand.NextInt();
}
}
else
{
// no need to calculate a fake trainer
isShiny = para.Shiny == Shiny.Always;
}
ForceShinyState(pk, isShiny, ref pid);
if (pk.PID != pid)
return false;
Span<int> ivs = stackalloc[] { UNSET, UNSET, UNSET, UNSET, UNSET, UNSET };
const int MAX = 31;
for (int i = 0; i < para.FlawlessIVs; i++)
{
int index;
do { index = (int)rand.NextInt(6); }
while (ivs[index] != UNSET);
ivs[index] = MAX;
}
for (int i = 0; i < 6; i++)
{
if (ivs[i] == UNSET)
ivs[i] = (int)rand.NextInt(32);
}
if (pk.IV_HP != ivs[0])
return false;
if (pk.IV_ATK != ivs[1])
return false;
if (pk.IV_DEF != ivs[2])
return false;
if (pk.IV_SPA != ivs[3])
return false;
if (pk.IV_SPD != ivs[4])
return false;
if (pk.IV_SPE != ivs[5])
return false;
int abil = (int)rand.NextInt(2);
abil <<= 1; // 1/2/4
var current = pk.AbilityNumber;
if (abil == 4 && current != 4)
return false;
// else, for things that were made Hidden Ability, defer to Ability Checks (Ability Patch)
int gender = para.GenderRatio switch
{
PersonalInfo.RatioMagicGenderless => 2,
PersonalInfo.RatioMagicFemale => 1,
PersonalInfo.RatioMagicMale => 0,
_ => (int)rand.NextInt(252) + 1 < para.GenderRatio ? 1 : 0,
};
if (pk.Gender != gender)
return false;
var nature = (int)rand.NextInt(25);
if (pk.Nature != nature)
return false;
var (height, weight) = para.IsAlpha
? (byte.MaxValue, byte.MaxValue)
: ((byte)((int)rand.NextInt(0x81) + (int)rand.NextInt(0x80)),
(byte)((int)rand.NextInt(0x81) + (int)rand.NextInt(0x80)));
if (pk is IScaledSize s)
{
if (s.HeightScalar != height)
return false;
if (s.WeightScalar != weight)
return false;
}
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void ForceShinyState(PKM pk, bool isShiny, ref uint pid)
{
if (isShiny)
{
if (!GetIsShiny(pk.TID, pk.SID, pid))
pid = GetShinyPID(pk.TID, pk.SID, pid, 0);
}
else
{
if (GetIsShiny(pk.TID, pk.SID, pid))
pid ^= 0x1000_0000;
}
}
}
public readonly record struct OverworldParam8a(bool IsAlpha, byte GenderRatio, byte FlawlessIVs, byte RollCount, Shiny Shiny = Shiny.Random);