squidpony.squidmath

Class PermPointHash

java.lang.Object

squidpony.squidmath.IPointHash.IntImpl

squidpony.squidmath.PermPointHash

All Implemented Interfaces:

IPointHash

public class PermPointHash
extends IPointHash.IntImpl

A mid-to-low quality point hash that uses a similar (not identical) technique to what OpenSimplex2 uses, with a permutation array created at construction. To get an x,y,z point, this looks up x in the permutation array (using only the bottom 11 bits of x), which gets an 11-bit number, then XORs that with y, masks to 11 bits, and looks that up again in the same permutation array, finishing by XORing with z and masking to 11 bits. To match the behavior of other IPointHash implementations, this finishes by attempting to include variable state using: (((...) - state ^ 0xD1B54A35) * 0x125493 + state ^ 0xD1B54A35) * 0x125493;, which also pushes the usable bits up throughout the returned int, instead of just in the lowest 11 bits.
This is fast in OpenSimplex2, but the quality is so lackluster here, even with extra operations, that this isn't recommended at all.

Nested Class Summary

Nested classes/interfaces inherited from interface squidpony.squidmath.IPointHash

IPointHash.IntImpl, IPointHash.LongImpl

Field Summary

Fields inherited from class squidpony.squidmath.IPointHash.IntImpl

state

Constructor Summary

Constructors

Constructor and Description
PermPointHash()
PermPointHash(int state)

Method Summary

Modifier and Type	Method and Description
int	getState()
int	hashWithState(int x, int y, int state)
int	hashWithState(int x, int y, int z, int state)
int	hashWithState(int x, int y, int z, int w, int state)
int	hashWithState(int x, int y, int z, int w, int u, int state)
int	hashWithState(int x, int y, int z, int w, int u, int v, int state)

Methods inherited from class squidpony.squidmath.IPointHash.IntImpl

hash, hash, hash, hash, hash, setState, setState

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PermPointHash

public PermPointHash()

PermPointHash

public PermPointHash(int state)

Method Detail

getState

public int getState()

hashWithState

public int hashWithState(int x,
                         int y,
                         int state)

hashWithState

public int hashWithState(int x,
                         int y,
                         int z,
                         int state)

hashWithState

public int hashWithState(int x,
                         int y,
                         int z,
                         int w,
                         int state)

hashWithState

public int hashWithState(int x,
                         int y,
                         int z,
                         int w,
                         int u,
                         int state)

hashWithState

public int hashWithState(int x,
                         int y,
                         int z,
                         int w,
                         int u,
                         int v,
                         int state)