squidpony.squidmath

Class WhiteNoise

java.lang.Object

squidpony.squidmath.WhiteNoise

All Implemented Interfaces:

Noise.Noise1D, Noise.Noise2D, Noise.Noise3D, Noise.Noise4D, Noise.Noise6D

public class WhiteNoise
extends java.lang.Object
implements Noise.Noise1D, Noise.Noise2D, Noise.Noise3D, Noise.Noise4D, Noise.Noise6D

Performance-oriented white noise generator for 1D, 2D, 3D, 4D, and 6D. Produces noise values from -1.0 inclusive to 1.0 exclusive. Should produce a completely different double even for extremely-nearby points, so this is not a kind of continuous noise like SeededNoise. It is not actually random, and the value is always determined by the exact double positions (and possibly a long seed) given to it. Even a slight change should drastically alter the returned value, though below some very small epsilon the results might not be different between two very close points in space. The output should look like "TV static" if rendered as grayscale pixels.
Meant for cases where you want to use a different number for every pixel, tile, or other unit of noise generated, often coupled with another kind of noise but with the result of the WhiteNoise made less significant to add a "fuzzy" effect to the appearance.
Implementation is based on CrossHash.Wisp.hash64(double[]), treating doubles as ints by using NumberTools.doubleToMixedIntBits(double), which XORs the bottom and top halves of the long bits of each double. Finishes by passing the top 52 bits as a significand to NumberTools.longBitsToDouble(long), using an exponent that allows this to produce numbers between -1.0 and 1.0. Has special treatment for the seed when present (since it is a long).
This can also be used as a sort of hashing function that produces a double, if you find a need for such a thing, with hash(double...).

Field Summary

Fields

Modifier and Type	Field and Description
static WhiteNoise	instance

Constructor Summary

Constructors

Constructor and Description
WhiteNoise()

Method Summary

Modifier and Type	Method and Description
double	getNoise(double x)
double	getNoise(double x, double y)
double	getNoise(double x, double y, double z)
double	getNoise(double x, double y, double z, double w)
double	getNoise(double x, double y, double z, double w, double u, double v)
double	getNoiseWithSeed(double x, double y, double z, double w, double u, double v, long seed)
double	getNoiseWithSeed(double x, double y, double z, double w, long seed)
double	getNoiseWithSeed(double x, double y, double z, long seed)
double	getNoiseWithSeed(double x, double y, long seed)
double	getNoiseWithSeed(double x, long seed)
static double	hash(double... data) Hashes the input double array or vararg and produces a double with unpredictable value, between -1.0 inclusive and 1.0 exclusive.

Methods inherited from class java.lang.Object

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

Field Detail

instance

public static final WhiteNoise instance

Constructor Detail

WhiteNoise

public WhiteNoise()

Method Detail

getNoise

public double getNoise(double x)

Specified by:

getNoise in interface Noise.Noise1D

getNoiseWithSeed

public double getNoiseWithSeed(double x,
                               long seed)

Specified by:

getNoiseWithSeed in interface Noise.Noise1D

getNoise

public double getNoise(double x,
                       double y)

Specified by:

getNoise in interface Noise.Noise2D

getNoiseWithSeed

public double getNoiseWithSeed(double x,
                               double y,
                               long seed)

Specified by:

getNoiseWithSeed in interface Noise.Noise2D

getNoise

public double getNoise(double x,
                       double y,
                       double z)

Specified by:

getNoise in interface Noise.Noise3D

getNoiseWithSeed

public double getNoiseWithSeed(double x,
                               double y,
                               double z,
                               long seed)

Specified by:

getNoiseWithSeed in interface Noise.Noise3D

getNoise

public double getNoise(double x,
                       double y,
                       double z,
                       double w)

Specified by:

getNoise in interface Noise.Noise4D

getNoiseWithSeed

public double getNoiseWithSeed(double x,
                               double y,
                               double z,
                               double w,
                               long seed)

Specified by:

getNoiseWithSeed in interface Noise.Noise4D

getNoise

public double getNoise(double x,
                       double y,
                       double z,
                       double w,
                       double u,
                       double v)

Specified by:

getNoise in interface Noise.Noise6D

getNoiseWithSeed

public double getNoiseWithSeed(double x,
                               double y,
                               double z,
                               double w,
                               double u,
                               double v,
                               long seed)

Specified by:

getNoiseWithSeed in interface Noise.Noise6D

hash

public static double hash(double... data)

Hashes the input double array or vararg and produces a double with unpredictable value, between -1.0 inclusive and 1.0 exclusive.

Parameters:

data - an array or vararg of double items; should not include NaN or infinite values but has no other limits

Returns:

an unpredictable double between -1.0 inclusive and 1.0 exclusive