Class PixelNoise

Generates random per-pixel noise similar to Photoshop's "Add Noise" filter. Supports Uniform and Gaussian distributions, monochromatic and color modes. Provides both RNG-based (sequential) and hash-based (coordinate-addressable) evaluation paths.

Inheritance

object

PixelNoise

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Scylla.Core.Util.Noise

Assembly: ScyllaCore.dll

Syntax

public static class PixelNoise

Remarks

Unlike coherent noise algorithms (OpenSimplex2, Perlin, Value, etc.) which produce spatially correlated patterns with smooth gradients, pixel noise generates statistically independent random values at each pixel. Neighboring pixels share no spatial correlation, which is the defining characteristic of this technique. Common uses include film grain, texture roughening, dithering, aging, and photographic noise simulation.

Two API styles are provided:

RNG-based (Fill(Color32[], PixelNoiseSettings, IRandomSource) etc.): Consumes sequential values from an IRandomSource. Best for generating noise once - for example, baking a texture at application startup - where reproducibility is not required across runs.
Hash-based (Fill(Color32[], int, int, long, PixelNoiseSettings) etc.): Uses a seed and pixel (x, y) coordinates to produce deterministic, random-access values via HashToFloat(long, int, int). Best for procedural textures where any pixel can be re-evaluated in isolation, or where the same seed must always produce identical output.

Gaussian distribution is approximated using an Irwin-Hall sum of four uniform [-1, 1] hashes scaled to unit standard deviation. In hash mode, four independently seeded hashes of the same pixel coordinates are averaged; in RNG mode, NextGaussian is used directly.

All output pixels are centered on mid-gray (128/255 = 0.5 in float, 128 in Color32). Alpha channels are never modified by any method in this class. All methods are allocation-free after the output array is provided by the caller.

Methods

Apply(Color32[], PixelNoiseSettings, IRandomSource)

Applies additive RNG-based pixel noise to an existing UnityEngine.Color32 array, modifying each pixel's R, G, and B channels in place by adding a noise offset to the existing channel value. The result is clamped to [0, 255]. Alpha channels are preserved unchanged. When Amount is zero or negative, the array is not modified.

Declaration

public static void Apply(Color32[] pixels, PixelNoiseSettings settings, IRandomSource rng)

Parameters

Type	Name	Description
Color32[]	pixels	The pixel array to modify in place. Must not be `null`.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.
IRandomSource	rng	The random source that provides sequential noise samples. Must not be `null`.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `pixels` or `rng` is `null`.

Apply(Color32[], int, int, long, PixelNoiseSettings)

Applies additive hash-based pixel noise to an existing UnityEngine.Color32 array, modifying each pixel's R, G, and B channels in place. The noise offset for each pixel is derived from its (column, row) coordinate and the provided seed, producing the same noise pattern every time for the same inputs. The result is clamped to [0, 255]. Alpha channels are preserved unchanged. When Amount is zero or negative, the array is not modified.

Declaration

public static void Apply(Color32[] pixels, int width, int height, long seed, PixelNoiseSettings settings)

Parameters

Type	Name	Description
Color32[]	pixels	The pixel array to modify in place. Must have at least `width` * `height` elements. Must not be `null`.
int	width	The number of pixel columns. Must be at least 1.
int	height	The number of pixel rows. Must be at least 1.
long	seed	The seed for deterministic noise generation.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `pixels` is `null`.
ArgumentException	Thrown if `pixels`.Length is less than `width` * `height`.
ArgumentOutOfRangeException	Thrown if `width` or `height` is less than 1.

Apply(Color[], PixelNoiseSettings, IRandomSource)

Applies additive RNG-based pixel noise to an existing UnityEngine.Color array, modifying each pixel's R, G, and B channels in place by adding a noise offset to the existing channel value. The result is clamped to [0, 1]. Alpha channels are preserved unchanged. When Amount is zero or negative, the array is not modified.

Declaration

public static void Apply(Color[] pixels, PixelNoiseSettings settings, IRandomSource rng)

Parameters

Type	Name	Description
Color[]	pixels	The pixel array to modify in place. Must not be `null`.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.
IRandomSource	rng	The random source that provides sequential noise samples. Must not be `null`.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `pixels` or `rng` is `null`.

Apply(Color[], int, int, long, PixelNoiseSettings)

Applies additive hash-based pixel noise to an existing UnityEngine.Color array, modifying each pixel's R, G, and B channels in place. The noise offset for each pixel is derived from its (column, row) coordinate and the provided seed, producing the same noise pattern every time for the same inputs. The result is clamped to [0, 1]. Alpha channels are preserved unchanged. When Amount is zero or negative, the array is not modified.

Declaration

public static void Apply(Color[] pixels, int width, int height, long seed, PixelNoiseSettings settings)

Parameters

Type	Name	Description
Color[]	pixels	The pixel array to modify in place. Must have at least `width` * `height` elements. Must not be `null`.
int	width	The number of pixel columns. Must be at least 1.
int	height	The number of pixel rows. Must be at least 1.
long	seed	The seed for deterministic noise generation.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `pixels` is `null`.
ArgumentException	Thrown if `pixels`.Length is less than `width` * `height`.
ArgumentOutOfRangeException	Thrown if `width` or `height` is less than 1.

Evaluate(long, int, int, PixelNoiseSettings)

Evaluates hash-based pixel noise for a single pixel at the given integer coordinates, returning a mid-gray-centered noisy UnityEngine.Color32 value. The result is fully deterministic: the same seed, x, y, and settings always produce the same output. This method is useful for coordinate-addressable noise where any pixel can be evaluated independently, without iterating over the full array.

Declaration

public static Color32 Evaluate(long seed, int x, int y, PixelNoiseSettings settings)

Parameters

Type	Name	Description
long	seed	The seed for deterministic noise generation.
int	x	The X coordinate of the pixel in the virtual noise grid.
int	y	The Y coordinate of the pixel in the virtual noise grid.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode. When Monochromatic is `true`, a single noise value is shared across R, G, and B. When `false`, independent noise values are generated per channel using decorrelated seeds.

Returns

Type	Description
Color32	A noisy UnityEngine.Color32 centered on mid-gray (128, 128, 128). Alpha is always 255. When Amount is zero or negative, returns neutral mid-gray (128, 128, 128, 255) with no noise applied.

Fill(Color32[], PixelNoiseSettings, IRandomSource)

Fills a UnityEngine.Color32 array with RNG-based pixel noise, writing mid-gray-centered noise values to every element. Each pixel is written as (r, g, b, 255) where the channel values are 128 plus the noise offset, clamped to [0, 255]. When Amount is zero or negative, all pixels are set to neutral mid-gray (128, 128, 128, 255) with no noise.

Declaration

public static void Fill(Color32[] output, PixelNoiseSettings settings, IRandomSource rng)

Parameters

Type	Name	Description
Color32[]	output	The output array to fill. Every element is overwritten. Must not be `null`.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.
IRandomSource	rng	The random source that provides sequential noise samples. Must not be `null`. The caller is responsible for seeding this source to achieve reproducibility.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `output` or `rng` is `null`.

Fill(Color32[], int, int, long, PixelNoiseSettings)

Fills a UnityEngine.Color32 array with hash-based pixel noise, using each pixel's (column, row) coordinates as the hash inputs. The output is fully deterministic: the same seed and settings always produce the same result. Pixels are written in row-major order starting at index 0. Each pixel is a mid-gray-centered noise value (128, 128, 128) with the noise offset applied. Alpha is always 255. When Amount is zero or negative, all pixels are set to neutral mid-gray with no noise.

Declaration

public static void Fill(Color32[] output, int width, int height, long seed, PixelNoiseSettings settings)

Parameters

Type	Name	Description
Color32[]	output	The output array to fill. Must have at least `width` * `height` elements. Must not be `null`.
int	width	The number of pixel columns. Must be at least 1.
int	height	The number of pixel rows. Must be at least 1.
long	seed	The seed for deterministic noise generation.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `output` is `null`.
ArgumentException	Thrown if `output`.Length is less than `width` * `height`.
ArgumentOutOfRangeException	Thrown if `width` or `height` is less than 1.

Fill(Color[], PixelNoiseSettings, IRandomSource)

Fills a UnityEngine.Color array with RNG-based pixel noise, writing mid-gray-centered noise values to every element. Each pixel is written as (r, g, b, 1) where the channel values are 0.5 plus the noise offset, clamped to [0, 1]. When Amount is zero or negative, all pixels are set to neutral mid-gray (0.5, 0.5, 0.5, 1) with no noise.

Declaration

public static void Fill(Color[] output, PixelNoiseSettings settings, IRandomSource rng)

Parameters

Type	Name	Description
Color[]	output	The output array to fill. Every element is overwritten. Must not be `null`.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.
IRandomSource	rng	The random source that provides sequential noise samples. Must not be `null`. The caller is responsible for seeding this source to achieve reproducibility.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `output` or `rng` is `null`.

Fill(Color[], int, int, long, PixelNoiseSettings)

Fills a UnityEngine.Color array with hash-based pixel noise, using each pixel's (column, row) coordinates as the hash inputs. The output is fully deterministic: the same seed and settings always produce the same result. Pixels are written in row-major order starting at index 0. Each pixel is a mid-gray-centered noise value (0.5, 0.5, 0.5) with the noise offset applied. Alpha is always 1. When Amount is zero or negative, all pixels are set to neutral mid-gray with no noise.

Declaration

public static void Fill(Color[] output, int width, int height, long seed, PixelNoiseSettings settings)

Parameters

Type	Name	Description
Color[]	output	The output array to fill. Must have at least `width` * `height` elements. Must not be `null`.
int	width	The number of pixel columns. Must be at least 1.
int	height	The number of pixel rows. Must be at least 1.
long	seed	The seed for deterministic noise generation.
PixelNoiseSettings	settings	The pixel noise configuration controlling intensity, distribution, and channel mode.

Exceptions

Type	Condition
ArgumentNullException	Thrown if `output` is `null`.
ArgumentException	Thrown if `output`.Length is less than `width` * `height`.
ArgumentOutOfRangeException	Thrown if `width` or `height` is less than 1.