UnityGame/Library/PackageCache/com.unity.shadergraph/Documentation~/Gradient-Noise-Node.md

Gradient Noise Node

Description

Generates a gradient, or Perlin, noise based on input UV. The scale of the generated noise is controlled by input Scale. In terms of performance cost, Gradient Noise node can be slightly more computationally intensive than sampling a texture map.

You can also choose to use two different hashing methods for calculating the noise. As of Unity version 2021.2, the Gradient Noise node defaults to the Deterministic hash, to ensure consistent results for noise generation across platforms. Because the UV value is used as the seed for the noise generation, you can offset, scale, or distort the UV value to generate different noise patterns.

Ports

Name	Direction	Type	Binding	Description
UV	Input	Vector 2	UV	Input UV value
Scale	Input	Float	None	Noise scale
Out	Output	Float	None	Output value in the range 0.0 to 1.0

Controls

Name	Type	Options	Description
Hash Type	Dropdown	Deterministic, LegacyMod	Selects the hash function used to generate random numbers for noise generation.

Generated Code Example

The following example code represents one possible outcome of this node.

float2 unity_gradientNoise_dir(float2 p)
{
    p = p % 289;
    float x = (34 * p.x + 1) * p.x % 289 + p.y;
    x = (34 * x + 1) * x % 289;
    x = frac(x / 41) * 2 - 1;
    return normalize(float2(x - floor(x + 0.5), abs(x) - 0.5));
}

float unity_gradientNoise(float2 p)
{
    float2 ip = floor(p);
    float2 fp = frac(p);
    float d00 = dot(unity_gradientNoise_dir(ip), fp);
    float d01 = dot(unity_gradientNoise_dir(ip + float2(0, 1)), fp - float2(0, 1));
    float d10 = dot(unity_gradientNoise_dir(ip + float2(1, 0)), fp - float2(1, 0));
    float d11 = dot(unity_gradientNoise_dir(ip + float2(1, 1)), fp - float2(1, 1));
    fp = fp * fp * fp * (fp * (fp * 6 - 15) + 10);
    return lerp(lerp(d00, d01, fp.y), lerp(d10, d11, fp.y), fp.x);
}

void Unity_GradientNoise_float(float2 UV, float Scale, out float Out)
{
    Out = unity_gradientNoise(UV * Scale) + 0.5;
}