GPUNoiseTexture

A Godot engine plugin that introduces two new Texture resources: GPUNoiseTexture2D and GPUNoiseTexture3D. These new texture types permit the creation of custom noise patterns via compute shaders. Compute shaders implementations can be hotswapped in the editor for rapid prototyping.

This plugin originated as a quick tool for personal use, but was found to be significant enough to be separated into its own repository. I hope it can be useful to some!

[!IMPORTANT] Basic familiarity with compute shaders is a prerequisite to use this plugin! To learn more about what compute shaders are and how they are used in Godot, please take a look at this tutorial.

Usage

Both GPUNoiseTexture2D and GPUNoiseTexture3D require a compute shader which implements the desired noise, writing the noise values to a texture. Noise parameters (e.g., frequency) are passed in as a push constant and roughly match the parameters used in Godot's FastNoiseLite class. How/whether the parameters actually affect the generated noise is entirely up to the shader implementation.

GPUNoiseTexture's also require specifying the DataFormat of the generated noise texture. One useful consequence of this is that custom noise implementations can write to multiple color channels in the output texture if desired.

[!NOTE] For noise implementations written in GLSL, the format qualifier of the image uniform (r8 is used in the examples below) should match the DataFormat specified in its respective GPUNoiseTexture resource. This is not a concern for implementations written in HLSL as format qualifiers are implicit in that language.

Examples

Below are some generic examples for how one might implement a compute shader for a GPUNoiseTexture.

Example GLSL pseudocode for GPUNoiseTexture2D

#[compute]
#version 450

layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;

layout(r8, set = 0, binding = 0) uniform restrict writeonly image2D noise_image;

layout(push_constant) uniform PushConstants {
    bool invert;
    uint seed;
    float frequency;
    uint octaves;
    float lacunarity;
    float gain;
    float attenuation;
};

void main() {
    ivec2 id = ivec2(gl_GlobalInvocationID.xy);

    // Discard threads outside image dimensions.
    if (any(greaterThanEqual(id, imageSize(noise_image)))) return;

    float noise = get_noise(id, frequency, seed, octaves, lacunarity, gain);
    noise = mix(noise, 1.0 - noise, int(invert));
    noise = pow(noise, attenuation);
    imageStore(noise_image, id, vec4(vec3(noise), 1));
}

Example GLSL pseudocode for GPUNoiseTexture3D

#[compute]
#version 450

layout(local_size_x = 8, local_size_y = 8, local_size_z = 8) in;

layout(r8, set = 0, binding = 0) uniform restrict writeonly image3D noise_image;

layout(push_constant) uniform PushConstants {
    bool invert;
    uint seed;
    float frequency;
    uint octaves;
    float lacunarity;
    float gain;
    float attenuation;
};

void main() {
    ivec3 id = ivec3(gl_GlobalInvocationID);

    // Discard threads outside image dimensions.
    if (any(greaterThanEqual(id, imageSize(noise_image)))) return;

    float noise = get_noise(id, frequency, seed, octaves, lacunarity, gain);
    noise = mix(noise, 1.0 - noise, int(invert));
    noise = pow(noise, attenuation);
    imageStore(noise_image, id, vec4(vec3(noise), 1));
}

For real-world implementations, please check out the samples included in the examples/ directory.