sdf-playground

Signed distance functions + Rust (CPU & GPU) = ❤️❤️

Platforms: Windows, Mac & Linux.

About

sdf-playground is a demo showcasing how you can run Rust code on the GPU - it consists of two parts:

• the application (run on the CPU, inside ./app),
• the shader (run on the GPU, inside ./shader).

Application is responsible for spawning the window and telling GPU to execute the shader, while shader is the one which generates all the colors.

Shader here implements a ray-marcher for signed distance functions, but in principle it can be anything you want, e.g.:

#[spirv(fragment)]
pub fn main_fs(out_color: &mut Vec4) {
    // out_color.x = R (0..1)
    // out_color.y = G (0..1)
    // out_color.z = B (0..1)
    // out_color.w = alpha (technically 0..1, but actually unused here)

    // Renders a yellow rectangle
    *out_color = vec4(1.0, 1.0, 0.0, 1.0); 
}

Usage

Assuming you've got Rust installed:

$ git clone https://github.com/Patryk27/sdf-playground
$ cargo run --release
# (might take a few minutes the first time, but should be faster then)

Note that the code first builds the application, then starts it, and then builds the shader - so for a few moments (until the shader is ready), the window will be just pitch-black (you should be able to see the shader's compilation progress in the terminal, though).

On the upside, modifying the shader doesn't require restarting the application - simply change shader/src/lib.rs, save it and wait a few seconds for the application to refresh!

Caveat Emptor

rust-gpu (the software that compiles your Rust code into a shader) doesn't support all features of the Rust language:

• understandably, there's no standard library (no std::fs, no vec![] etc.),
• there's no support for ADTs (no enum Option<T> { Some(T), None } etc.),
• stick to bool, u8, u32 and f32 - other types (might) not work,
• miscompilations are possible, though unlikely.

License

MIT License

Copyright (c) 2023 Patryk Wychowaniec