#bevy #bevy-plugin #compute


App compute plugin for Bevy

3 releases

0.10.3 Apr 19, 2023
0.10.2 Apr 17, 2023
0.10.1 Apr 16, 2023
0.10.0 Apr 14, 2023

#526 in Game dev



Bevy App Compute

MIT/Apache 2.0 Doc Crate

Dispatch and run compute shaders on bevy from App World .

Getting Started

Add the following line to your Cargo.toml

bevy_app_compute = "0.10.3"



Declare your shaders in structs implementing ComputeShader. The shader() fn should point to your shader source code. You need to derive TypeUuid as well and assign a unique Uuid:

#[uuid = "2545ae14-a9bc-4f03-9ea4-4eb43d1075a7"]
struct SimpleShader;

impl ComputeShader for SimpleShader {
    fn shader() -> ShaderRef {

Next, declare a struct implementing ComputeWorker to declare the bindings and the logic of your worker:

struct SimpleComputeWorker;

impl ComputeWorker for SimpleComputeWorker {
    fn build(world: &mut World) -> AppComputeWorker<Self> {
        let worker = AppComputeWorkerBuilder::new(world)
            // Add a uniform variable
            .add_uniform("uni", &5.)

            // Add a staging buffer, it will be available from
            // both CPU and GPU land.
            .add_staging("values", &[1., 2., 3., 4.])

            // Create a compute pass from your compute shader
            // and define used variables
            .add_pass::<SimpleShader>([4, 1, 1], &["uni", "values"])


Don't forget to add a shader file to your assets/ folder:

@group(0) @binding(0)
var<uniform> uni: f32;

@group(0) @binding(1)
var<storage, read_write> my_storage: array<f32>;

@compute @workgroup_size(1)
fn main(@builtin(global_invocation_id) invocation_id: vec3<u32>) {
    my_storage[invocation_id.x] = my_storage[invocation_id.x] + uni;

Add the AppComputePlugin plugin to your app, as well as one AppComputeWorkerPlugin per struct implementing ComputeWorker:

use bevy::prelude::*;
use bevy_app_compute::AppComputePlugin;

fn main() {

Your compute worker will now run every frame, during the PostUpdate stage. To read/write from it, use the AppComputeWorker<T> resource!

fn my_system(
    mut compute_worker: ResMut<AppComputeWorker<SimpleComputeWorker>>
) {
    if !compute_worker.available() {

    let result: Vec<f32> = compute_worker.read_vec("values");

    compute_worker.write_slice("values", [2., 3., 4., 5.]);

    println!("got {:?}", result)

(see simple.rs)

Multiple passes

You can have multiple passes without having to copy data back to the CPU in between:

let worker = AppComputeWorkerBuilder::new(world)
    .add_uniform("value", &3.)
    .add_storage("input", &[1., 2., 3., 4.])
    .add_staging("output", &[0f32; 4])
    // add each item + `value` from `input` to `output`
    .add_pass::<FirstPassShader>([4, 1, 1], &["value", "input", "output"]) 
    // multiply each element of `output` by itself
    .add_pass::<SecondPassShader>([4, 1, 1], &["output"]) 

    // the `output` buffer will contain [16.0, 25.0, 36.0, 49.0]

(see multi_pass.rs)

One shot computes

You can configure your worker to execute only when requested:

let worker = AppComputeWorkerBuilder::new(world)
    .add_uniform("uni", &5.)
    .add_staging("values", &[1., 2., 3., 4.])
    .add_pass::<SimpleShader>([4, 1, 1], &["uni", "values"])

    // This `one_shot()` function will configure your worker accordingly

Then, you can call execute() on your worker when you are ready to execute it:

// Execute it only when the left mouse button is pressed.
fn on_click_compute(
    buttons: Res<Input<MouseButton>>,
    mut compute_worker: ResMut<AppComputeWorker<SimpleComputeWorker>>
) {
    if !buttons.just_pressed(MouseButton::Left) { return; }


It will run at the end of the current frame, and you'll be able to read the data in the next frame.

(see one_shot.rs)


See examples

Features being worked upon

  • Ability to read/write between compute passes.
  • add more options to the api, like deciding BufferUsages or size of buffers.
  • Optimization. Right now the code is a complete mess.
  • Tests. This badly needs tests.

Bevy version mapping

Bevy bevy_app_compute
main main
0.10 0.10.3


~1M SLoC