Unable to find webgpu backend adapter when feture webgl enabled?

[ReaNAiveD]

Hello, I'm making an wasm application where user can specify WebGPU or WebGL as backend using a parameter from js.

static new(canvas: HTMLCanvasElement, backend: Backend): Promise<any>;

#[wasm_bindgen]
pub fn new(canvas: &web_sys::HtmlCanvasElement, backend: Backend) -> js_sys::Promise {
    ......
    let backends = match backend {
        Backend::All => wgpu::util::backend_bits_from_env().unwrap_or(wgpu::Backends::all()),
        Backend::WebGPU => wgpu::Backends::BROWSER_WEBGPU,
        Backend::WebGL => wgpu::Backends::GL,
    };
    let instance = wgpu::Instance::new(backends);
    let size = CanvasSize::new(canvas.width(), canvas.height());
    let surface = instance.create_surface_from_canvas(&canvas);
    wasm_bindgen_futures::future_to_promise(async move {
        let adapter = wgpu::util::initialize_adapter_from_env_or_default(
            &instance,
            backends,
            Some(&surface),
        )
        .await
        .expect("No suitable GPU adapters found on the system!");
    ......
}

I have managed to run my application in Chrome Canary with WebGPU without feature webgl. However, the browser cannot find a suitable WebGPU adapter when I enable the feature webgl.

Does this case work as expected? What should I do if I want to get a WebGPU Backend with feature webgl enabled?

[grovesNL]

Hi! 👋 The choice between WebGL vs. WebGPU is currently decided at compile-time, although we plan to allow picking an adapter at run-time later.

For now you could use two separate JavaScript+wasm bundles and either redirect to another page or conditionally load one bundle.