html5_webgpu.h missing (import/export for device/texure)

[Schlabbermampf]

trying to import the device and texture from JavaScript WebXR, the html5_webgpu.h also went away in favor of the dawn port #25398 .

the previous implementation looked like this:

#include <emscripten/html5_webgpu.h>

EM_ASYNC_JS(int, init_js_device, (), 
{
    const adapter = await navigator.gpu.requestAdapter( {xrCompatible: true} );
    const device = await adapter.requestDevice();
    return JsValStore.add(device);
});

WGPUDevice device = emscripten_webgpu_import_device( init_js_device() );

is there any proper way now to import the device? (I also planned to make a getter for the WGPUTexture from the WebXR frame to render into on the C++ side of code.

[sbc100]

@kainino0x

[kainino0x]

Apologies we haven't really documented this! Emdawnwebgpu has - for all objects, but with Texture as an example:

• WebGPU.importJsTexture(obj) takes a JS object, puts it in the Wasm object table, and returns its ID which you need to cast to WGPUTexture. (Imports it with a C refcount of 1 and, once we implement auto-destroy, imported objects probably won't be auto-destroyed.) Then if you want that in C++, use wgpu::Texture::Acquire(WGPUTexture).
• WebGPU.getJsObject(id) for getting the JS object from a Wasm WGPUTexture ID. (Doesn't affect the C refcount.)

These are both called from JS - you no longer need to explicitly call any C API to export something before getting it from JS.

We haven't totally committed to a stable API for this. I don't think it will change too much, but note in particular that getJsObject isn't typed, and we might need to separate objects by table at some point for an optimization - TBD.

(EDIT: Added some extra details)

Dawn tracking bug for documentation/samples: https://crbug.com/416377157

[Schlabbermampf]

thank you, seems super convenient. using the webgpu.h (not cpp) this one works fine so far for the Device:

EM_ASYNC_JS( WGPUDevice, init_js_device, (), 
{
    const adapter  = await navigator.gpu.requestAdapter( {xrCompatible: true} );
    const device = await adapter.requestDevice();

    return WebGPU.importJsDevice( device );
});

...
    WGPUDevice device = init_js_device();
    wgpuDeviceAddRef( device ); 

[kainino0x]

BTW, I should have mentioned - if you just need xrCompatible, you can do that directly from C using the WGPURequestAdapterWebXROptions extension struct.

[Schlabbermampf]

indeed, requesting the adapter with these options:

        WGPURequestAdapterWebXROptions xrOptions = {};
        xrOptions.chain.sType = WGPUSType_RequestAdapterWebXROptions;
        xrOptions.xrCompatible = WGPU_TRUE;

        WGPURequestAdapterOptions adapterOpts = {};
        adapterOpts.nextInChain = &xrOptions.chain;
        ...

then creating the device as well and setting it in JS for later usage with WebXR:

EM_ASYNC_JS( void, js_set_device, (WGPUDevice device), 
{
    Module['device'] = WebGPU.getJsObject(device);
})