Reading glb with external resource uri (with absolute paths)

[repalash]

Hi,
I am trying to read GLB with some external URI images and write them with Draco compression.

I see from #193 (comment) that it's not possible to resolve relative paths in binaryToJSON, but absolute paths should be possible.

In the source of binaryToJSON it throws an error when any URI is found.

Is there any way to handle this? I thought of replacing the external images with placeholder data URIs, but I guess from the source, that will not work either.

Thanks.

[donmccurdy]

If you use a method that takes a URI or path, these external references can be resolved:

const document = await io.readBinary('path/to/model.glb');
const jsonDocument = await io.readAsJSON('path/to/model.glb');

If the GLB is already in memory and that's not an option, then I think the only workaround the library currently supports would be to unpack the GLB container manually (example), append the resources you need to the resources map, and then parse it with io.readJSON(...).

Perhaps we could make that second method a bit easier by adding a second parameter to the binaryToJSON method, allowing you to "opt out" of the checks for external resources:

const jsonDocument = io.binaryToJSON(binary, skipExternal = true);

That option hasn't been added yet, and isn't the default behavior because I do think it's important to know that the JSONDocument returned is not actually self-contained. But adding the option would sound reasonable to me.

[repalash]

I see, didn't realise there is already a readExternalResources function already through the readAsJSON path. Thanks for this, I will try it out today. (Maybe this could be mentioned in the throw Error in binaryToJSON function?)
For glb, readBinary doesn't take a string argument, I guess you mean io.read.
It looks like passing the data URL should work for memory objects.

But, would it work for object URLs created from memory objects with URL.createObjectURL? appending the extension with #.glb .

Adding a skipExternal parameter to binaryToJSON sounds great, or to make the functions _binaryToJSON and _readResourcesInternal/External public

Thanks

[repalash]

I see readResourceExternal also downloads the file with fetch, is it also possible to skip the external downloads and work with just the URI?

[donmccurdy]

I see readResourceExternal also downloads the file with fetch, is it also possible to skip the external downloads ...

I think that'd be what the skipExternal flag should do – would you want to open a feature request ticket for this?