Implement EXT_meshopt_compression decompression

[berbschloe]

I'm having an issue loading a GLB file that is compressed with Meshopt (EXT_meshopt_compression).

Smilies_20220815.glb.zip

It is crashing on the load step.

Would it be possible get support for loading these files (similar to Draco)?

If not, is there a way to check if a compression is used on a GLB file so I can pop up an alert saying "unsupported"? Thanks in advance for any support.

[warrenm]

Sorry about the crash. We should definitely be better about checking required extensions so we don't blow up in cases like this.

Much like Draco, I'm not interested in taking meshoptimizer on as a hard dependency, but I imagine a similar plugin approach would work. If you have opinions on what that should look like, I'm open to proposals.

I don't have any bandwidth to actually fix this this month, though, just to set expectations.

[warrenm]

Required extension validation is implemented in 382b798.

[berbschloe]

Thanks for getting back to me, for the time being I'm filtering out any GLTFAsset that have any extensionsRequired and throwing an error.

[donmccurdy]

Much like Draco, I'm not interested in taking meshoptimizer on as a hard dependency, but I imagine a similar plugin approach would work. If you have opinions on what that should look like, I'm open to proposals.

Unlike Draco, it is very possible to implement Meshopt decompression without any dependencies. The project provides an unoptimized "reference" implementation in 300 lines of JavaScript:

https://github.com/zeux/meshoptimizer/blob/master/js/meshopt_decoder_reference.js

[warrenm]

Hey @donmccurdy, thanks for the note. This makes me more comfortable with including meshopt decompression in GLTFKit2 core. Will investigate for future implementation.

[warrenm]

EXT_meshopt_compression is supported as of ebfee4a.

[warrenm]

This issue will be closed as completed in seven days if no further feedback is received.

[warrenm]

Closing as complete.