Drag&Drop failing on Linux

When I Drag&Drop the BusterDrone glTF dir on the model-viewer, it simply errors and doesn't load anything - but no one can reproduce it on Mac or Windows (I use Linux Mint). Interestingly https://sandbox.babylonjs.com/ has the same bug, but then it works on https://gltf-viewer.donmccurdy.com/

TLDR:
Works:

• https://gltf-viewer.donmccurdy.com/
• https://github.com/playcanvas/playcanvas-gltf

Half-broken (does't work with dir drop, but half-works with selecting all individual files and then dropping):

• https://sandbox.babylonjs.com/

Can't get it to work at all:

• https://playcanvas.com/model-viewer

Steps to reproduce the problem:

1. Go to https://playcanvas.com/model-viewer
2. Drag&drop the dir of the BusterDrone glTF
3. Open DevTools and see the "Network error"

Because it works in Linux/Firefox and @slimbuck tested on Mac/Chrome, I started to think it must be a Chrome bug, so I started an issue here too: https://issues.chromium.org/issues/404044460

From the technical POV, I figured that even the old playcanvas-gltf version works, so I just ported the Promise-based Drag&Drop code from this repo to the old playcanvas-gltf viewer in the hope it would crash too, so I could debug line by line - but it just kept working. So I'm just baffled still and hope this is actually a Chrome bug.

After digging more through the code I finally found:

this.supportsImageBitmap = !isSafari && typeof ImageBitmap !== 'undefined';

It is true on Chrome/Linux, but for some reason Chrome on Linux laggs behind at everything (e.g. WebGPU is still a headache too). Or maybe just another driver issue because NVIDIA can't write proper Linux drivers.

The code where it makes a difference:

https://github.com/playcanvas/engine/blob/03d30259c91af8f8f154f546b28ae7abc4886622/src/framework/parsers/texture/img.js#L63-L68

https://github.com/playcanvas/engine/blob/03d30259c91af8f8f154f546b28ae7abc4886622/src/framework/parsers/texture/img.js#L37-L47

We could rewrite the condition like:

- this.supportsImageBitmap = !isSafari && typeof ImageBitmap !== 'undefined'
+ this.supportsImageBitmap = !isSafari && typeof ImageBitmap !== 'undefined' && !(navigator.userAgent.includes('Chrome') && navigator.userAgent.includes('Linux'))

But then again, maybe it works on some Linux systems, uff - so it would be like: wait until error happens, reset the this.supportsImageBitmap and try again

Start by reproducing the directory drop on Linux Chrome at https://playcanvas.com/model-viewer, then inspect src/framework/parsers/texture/img.js around the linked ImageBitmap support checks and texture loading paths. Compare the behavior with individual-file drops and the working gltf-viewer. Done means BusterDrone glTF directory drops load without the network error on affected Linux systems, with the behavior verified across the relevant browser environments.