Draco decoding errors result in uncaught promise rejections.

Describe the bug

When decoding a GLTF model with Draco compression, in some cases if the decoding process fails a promise in GLTFLoader is rejected but not caught. Thus in my code neither the onError nor the onLoad arguments are ever executed.

I believe I have a fix here: https://github.com/mrdoob/three.js/compare/dev...twastvedt:dracoCatchPromise. Tested with the Draco example. I’m happy to create a PR, but I’m sure I’m ignorant of what all is at play here, so wanted to make sure first. My fix substitutes the current use of decodeDracoFile, which is marked deprecated in DRACOLoader, with decodeGeometry, which returns a promise that we can catch.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://jsfiddle.net/srq463dg/
2. Note that in the console the onError method (line 58) never executes.
3. Open developer tools and note that an error has occurred in the Draco loader (“THREE.DRACOLoader: Decoding failed: Failed to decode point attributes”).

Note: The errorModel data url in the fiddle is a valid gltf model that has been truncated. In my app’s environment there is a string length limit imposed on models, thus this entire investigation.

Code

loader.load(errorModel, function (data) {
    		console.log("Loaded model");
        scene.add(data.scene);
    }, null, function (error) {
    	console.log(`In error handler: ${error}`);
    });

Expected behavior

Any error in the Draco loader should cause the onError argument of GLTFLoader.load to be executed.

Platform:

• Device: Desktop
• OS: Windows
• Browser: Chrome
• Three.js version: dev

[donmccurdy]

I think we may need to overhaul DRACOLoader a bit anyway (see https://github.com/mrdoob/three.js/issues/22445 …) and have it use the new WorkerPool utility. Probably better to resolve this all at the same time, I’ll self-assign it in that case.

[fanciful-marmot]

I’ve run into a similar unhandled promise rejection error with DRACO decoding in some environments where there isn’t enough memory for the wasm decoder to run properly. I get an unhandled promise rejection with memory access out of bounds. I can setup an example that illustrates the problem if needed but it’s similar to what’s described in the issue.

It would be great if I could handle the error properly and fallback to something else. Is there an update on this issue?