`instance_errors` is all NaN in threejs library

[matthewhilton]

Ran this locally with Threejs / React Three Fiber

I found that it was loading every single piece, and then never doing anything else. Additionally the instance_errors attribute was entirely NaN (except for the last which was zero)

After debugging this, I tracked it down to the viewport variable - It was coming in as a object {x,y,z,w} meaning indexing using numbers was returning NaN,

nexus/nexus3d/src/Traversal.js

Lines 28 to 29 in 2bc3739

	for(let i = 0; i < 4; i++)
	t.viewport[i] = viewport[i];

If replaced with this:

for(let i = 0; i < 4; i++) {
    t.viewport[i] = Object.values(viewport)[i];
}

The instance_errors is correctly populated and the loading now works again.

I'm using a slightly newer version of Threejs, 0.183.2 (0.181 is mentioned in the readme) but I doubt this would have changed as it would have been a breaking change.

[ponchio]

This is a bit strange as viewport variable is the result of renderer.getViewport call, which returns a Vector4 (which is enumerable, line 1052 of Vector.js).

I would instead prefer to investigate on the reason the viewport variable is coming as an object.

Could you send me a sample, or since you can debug, have a look at the origin of the variable?