Quantization creates invalid skinning weights for CesiumMan.glb

Quantizing CesiumMan with gltf-transform quantize CesiumMan.glb CesiumMan+quant.glb we see validation errors and visible 'spikes' in the geometry. Problem appears related to sorting and normalizing the skinning weights. Tested in v4-alpha.

CesiumMan.glb.zip

glTF-Transform/packages/functions/src/sort-primitive-weights.ts

Lines 74 to 75 in 13fbccf

    
           // (3) Normalize. 
        
           normalizePrimitiveWeights(prim);

https://discourse.threejs.org/t/gltf-meshopt-compression/66244/2

Just saw this issue appear in one of our meshes here as well - draco doesn't have this issue but in this case meshopt is much preferred due to blendshape compression 😊

In progress:

#1439

Thanks a lot for the superfast fix!