Texture transform is not written for property textures

[javagl]

The block at

3d-tiles-tools/src/gltfExtensions/EXTStructuralMetadata.ts

Line 1291 in 1946693

const basicTextureDef = context.createTextureInfoDef(texture, textureInfo);

(or the corresponding block in the state after merging #64 ) has to be replaced with a block like this, which also contains some information about what went wrong there:

    // The 'textureInfoDef' that is created here will be stored 
    // by glTF-Transform internally. If there are extensions for
    // this object (e.g. a KHR_texture_transform extension), then
    // the extension information will be added to THE exact object.
    // Creating and returning a new object here would cause this
    // information to be omitted. So the object that is returned here
    // has to be THE exact object that was created internally, but
    // extended with the structural metadata extension information.
    const basicTextureDef = context.createTextureInfoDef(texture, textureInfo);
    const propertyTexturePropertyDef = basicTextureDef as any; 
    propertyTexturePropertyDef.channels = propertyTextureProperty.getChannels();
    propertyTexturePropertyDef.offset = propertyTextureProperty.getOffset();
    propertyTexturePropertyDef.scale =  propertyTextureProperty.getScale();
    propertyTexturePropertyDef.max =  propertyTextureProperty.getMax();
    propertyTexturePropertyDef.min =  propertyTextureProperty.getMin();
    return propertyTexturePropertyDef as PropertyTexturePropertyDef;

[javagl]

The proposed snippet will not resolve the issue. There's a deeper, darker issue lurking beneath that. After some investigation, I opened donmccurdy/glTF-Transform#1256 , to sort out where and how this issue has to be handled.