Fix a crash in gltfio when not using ubershaders (#7135)

NEW_RELEASE_NOTES.md

@@ -13,4 +13,5 @@ appropriate header in [RELEASE_NOTES.md](./RELEASE_NOTES.md).
   dark fringes to appear (recompile materials)
 - Allow glTF materials with transmission/volume extensions to choose their alpha mode
   instead of forcing `MASKED`
+- Fix a crash in gltfio when not using ubershaders
 - Use flatmat for mat parameter in jsbinding

libs/gltfio/src/JitShaderProvider.cpp

@@ -287,7 +287,7 @@ std::string shaderFromKey(const MaterialKey& config) {
 
                 // TODO: Provided by Filament, but this should really be provided/computed by gltfio
                 // TODO: This scale is per renderable and should include the scale of the mesh node
-                float scale = object_uniforms.userData;
+                float scale = getObjectUserData();
                 material.thickness = materialParams.volumeThicknessFactor * scale;
             )SHADER";