Draco loader seems to have problems with some gltfs / glbs

[cansik]

I was able to load the test glb file you were using in the official draco issue #27, but I struggle with my own files.

Here are the files to reproduce the issue: bunny.zip
The files both work in gtlf-viewer with just the following warning:

Info	Message	Pointer
UNUSED_OBJECT	This object may be unused.	/bufferViews/0

• bunny.glb is just the bunny packed into a glb => this opens without any problems
• bunny-draco.glb has been converted with gltf-pipeline -i bunny.glb -o bunny-draco.glb -d

And if I drag the bunny-draco.glb into my Unity project, there is the following error:

Mesh 0 import error
UnityEngine.Debug:LogWarning(Object)
Siccity.GLTFUtility.<OnCoroutine>d__5:MoveNext() (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Spec/GLTFMesh.cs:358)
Siccity.GLTFUtility.ImportTask`1:RunSynchronously() (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Importer.cs:161)
Siccity.GLTFUtility.Importer:LoadInternal(GLTFObject, String, Byte[], Int64, ImportSettings, AnimationClip[]&) (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Importer.cs:207)
Siccity.GLTFUtility.Importer:ImportGLB(String, ImportSettings, AnimationClip[]&) (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Importer.cs:69)
Siccity.GLTFUtility.Importer:LoadFromFile(String, ImportSettings, AnimationClip[]&, Format) (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Importer.cs:26)
Siccity.GLTFUtility.GLBImporter:OnImportAsset(AssetImportContext) (at Library/PackageCache/com.siccity.gltfutility@3d5d97d7e1/Scripts/Editor/GLBImporter.cs:16)
UnityEditor.Experimental.AssetImporters.ScriptedImporter:GenerateAssetData(AssetImportContext)
UnityEditorInternal.InternalEditorUtility:ProjectWindowDrag(HierarchyProperty, Boolean)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&) (at /Users/builduser/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:189)

It does not even seem to be a problem with draco (looking at the stacktrace), but that's the only thing that changed. How can I find out what the error was, because atm I am just getting a stacktrace which does not tell me what went wrong?

I am working on MacOS and it did not matter if I used a gltf or a glb file.

Update: #133 could be related