Issue with a GLB file (unable to open)

[NathanaelA]

Describe the bug
I have a GLB (& GLTF) file that has invalid data in only one of the JSON fields. However the data in this field is creates a BADLY malformed JSON part of the file, but it is what the Unreal Engine exports in apparently rare cases. I jumped into the code on unreal and there is no checks against this on ANY of the number fields it exports, so it is reasonable to assume that this invalid data could show up in other fields when exporting GLB/GLTF files.

Effectively it breaks JSON parsing. In this specific case it spit out { "KHR_materials_ior": inf} this of course is totally broken JSON, it apparently was trying to output "infinity" , but even if it put "infinity" into the JSON it would still be invalid JSON. Manually using a HEX editor I changed this to "1.5" and the file loaded perfectly.

I'm not SURE if this is a wont-fix (since it really is NOT your problem) or if it is trivial to replace in your JSON parser if it sees inf in a value files to change it to "1.0" or something like that so that these files work.

[Meakk]

I suppose it's reasonable to ignore the field if the value is invalid. In this specific case it will fallback to the default value (1.5)

[snoyer]

I suppose it's reasonable to ignore the field if the value is invalid. In this specific case it will fallback to the default value (1.5)

It shouldn't be too hard to handle { "KHR_materials_ior": "inf" } which is valid JSON but not valid GtTF, but for { "KHR_materials_ior": inf } you'd need a JSON parser lenient enough to accept the syntactically invalid input in the first place, is that the case of VTK's?

[mwestphal]

Agreed, can you share such malformed file @NathanaelA ?

[NathanaelA]

Broken_Inf.zip

The file is attached -- the actual broken JSON is (I thought it was the primary, key, but I just checked and it is a child key that has the inf ):

                 "KHR_materials_ior":
				{
					"ior": inf
				}

One thing is that if you can, I would replace any inf with 1.0 or 1.5 or something like that. The code in Unreal does NOT appear to have ANY safety checks on export, so literally ANY floating point value could potentially be exported as "inf"inity.