iOS 12.5.1 improperly renders mesh instances with skeletons, but not on earlier or later iOS version

auto

Hey all, really getting into the nitty gritty of trying to figure out what I'm worried is a quirk with iOS 12.X, that I hope I can code around in engine, I've detailed the whole thing here: Github Issue Link

Basically, from what I can tell Skeleton nodes are broken in iOS 12.5.1, which is the highest version that anything older than and including the iPhone 6 plus can upgrade to. However, they aren't broken in older versions, or at least 11.3.

Does anyone have an example of a project that runs on an up to date older iOS device with 12.5.1, that actually handles Skeletons, or really any rigged model correctly? Even the example IK project from the docs renders incorrectly, so this isn't limited to my current project.

TL;DR As far as I can tell, right now rendering rigged models are broken for all iOS devices older than a 6S that are running their latest iOS version, which is the last version they're going to get, barring extreme security/exploit updates.

Calinou

Unfortunately, I doubt this can be fixed considering few people even have access to an iPhone 6 or iPhone 6 Plus. (Most Godot contributors don't own Apple hardware in the first place, and those who do likely have more recent devices.)

auto

I've definitely gathered that from other issue conversations I've seen around iOS.

That said, I'm happy to guinea pig any ideas anyone has. I'm a C++ firmware dev by trade, and have poked around in the engine source before, so I'm comfortable with the tweak/engine compile/debug cycle if anyone has any broad direction.

From the current numbers I'm seeing at Apple, this is still almost 10% of the market on iOS, so I'm hesitant to just accept it as busted.

Megalomaniak

I think you are best off taking this to the tracker then. More active developers there to pitch in and advise you.

auto

For anyone who comes across this, the issue is that iOS 12 seems to have a bug around a particular OpenGL extension necessary for gltf skinning to be done in hardware, and GLES3 did not support software fallback. I've submitted a PR here that addresses the issue.