Framerate drop on iOS15 with scaling 0

Hello Babylon team! I ran into a strange issue, where the frame rate drops significantly in the following scenario on iOS15:

  • Import a geometry and create several instances of it
  • Add the instances under a parent (e.g. a box geometry)
  • Scale the parent to 0

At that point the frame rate drops a lot. On older Apple devices, with older iOS, the frame doesn’t drop at all.

Here’s the playground that I used to replicate the issue, let’s call it (1):
https://playground.babylonjs.com/#SM5RNH#24
Here is a playground where the issue can not be replicated. The only difference is that the scaling of the parents is 1, let’s call it (2):
https://playground.babylonjs.com/#SM5RNH#23

Photos from the issue being replicated:
This is a photo of playground(2). On the left, the older device has lower frame rate, which is expected. The scaling is 1 so there is no issue here.

This is a photo of playground (1). On the left, the older device with iOS 13 has more or less the same frame rate. The device with iOS 15 though drops to 4 fps.

Let me know what you think about this!

This is such a weird issue !!!

Sounds like a metal issue which is deadly strange as basically nothing should be rendered but one pixel making it faster in theory.

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Yes totally something to report to webkit team

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Hi @geobalas just checking in, were you able to create a report to webkit as suggested? :slight_smile:

Hello @carolhmj! I didn’t have time to do it, but thanks of reminding. I hope I will have time to do it soon. I will let you know in any case!

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