Issue with premultipliedAlpha in Spine Animation on iOS

Shastri

We are currently working with Spine animations. The animator provided us with Spine version 4.2 and enabled premultipliedAlpha. The animation displays correctly and handles transparency on an Android project using the libGDX runtime. However, on our native iOS runtime project (UIKit & Metal), the same animation does not display transparency correctly and the background color shows as black when premultipliedAlpha is enabled.

I have submitted this issue on GitHub issues-2586 but I haven’t received a useful response yet. Can anyone provide help or insight into this issue?

Thank you for your assistance!

Animator’s effect:
user-attachments/assets246efe67-c38a-455b-b203-979c04b4fd2e

spine file:
user-attachments/files16386077/explosion.zip

Actual effect on iOS(spine-ios):
user-attachments/assets061bacb4-7e1d-4dee-a98d-684977b614a2

Effect on Android(spine-libgdx):
user-attachments/assetsf77f544d-b3bb-4436-a3bc-6597e3729958

Spinebot

The issue you're experiencing with premultiplied alpha on iOS could be due to several factors. Here are some steps and considerations based on similar issues discussed in the forums:

Premultiplied Alpha Settings: Ensure that the premultiplied alpha settings are consistent between your Spine export and the runtime settings. If premultiplied alpha is enabled during export, it should also be enabled in the runtime. Refer to the Spine Texture Packer documentation for more details.
Texture Import Settings: For iOS, make sure that the texture import settings are correctly configured. Specifically, check that Alpha is Transparency is enabled if you are using straight alpha textures. This setting can be found in the [Spine-Unity documentation](https://esotericsoftware.com/spine-unity#Advanced

Davide

As I 've already replied in the other thread, the issue you reported is already under our consideration. Mario, who is following the issue is currently unable to respond to you due to some health issues. He will answer to you on the github issue as soon as he is back and operative 👍️

Shastri

Thank you for the update. However, the issue remains unresolved and I'm still experiencing the same problem. Could you please advise on the next steps or provide an alternative solution? I appreciate your help in this matter.