Bug Artifacts around edges of sprites, only on iOS, since Unity 2021

Hi, I upgraded my project to 2021 (from 2020.3), and now my project has visual artifacts on the edges of various sprites, particularly ones that are transparent. These artifacts only appear in the built player on iOS, not in the editor or on Android.

Here are several examples:

 

Seems similar to this: https://forum.unity.com/threads/custom-2d-sprite-shader-iphone13.1202113

Do a bug report.

 

Thanks. I'm not using a custom shader, just the built-in

Sprite-Unlit-Default

and URP, so I'm not sure that thread applies to me. I'll create a test project to see if I can reproduce the issue and then file a bug if so.

 

Ahhh, very interesting. This issue seems to be related to the URP "HDR" option...
in a blank 2D URP project in Unity 2021:

HDR checked in URP Asset = no artifact
HDR un-checked in URP Asset = artifacts

This makes no sense to me, because the texture isn't an HDR texture — it sRGB mode selected in the texture settings...

 

For now, the workaround seems to be as simple as enabling HDR in URP settings. I've filed a bug for this with a minimal repro project as Case 1384814.

 

Hey, I suggest you try to put your iOS device in "Dark Mode" to see if it still happens. There are weird rendering issues when your device is in Light Mode in the latest 2020 and 2021 builds.

 

Yup! This is it.

I had my phone on Dark mode, so I wasn't seeing any issues, but switching to light mode breaks a whole bunch of transparency stuff.

 

Oh god... you're right. Toggling back and forth between light mode and dark mode breaks my app *in real time*. Light mode = broken, dark mode = fine.

Does anyone know if there's a bug tracking this already? Thankfully, I did seem to discover a workaround which is to enable HDR mode. Anyone know of other workarounds? (To avoid the overhead of HDR pipeline when I don't need it?)

 

I can’t find anything with a quick search of the issue tracker, so probably not?

 

Is this the issue?

https://forum.unity.com/threads/alpha-13-ios-shader-issues.1196518/

https://issuetracker.unity3d.com/is...ndered-with-different-colors-in-the-ios-build

 

Definitely looks like the same issue as the second thread. Not sure about the first one. I might look into the workaround about forcing dark theme in Xcode config described in that thread.

 

Yup, I believe it's the same issue!

It's not exclusive to URP / HDRP btw, I can recreate it with built-in.

 

I spent many hours trying to solve the same issue (was happening with unlit, mobile particle, and font shaders), and did not find any forum threads to help. Eventually I solved it by adding DisplayP3 to the Color Gamut in Player Settings and placing it first on the list. I will be submitting a bug report when I have got my update out that has been delayed by this problem.

 

That sounds similar to the "enable HDR" fix.

Please be warned that things will start looking a little different after you add DisplayP3. At least they did for our game.

 

Yes, my game actually looks a bit better, although it could affect others negatively. But looking a little different is rarely good for artistic intent.

 

The simplest repro I've found for this general issue is an empty scene with only a camera that has a non-white "clear" color. With light mode the screen is white, with dark mode the screen is of the selected clear color. Here's the bug, affects Unity 2019 to 2022: https://issuetracker.unity3d.com/is...hite-when-the-device-appearance-is-light-mode

 

Seems like Unity is aware and already working on the fix. Unity QA replied to my bug report and said:

Hi,

Thanks for getting in touch, as you may already know, we're aware of this issue and you can check the status here:
https://issuetracker.unity3d.com/product/unity/issues/guid/1379817

Do reach out if I can answer any questions or be of further help.

Cheers,
Edvinas
Customer QA Team

 

Hmm, this workaround did not work for me with Unity 2021.2.4f1 + 2D URP.

 

They back ported the bug to 2020.3.23f1...

I'm always floored to see how bugs are back ported to LTS faster than fixes are.

 

It is 2020.3.23 that I had the issue, but also previously saw it in an earlier version (2020.3.21 I think).

 

I definitely did not have this issue a few versions back.

Maybe 2020.3.20? I don't remember exactly.

 

Any fix on this as of now? Working with Unity version 2021.2.7f1.4128.

Should I simply update Unity to a few versions later or does the problem still exist in the latest version as well?

 

Yes, this was fixed in 2021.2.8. The bug that tracked it is here.