ImageryLayer with dayAlpha/nightAlpha and showGroundAtmosphere=false breaks 2D

[Jing9010]

What happened?

Reproduction steps

...

Sandcastle example

https://sandcastle.cesium.com/#c=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

Environment

Browser: Chrome v129
CesiumJS Version: 1.122.0
Operating System: macOS

[ggetz]

Hi @Jing9010, I'm not sure I understand what the issue is you're seeing. Can you add more details about the expected behavior?

CesiumJS is a big project, so we use GitHub for feature requests and bug tracking exclusively. In the future, please take any questions to the Cesium Forum where there are members of the community and developers from the team who can help. Thanks!

[Jing9010]

1.Create an ImageryLayer
2.Set dayAlpha or nightAlpha: imageryLayer.dayAlpha = 0.0
3.viewer.scene.globe.showGroundAtmosphere = false
4. Change the sceneMode

[ggetz]

Ah thank you @Jing9010. I see that this broken behavior only occurs when

1. dayAlpha or nightAlpha is set, AND showGroundAtmosphere is disabled
2. There is some delay before morphing to 2D.

[bbbbx]

I think https://github.com/CesiumGS/cesium/pull/12149/files#r1861546852 is related to this issue