Switching between tabs in the editor causes flickering between tab contents

[wwaltb]

Tested versions

• Reproducible in 4.3.rc1, 4.2.2.stable and 4.1.4.stable. Have not tested any earlier versions yet.

System information

Godot v4.3.rc1 - Arch Linux #1 ZEN SMP PREEMPT_DYNAMIC Fri, 28 Jun 2024 04:32:27 +0000 - Wayland - Vulkan (Forward+) - dedicated NVIDIA GeForce GT 730M (nvidia; 470.256.02) - Intel(R) Core(TM) i5-4300M CPU @ 2.60GHz (4 Threads)

Issue description

When I switch between tabs, like the Scene and Import tabs, or the different scenes in the editor, then the view for the content that the tab represents starts flickering back and forth between the previous tab and new one. It also sometimes causes other elements of the UI to flicker as well. When I move my cursor off of the tabs then the flickering subsides.

IMG_2972.mp4

IMG_2970.mp4

Steps to reproduce

The bug is visible in new projects.

Minimal reproduction project (MRP)

N/A

[Calinou]

Vulkan (Forward+) - dedicated NVIDIA GeForce GT 730M

I suggest using the Compatibility rendering method, as Vulkan on Kepler GPUs tends to be pretty broken. In fact, I'm surprised it even works on your end since NVIDIA has never implemented support for Vulkan on mobile Kepler GPUs (only desktop).

Also, try reproducing this with Update Continuously enabled in the Editor Settings.

[wwaltb]

Okay thanks for the suggestions. I was unable to reproduce with Update Continuously checked and when using Compatibility rendering. Would you recommend I switch to Compatibility rendering for my projects or continue using Forward+ with Update Continuously on? Also, should one of these options be selected by default or suggested to users when a mobile Kepler GPU is detected?

[Calinou]

Would you recommend I switch to Compatibility rendering for my projects or continue using Forward+ with Update Continuously on?

Update Continuously greatly increases CPU/GPU utilization in the editor, so it's a bad idea to use on a laptop as it'll get hot quickly and reduce battery life.

I suggest sticking to the Compatibility rendering method, especially since mobile Kepler GPUs are too slow by 2024 standards to really benefit from Forward+/Mobile features.

Also, should one of these options be selected by default or suggested to users when a mobile Kepler GPU is detected?

Detecting such GPUs is feasible, but I would probably do two things to ensure they fall back to Compatibility correctly:

• Implement fallback to OpenGL 3 / Compatibility renderer when Vulkan is not supported godot-proposals#8006 needs to be implemented first.
• Require Vulkan 1.3 to be supported on NVIDIA and AMD GPUs, so that Forward+ or Mobile can't be run using highly outdated drivers (which includes NVIDIA Kepler in general). There are some Intel IGPs that only support Vulkan 1.2 but can run Forward+/Mobile in an acceptable capacity, so these should still be able to run Godot with just Vulkan 1.2.