wezterm no longer respects window_background_opacity if gpu is in use with other program

[ListeningGarden]

What Operating System(s) are you seeing this problem on?

Windows

Which Wayland compositor or X11 Window manager(s) are you using?

n/a

WezTerm version

20240127-113634-bbcac864

Did you try the latest nightly build to see if the issue is better (or worse!) than your current version?

Yes, and I updated the version box above to show the version of the nightly that I tried

Describe the bug

wezterm in the previous regular release (20230712-072601-f4abf8fd and prior would respect the window_background_opacity value even if another app was open that used the gpu - i.e., a videogame. as of 20240127-113634-bbcac864, it now remains completely opaque which is not only visually undesirable, it causes issues with usability as well on lower values

To Reproduce

install 20240127-113634-bbcac864 load a game of some kind load wezterm

Configuration

window_background_opacity = .20

Expected Behavior

wezterm should display a transparent background relative to the value of window_background_opacity

Logs

wezterm version: 20240127-232820-e23ab472 x86_64-pc-windows-msvc Window Environment: Windows WebGPU: name=NVIDIA GeForce RTX 3070, device_type=DiscreteGpu, backend=Vulkan, driver=NVIDIA, driver_info=546.29, vendor=4318, device=9348

Anything else?

No response

[wez]

Try setting front_end = "OpenGL"

[ListeningGarden]

setting front_end = 'OpenGL' has restored expected behaviour for transparency, thank you! seems like webgpu is still a bit finicky on windows

[raggi]

I have found that it's the first window per process that has this problem, opening a second window is fine.

[xieve]

I'm having this problem as well and setting front_end = 'OpenGL' did not help, sadly. I'm also experiencing this: https://github.com/wez/wezterm/issues/4145, maybe they're connected? I have a dedicated Nvidia GPU.