Transparent windows become permanently opaque when opened on an HDR-enabled monitor in Windows

[CW-Jesse]

Tested versions

• Reproducible in: v4.3.stable

System information

Godot v4.3.stable - Windows 10.0.22631 - GLES3 (Compatibility) - AMD Radeon RX 6600 (Advanced Micro Devices, Inc.; 32.0.12011.1036)

Issue description

Transparent windows become permanently opaque if they open on an HDR-enabled monitor in Windows. Disabling "Auto HDR" in Windows has no effect.

Steps to reproduce

Requires an HDR monitor. Not tested on Windows 10 or Nvidia GPUs.

To create MRP, create project with the following settings:

[display]

window/size/transparent=true
window/per_pixel_transparency/allowed=true

[rendering]

renderer/rendering_method="gl_compatibility"
renderer/rendering_method.mobile="gl_compatibility"
viewport/transparent_background=true

With MRP:

Run project on HDR-enabled monitor in Windows -> black background ❌
Run project on HDR-disabled monitor -> transparent background ✅
Run project on HDR-disabled monitor and move window to HDR-enabled monitor -> transparent background ✅
Run project on HDR-disabled monitor and enable HDR on that monitor -> transparent background ✅

Minimal reproduction project (MRP)

mrp-godot-hdr-transparency.zip (Godot v4.3.stable, 2 KiB)

[0x0ACB]

This is due to AMD forcing layered on dxgi for OpenGL and Vulkan if HDR is turned on #76167 (comment)

[CW-Jesse]

Good find, @0x0ACB.

Confirmed here.