How do I build ANGLE for WinUI3?

[Twada (Twada2004)]

Hello!
I want to use ANGLE with WinUI3, but it seems that ANGLE built with vcpkg doesn't support WinUI3.
Is it possible to change the settings and rebuild?

WinUI3 is officially supported in ANGLE, but you must build it with the flag set:
https://github.com/google/angle/blob/3b96a73a23bd5bfe397ac34736dac2031f22458f/doc/DevSetup.md?plain=1#L94
angle_is_winappsdk=true

Furthermore, to support unpackaged exe files, you must set a complex flag:
mono/SkiaSharp#3338
libegl.dll: angle_is_winappsdk=false
libeglsv2.dll: angle_is_winappsdk=true

Thank you in advance.

[Aleksandr Kovalko (gistrec)]

The vcpkg-native way to do this is an overlay port

angle does not currently expose a winappsdk feature, so you cannot enable it directly with something like:

vcpkg install angle[winappsdk]

Instead:

1. Copy ports/angle from your vcpkg checkout into an overlay directory:

   my-overlay/
     angle/
       portfile.cmake
       vcpkg.json
       ...
   

2. Patch the overlay port to enable the WinAppSDK-related ANGLE build option.

3. Build with:

   vcpkg install angle --overlay-ports=./my-overlay

One caveat: the current vcpkg angle port uses a CMake-based build generated from ANGLE's GN/GNI files, so the change may need to be added as a CMake option or a small patch to the port's CMake build files, not just as a raw GN argument

If this works and the use case is common enough, the clean long-term solution would be a PR adding an angle[winappsdk] feature to vcpkg

[Twada (Twada2004)]

Thank you for showing me how to build the vcpkg port natively!

It seems I need to study more to create a patch....