Crash when rendering in an FBO

[acolombier]

Hi,

I am trying to run an open source software called Mixxx, specifically this branch on a Windows 11 VM with libvirt. I'm encountering a crash in d3d11 when calling QQuickRenderControl::sync. This relies on a FBO to render off-screen sections.

This is a work in progress feature, so it could very much be that I am misusing the API on my end, but I was wondering if you had some tips on how I could confirm this isn't an issue with mesa.

I am running the program with MESA_GL_VERSION_OVERRIDE=4.5COMPAT, on a system-wide mesa install.

I have tried the following:

• Run with GALLIUM_DRIVER set to zink, softpipe, llvmpipe and lavapipe, but I get no FBO capabilities
• Tried to use other DDL with QT_OPENGL_DLL but I either get missing functions or unavailable FBO

Is there some other thing I could try?

Appreciate your help,
Antoine

[pal1000]

GALLIUM_DRIVER=lavapipe ls invalid because lavapipe is a Vulkan driver. That will disable OpenGL as ;long as it's set.

I am not a graphics developer so I recommend asking for help elsewhere.

Also MESA_GL_VERSION_OVERRIDE is no longer necessary with llvmpipe at least, since 23.3.0 as it already advertises OpenGL 4.5 compatibility profile out of the box. For zink and d3d12 I didn't do any tests on feature limitations on current Mesa3D releases.

[acolombier]

Thanks for you fast reply!
It turns out that the issue was with Qt setup, which defaulted to use d3d11 as a RHI backend, even when the the desktop uses OpenGL. I managed to get output about this after following Qt troubleshooting instructions.

Once I set QSG_RHI_BACKEND=opengl, I was able to use the Mesa driver, and fixed the crash.

Hopefully this helps someone else! :)