The rendering negatively affects the main window container drag operation.

During a drag event, the window container will impact QtDirect3D frames per seconds and start stuttering.

This issue is considerably more pronounced in real time and with—to be confirmed—iGPU.

2.mp4

[giladreich]

Thanks a lot for reporting and for the videos!

This is quite interesting. Did you change something that in the second video doesn't happen anymore?

When I tested this on my machine (GTX 1050 Ti), it was only dropping 5 frames at max, so it didn't drop below 55 FPS. I'm suspecting it could possibly be related to QTimer that Qt's dragging event interferes with it.
Since the real interaction with the windows takes place within the actual scene/render surface, it's not a major issue, however It would be nice to solve it once I get better reproducibility.

Hey sorry about that, the second video is a standalone DirectX rendering with ImGui and not related to Qt and QtDirect3D. The confusion is on me. That aside, I currently run with Intel® UHD Graphics 750 which explain the disparity between our tests. I’d suggest to try CPU Rendering to get a possibly better reproducibility.

[giladreich]

I’d suggest to try CPU Rendering to get a possibly better reproducibility.

Many thanks! I'll try to have a look at this next weekend hopefully. 🍻