ZDoom

When software canvas is set to Direct3D and resolution scale isn't 1, the engine can't run in fullscreen mode and always falls back to windowed.
In addition, if resolution scale is less than 1, the screen appears to be botched with only a fraction of it being rendered:



At least the following video modes are affected for me:
1360x768
1366x768 (native monitor resolution)
1980x1080
1024x640
800x500
Other modes like 800x600, 1024x768, 1280x720, 1280x768, 640x480, 720x480 etc are not affected.
None of this happens with OpenGL canvas.

Tested on gzdoom-g3.3pre-402-ged23008.
The system specs are: Windows 7 x64, GeForce GTX750 Ti, driver v.384.76

Working on this one is definitely like tumbling down the rabbit hole in Alice in Wonderland.

The resolution code is so spaghetti right now that every time I change one thing to fix this, something else breaks.

I'm working on a fix for this, but it may need to be refactored down the line.