Black background on constraints

[leoheck]

This black background looks something wrong for me.

Is this a new feature or a bug?

Screenshot-20200601211106-732x655.png (21.79 KiB) Viewed 1675 times

OS: Ubuntu 20.04 LTS (ubuntu:GNOME/ubuntu)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.21280 (Git) AppImage
Build type: Release
Branch: master
Hash: 6f3160db3e88733536c7eaf97ad7d6ebd21baccd
Python version: 3.8.2
Qt version: 5.12.5
Coin version: 4.0.0
OCC version: 7.4.0
Locale: English/United States (en_US)

[vocx]

Is this a new feature or a bug?

It tends to appear sometimes. It disappears by itself. It seems to be a "bug" but not a serious one. Some sort of rendering artifact.

[chrisb]

Werner commented on this. It seems to be that some display buffers run out of memory and use some fallback solution.

[TheMarkster]

I haven't seen this, but I have seen on occasion all the points in a sketch turn black. Sometimes when it happens it goes away by zooming in and out.

[kevin_fc]

hi, i found same problem when selected render :
edit ▻preferences ▻ Display ▻ render : Anti-aliasing : Line Smooth
but selected "MSAA 2X~8X" will not happen.
you can try it.

edit: forgotten to say that test in arch linux 5.12.15, freecad 0.19 with intel uhd620

and i test again, if a saved file that it's drawing has the problem, changed anti-aliasing to other can display as normal.
if a saved file made a drawing that original display as normal, changed to 'Line Smooth' not reproduce black background problem.

[Shalmeneser]

It tends to appear sometimes.
It disappears by itself.
Sometimes when it happens it goes away by zooming in and out.
I confirm.

[leoheck]

Werner commented on this. It seems to be that some display buffers run out of memory and use some fallback solution.

Chrisb, do you know something that we can do to check this statement (where the buffers run out off memory) when I see this black-bg issue again?

I am not seeing this issue anymore.

My machine has a lot of RAM (32GB), maybe this is not the problem for me, unless the display uses a different, less available memory or maybe that time I was running to many things at the same time.

[chrisb]

Chrisb, do you know something that we can do to check this statement when we see this black-bg issue? I am not seeing anymore anymore. My machine has a lot of RAM (32GB), maybe this is not the problem for me, unless the display uses a different, less available memory or maybe that time I was running to many things at the same time.

I don't know how to provoke the phenomenon, but I haven't seen it for quite some time. Perhaps the different library versions used have improved the situation.

[DFT]

As commented kevin_fc, this problem appears if selected "Line Smooth" anti-aliasing mode:
Edit>Preferences>Display>Rendering: Anti-aliasing=Line Smooth
After setting to another mode - problem disappears.
My system:
Linux Mint 19.1 (Mate desktop), 4.15.0-158
VGA Intel UHD 630
FreeCAD 0.19 (14555)

[chrisb]

As commented kevin_fc, this problem appears if selected "Line Smooth" anti-aliasing mode:
Edit>Preferences>Display>Rendering: Anti-aliasing=Line Smooth

Can you please retry in 0.20?