Is your system glvnd enabled? I.e. do you have stuff in /var/lib/snapd/lib/glvnd/egl_vendor.d?

Provide the output of snap version too, please.

ppd, thank you for reply!
My /var/lib/snapd/lib/glvnd/ directory is empty.

root@kitchen:~# snap version
snap    2.43.3
snapd   2.43.3
series  16
debian  9
kernel  4.9.0-12-amd64

I have installed all packages that contains glvnd (except nonglvnd) and nvidia in their names from Debian repository. After reboot I still have same error.

That's quite odd. Will try on my nvidia machine at work.

My /var/lib/snapd/lib/glvnd/ directory is empty.

Apologies. It's only non-empty from the perspective of the snap. Could you do the following?

mfederle@maxi:~$ snap run --shell solvespace
To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.

mfederle@maxi:/home/mfederle$ ls -al /var/lib/snapd/lib/glvnd/egl_vendor.d/
total 0
drwxr-xr-x 2 root mfederle 60 Mär  6 09:32 .
drwxrwxrwt 3 root mfederle 60 Mär  6 09:32 ..
lrwxrwxrwx 1 root mfederle 65 Mär  6 09:32 10_nvidia.json -> /var/lib/snapd/hostfs/usr/share/glvnd/egl_vendor.d/10_nvidia.json

It should have somewhat comparable output.

Do you have libglvnd0-nvidia installed? I've seen a few workarounds that mention removing libglvnd0-nvidia and installing libglvnd0.

I have same file:

user@kitchen:~$ snap run --shell solvespace
user@kitchen:/home/user$ ls -al /var/lib/snapd/lib/glvnd/egl_vendor.d
total 0
drwxr-xr-x 2 root user 60 Mar  5 22:38 .
drwxrwxrwt 3 root user 60 Mar  5 22:38 ..
lrwxrwxrwx 1 root user 65 Mar  5 22:38 10_nvidia.json -> /var/lib/snapd/hostfs/usr/share/glvnd/egl_vendor.d/10_nvidia.json

Yes, I have libglvnd0-nvidia installed.
I'm just replaced libglvnd0-nvidia with libglvnd0. Now solvespace runs but with text "Unable to create a GL context" in every window.

Fair enough. So the bug wasn't related to the snap package.

Now solvespace runs but with text "Unable to create a GL context" in every window.

That's unrelated. What GPU do you have? I think Gtk::GLArea requires >= OpenGL 3.0 features. I wonder if it's possible that your card or driver is too old. But that seems a bit unlikely 🤔

GeForce GTX 950.

$ glxinfo | grep 'OpenGL version'
OpenGL version string: 4.6.0 NVIDIA 390.116

I ran Debian 9 from a USB stick and installed nvidia-driver via stretch-backports.

The good news: I can reproduce the issue.
The bad news: It is not specific to solvespace. Other snaps fail just the same with something like:

libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast

So clearly we're not using the nvidia driver for some reason, yet snapd seems to expose it just fine at a first glance. Something's probably different in the packaging or setup of the Debian driver vs. the Ubuntu one.

Support request upstream: https://forum.snapcraft.io/t/no-opengl-on-debian-9-nvidia/15848

Further investigation shows that it's certainly not a solvespace bug. Also, this investigation is way beyond the scope of the issue's title...

I quote

It looks like Debian is now using the alternatives system to allow multiple libGL implementations to exist with the option to switch between them. I think this will need some snapd changes in the opengl interface to allow the symlink to be followed.

@whitequark We should probably close this or maybe create an "info issue" with those details until snapd receives the necessary fixes.

Is it possible somehow to workaround this problem?
I install Debian 10 on second hard drive and it has same problem.

You could install the nvidia driver from the official installer or use the nouveau driver.

Whether the layout of the official Nvidia driver is compatible with current snapd is another question. Probably, but I haven't tried myself.

I just installed nvidia driver 440.64 from the official installer.
Again, solvespace runs but with text "Unable to create a GL context" in every window.

I installed nouveau driver. Solvespace runs, but 3D graphics in other applications is slow.

Is it possible somehow to workaround this problem?

This isn't ideal but building SolveSpace from source should make it work. (Ideally the snap should still be fixed.)

Or run it without any of the snap confinement:

mfederle@maxi-xps:~$ cd /snap/solvespace/current
mfederle@maxi-xps:/snap/solvespace/current$ LD_LIBRARY_PATH="$(pwd)/lib:$(pwd)/usr/lib:$(pwd)/usr/lib/x86_64-linux-gnu" ./usr/bin/solvespace
SolveSpace!

Missing (absent) translation for '&Helix'
Missing (absent) translation for 'Re&volve'
Missing (absent) translation for 'Show &Underconstrained Points'
^C
mfederle@maxi-xps:/snap/solvespace/current$ 

It might need a few libraries from the core snap, but hopefully the rest is available and compatible on Debian 9.

@whitequark

(Ideally the snap should still be fixed.)

The fix will come by update of the snap daemon itself, as it does some magic to expose the nvidia libraries from the host to the app within the snap. We do not ship proprietary drivers in the snap, only the mesa stack, afaik.

Upstream bug: https://bugs.launchpad.net/snapd/+bug/1866855

Or run it without any of the snap confinement:

mfederle@maxi-xps:~$ cd /snap/solvespace/current
mfederle@maxi-xps:/snap/solvespace/current$ LD_LIBRARY_PATH="$(pwd)/lib:$(pwd)/usr/lib:$(pwd)/usr/lib/x86_64-linux-gnu" ./usr/bin/solvespace

This workaround works! Thank you! :)

For the sake of completeness, I quote upstream's findings:

I think right now we have no chance to fix it.

So don't hold your breath; it might take a while...