WSL__empty_window

[111Seven]

Installed Glvis on WSL. When I try to run an example using below command it is showing an empty window.
./glvis -m ../mfem-4.3/data/escher.mesh

Installed all the dependencies using below command
sudo apt-get install libfontconfig1-dev libfreetype-dev libsdl2-dev libglew-dev libglm-dev libpng-dev

Also installed VcXsrv X server as suggested in https://github.com/GLVis/glvis/blob/master/INSTALL#L136-L138

Please find the empty window I am seeing. Thank you in advance for your help.

[111Seven]

Further details: I have windows 11, and the WSL2 is having Ubuntu-20.04. I checked the mesh details are good. It seems like it is missing some dependencies. I will keep working on this, but in the meantime any directions to resolve this is really helpful. Thank you for all the assistance.

[tzanio]

Hi @MohanElapolu,

I recently installed GLVis on a Windows 11 system with WSL2 and Ubuntu without any issues. I'll try to take a look this weekend and respond. If anyone else (@kanye-quest, @acfisher) has any advice, please speak up!

Tzanio

[v-dobrev]

Are you using the latest release v4.1, the latest master branch, or some older commit/version?

If you are not using the latest master branch, can you try that?

In the past, I've had a similar issue (which just happened randomly, not always) where the window will not show anything initially. However, when I force it to update the contents (by pressing a key like r that forces a re-draw, or just resizing the window) then the window contents is updated properly. Try one of these methods to force a re-draw just to see if that helps.

[111Seven]

Thank you for the quick response. I am using the latest version4.1 posted on https://glvis.org. I tried to update the content by pressing r/resizing window which unfortunately didn't work.

[v-dobrev]

One thing that might help us, is to build GLVis in debug mode:

make GLVIS_DEBUG=YES [any other options you use for building]

and then post here the output you get in the terminal when you run GLVis to view a mesh (as you mentioned above). That may give us some clues.

[111Seven]

I built the GLVis in debug mode and ran the below command to test it.
./glvis -m ../mfem-4.3/data/escher.mesh

Here is the screenshot of the output on the terminal

[tzanio]

Can you try ./glvis -oldgl -m ../mfem-4.3/data/escher.mesh

[111Seven]

Yes, please find below screenshot of output.

[v-dobrev]

One potential issue: I'm not sure we've tested GLVis with the SDL2 version you are using, v2.0.10. I think the oldest version we tested is 2.0.12. If you want to try a newer SDL2 version, here are some basic instructions how to build it from source:

glvis/INSTALL

Lines 243 to 257 in e7c5dd4

	------
	SDL2
	------
	From the directory containing the 'glvis' directory run the commands:
	wget "https://www.libsdl.org/release/SDL2-2.0.12.tar.gz"
	tar zxf SDL2-2.0.12.tar.gz
	To build the library run the commands (see also SDL2-2.0.12/INSTALL.txt):
	cd SDL2-2.0.12
	./configure --prefix=`dirname $PWD`/SDL2
	make -j 4
	make install
	cd ..

[111Seven]

I installed SDL2 using commands as suggested above. I still have the blank screen window. Here is the screenshot of the output (Note: in the previous outputs we have shader missing, in this it is not there. I installed libglfw3-dev libgles2-mesa-dev as suggested in https://askubuntu.com/questions/244133/how-do-i-get-egl-and-opengles-libraries-for-ubuntu-running-on-virtualbox hoping that it will fix the problemw)

Now coming to the problem, it seems like it is somehow still using SDL 2.0.10. I removed that version by using
sudo apt-get remove libssdl2-dev
I tried to reinstall GLVis and now I am getting the below error(partial). It seems like it is unable to find the SDL.h. Please let me know your thoughts if I am missing something.

[v-dobrev]

Did you install SDL2 in ../SDL2 relative to the GLVis source directory? If not, you should add SDL_DIR=<path to the SDL2 dir> to your make command line, where <path to the SDL2 dir> should be the directory where SDL2 was installed -- SDL.h is expected to be in this location: <path to the SDL2 dir>/include/SDL2/SDL.h.

[111Seven]

Yes, installed SDL2 in GLVis source directory. I followed the instructions as suggested in your yesterday's comment. I am checking the SDL2 directory there is no SDL.h file. Please see the below screenshot

[v-dobrev]

Okay, with this directory layout, use the following command from the glvis-4.1 directory:

make SDL_DIR=./SDL2 [other build flags]

To check if SDL.h is in the right place, you can use (again, from the glvis-4.1 directory):

ls -l ./SDL2/include/SDL2/SDL.h

[111Seven]

Yes, that fixed the installation. Now, GLVis is using SDL-2.0.12, but still getting the blank window. Please check the below screenshot of the output in the terminal.

[tzanio]

Unfortunately I can't reproduce this, but I may very well be missing something -- I rarely use Windows and I am new to WSL.

My system is Win11 with WSL+Ubuntu and the following packages:

libfontconfig1-dev is already the newest version (2.13.1-2ubuntu3).
libglm-dev is already the newest version (0.9.9.7+ds-1).
libpng-dev is already the newest version (1.6.37-2).
libglew-dev is already the newest version (2.1.0-4).
libsdl2-dev is already the newest version (2.0.10+dfsg1-3).

I do not have the VcXsrv X server installed.

mfem-4.3 and glvis-4.1 are built as follows:

~/mfem-4.3$ make serial
~/mfem-4.3$ cd ../glvis-4.1/
~/glvis-4.1$ make

With that ./glvis -m ../mfem-4.3/data/escher.mesh works fine and the output is:

~/glvis-4.1$ ./glvis -m ../mfem-4.3/data/escher.mesh

       _/_/_/  _/      _/      _/  _/
    _/        _/      _/      _/        _/_/_/
   _/  _/_/  _/      _/      _/  _/  _/_/
  _/    _/  _/        _/  _/    _/      _/_/
   _/_/_/  _/_/_/_/    _/      _/  _/_/_/

Generating coloring starting with element 10 / 42
Number of colors: 3
NVD3D10: CPU cyclestats are disabled on client virtualization
NVD3D10: CPU cyclestats are disabled on client virtualization
Using GLSL 140
Subdivision factor = 16
VisualizationSceneSolution3d::PrepareFlat2() : [min,max] = [0,2]
Shading type : non-conforming (with subdivision)
VisualizationSceneSolution3d::PrepareFlat2() : [min,max] = [0,2]
GLVis window closed.
Thank you for using GLVis.

[v-dobrev]

I also tried building GLVis (v4.1 and master) on Windows 10 with WSL2 and Ubuntu (20.04 LTS) using VcXsrv X server. I do see sometimes an issue with the GLVis window content becoming just a black rectangle, however, pressing r or F2 fixes the issue. I see this issue when I drag the window from the title bar to move it; I also see this when resizing the window but not all the time.

One difference I see, compared with the output you posted, is that you get "Testing if OpenGL core profile window can be created...success!" -- for me this always fails. Is it possible that you are running the WSL preview version with built-in X-server support described here: https://docs.microsoft.com/en-us/windows/wsl/tutorials/gui-apps? If that is the case, that might explain why the "OpenGL core profile window" test succeeds.

@tzanio, if you are not using VcXsrv, are you using the above mentioned WSL preview version, or are you using some other X-server app?

[publixsubfan]

Sorry, I just saw this thread. @MohanElapolu: can you install and run the glxinfo tool (mesa-utils package on Ubuntu), and post its output? The OpenGL context version being reported by the glvis output is 3.1 Mesa 21.0.3, which is odd - that seems to indicate that your setup is falling back to software rendering with Mesa.

When you start VcXsrv, is the "Native opengl" option checked in the settings?

[tzanio]

Thanks for helping @kanye-quest!

@v-dobrev, I'll have to look more carefully in my installation. It was relatively recent, but I don't recall explicitly following the instructions you linked to.

[111Seven]

Thank you @tzanio @kanye-quest @v-dobrev for your support. It seems like the installation of VcXsrv is not very straightforward. I am figuring out if the issue is with this installation. @kanye-quest yes "Native opengl" is checked and below is the different snapshots of the output of the $glxinfo

[publixsubfan]

Ah, based on that output it seems like Mesa is using the new built-in 3D accelerated X server for WSL that @v-dobrev mentioned. Since it's using direct rendering, VcXsrv will have nothing to display - the rendering is done through Direct3D 12.

I think there are two potential paths you could try:

• Uninstall VcXsrv and try to run with the built-in X server - this might be preferable since Windows gives you a newer version of OpenGL
• Run with the environment variable LIBGL_ALWAYS_INDIRECT=1 ./glvis ... - this should force Mesa to pass GLX rendering commands to VcXsrv, but will only support an older OpenGL version

[111Seven]

thank you @kanye-quest, I followed your first path and the directions as given in (microsoft/wslg#334.) I uninstalled the VcXsrv and used the following command. I am not sure this is best way but its working, will use it...:) Please post if we can do in a better way.
$GALLIUM_DRIVER==llvmpipe ./glvis -m ../mfem-4.3/data/escher.mesh
Here is the terminal output

Here is the window showing the mesh

thank you @kanye-quest @tzanio @v-dobrev for the timely responses and support