More robust EGL display initilization.

[tritao]

@VolkerEnderlein Before merging lets wait until folks confirm it fixes the issue.

Based on a patch by @lepalom.

[tritao]

@Rexbas @lepalom Can you try this?

[Rexbas]

I still get this:
Coin warning in cc_glglue_instance(): Error when setting up the GL context. This can happen if there is no current context, or if the context has been set up incorrectly.

But now I also get this message. I did not get this previously with the NVIDIA proprietary drivers:
libEGL warning: egl: failed to create dri2 screen

I remember that without the NVIDIA proprietary drivers, I also got this message. So I think the PR might be some positive progress.

Also now I get a black FreeCAD instead of white:

Aside from the dri2 screen message, Hello Cone is still the same (no cone).

[tritao]

I still get this: Coin warning in cc_glglue_instance(): Error when setting up the GL context. This can happen if there is no current context, or if the context has been set up incorrectly.

But now I also get this message. I did not get this previously with the NVIDIA proprietary drivers: libEGL warning: egl: failed to create dri2 screen

I remember that without the NVIDIA proprietary drivers, I also got this message. So I think the PR might be some positive progress.

Also now I get a black FreeCAD instead of white:

Aside from the dri2 screen message, Hello Cone is still the same (no cone).

I think our best bet is to duplicate whatever logic SDL or GLFW do to set up EGL: https://github.com/glfw/glfw/blob/master/src/egl_context.c

At the same time it makes me think I'd rather have Coin not need to deal directly with such logic and leave it to windowing libraries which already do a perfect fine job.

[lepalom]

@tritao I have tested your fork, the egl-fixes and I see a black cone :-( it is not working properly ... I really don't know what to do.

[lepalom]

Anton Gladky solved, at leat for Debian, could you check it?
https://salsa.debian.org/science-team/coin3/-/blob/master/debian/patches/Egl_dust_off2.patch?ref_type=heads
@tritao

[heiserhorn]

@lepalom I am running Debian sid with the latest version of coin3 with the patch mentioned above but I have exactly the same problem. I have commented on the debian closed bug which should be reopened.