Enable Headless support

[siddhartpai]

Currently the gltf-viewer supports a faux headless mode where the window is made invisible while it's still running with the need of some kind a Xserver backend requirement. Is it possible to enable proper headless support so that the entire screenshot generation process could be run in an automated environment without the need of X .

[bwasty]

I've tried to do proper headless support, but had some trouble with the framebuffer (it remained black). I think it should work with some further debugging, there's probably only a tiny error somewhere.

The code is still there, you could try to get it working (I'd add a link to it, but I'm currently on mobile).

Otherwise I might try again, but I'm not sure when I'll find the time.

[siddhartpai]

okay thanks @bwasty I'll look into it .

[bwasty]

Figured it out -> #14 (a gl::Viewport call was missing)
NOTE: I'm not entirely sure it will really work without an X server now. If not, there's always xvfb...

[bwasty]

To summarize #14 - 'real' headless mode now works fine on macOS, but not on Linux. It would require quite a bit of further debugging and possibly fixes to glutin to get working.

But #15 should provide a decent workaround 😃
EDIT: Final version is described in the readme: https://github.com/bwasty/gltf-viewer#headless-screenshot-generation.

[bwasty]

Created an issue for glutin: rust-windowing/glutin#988

[nick13jaremek]

@bwasty It seems the headless issue was fixed in the glutin library on version 0.21.0. However, there seems to be lots of breaking changes that are not trivial to apply to gltf-viewer.

The PR that fixed the issue itself: rust-windowing/glutin#1125