Black screen when using Mesa drivers (?)

[wahn]

After installing the -lSDL2 dependency:

apt-get install libsdl2-dev

I can compile and run the examples (on Debian), but they all render black without error messages:

$ uname -a
Linux purism 4.15.0-2-amd64 #1 SMP Debian 4.15.11-1 (2018-03-20) x86_64 GNU/Linux
$ cargo run --example hello_world
    Finished dev [unoptimized + debuginfo] target(s) in 0.05s
     Running `target/debug/examples/hello_world`
OpenGL Device: Mesa DRI Intel(R) Iris 6100 (Broadwell GT3)
OpenGL Driver: 3.0 Mesa 18.1.9
OpenGL Vendor: Intel Open Source Technology Center
Swap Interval: VSync

[wahn]

They do work on another machine (CentOS) though:

> cat /etc/centos-release
CentOS Linux release 7.5.1804 (Core) 
> cargo run --example texture
   Compiling tetra v0.1.2 (/mill3d/users/jan/git/github/tetra)                                                                              
    Finished dev [unoptimized + debuginfo] target(s) in 4.58s                                                                               
     Running `target/debug/examples/texture`
OpenGL Device: Quadro 4000/PCIe/SSE2
OpenGL Driver: 4.6.0 NVIDIA 390.59
OpenGL Vendor: NVIDIA Corporation
Swap Interval: VSync

[17cupsofcoffee]

Thank you for the report! I'll look into it further this evening - my work laptop has Intel integrated graphics too, so hopefully I'll be able to reproduce the issue on there. Failing that, might need to spin up a Debian VM or something...

[17cupsofcoffee]

I wasn't able to replicate on my laptop, but I think I understand why - from the looks of your log output, it looks like your drivers might be using OpenGL 3.0? I've been targeting 3.2, so perhaps I've used an incompatible feature somewhere... I'll try to force it into 3.0 mode on my machine and see if it breaks :)

[17cupsofcoffee]

Dang, no luck - I set the context version to 3.0 on my laptop, and it still seems to work fine for me. Perhaps it's something to do with the Mesa drivers?

[wahn]

Let me try something on my side and I will report back ...

# maybe this will help?
apt-get upgrade mesa-common-dev

[wahn]

I upgraded a couple of things (Mesa + Intel Graphics related) but it didn't fix the problem:

OpenGL Device: Mesa DRI Intel(R) Iris 6100 (Broadwell GT3)
OpenGL Driver: 3.0 Mesa 18.2.5
OpenGL Vendor: Intel Open Source Technology Center
Swap Interval: VSync

[wahn]

Anyway, don't worry, I can work on the CentOS box. Close if you want ...

[17cupsofcoffee]

Strange! Thanks for the report, anyway - I'll close it for now, but hopefully I'll get chance to play around on Debian at some point and see if I can replicate.

Hope you have better luck on your CentOS box!

[17cupsofcoffee]

I'm re-opening this, as @VictorKoenders seems to be having a similar issue on Ubuntu.

[VictorKoenders]

Ubuntu 18.10
libsdl2-dev: 2.0.8+dfsg1-4ubuntu1
OpenGL Device: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2)
OpenGL Driver: 3.0 Mesa 18.2.2
OpenGL Vendor: Intel Open Source Technology Center
Swap Interval: VSync

Also doesn't seem to work with sdl2's bundled feature. I fear it's an openGL issue.

[17cupsofcoffee]

@VictorKoenders My suspicion is that the issue might be due to me using #version 330 stuff in my GLSL - could you try running the examples on the simplified-glsl branch that I've just pushed?

[VictorKoenders]

That seemed to fix it for me!

[VictorKoenders]

A friend found this resource: https://stackoverflow.com/a/21567167

What they do not tell you, but indirectly imply ("Some drivers don't support all the features required in 
OpenGL 3.3."), is that in the last official release of Mesa (10.0), GL 3.3 only works on Intel hardware. This
 is one of the joys of Intel's close involvement with the Mesa project. If you want reliable GL 3.3 support
 in any form on AMD hardware, you should use fglrx (the proprietary AMD driver) for the time being.

[17cupsofcoffee]

Ah, the joys of OpenGL...

Anyway, the shader changes don't add any extra complexity/lose us any functionality, so I've merged them into master :)