Running OpenGL + SDL2 on AWS EC2 - amazon-web-services

Question

I'm using AWS EC2 Ubuntu 14.04 to test my OpenGL + SDL2 application. I am using SDL version 2.0.2. Because AWS EC2 is headless, I am using xvfb and use this script in /etc/init.d/xvfb:
XVFB=/usr/bin/Xvfb
XVFBARGS=":99 -ac -screen 0 1024x768x24"
PIDFILE=/tmp/cucumber_xvfb_99.pid
case "$1" in
start)
echo -n "Starting virtual X frame buffer: Xvfb"
/sbin/start-stop-daemon --start --quiet --pidfile $PIDFILE --make-pidfile --background --exec $XVFB -- $XVFBARGS
echo "."
;;
stop)
echo -n "Stopping virtual X frame buffer: Xvfb"
/sbin/start-stop-daemon --stop --quiet --pidfile $PIDFILE
rm -f $PIDFILE
echo "."
;;
restart)
$0 stop
$0 start
;;
*)
echo "Usage: /etc/init.d/xvfb {start|stop|restart}"
exit 1
esac
exit 0
These are the linux command before i run the app :
export DISPLAY=:99.0
sh -e /etc/init.d/xvfb start
sleep 3
But I got "Failed to connect to the Mir Server" error from calling SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER)
I am actually doing this because I follow instruction from https://docs.travis-ci.com/user/gui-and-headless-browsers/ and want to do the same in my AWS machine. I tried it also with travis, and The xvfb script is also taken from travis ci setup.
Not sure if this is gonna help but these are the output from glxinfo | grep OpenGL :
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.4, 256 bits)
OpenGL version string: 2.1 Mesa 10.1.3
OpenGL shading language version string: 1.30
OpenGL extensions:
So, I guess essentially my question is : how to setup OpenGL (preferably version 3) + SDL2 in headless Ubuntu 14.04 ?
Thanks in advance

Answer 1

You have two options.
Use a real X11 server. Headless OpenGL is not supported by most OpenGL implementations. This will allow you to use hardware acceleration. You will need to choose an EC2 instance with the right hardware support.
Use OSMesa. This will give you a software-only implementation that does not require X11 or any other window server at all.
It is normal / expected to get Gallium + llvmpipe as the implementation when hardware acceleration is not available. This is fine. If you need a newer version of OpenGL, you will want to install a newer version of Mesa. Mesa 10.1.3 is more than two years old at this point (it's from May 2014). Getting a newer version of Mesa either means using an alternate repo, installing a different version of Ubuntu, or compiling Mesa yourself.
If you compile Mesa yourself, you can configure it for OSMesa ("off-screen Mesa") which means it will have no dependencies on X11. See Off-screen Rendering for more details.

Answer 2

So, It turns out I need to put this into ~/.bashrc :
export DISPLAY=:99.0
sh -e /etc/init.d/xvfb stop
sh -e /etc/init.d/xvfb start
sleep 3
so that the above script will be run everytime I connect to the machine.
But then, I got a different error saying that the SDL_GL_CreateContext failed. Like #dietrich-app said, I need to update my mesa. The oibaf's graphic drivers ppa are no longer working (every google searches seem to suggest to use that) because it does not support ubuntu 14.04 anymore. I tried to compile mesa on my own but compiling dependencies are very time consuming and cumbersome. Finally, after hours of searching, I found this https://wiki.ubuntu.com/Kernel/LTSEnablementStack and copy paste the following command from that link :
sudo apt-get install --install-recommends linux-generic-lts-wily xserver-xorg-core-lts-wily xserver-xorg-lts-wily xserver-xorg-video-all-lts-wily xserver-xorg-input-all-lts-wily libwayland-egl1-mesa-lts-wily
And I got my mesa updated, and can now run OpenGL + SDL2 on AWS EC2 headless
Thank you for all the helpo