Remote desktop capture

[Brian Paul]

eberrocal at laurel.datsi.fi.upm.es wrote:
> Hi to everybody, this is the first time that I write to this mailing list.
> Sorry if my English is not very well.
> 
> I have been searching information but I do not find anything about this. I
> pretend to execute 3D applications (OpenGL applications) in a remote X
> session (normally in a power 3D cluster) and watch the result in my local
> (normally poor) machine.
> 
> One of the solutions that I have thought to transport the rendered data
> are video. There are a lot of applications allow me to capture the openGL
> buffer, compress it in a video frame and make a video with this video
> frames (or send this video thought the network with vlc for example) like
> yukon, recordMyDesktop, etc.
> 
> visit  http://linuxmafia.com/faq/Apps/desktop-video-capture.html
> 
> Via ssh the user open a X session with the command:
> 
> user at node0:~$ startx -- :1 &
> user at node0:~$ export DISPLAY=:1
> 
> in the remote machine, and now I can execute any openGl application like
> 
> user at node0:~$ glxgears
> 
> The problem comes when I pretend to capture the window of the openGL
> applications or the entire desktop where this application is running. The
> result is a video where the openGL application zone is absolutely black,
> there are nothing to capture.

This generally happens because the OpenGL library is using direct 
rendering to bypass the X server.  I'm not sure what tool you're using 
to capture the desktop though.


> I do not know if I can do this in a different way or if It is impossible.
> I suspect that the problem is clipping, because this X session is not been
> displaying in a monitor and possibly the clipping algorithm fail for the
> entire openGL zone.

The Chromium Renderserver project might help you out.  It's a 
combination of packages that will let you view a remote X desktop with 
OpenGL rendering using a standard VNC viewer.

See http://vncproxy.sourceforge.net/

-Brian