[vtkusers] Re: Offscreen Rendering

[John Shalf]

You are running into X11 security.  Someone (anyone) needs
to be logged into the console and exec 'xhost +localhost'. 
Alternatively, you can fix things in your X11 startup to do
the equivalent thing (allow users on the same host to access
the graphics even if they are entering remotely).  I can't
remember the exact recipe, but the relevant config files are
primarily in /usr/lib/X11/xdm.

Someone at Kitware sent me email a while back about
incorporating the offscreen renderer code directly into the
OpenGL render window as an alternative the existing
OSMesa-based software offscreen rendering that is already in
there.  What ever became of that?

-john

Miguel Angel Martin Fernandez wrote:
> 
> Hi vtkusers!
> 
> I am having a problem with vtkOpenGLOffscreenRenderWindow, sometimes when
> I compile (on a remote host using telnet) a program that uses it, i get
> the following error as i try to run my program:
> 
> Xlib: connection to ":0.0" refused by server Xlib: Invalid
> MIT-MAGIC-COOKIE-1 key
> 
> ERROR: In vtkOpenGLOffscreenRenderWindow.cxx, line 683
> vtkOpenGLOffscreenRenderWindow (0x807f478): bad X server connection.
> 
> p1_27512:  p4_error: interrupt SIGSEGV: 11 rm_l_1_27513:  p4_error:
> interrupt SIGINT: 2 p0_22175: (2.142237) Trying to receive a message when
> there are no connections; Bailing out
> 
> The cxx code line involved in this error is:
> 
>   if (!this->DisplayId) {
>     this->DisplayId = XOpenDisplay(":0");
>     if (this->DisplayId == NULL) {
>       vtkErrorMacro(<< "bad X server connection.\n");
>     }
> 
> However, if I compile the program while I am fisically in front of the
> computer (not using telnet) then everything works OK, and  i don't get any
> erorrs even if i then run it using telnet.
> 
> Maybe when I am actually sitting by the computer, then this->DisplayId
> does exist, and therefore it doesn't enter that "if"??
> 
> Any ideas on how to fix this without having to run around the lab will be
> definitely welcome!!!
> 
> Thank you very much in advance
> 
>                         Diego Hernando
> 
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