[vtkusers] Offscreen rendering

[Randall Hand]

Well, I've never gotten it to work in the manner you've described either.  I
always wound up with one of 2 problems: 1) an unwanted popup window, or 2)
blank displays.

The only way I know to get it to work the way you're describing is by using
true Mangling.  While I haven't tried AIX, I have gotten MAngledMesa to work
on SGI Irix, Compaq Tru64, and Linux.  There are instructions on the VTK
Wiki at
http://www.vtk.org/Wiki/VTK_FAQ#How_to_build_VTK_for_offscreen_rendering.3Falthough
they have to be "tweaked to fit".  In my version I change the names
of all the output libraries (as recommended) and compile everything 64-bit.
If those instructions don't shed any light on it, then I'll be happy to send
you my config scripts tomorrow to see if they shed any further light on the
subject.

I'm using Mesa 6.4.2 and VTK 5.0 (cvs branch).

On 4/13/06, John Norris <jnorris at mcs.anl.gov> wrote:
>
> There's something I'm missing when I compile the MesaGL libs, whether
> mangled or not.  In both cases, the osdemo doesn't work properly.  The
> generated tga file is just a black square.  So it isn't really
> surprising that VTK with Mesa or MangledMesa doesn't render offscreen
> properly.  I've done some googling on this but haven't found anything
> helpful.
>
> If I compile only libOSMesa, then the osdemo works.  This is with Mesa
> 6.5 on AIX 5.3 (I copied and edited linux-osmesa16, as per the README).
>   With the OSMesa build and the system OpenGL libs, I can compile VTK
> and VTK programs.  In this case, I'm /not/ using mangling (since I'm not
> compiling MesaGL or MesaGLU), and I don't have VTK_USE_MANGLED_MESA
> turned on.  I have turned on VTK_OPENGL_HAS_OSMESA and have properly
> defined OSMESA_INCLUDE_DIR and OSMESA_LIBRARY.  The GL-related options
> point to the system OpenGL stuff.
>
> I would prefer to be able to compile only OSMesa, since I'll use the
> system OpenGL libs for everything except offscreen rendering.  But at
> this point I'll take anything that works.
>
> John
>
> Randall Hand wrote:
> > I've been using VTK Offscreen for a little over a year now and haven't
> > had too much trouble with it.  I use MAngled Mesa & VTK on x-less
> > systems all the time.
> >
> > 1) Did you properly compile Mesa with the -DUSE_MGL_NAMESPACE and other
> > options enabled?
> > 2) Did you enable VTK_USE_MANGLED_MESA in VTK?
> > 3) Did you specify the correct Mesa libraries & include files?
> > 4) What version of VTK & Mesa are you using?
> >
> > On 4/13/06, *Kevin H. Hobbs* <kevin.hobbs.1 at ohiou.edu
> > <mailto:kevin.hobbs.1 at ohiou.edu>> wrote:
> >
> > On Thu, 2006-04-13 at 09:07 -0500, John Norris wrote:
> > > Progress!  I can render offscreen, but it still requires a connection
> to
> > > an X server.  This is despite the fact that I'm setting
> > > vtkGraphicsFactory::OffScreenOnlyMode to 1.  Either it's not working
> as
> > > advertised (the program still makes X calls), or there's some CMake
> > > option that I need to set.
> > >
> > > Is there any possible way to render offscreen in Unix without
> connecting
> > > to an X server?
> > >
> > > This is with straight OpenGL, no Mesa.  I could never get that to work
> > > at all.
> > >
> > > John
> >
> > I'm very interested in what you discover. I've tried for a while to do
> > this and failed.  I used the system OpenGL only, Mesa only, and system
> > OpenGL + mangled Mesa, without success.
> >
> > I know I'm missing something.
>
> --
> John Norris
> Research Programmer
> Center for Simulation of Advanced Rockets
> http://www.uiuc.edu/ph/www/jnorris
>
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