[vtk-developers] Re: MangledMesa & VTK

[Jeff Lee]

On 1/2/07, Berk Geveci <berk.geveci at kitware.com> wrote:
>
> I haven't looked at/used mangled mesa in a while. I used to enable it
> on all my builds for testing but eventually gave it up. As Brian
> mentioned, having a separate mesa build is more practical. There are
> two maintenance issues with mangled mesa: 1. mangling support in the
> mesa library itself, 2. mangled mesa support in VTK. (2) is not too
> much of a burden although as Randall found out, it is not being tested
> (therefore it may be considered broken). (1) is more of a problem
> since Mesa folks are not really interested in it and do not test
> mangled mesa. The last time I tried, the latest mesa could not be
> built mangled. I think there are some users of mangled mesa out there
> but I am not sure how many. Jeff Lee may be one of them.


Hi All,
Yes, we are using it to do offscreen rendering in an interactive client.
The nice thing is that the same version of our rendering libraries work both
in batch and interactive, but the same thing could be accomplished by having
2 builds of the rendering libs, as Berk said above (it would be nice if
cmake produced the 2 different versions, instead of having completely
separate builds).  In batch, osmesa seems to be the only real choice for
rendering without an xserver, but interactive we can use glxpixmap, pbuffer,
or fbo, so no real need to do mangled mesa when interactive to get higher
resolution hardcopy.

On another note, for what we're trying to do (and probably most people), it
would be much more convenient to have an offscreen context in the
renderwindow that we can just make current and use, instead of the
SetOffscreenRendering() call.  The two scenarios I commonly see are you are
either always rendering offscreen, or you are making a high-res hardcopy and
don't want the current context to be messed with, but you don't really need
to go through all that SetOffscreenRendering() does to accomplish that.
Lets say you were creating an animation and wanted to save the animation as
a higher resolution than the onscreen context - basically every frame you
have to call SetOffscreenRendering to get your offscreen context to render
to, and then you have to throw it away when you update the onscreen context
- why not just add the ability for a vtkRenderWindow to have an additional
(or many) context(s) to render into.
-J

-berk
>
> On 1/2/07, Moreland, Kenneth <kmorel at sandia.gov> wrote:
> >
> >
> >
> > I'm pretty sure the current use of this feature at Sandia is zero.  All
> of
> > our distributions of ParaView use either a hardware driver or straight
> Mesa,
> > not both.  As several other members of these lists have just testified,
> it's
> > much easier.
> >
> > Concerning the maintenance overhead of maintaining the mangled Mesa
> stuff, I
> > would rather have someone from Kitware speak to that since they are
> really
> > the ones doing that.  I recall Berk grumbling about it in the
> past.  Perhaps
> > he can elaborate.
> >
> > I also cannot speak for any other organizations that may be using
> > VTK/ParaView.  If any of you out there use the vtkMesa* classes or
> otherwise
> > compile with the mangled Mesa features, now would be a really good time
> to
> > chime in.
> >
> > -Ken
> >
> >  ________________________________
> >  From: paraview-bounces+kmorel=sandia.gov at paraview.org on behalf of
> James P.
> > Ahrens
> > Sent: Sat 12/30/2006 4:35 PM
> > To: paraview at paraview.org
> > Cc: ahrens at lanl.gov
> > Subject: [Paraview] Re: ParaView Digest, Vol 32, Issue 23
> >
> >
> >
> >
> > > Message: 1
> > > Date: Fri, 29 Dec 2006 09:05:35 -0600
> > > From: "Randall Hand" <randall.hand at gmail.com>
> > > Subject: Re: [Paraview] RE: [vtkusers] MangledMesa & VTK
> > > To: "Sean Ziegeler" <seanzig at users.sourceforge.net>
> > > Cc: paraview-developers at public.kitware.com, VTK Users
> > >       <vtkusers at vtk.org>,     paraview at paraview.org
> > > Message-ID:
> > >
> > <b02264720612290705h54bc20a6yf45d6b335f1f644e at mail.gmail.com>
> > > Content-Type: text/plain; charset="iso-8859-1"
> > > >
> > > So maybe mangling isn't really necessary anymore, except for those
> times
> > > where you need to switch between Hardware OpengL & Mesa on the fly..
> > > Anyone
> > > actually doing that tho?
> > >
> >
> > The original purpose of the mangled mesa extension was a heterogeneous
> > configuration with hardware acceleration and OS rendering at the same
> > time. It was a long time ago, so I've forgotten the exact configuration.
> I
> > know SGI pipes were part of the mix. This was in the parallel VTK days;
> > ParaView did not exist, therefore no client/server architecture etc...
> >
> > One application is rendering extremely large offscreen imagery using
> > mangled Mesa (limited by memory)  and hardware accelerated rendering
> > smaller imagery for onscreen interactive use. This requires both
> libraries
> > in the same executable.
> >
> > Brian, what is the maintainence issue? What is the current cost etc.?
> >
> > --Jim
> >
> >
> >
> > _______________________________________________
> > ParaView mailing list
> > ParaView at paraview.org
> > http://www.paraview.org/mailman/listinfo/paraview
> >
> >
>
>
> --
> Berk Geveci
> Kitware Inc.
> 28 Corporate Drive
> Clifton Park, NY, 12309
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20070103/9e829e6d/attachment.html>