Re: Do we really need to replace gnuplot?

[Shai Ayal]

On 10/16/07, Berk Geveci <address@hidden> wrote:
> There are many implementations of offscreen rendering with OpenGL:
> * All platforms: Mesa (software), framebuffer (hardware, based on driver
> support)
> * Windows: Win32 implementation of OpenGL
> * Unix/Linux: glxpixmaps (most probably software), pbuffers (sometimes
> hardware, depends on driver support)
>

OK, thanks for the input. I was under the impression that osmesa
replaces the mesa library and so you loose all hardware accelaration
for all your application if you install it. I was wrong. It looks like
the way to go since it is platform indpendant and does not need a
connection to a x-server

> We use all of these in VTK and they work reasonably well. We run into driver
> issues now and then but I wouldn't hold off using OpenGL because of those.
>
> In addition, if you stick to a subset of OpenGL, you can use gl2ps to
> produce (offscreen) vector graphics output to ps, eps, pdf or svg.

but for gl2ps you need an OpenGL context, so you would need to open a
window (or use on of the methods above to open an offscreen context)
or am I wrong here also ?

> -berk
>
> On 10/15/07, Shai Ayal <address@hidden> wrote:
> > On 10/15/07, John W. Eaton <address@hidden> wrote:
> > > On 15-Oct-2007, Shai Ayal wrote:
> > >
> > > | But are you willing to sacrifce offscreen rendering for them?
> > >
> > > Precisely what do you mean by offscreen rendering?
> >
> > I mean the ability to produce a plot in a file (e.g ps or png) w/o the
> > need for opening a window or indeed using any graphical capabilities
> > in the computer. gnuplot does this easily, However OpenGL is meant for
> > screen rendering, so even if you wish to produce a png file, you must
> > first render the scene to the screen and then convert it to a png
> > file.
> >
> > There might be a solution for this using OpenGL pbuffers. I'm looking into
> it ..
> >
> > Shai
> >
>
>