Re: Do we really need to replace gnuplot?

[Shai Ayal]

On 10/15/07, Alexander Barth <address@hidden> wrote:
>
>
> 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
>
>
>
> You can do off-screen rendering in opengl with GLX Pixmap and OS Mesa.
> For GLX Pixmap you need a connection to a X server but no window is
> displayed. This is not necessary for OS Mesa. A nice overview can be found
> here:
>
> http://www.mesa3d.org/brianp/sig97/offscrn.htm
>
> Also, toolkits such as GTK (gtkglext) provide a higher level interface for
> off-screen pixmaps.
> http://gtkglext.sourceforge.net/reference/gtkglext/gtkglext-gdkglpixmap.html
>
> The advantage of using a toolkit for off-screen rendering is that your code
> is probably more portable.
It looks to me like gtkglext does require a connection to an x-server,
which I don't think we should require of windows and mac users.
osmesa seems like the way to go, but I must ascertain that it exists
for windows and mac before I commit

thanks for the tips
Shai

>
> Alex
>
>
>