[linux-audio-dev] Re: GTK performance?

[Steve Harris]

On Tue, May 03, 2005 at 06:42:29 +0300, Juhana Sadeharju wrote:
> >From: Jens M Andreasen <jens.andreasen at chello.se>
> >
> >Is it gtk then? Or the pixmap engine?
> 
> I don't use pixmap decorations in my application, but
> only one pixmap of size 800x600 was too slow. I used
> the preferred pixmap functions of GTK2. The expose of
> the whole 800x600 pixmap took 120 ms (8 fps). That was
> impractical.
> 
> Then I switched to gtkglext which in my system apparently
> uses Mesa with software renderer. (How to verify it?)
> Now the system is fast. One app renders 3D objects and another
> app draws 2D objects (http://www.funet.fi/~kouhia/enved7.png).
> 
> I would like to know if gtkglext in my system uses Mesa and
> if Mesa uses software renderer. How that can be tested?

I think Mesa is the software renderer. If you run glxinfo it will tell you
the vendor of the driver, which will be Mesa if its software, or thename of
the graphics card manufacturer or Xorg driver etc. if its hardware.

> What I would like to have would be vertex and fragment
> shaders for audio widgets. E.g., a 2D or 3D knob would
> rotate with vertex shaders. E.g., a level meter a la
> SoundForge would have a fragment shader dimming the top of
> the black-green-yellow-red texture map based on the meter
> value.

Beware: not all current cards have shader support, though basic GL is
widespread. Also linux support for shaders is limited to the closed source
drivers I think, which many people will object to on philoshical grounds.

- Steve