[Mesa-users] Frame buffer object extension (FBO) support for Intel 945 graphic core

Brian Paul brianp at vmware.com
Thu Jul 22 15:41:23 PDT 2010

On 07/21/2010 10:41 AM, Wei, Brian wrote:
> Hello all,
> We have a linux box with Intel N270 processor (with 945 graphic core
> inside). Our Linux supplier downloaded and installed libGLgn3.so from
> Intel IEGD package. However, this openGL library from IEGD does not seem
> to support frame buffer object (FBO) extension, as no related string
> output from glxinfo is found.
> Besides IEGD library, there seems to have another way to include Intel
> linux graphic driver (xf86-video-intel+mesa3d):
> http://intellinuxgraphics.org/
> What's the difference between two Intel graphic driver approaches?
> a. Intel IEGD openGL
> b. Intel linux graphic driver (xf86-video-intel for 2D rendering and
> Mesa3d for 3D rendering)

They're different drivers for the same hardware.  (a) was developed 
in-house by Intel while (b) was developed by Tungsten Graphics years 
ago.  I've never used (a).

> and can I use either approach for hardware-acceleratation of 945 graphic
> core?


> A separate question:
> With software rendering of mesa3d (./configure --with-driver=xlib), I
> have FBO extension available. Occasionally the background of frame
> buffer object is cleared to a different color than what I specified via
> glClearColor(red,green,blue,alpha). It occurs very rarely and I can not
> reproduce it on demand. Any way to debug framebuffer object drawing?

Does it happen with a single executation of your app if you leave it 
running long enough?  Or do you have to re-run the app a bunch of 
times to see the bug?

I'd add some code to do a glReadPixels() after the glClear to verify 
that the color is what's exected.  See if that catches it.

Maybe running with valgrind would turn up something.


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