Phil Keslin (philk++at++cthulhu.engr.sgi.com)
Wed, 23 Dec 1998 10:26:57 -0800
- Phil
Liu Xiaoyan wrote:
>
> Hi, all
>
> In case you want to know the outcome.
>
> I allocated the puffer with PRESERVED_CONTENTS_SGIX, and read the image
> immediately after pfDraw, it works now. Maybe the cause is just as what Phil
> says below: depth planes are clobbered. But, does this mean we should ALWAYS
> use a preserved pbuffer?
>
> Many thanks......
>
> Phil Keslin wrote:
>
> > When do you read the contents of the pbuffer? Did you allocate the
> > pbuffer with PRESERVED_CONTENTS? If not, any process with an active GL
> > context could force your pbuffer to get clobbered. On the OCTANE MXI and
> > a display resolution of 1280x1024, your pbuffer will share depth with
> > the front planes. It is possible that your depth planes are getting
> > clobbered resulting in failure of the depth test. The contents of the
> > pbuffer color buffers won't change in that instance.
> >
> > - Phil
> > --
> > Phil Keslin <philk++at++engr.sgi.com>
>
> ***********************************************************************
> Liu Xiaoyan Institute of High Performance Computing
> Research Engineer National University of Singapore
> Data Visualisation Group http://www.ihpc.nus.edu.sg Tel:(65)7709267
> ***********************************************************************
>
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-- Phil Keslin <philk++at++engr.sgi.com>
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