Angus Dorbie (dorbie++at++sgi.com)
Tue, 22 Dec 1998 09:20:17 -0800
Try something like switching current glDrawBuffer, maybe
that'll ferret out the bug, even if it should have no
bearing on your pbuffer.
If you have isolated this then report it as a bug.
Cheers,Angus.
Liu Xiaoyan wrote:
>
> Hi, all,
>
> I'm having a very strange problem here rendering to a pbuffer with depth
> buffer( r/g/b = 8, Z=24). The images I save from this pbuffer are always
> the same each time I run it with different objects or even empty scene
> graph attached to this channel. I don't know where does this image come
> from, doesn't look like garbage, looks like the very very first objects
> I used to run the program and then it sticks to the memory. Even I
> explicitly clear the buffers in the draw callback or even stupidly
> reboot my Octane, the same image comes out.
>
> However, if I allocate a pbuffer without depth buffer, things go fine.
> What could cause such behaviour?
>
> I'd like to point out that I'm doing all these with another package
> library (CAVE) which deals with stereo display and allocates pipes and
> channels before my code for pbuffer allocation.
>
> void DrawPbuf (pfChannel *channel, void *data)
> { static int no = 0;
> int depth, color;
>
> glGetIntegerv(GL_DEPTH_BITS, &depth);
> glGetIntegerv(GL_COLOR_ARRAY_SIZE, &color);
> glClearColor(1, 0, 0, 0);
> glClearDepth(0.0f);
> glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
> glEnable(GL_DEPTH_TEST);
>
> /* pfClearChan(channel); */
> /* pfDraw(); */
> /* pfDrawChanStats(channel); */
> }
>
> Thanks for any help,
>
> Liu
>
> ***********************************************************************
> 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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-- "Only the mediocre are always at their best." -- Jean GiraudouxFor advanced 3D graphics Performer + OpenGL based examples and tutors: http://www.dorbie.com/
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