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equentric
11-26-2003, 06:51 AM
hi,

I'm struggling against a strange problem with pbuffers.
My pbuffer used with RGBA or Z is polluted by some kind of empty dash-dot lines (??!!)

I mean i fill my pbuffer with a Z or RGBA, and Some pixels are not filled and remain empty. don't understand why !?

If I switch to use a framebuffer (or zbuffer) instead of pbuffer, the problem disapear.

here's a picture (hope it works)
blue is the clear color, other is my pbuffer partially filled.
F:\Docs_TTS\bug_pbuffer.bmp


My card is geforce 4 ti 4600.

Relic
11-26-2003, 07:50 AM
The above link would help if you also gave us access to your F: drive. http://www.opengl.org/discussion_boards/ubb/wink.gif

equentric
11-26-2003, 12:02 PM
so here's the picture.
now you will understand what I mean
dash in pbuffer (http://mapage.noos.fr/equentric/index.html)

thanks

Relic
11-26-2003, 10:48 PM
Looks like an enlarged polygon stipple pattern. Is polygon stipple enabled?
For more insights you need to show the code which sets up the pbuffer and draws into it.

equentric
11-26-2003, 11:24 PM
thx relic,
yep, if I disable the polygon stipple my pb does not occur any more.

That's strange, cause when I render directly in framebuffer the stipple does not appear.
And in Pbuffer the stipple sometime appears and disappears. depends where I am in the 3d scene. strange , isn't it ?!

anyway thx for your help
now I can move forward.

Relic
11-27-2003, 04:27 AM
That's simple to figure out if you have all the code doing OpenGL rendering under you control:
Polygon stipple is off and the pattern is solid per default.
Do a search for GL_POLYGON_STIPPLE and glPolygonStipple in the code. It must be set and enabled somewhere.
If there's a mismatch between the enables and disables in the pbuffer case, fix it.
If not, search for all glPush- and glPopAttrib to see if there's a mismatch and fix it.
If not, things get difficult. Maybe render contexts not current, or driver bug.
However, fine that it works now.