From: Tom Jolley (jolley++at++fltsim.stl.mo.boeing.com)
Date: 10/17/2001 13:00:07
Hi Ken,
I ran across a similar problem a couple of years ago. It only
occured with the following combination:
1) More than one channel uses the clip texture.
2) The currently bound texture is the clip texture when I call my
drawing function.
3) And, glPushAttrib( GL_TEXTURE_BIT ) is called in my drawing
function.
My ugly workaround (because I use glGetIntergerv) was to save the
currently bound texture id, bind texture 0, call my drawing
function, and finally restore the saved texture id.
I was never sure if it was a problem in my code, Performer, or
OpenGL. I tried to modify perfly to duplicate the problem without
success.
Ken Sewell wrote:
>
> I have an application that draws terrain w/clipmap
> in one channel and some OpenGL geometry in the other. In
> the OpenGL draw callback, I call glPushAttrib with the
> texture bit set. When I do this I get a strange effect on
> the clipmap. At the border of every cliplevel, there
> is a stripe of imagery than does not belong. The imagery
> is from elsewhere in the clipmap. After about a second the
> stripe is replaced by the correct imagery. About a second
> later it repeats. My best guess is that the clipcenter is
> being updated but its being drawn before the cliptexture is
> updated. If I don't call glPushAttrib, my terrain shows up,
> but no cliptexture.
> Right now I've stripped down the callback for the
> OpenGL channel, all it does is glPushAttrib, glClear, and
> glPopAttrib and I get this effect. Has anyone encountered
> this problem before? Attached is a screenshot showing the
> cliptexture problem. Thanks.
>
> Ken.
>
> --
> Ken Sewell Defense Research Associates
> Project Engineer 1430 Oak Ct., Suite 303
> sewell++at++dramail.com Beavercreek, Ohio 45430
> 937-255-2811 x4377 (voice) 937-255-6663 (fax)
>
> --------------------------------------------------------------------------------
> Name: clipedges.jpg
> clipedges.jpg Type: JPEG Image (image/jpeg)
> Encoding: base64
-- Tom Jolley jolley++at++fltsim.stl.mo.boeing.com
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