Re: Texturing, IRIX >5.2, and OpenGL

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Rob Jenkins (robj++at++quid)
Fri, 20 Jun 1997 18:00:53 -0700

I've seen exactly this before, replacing the OpenGL texture calls with
pfTexture calls did the trick. Direct calls to OpenGL are normally OK ( with
caution ) from Performer but Performer works hard to manage the current
graphics state efficiently and in the case of the pfuTexList stuff, Performer
tries to implement sharing of texture efficiently. One of the assumptions it
makes is that it knows what gfx state it changed, if your application makes
those changes too ( for example to currently bound texture ) then Performer
doesn't know that and things get messed up. If you didn't change to using
pfTexture stuff ( recommended ) then you might find that doing glGet(
GL_TEXTURE_2D_BINDING_EXT ) and then restoring that after you've done you're
OpenGL thing would work but I doubt it would be as efficient as Performer.
Probably the changes to OpenGL after Irix 5.3 would account for the change in
behaviour.

Cheers
Rob

On Jun 20, 11:35am, Matthew M Mckeon wrote:
> Subject: Texturing, IRIX >5.2, and OpenGL
>
>
> I have an interesting problem.
>
> I've apparently run into some sort of
> bug involving Performer, OpenGL texturing,
> and possibly post-5.3 Irix.
>
> Our Onyx RE runs 5.3, and our application
> (a perfly hack) runs just fine on it.
> In the localPostDraw() function, I used OpenGL calls to
> display a translucent overhead map by texturing an
> alpha-blended poly with rgb data read from a file.
> Worked quite nicely, with little to no affect on
> our refresh rate.
>
> I tested it on our other SGI's (I^2s, O2s, and an Octane)
> by running it first remotely, then locally.
> That's when I found myself perplexed.
>
> When I run the app remotely on a post-5.3 machine
> and display it on the Onyx console, it works fine.
> When I run the app locally on a machine running 5.3,
> it works fine. When I run the app remotely on the
> Onyx and view it on a post-5.3 console, everything's
> OK. _However_, when I run it locally on the O2's and
> the Octane (can't set up our post-5.3 I^2 for it
> just yet), the map texture replaces every other texture
> on the terrain.
>
> Did I mention this is only under OpenGL and not IrisGL?
> :,
>
> Has anyone encountered something similar to this before?
> What can I do about it? I've alread checked, re-checked,
> and triple-checked my code. The OpenGL portion is
> thoroughly kosher.
>
> Thanks,
>
> --------------------- Matthew M. McKeon ->mckeon++at++cs.cmu.edu
> ---------- Research Programmer ----------|www.andrew.cmu.edu/~mmm
> - CMU Digital Mapping Project (MAPSlab) -|Feel free to blither now
>
> =======================================================================
> List Archives, FAQ, FTP: http://www.sgi.com/Technology/Performer/
> Submissions: info-performer++at++sgi.com
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>-- End of excerpt from Matthew M Mckeon

-- 
________________________________________________________________
Rob Jenkins mailto:robj++at++csd.sgi.com
Silicon Graphics, Mtn View, California, USA
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