[Gtkradiant] Re: ATI drivers / GtkRadiant

David Olofson gtkradiant@zerowing.idsoftware.com
Wed, 26 Mar 2003 18:35:39 +0100

On Monday 24 March 2003 08.31, WolfWings wrote:
> > There is also something related to backface
> > drawing if I remember right. At the time there was someone
> > supposed to work on a fix but it never happened.

Yeah; mixing drawing modes when one face is culled gives you textured=20
outlines or just some dots at the vertices.

Anyway, that "someone" was me I guess, but the closest I've been to Q3=20
engines the last few months is playing some Q3A and RTCW. Too much=20
RL, work and other stuff.

I was going to send a detailed bug report to ATI (because the bug was=20
still there in the third driver release), but I lost the developer=20
contact address, and no one seems to have it. Anyone...?

> Ah, okay. I'd offer, but I'm simply not equipped to even compile
> Win32 code, my main dev-box and work being on Linux unfortunately.
> The extent of Win32 code I can compile is the Q3A .qvm compiler
> itself, using MinGW.

Well, at least with the FireGL 8800, the exact same thing happens=20
regardless of what OS and driver version is used. Never tried my=20
quick "fix" on Win32, though, but I'm quite sure it's the same bug,=20
so the hack should work.

The "fix":
=09Whenever one face is culled, make sure that face is
=09set to the same drawing mode as the visible face.

Doesn't break anything with solid drivers, but it avoids triggering=20
the ATI bug, which is triggered by things that should have no effect=20
at all. The downside is that it (probably) causes some extra GL=20
calls. (You shouldn't have to set the drawing mode for culled faces=20
at all, AFAIK, but with the ATI drivers, you have to.)

//David Olofson - Programmer, Composer, Open Source Advocate

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