Re: [Dri-users] Z-buffer problems with Radeon 7200 (a.k.a. Radeon 64 DDR VIVO)

[magenta <ma...@tr...>]

On Thu, Dec 19, 2002 at 08:51:41PM -0500, Brandon Atkinson wrote:
> I am not sure that it is a driver issue, but I contacted the BZFLAG boys 
> and they mentioned that they thought it was (I also found another poor 
> guy with the same video card having the same issue under Linux and DRI).
> 
> The problem is this:
> Enabling 'depth buffer' in the video options section of the game causes 
> the polygons on the right 3/4 of the screen to disappear.  All that can 
> be seen on this part of the screen is the pixmap background.  The 1/4 to 
> the left seems to look O.K.
> 
> I played with all the options in the video section, and went through all 
> possible combinations.  The only thing that alleviates the problem is 
> disabling the 'depth buffer'.  This obviously slows down 3d performance 
> to an almost unplayable level.  

When 'depth buffer' is enabled, do they do a readback of the depth buffer
to occlusion-cull objects out?  I've noticed that on my Radeon 7000, when
reading the depth buffer it just gets "noise" (though it's noise which
looks like it could be the internal wavelet representation of the zbuffer).

> Quake 3 works correctly and so does all other 3d applications.

Most 3D applications don't use depth buffer readback for culling.

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