From: Tom Flynn (flynnt++at++engr.sgi.com)
Date: 01/26/2001 00:31:05
On Fri, 26 Jan 2001, Yves GAUVIN wrote:
> Hello Harry,
>
> With Linux, the Z Buffer is dependant of the number of color you have
> choosen for your environment. If you have choosen a 16 bit color mode, you
> will have a 16 bit Z Buffer, so you have to choose a 24 bit color Mode to
> have a 24 bit Z buffering. That's a limitation of XFree 4...
Actually, XFree itself has no knowledge about Z buffer (Linux doesn't
either :). What little XFree will know about Z buffer would be through
the GLX extension. Z buffer precision is a limitation of the graphics
chip. In the case of current NVidia hardware, the amount of Z buffer
precision is dependent on the color mode you are in. As you mention, with
16bpp, will give you 16bit Z. With 32bpp (8888, X doesn't know about
alpha, so you specify 24bpp to get 8888), you get 24bit Z.
With some PC graphics hardware, you can _only_ ever have 16bit Z and/or
only 16bit color. One generally has an exteremely limited number of
visuals available on consumer PC graphics (part of why they are so cheap
:-).
-tom
-- "Mongooses are famous for their snake-fighting ability, and are almost always victorious because of their speed, agility, and timing and also because of their thick coat."
This archive was generated by hypermail 2b29 : Fri Jan 26 2001 - 00:31:21 PST