[vox-tech] Debian configuration: X and modem and zip: all resolved!

Peter Jay Salzman p at dirac.org
Mon Jul 26 11:27:43 PDT 2004


On Mon 26 Jul 04, 10:31 AM, ashleigh smythe <absmythe at ucdavis.edu> said:
> I used the "nv" driver that came with XFree86 (4.1.0), even though my
> understanding from folks here and elsewhere is that that doesn't support
> 3D graphics.

That's not quite true.  It can certainly display 3D graphics.

Modern 3D applications are very CPU intensive, and require a LOT of CPU
power to do all the necessary calculations to render a 3D image.  Games
and things like flight simulators in particular need to render this
stuff roughly 60 times a second.  We're talking millions of matrix
operations (quaternion multiplications, whatever) per second.

A modern application like Quake III has other things to worry about too.
Networking, sound (which is very CPU intensive as well), timing, off
screen rendering.  And on top of all that, the CPU (which ultimately
handles all these things) needs to devote its time, unconditionally, to
things that make the computer "go", like handling interrupts or
scheduling processes.

In an attempt to "offshore" the CPU intensive graphics calculations,
modern video cards have their own CPU, commonly called a GPU (guess what
"G" stands for) that does many of the very common 3D calculations that
the CPU would normally do.

The short / boiled down version is that when the graphics library
encounters a common graphics instruction "rotate the polygon", it sends
the instruction to the graphics card so that the GPU does the
calcualtions.  This frees up the CPU to worry about other things.

It's kind of like DMA, if you're familiar with that.  Having something
else do the job that the CPU would normally do.

Of course, it's much more complicated than that, but that's the general
gist.  The process is called "3D acceleration", because the GPU does
exactly that -- it speeds up 3D calculations needed for rendering using
special hardware on the video card designed for that specific purpose.

Your system can do 3D graphics.  To prove that to yourself, run "glxgears"
if it's on your system.  What your system can't do, until you install
Nvidia's drivers, is 3D accelerated graphics.  The specialty hardware on
your graphics card is unused because the graphics library (Mesa) doesn't
know how to access the card's 3D accleration hardware without Nvidia's
drivers.

Supposedly, there's only small pieces of OpenGL code that technically
make the drivers closed source.  This may mean that the drivers MAY be
released someday in the future.  OTOH, I'm sure Nvidia isn't crying over
not releasing their drivers.  But then again, neither is ATI.

What we REALLY need is the equivalent of the GNU operating system for
hardware.

Pete


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