[rescue] ZX coolness

[Joshua D Boyd]

On Tue, Oct 08, 2002 at 02:00:37AM -0400, Patrick Giagnocavo +1.717.201.3366 wrote:
> Um, if Linux let it happen, it is Linux's fault.  Unless you were
> running everything as root, which I doubt you were.

XFree runs as root to my understanding.  Besides, the nvidia drivers
require a kernel module be loaded.
 
> As far as SGI's go, I think any hw that quotes Tmesh numbers is going
> to have accelerated tesselation as well (at the very least).  Thus XZ
> and up offer some acceleration.  

Entirely possible.  I'm just being to lazy to verify from the SGI docs
what else would do.
  
> Google is your friend on this kind of stuff.

Yes, but time isn't.
 
> A 2D analog to this would be a Bezier curve.

A 3D analog would be a bezier curve.  And there are 2D NURBS also.
 
> > So, what the ZX board does is rather than the host CPU calculate the
> > triangulation, the board can do it itself, leaving the CPU to worry
> > about other things.  The only other case of graphics hardware that I
> > know of that does that is Infinate Reality (although it would surprise
> > me if Impact did also).
> 
> I think you are conflating things here Josh (but I could be wrong).
> 
> An analog to trimming might be the calculation of clipping paths in
> Postscript, or hidden line removal in a 2D view of a 3D object.
> 
> Tesselation is the step where a surface is turned into a bunch of
> small triangles.  
> 
> Trimming the NURBS would occur in a step previous to tesselation.  You
> could, with a stretch, say that tesselation is a step similar to
> rasterizing a bitmap from a Postscript or other vector description of
> an image.  

Well, as I said, I didn't know off the top of my head what trimming was,
but they said it was supported by the ZX board in the doc.  When I dealt
with NURBS in numerical analysis, the topic of trimming was never
raised, since they weren't using NURBS for graphics or surfaces.
 
> As such it would be perfect for an accelerated function, since:
> 
> a) sending all those triangles across a bus would be slow and you
> would see immediate speedups due to reduced bus use and the data being
> rendered locally
> b) it is a simple function that lends itself well to being put on a chip
> c) it is common in many applications and is done the same way each time

Pretty much.

-- 
Joshua D. Boyd