NURBS again

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Marco Crocetta (onyx++at++datamat.it)
Tue, 30 May 95 9:27:48 METDST

> Since the ocean probably doesn't need a whole lot of
> trimming, you might be able to do pretty well building a
> pfGeoSet of tristrips and setting the vertex positions based
> on a simpler surface primitive which you evaluate on the
> host, like Bezier patches. In order to avoid slowing down
> the DRAW with this processing, you probably want to put it in
> the APP, however this will require multibuffering the
> geometry yourself under a pfSwitch node so that you don't
> cause tearing by moving a vertex in the APP while it is being
> drawn in the DRAW.

Thanks very much.

> Also, we may do some surface primitives in a
> future version of Performer, so let us know what's useful.

It's the problem of how to build a good simulation of dynamic waves as seen
from a very low height from the sea surface.
Using triangles (remember the old lake demo) I have the problem that
the waves are not "smooth" and the effect of light above the surface
(i.e at sunset) when the waves are moving is quite bad.
Yes, I know we have to find the right tradeoff between a realistic
scene and good performance ...
It could be nice to have in a future release of Performer some
utilities or primitives the could help to buld up a good sea
simulation (as ptu helps for terrain and pfESky helps for
Sky modelling).

Thank you very much

--------------------------
Marco Crocetta
DATAMAT SpA, Rome
e-mail: onyx++at++datamat.it
--------------------------

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