[ODE] visibility detemination?

[Adam D. Moss]

skjold@cistron.nl wrote:
> Yes, you are right of course. Just now I posted something to
> indicate I did not intend to imply that actually using dCollide
for this is a good idea. But like you said, things like those
> AABB's and spaces can be used rather effectively for culling
> quickly, especially since they're just there even if you don't
> take advantage of them. It just takes a little thought to do
> that in a way that makes it worthwhile over regular FOV
> calculations (or as a preliminary step to quickly narrow down
> the selection before further processing).

Do be aware, though, that if you're going to cull drawing primitives
based on the geometries that represent them then those primitives
should lay wholly within their geometries, otherwise it would
not be correct to assume that if the geometry does not collide
with the viewing frustum then the primitives may be culled away.

Further, ODE's current geom primitives don't offer any half-
reasonable way to construct a vaguely accurate frustum volume to
cull against.  You can use a number of plane geoms, but ODE's
hashSpace doesn't do anything clever with planes yet (they
never fit into a single cell of any resolution) so you wouldn't
gain anything over walking the AABBs in your scene and testing
them manually.

Now I'd like to piggyback a vote for reply-to-list to be the
default, too, as if this were a democracy. ;)

--Adam
-- 
Adam D. Moss   . ,,^^   adam@gimp.org   http://www.foxbox.org/   co:3
busting makes me feel good
kthx bye