Re: [Algorithms] Colliding against polygon soup

[Neal T. <ne...@ps...>]

From: Robert Dibley <RD...@ac...>


> > I think the most fundamental reason that I've hardly ever
> > done this (though I have used it in some situations) is
> > that the need to reserve memory for both rendering and
> > collisions representations of the world database usually
> > turns out to be a problem on consoles.  Your mileage may,
> > of course, vary...
> > Especially if you're not doing a console version:-)
>
> But if you are doing a console version, depending on the console, you will
> probably have your render data in a highly render dependent format, which
> most likely won'y include the info you would require for collision.  For
> example if your collision requires vertices and a normal, but your
renderer
> doesn't bother with a normal because your pixel fill rate is so high you
may
> as well draw everything.  Or your render data is organised by texture to
> speed up rendering, but you need your collision data organised by locale
to
> speed up collision.

All good points, certainly.  Personally I tend to try and minimise the
memory requirements by having a common set of data for rendering and
collisions at the triangle / vertex level (including e.g. face normals if
they're required for collisions but not rendering, and can't reasonably be
calculated at runtime for the cases when you need them), and then have two
sets of (much smaller) higher level structures which organise access to the
data differently for collisions and rendering.

> As you say, your mileage may vary!

Indeed:-)

Neal Tringham (Sick Puppies / Empire Interactive)

ne...@ps...
ne...@em...