[ODE] Re: Call to set a space's AABB.

[gl]

Well, now that I'm thinking (don't stop me, I'm on a roll), I might aswell
bite the bullet and do my own culling - there's no point duplicating all
this functionality, and I can actually optimize this further than I could
with ODE spaces.

I guess the spaces are fine as they are - anybody trying to do what I was is
probably better off doing their own culling.
--
gl

----- Original Message -----
From: "gl" <gl@ntlworld.com>
To: <ode@q12.org>
Sent: Friday, February 21, 2003 5:49 PM
Subject: [ODE] Re: Call to set a space's AABB.


>
> Seconds after sending this, it ocurred to me that what I really want is
> placeable (position-only) spaces.  I would then have spaces centered in
> their correct place in the graph/world (ie. their bound extents would
still
> default to zero, but the values would be offset by their position) - they
> could now grow and shrink (which is helpful in this case), and would still
> never overlap, eliminating the need for all-zero checks.
>
> Would this be of use to anyone else?
> --
> gl
>
> ----- Original Message -----
> From: "gl" <gl@ntlworld.com>
> To: <ode@q12.org>
> Sent: Friday, February 21, 2003 5:41 PM
> Subject: Call to set a space's AABB.
>
>
> >
> > OK, my scene graph is quadtree based.  I may do my own collision culling
> in
> > the future, but for now I create a simple space for each quadtree node,
> > giving me a deep space hierarchy that matches the graph.
> >
> > The problem is that any spaces/nodes that contain no objects have their
> > bounds set to all-zeros.  Worse, any spaces that contain only other
empty
> > spaces (ie. most of them) also have their bounds all zero.
> >
> > Worst of all, if I now add a a _static_ geom to the graph, I put it into
> the
> > world's static space to avoid collision between other statics.  Problem
is
> > that now the space belonging to the node the geom was sorted into still
> > keeps its bounds at 0,0,0 (as it's never added to it).
> >
> > To speed up the collison callback I currently skip spaces who's bounds
are
> > all zero, but in this scenario that no longer works.  Worse, if I remove
> > this check I now have to test zillions of these 'contains only other
> spaces'
> > spaces that all overlap each other (because they're all zero), or cull
> them
> > some other way.
> >
> > All of these problems could be avoided if I could preset each space's
AABB
> > to the correct dimensions.  In fact, I would like to lock this AABB so
> that
> > it never grows or shrinks - it should never grow because I currently
don't
> > allow node overlapping, and it certainly should never shrink, so it
> removes
> > the need for the internal AABB housekeeping altogether.
> >
> > I can of course hack this in myself, but would anybody else find this
> > useful?  Or does anyone have another approach to this?
> > --
> > gl
> >
>
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