Hi J-S,
On Mon, 2005-12-05 at 13:56 -0500, Jean-Sebastien Guay wrote:
> Now, one other thing. I tried using IntersectAction and it ended up being too
> slow for my needs. So I tried doing a volume intersection first, and then
> doing
> the IntersectAction to be sure the objects actually intersect :
>
> bool Arrow::hit( const Target *target ) {
> DynamicVolume arrow_volume = getRoot()->getVolume(false);
> DynamicVolume target_volume = target->getRoot()->getVolume(false);
>
> if ( arrow_volume.intersect( target_volume ) ) {
> // We should now check if the polygons actually intersect, maybe with
> // the IntersectAction, now that we know that the bounding boxes
> // intersect and have saved ourselves lots of time...
> return true;
> }
>
> return false;
> }
Note that these volumes are in local coordinate space, so they never
change unless you change Nodes underneath them. If you want world
volumes you need to call getWorldVolume();
> This works fine if my targets are immobile, but it doesn't work when they're
> moving.
>
> I expect this is because of the way I do the movement. Instead of moving the
> observer (which I found needlessly complicated, since the camera is not part
> of
> the scene graph [why isn't it, btw? It would make some things much easier,
> like
> moving the camera and avatar at the same time])
In a sense the Camera is part of the scene graph, at least the part that
matters: the beacon. The Observers are set on top of the camera, as they
need information that can't be extracted from the Beacon matrix.
> I move the scenery in the
> opposite direction. So for example, when the observer moves forward, I have a
> Transform node which has the whole scenery as its children, and I move that
> backwards by the same amount.
Hm, yes, that sounds complicated. What are you trying to achieve? Have a
third-person view, where the observer is always behind the avatar? You
can achieve that by putting the Avatar under the beacon Node. If using
the SSM the beacon is a little hidden, but you can get it from the SSM's
camera.
> What I suspect is happening is that the bounding volumes are staying at their
> original positions when I move the scenery (which the targets are part of).
> But
> how do I make them get updated? I tried using invalidateVolume() on many
> different nodes, and none made a difference...
They are invalidated automatically, you should never have to call this
by hand. But you never update them, so they are always out of date. If
you call getVolume(true); (or just getVolume();) they will be updated
and should be fine.
Hope it helps
Dirk
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