Re: ssgVtxArrary and ssgSimpleList addtions + pui resize additions (was Re: [Plib-devel] Changing VTable triangles (+ blend and texture modes))

[Steve B. <sjb...@ai...>]

Sam Stickland wrote:

> Actually it would be nice to be able to provide the bounding sphere
> myself :).   In the case of an explosion if you know the position of the
> fastest moving particle you can calculate the radius of the bounding
> sphere from that.

Hmmm - same as vertices - you can get a pointer to the bsphere:

   sgSphere *ssgEntity::getBSphere() ;
 
...then you can set the center and radius.

   sphere -> setCenter ( x, y, z ) ;
   sphere -> setRadius ( r ) ;

Finally, you have to tell the API that you messed with it:

   ssgEntity::dirtyBSphere () ;

...which will cause all the bounding spheres from there on upwards to
be dirtied and hence recalculated the next time they are rendered.

> You could have a setBoundingSphere method (that would also have to dirty
> all the spheres above it), but then changing an sgTransform would still
> cause the explosions bounding sphere to be recalculated the expensive
> way - perhaps a callback hook for bounding sphere calculations would be
> best?

Well, I think most people would just set the bsphere to the maximum
radius and leave it there.

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