Hi Jannik, I don't feel a "null" bounding sphere that is simply a zero radius bounding sphere is appropriate. A zero radius bounding sphere is perfect valid bounding volume, it has a well determined centre and radius it's certainly not something I would specify as null.
If there are cases where NaN's are being generated then these should be addressed specifically in the problem code. If you want to discuss the general topic further please use the osg-users mailing list forum as this is no longer a submissions topic. Thanks, Robert. On 20 November 2015 at 14:22, Jannik Heller <[email protected]> wrote: > > > For your own task I suspect the solution will not be to change the core, > but to address the problems so you don't generate scene graphs in a > indeterminate state. > > > > The problem is that we don't have a way to differentiate between > "indeterminate" and "empty" bounds, so there is currently no way for a > determinate state in some cases. > > > > ideally you don't have scene graphs with invalid bounding volumes > > osgAnimation, the official osg component does heavily make use of bone > nodes which have generally an indeterminate (null) bounds by default. There > is a legimitate need for a new core feature when one or more node kits > could make good use of it. > > How would you feel about adding support for a "null" bounding sphere? > Users can then explicitely mark empty nodes to have "null" bounds by > default so that they can be culled. Something akin to this: > > > Code: > > diff --git a/include/osg/BoundingSphere b/include/osg/BoundingSphere > index 0b62c2c..73f37e5 100644 > --- a/include/osg/BoundingSphere > +++ b/include/osg/BoundingSphere > @@ -63,6 +63,15 @@ class BoundingSphereImpl > * otherwise. */ > inline bool valid() const { return _radius>=0.0; } > > + inline bool null() const { return _radius==0.0; } > + > + /** Set the bounding sphere to null (i.e. empty). */ > + inline void setNull() > + { > + _center.set(0.0,0.0,0.0); > + _radius = 0.0; > + } > + > inline bool operator == (const BoundingSphereImpl& rhs) const { > return _center==rhs._center && _radius==rhs._radius; } > inline bool operator != (const BoundingSphereImpl& rhs) const { > return _center!=rhs._center || _radius==rhs._radius; } > > @@ -181,10 +190,10 @@ template<typename VT> > void BoundingSphereImpl<VT>::expandBy(const BoundingSphereImpl& sh) > { > // ignore operation if incoming BoundingSphere is invalid. > - if (!sh.valid()) return; > + if (!sh.valid() || sh.null()) return; > > - // This sphere is not set so use the inbound sphere > - if (!valid()) > + // This sphere is not set or null so use the inbound sphere > + if (!valid() || null()) > { > _center = sh._center; > _radius = sh._radius; > @@ -231,9 +240,9 @@ void BoundingSphereImpl<VT>::expandBy(const > BoundingSphereImpl& sh) > template<typename VT> > void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingSphereImpl& sh) > { > - if (sh.valid()) > + if (sh.valid() && !sh.null()) > { > - if (valid()) > + if (valid() && !null()) > { > value_type r = (sh._center-_center).length()+sh._radius; > if (r>_radius) _radius = r; > @@ -253,7 +262,7 @@ void BoundingSphereImpl<VT>::expandBy(const > BoundingBoxImpl<BBT>& bb) > { > if (bb.valid()) > { > - if (valid()) > + if (valid() && !null()) > { > BoundingBoxImpl<vec_type> newbb(bb); > > @@ -284,7 +293,7 @@ void BoundingSphereImpl<VT>::expandRadiusBy(const > BoundingBoxImpl<BBT>& bb) > { > if (bb.valid()) > { > - if (valid()) > + if (valid() && !null()) > { > for(unsigned int c=0;c<8;++c) > { > diff --git a/include/osg/CullStack b/include/osg/CullStack > index f045a26..5f32254 100644 > --- a/include/osg/CullStack > +++ b/include/osg/CullStack > @@ -109,9 +109,9 @@ class OSG_EXPORT CullStack : public osg::CullSettings > > inline bool isCulled(const osg::Node& node) > { > - if (node.getNumChildrenWithCullingDisabled() == 0 && > node.getCullingActive()) > + if (node.isCullingActive()) > { > - if (!node.getBound().valid()) > + if (node.getBound().null()) > return true; > return getCurrentCullingSet().isCulled(node.getBound()); > } > > > > > A "null" bounding sphere could actually be useful for others cases. For > example, I noticed with intersection visitors you can get NaN errors when > going into 0-scaled nodes (something I've seen reported on this mailing > list as well). Now, we'd have explict way to test for null bounds so we can > prevent the intersection visitor from entering that node in the first > place, preventing NaNs from popping up. > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=65710#65710 > > > > > > _______________________________________________ > osg-submissions mailing list > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org >
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