Hello Erlend,
> The tutorials though use "dumb" pointers as in the Basic Geometry example:
> "
> ...
> int main()
> {
> ...
> osg::Group* root = new osg::Group();
> osg::Geode* pyramidGeode = new osg::Geode();
> osg::Geometry* pyramidGeometry = new osg::Geometry();
> "
>
> but i guess it's just for simplicity.
Well, since whenever you add almost anything to a Group, Geometry or
Geode (or their subclasses) it internally stores them as ref_ptrs, it's
as safe. For example:
osg::Group* group = new osg::Group;
osg::Geode* geode = new osg::Geode;
group->addChild(geode);
osg::Geometry* geometry = new osg::Geometry;
geode->addDrawable(geometry);
Internally, group stores its children as a vector of ref_ptrs, and geode
stores its drawables as a vector of ref_ptrs (check the source).
> In the guide "A Short Introduction to the Basic Principles of the Open Scene
> Graph" on the use of ref_ptr, they first create a node using ref pointer,
> then they add a node using new, and say:
>
> "
> Line 25 does more or less the same thing as the previous case. The
> difference is that the geode is allocated with new and added as group's
> child in a single line of code. This is quite safe, too, because there are
> not many bad things that can happen in between (after all, there is no
> in between.)
> "
>
> that may be a little missleading since it's not a smart pointer, and needs to
> be deleted explicitly.
No. You cannot delete a subclass of Referenced, because the destructor
is protected. You also cannot allocate one on the stack. So these are
illegal:
osg::Group group;
// or
osg::Group* group = new osg::Group;
// ...
delete group;
You will get compile errors for these, because the destructor is protected.
If you create a subclass of Referenced with a C pointer and never give
it to a ref_ptr, it will leak and there's nothing you can do about it.
But if you give it to for example a group as a child, it will be OK.
But that said, I find it easier to just use ref_ptrs all the time and
not think about it. For example:
osg::ref_ptr<osg::Group> group = new osg::Group;
osg::ref_ptr<osg::Geode> geode = new osg::Geode;
group->addChild(geode.get());
osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry;
geode->addDrawable(geometry.get());
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay [EMAIL PROTECTED]
http://www.cm-labs.com/
http://whitestar02.webhop.org/
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
