AutoDeleteChildCallback.h

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//-----------------------------------------------------------------------------------
//
// Pro-Vocation Light Engine (PVLE)
// Copyright (C) 2007-2009  Sukender, KinoX & Buzib
// For more information, contact us : sukender@free.fr
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3 of the License, or
// (at your option) any later version.
//
// For any use that is not compatible with the terms of the GNU 
// General Public License, please contact the authors for alternative
// licensing options.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
//-----------------------------------------------------------------------------------


#ifndef PVLE_AUTO_DELETE_CHILD_CALLBACK
#define PVLE_AUTO_DELETE_CHILD_CALLBACK

#include <osg/Group>
#include <osg/NodeCallback>

template <class T>
class AutoDeleteChildCallback : public osg::NodeCallback {
public:
    AutoDeleteChildCallback();
    AutoDeleteChildCallback(const T & reference);
    //virtual ~AutoDeleteChildCallback() {}
    virtual void operator()(osg::Node* node, osg::NodeVisitor* nv);

protected:
    std::string libraryName;
    std::string className;
};


template <class T>
AutoDeleteChildCallback<T>::AutoDeleteChildCallback() {
    osg::ref_ptr<osg::Node> reference = new T;      // T is supposed to be default-constructible (HAS_DEFAULT_CTOR==true).
    libraryName = reference->libraryName();
    className   = reference->className();
}

template <class T>
AutoDeleteChildCallback<T>::AutoDeleteChildCallback(const T & reference)
    : libraryName(reference.libraryName()), className(reference.className())
{
}


template <class T>
void AutoDeleteChildCallback<T>::operator()(osg::Node* node, osg::NodeVisitor* nv) {
    //osg::Group * pGroup = boost::polymorphic_downcast<osg::Group *>(node);        // Can't apply this callback to a non-group node.
    osg::Group * pGroup = node->asGroup();
    if (pGroup) {       // Can't apply this callback to a non-group node.
        for(int i=static_cast<int>(pGroup->getNumChildren())-1; i>=0; --i) {        // Cast to signed int to avoid underflow
            osg::Node* pChild = pGroup->getChild(i);
            if (pChild->className() == className && pChild->libraryName() == libraryName) {
                // We do a polymorphic downcast, similarily as boost's one
#ifdef _DEBUG
                if (dynamic_cast<T *>(pChild) != pChild) throw "AutoDeleteChildCallback cast error";        // Logic error
#endif
                // We do only a static_cast in release since testing the className and libraryName is enough
                if (static_cast<T *>(pChild)->autoDelete())     // If it fails to compile, check that you added a public "bool autoDelete()" method
                    pGroup->removeChildren(i, 1);
            }
        }
    }
    traverse(node, nv);
}

#endif  // PVLE_AUTO_DELETE_CHILD_CALLBACK

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