OSG的智能指针，osg::ref_ptr<>
osg::Referenced类管理引用计数内存块，osg::ref_ptr需要使用以它为基类的其它类作为模板参数。
osg::ref_ptr<>类模板重新实现了一系列C++重载符和成员函数，主要有：
- T* get(): 返回管理的指针, { return _ptr; }
- T& operator*(): 返回间接引用，{ return *_ptr; }
- T* operator->(): { return _ptr; }
- operator=(): 各种赋值
- operator==(), operator!=(), and operator!():
- valid(): { return _ptr!=0; }
- release():
简单示例：
#include <osg/ref_ptr>
#include <osg/Referenced>
#include <iostream> class MonitoringTarget : public osg::Referenced
{
public:
MonitoringTarget(int id) : _id(id)
{
std::cout << "构造目标 " << _id << std::endl;
}
protected:
virtual ~MonitoringTarget()
{
std::cout << "目标销毁 " << _id << std::endl;
} int _id;
}; int main(int argc, char *argv[])
{
osg::ref_ptr<MonitoringTarget> target = new MonitoringTarget();
std::cout << "引用前引用计数为: "
<< target->referenceCount() << std::endl;
osg::ref_ptr<MonitoringTarget> anotherTarget = target;
std::cout << "引用后引用计数为: "
<< target->referenceCount() << std::endl;
for (unsigned int i = ; i<; ++i)
{
osg::ref_ptr<MonitoringTarget> subTarget =
new MonitoringTarget(i);
}
}