OSG节点访问和遍历

遍历节点树：
osg::Node类中有两个辅助函数：

1void ascend(NodeVisitor& nv)     //虚函数，向上一级节点推进访问器
2void traverse(NodeVisitor& nv)   //虚函数，向下一级节点推进访问器
3NodeVisitor的traverse()函数实现如下：
4inline void traverse(Node& node)
5{
6    if (_traversalMode == TRAVERSE_PARENTS)
7    {
8        node.ascend(*this);
9    }
10    else if (_traversalMode != TRAVERSE_NONE)
11    {
12        node.traverse(*this);
13    }
14}
15
16#include <osg/Node>
17#include <osgDB/ReadFile>
18#include <iostream>
19
20using namespace std;
21
22class InfoVisitor: public osg::NodeVisitor
23{
24public:
25    InfoVisitor()
26        :osg::NodeVisitor(TRAVERSE_ALL_CHILDREN), _indent(0)
27    {}
28
29    virtual void apply(osg::Node& node)
30    {
31        for(int i = 0; i < _indent; i++)  cout << "    ";
32        cout << "[" << _indent << "]"<< node.libraryName()
33               << "::" << node.className() << endl;
34
35        _indent++;
36        traverse(node);
37        _indent--;
38
39       for(int i = 0; i < _indent; i++)  cout << "    ";
40        cout << "[" << _indent << "] "<< node.libraryName()
41               << "::" << node.className() << endl;
42    }
43
44    virtual void apply(osg::Geode& node)
45    {
46        for(int i = 0; i < _indent; i++)  cout << "    ";
47        cout << "[" << _indent << "] "<< node.libraryName()
48                << "::" << node.className() << endl;
49
50        _indent++;
51
52        for(unsigned int n = 0; n < node.getNumDrawables(); n++)
53        {
54            osg::Drawable* draw = node.getDrawable(n);
55            if(!draw)
56                continue;
57            for(int i = 0; i <  _indent; i++)  cout << "    ";
58            cout << "[" << _indent << "]" << draw->libraryName() << "::" 
59                   << draw->className() << endl;
60        }
61
62        traverse(node);
63        _indent--;
64
65        for(int i = 0; i < _indent; i++)  cout << "    ";
66        cout << "[" << _indent << "]"<< node.libraryName()
67                << "::" << node.className() << endl;
68    }
69private:
70    int _indent;
71};
72
73int main(int argc, char** argv)
74{
75    osg::ArgumentParser  parser(&argc, argv);
76    osg::Node* root = osgDB::readNodeFiles(parser);
77
78    if(!root)
79    {
80        root = osgDB::readNodeFile("avatar.osg");
81    }
82
83    InfoVisitor infoVisitor;
84    if(root)
85    {
86        root->accept(infoVisitor);
87    }
88
89    system("pause");
90    return 0;
91}

转自：https://www.cnblogs.com/hzhg/archive/2010/12/17/1908764.html