Open Inventor中SoWriteAction扩展

 

The following example shows the basic outline on how to set up your own extension action class:

 

  // This is sample code on how you can get progress indication on Coin  // export operations by extending the library with your own action  // class. The new class inherits SoWriteAction. The code is presented  // as a stand-alone example.  //  // The general technique is to inherit SoWriteAction and override it's  // "entry point" into each node of the scenegraph. The granularity of  // the progress callbacks is on a per-node basis, which should usually  // be good enough.  #include <Inventor/SoDB.h>  #include <Inventor/actions/SoWriteAction.h>  #include <Inventor/nodes/SoSeparator.h>  class MyWriteAction : public SoWriteAction {    SO_ACTION_HEADER(SoWriteAction);  public:    MyWriteAction(SoOutput * out);    virtual ~MyWriteAction();    static void initClass(void);  protected:    virtual void beginTraversal(SoNode * node);  private:    static void actionMethod(SoAction *, SoNode *);    int nrnodes;    int totalnrnodes;  };  SO_ACTION_SOURCE(MyWriteAction);  MyWriteAction::MyWriteAction(SoOutput * out)    : SoWriteAction(out)  {    SO_ACTION_CONSTRUCTOR(MyWriteAction);  }  MyWriteAction::~MyWriteAction()  {  }  void  MyWriteAction::initClass(void)  {    SO_ACTION_INIT_CLASS(MyWriteAction, SoWriteAction);    SO_ACTION_ADD_METHOD(SoNode, MyWriteAction::actionMethod);  }  void  MyWriteAction::beginTraversal(SoNode * node)  {    this->nrnodes = 0;    this->totalnrnodes = 0;    SoWriteAction::beginTraversal(node);  }  void  MyWriteAction::actionMethod(SoAction * a, SoNode * n)  {    // To abort the export process in mid-writing, we could just avoid    // calling in to the SoNode::writeS() method.    SoNode::writeS(a, n);    MyWriteAction * mwa = (MyWriteAction *)a;    SoOutput * out = mwa->getOutput();    if (out->getStage() == SoOutput::COUNT_REFS) {      mwa->totalnrnodes++;    }    else { //  (out->getStage() == SoOutput::WRITE)      mwa->nrnodes++;      SbString s;      s.sprintf(" # wrote node %p (%d/%d) /n", n, mwa->nrnodes, mwa->totalnrnodes);      out->write(s.getString());    }  }  int  main(int argc, char ** argv)  {    if (argc < 2) {      (void)fprintf(stderr, "/n/nUsage: %s <filename>/n/n", argv[0]);      exit(1);    }    SoDB::init();    MyWriteAction::initClass();    SoInput in;    if (!in.openFile(argv[1])) { exit(1); }    SoSeparator * root = SoDB::readAll(&in);    if (!root) { exit(1); }    root->ref();    SoOutput out;    MyWriteAction mwa(&out);    mwa.apply(root);    root->unref();    return 0;  }