Using New Action Classes

Like nodes, action classes must be initialized before any instances can be constructed. Also note that before you can add a method to the method list, you must initialize both the action class and the node class involved.

The example below reads in a scene graph from the file volume.iv and applies the GetVolumeAction action to it, printing the resulting volume.

Example : PrintVolume.c++

#include <Inventor/SoDB.h>
#include <Inventor/SoInput.h>
#include <Inventor/SoInteraction.h>
#include <Inventor/nodes/SoSeparator.h>
 
// Header file for new action class
#include "GetVolumeAction.h"
 
main()
{
  // Initialize Inventor
  SoInteraction::init();
 
  // Initialize the new action class
  GetVolumeAction::initClass();
 
  // Open the file and read the scene
  SoInput myInput;
  SoSeparator* root;
  if ( !myInput.openFile( "volume.iv" ) )
  {
    fprintf( stderr, "Can't open \"volume.iv\" for reading\n" );
    return 1;
  }
  root = SoDB::readAll( &myInput );
  if ( root == NULL )
  {
    printf( "Couldn't read scene from \"volume.iv\"\n" );
    return 2;
  }
  root->ref();
 
  // Compute the volume: apply a GetVolumeAction to the root
  GetVolumeAction va;
  va.apply( root );
 
  root->unref();
 
  // Print the result
  printf( "Total volume = %g\n", va.getVolume() );
 
  GetVolumeAction::exitClass();
  SoInteraction::finish();
 
  return 0;
}