NAME

       SoCallback — provides custom behavior during actions

INHERITS FROM

       SoBase > SoFieldContainer > SoNode > SoCallback

SYNOPSIS

       #include <Inventor/nodes/SoCallback.h>

     typedef void        SoCallbackCB(void *userData, SoAction *action)

          Methods from class SoCallback:

                         SoCallback()
     void                setCallback(SoCallbackCB *func, void *userData = NULL)
     static SoType       getClassTypeId()

          Methods from class SoNode:

     void                setOverride(SbBool state)
     SbBool              isOverride() const
     SoNode *            copy(SbBool copyConnections = FALSE) const
     virtual SbBool      affectsState() const
     static SoNode *     getByName(const SbName &name)
     static int          getByName(const SbName &name, SoNodeList &list)

          Methods from class SoFieldContainer:

     void                setToDefaults()
     SbBool              hasDefaultValues() const
     SbBool              fieldsAreEqual(const SoFieldContainer *fc) const
     void                copyFieldValues(const  SoFieldContainer  *fc,  SbBool  copyConnections =
                              FALSE)
     SbBool              set(const char *fieldDataString)
     void                get(SbString &fieldDataString)
     virtual int         getFields(SoFieldList &resultList) const
     virtual SoField *   getField(const SbName &fieldName) const
     SbBool              getFieldName(const SoField *field, SbName &fieldName) const
     SbBool              isNotifyEnabled() const
     SbBool              enableNotify(SbBool flag)

          Methods from class SoBase:

     void                ref()
     void                unref() const
     void                unrefNoDelete() const
     void                touch()
     virtual SoType      getTypeId() const
     SbBool              isOfType(SoType type) const
     virtual void        setName(const SbName &name)
     virtual SbName      getName() const

DESCRIPTION

       This node provides a general mechanism for  inserting  callback  functions  into  a  scene
       graph.  The  callback  function  registered  with the node is called each time the node is
       traversed while performing any scene graph action.  The  callback  function  is  passed  a
       pointer to the action being performed and a user data pointer registered with the callback
       function. You can use this node to make nonstandard OpenGL calls while rendering.  If  you
       do, be careful not to interfere with Inventor's use of OpenGL.

       If  you  use  a  callback  node  for  GL rendering, you should be careful to follow render
       caching rules. If your callback node can make different rendering calls each  time  it  is
       traversed,  it  cannot  be  cached.  In  such  a case, the node should invalidate any open
       caches, as in the following example:

          void
          myCallbackFunc(void *d, SoAction *action) {
              if (action->isOfType(SoGLRenderAction::getClassTypeId())) {
                              // Make my custom GL calls
                              ((MyClass *) d)->myRender();

                              // Invalidate the state so that a cache is not made
                              SoCacheElement::invalidate(action->getState());
              }
          }

METHODS

                         SoCallback()
          Creates a callback node with default settings.

     void                setCallback(SoCallbackCB *func, void *userData = NULL)
          Sets pointer to callback function and user data. By default, the  function  pointer  in
          the node is NULL and does nothing.

     static SoType       getClassTypeId()
          Returns type identifier for this class.

ACTION BEHAVIOR

       SoGLRenderAction, SoBoundingBoxAction, SoPickAction
          Calls the specified callback function for all actions.

FILE FORMAT/DEFAULTS

       Callback {
       }

SEE ALSO

       SoAction, SoCallbackAction, SoEventCallback

                                                                                SoCallback(3IV)()