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)()