NAME
SoCallback -
The SoCallback class is a node type which provides a means of setting
callback hooks in the scene graph.
By inserting SoCallback nodes in a scene graph, the application
programmer can set up functions to be executed at certain points in the
traversal.
SYNOPSIS
#include <Inventor/nodes/SoCallback.h>
Inherits SoNode.
Public Member Functions
SoCallback (void)
void setCallback (SoCallbackCB *function, void *userdata=NULL)
virtual void doAction (SoAction *action)
virtual void callback (SoCallbackAction *action)
virtual void GLRender (SoGLRenderAction *action)
virtual void getBoundingBox (SoGetBoundingBoxAction *action)
virtual void getMatrix (SoGetMatrixAction *action)
virtual void handleEvent (SoHandleEventAction *action)
virtual void pick (SoPickAction *action)
virtual void search (SoSearchAction *action)
virtual void write (SoWriteAction *action)
virtual void getPrimitiveCount (SoGetPrimitiveCountAction *action)
Static Public Member Functions
static void initClass (void)
Protected Member Functions
virtual ~SoCallback ()
virtual void copyContents (const SoFieldContainer *from, SbBool
copyconnections)
Detailed Description
The SoCallback class is a node type which provides a means of setting
callback hooks in the scene graph.
By inserting SoCallback nodes in a scene graph, the application
programmer can set up functions to be executed at certain points in the
traversal.
The callback function will be executed during traversal of any action,
so check the type of the action argument of the callback function if
you only want to run your code at specific actions.
FILE FORMAT/DEFAULTS:
Callback {
}
Constructor & Destructor Documentation
SoCallback::SoCallback (void) Constructor.
SoCallback::~SoCallback () [protected, virtual] Destructor.
Member Function Documentation
void SoCallback::initClass (void) [static] Sets up initialization for data
common to all instances of this class, like submitting necessary
information to the Coin type system.
Reimplemented from SoNode.
void SoCallback::setCallback (SoCallbackCB * function, void * userdata =
NULL) Set up the function to call at traversal of this node. userdata
will be passed back as the first argument of the callback function.
Setting function to NULL removes the previously set callback function.
If you want a callback only for a specific action, you must (in your
callback function) remember to check which action invoked the callback,
for instance like this:
void mycallback(void * userdata, SoAction * action)
{
if (action->isOfType(SoGLRenderAction::getClassTypeId())) {
// do stuff specific for GL rendering here.
}
}
Please note that SoCallback nodes under a Separator might be included
in a cache. Cached nodes are not traversed, and you’ll not receive any
callbacks. If you want to make sure that your callback is called every
time the scene graph is rendered, you must invalidate the render cache
in your callback:
void mycallback(void * userdata, SoAction * action)
{
if (action->isOfType(SoGLRenderAction::getClassTypeId())) {
SoCacheElement::invalidate(action->getState());
}
}
If you want to invalidate all caches (for instance also the bounding
box cache), you can do this in your callback:
void mycallback(void * userdata, SoAction * action)
{
SoState * state = action->getState();
if (state->isElementEnabled(SoCacheElement::getClassStackIndex())) {
SoCacheElement::invalidate(state);
}
}
void SoCallback::doAction (SoAction * action) [virtual] This function
performs the typical operation of a node for any action.
Reimplemented from SoNode.
void SoCallback::callback (SoCallbackAction * action) [virtual] Action
method for SoCallbackAction.
Simply updates the state according to how the node behaves for the
render action, so the application programmer can use the
SoCallbackAction for extracting information about the scene graph.
Reimplemented from SoNode.
void SoCallback::GLRender (SoGLRenderAction * action) [virtual] Action
method for the SoGLRenderAction.
This is called during rendering traversals. Nodes influencing the
rendering state in any way or who wants to throw geometry primitives at
OpenGL overrides this method.
Reimplemented from SoNode.
void SoCallback::getBoundingBox (SoGetBoundingBoxAction * action) [virtual]
Action method for the SoGetBoundingBoxAction.
Calculates bounding box and center coordinates for node and modifies
the values of the action to encompass the bounding box for this node
and to shift the center point for the scene more towards the one for
this node.
Nodes influencing how geometry nodes calculates their bounding box also
overrides this method to change the relevant state variables.
Reimplemented from SoNode.
void SoCallback::getMatrix (SoGetMatrixAction * action) [virtual] Action
method for SoGetMatrixAction.
Updates action by accumulating with the transformation matrix of this
node (if any).
Reimplemented from SoNode.
void SoCallback::handleEvent (SoHandleEventAction * action) [virtual]
Action method for SoHandleEventAction.
Inspects the event data from action, and processes it if it is
something which this node should react to.
Nodes influencing relevant state variables for how event handling is
done also overrides this method.
Reimplemented from SoNode.
void SoCallback::pick (SoPickAction * action) [virtual] Action method for
SoPickAction.
Does common processing for SoPickAction action instances.
Reimplemented from SoNode.
void SoCallback::search (SoSearchAction * action) [virtual] Action method
for SoSearchAction.
Compares the search criteria from the action to see if this node is a
match. Searching is done by matching up all criteria set up in the
SoSearchAction -- if any of the requested criteria is a miss, the
search is not deemed successful for the node.
See also:
SoSearchAction
Reimplemented from SoNode.
void SoCallback::write (SoWriteAction * action) [virtual] Action method for
SoWriteAction.
Writes out a node object, and any connected nodes, engines etc, if
necessary.
Reimplemented from SoNode.
void SoCallback::getPrimitiveCount (SoGetPrimitiveCountAction * action)
[virtual] Action method for the SoGetPrimitiveCountAction.
Calculates the number of triangle, line segment and point primitives
for the node and adds these to the counters of the action.
Nodes influencing how geometry nodes calculates their primitive count
also overrides this method to change the relevant state variables.
Reimplemented from SoNode.
void SoCallback::copyContents (const SoFieldContainer * from, SbBool
copyconnections) [protected, virtual] Makes a deep copy of all data of
from into this instance, except external scenegraph references if
copyconnections is FALSE.
This is the protected method that should be overridden by extension
node / engine / dragger / whatever subclasses which needs to account
for internal data that are not handled automatically.
For copying nodes from application code, you should not invoke this
function directly, but rather call the SoNode::copy() function:
SoNode * mynewnode = templatenode->copy();
The same also goes for engines.
Make sure that when you override the copyContents() method in your
extension class that you also make it call upwards to it’s parent
superclass in the inheritance hierarchy, as copyContents() in for
instance SoNode and SoFieldContainer does important work. It should go
something like this:
void
MyCoinExtensionNode::copyContents(const SoFieldContainer * from,
SbBool copyconnections)
{
// let parent superclasses do their thing (copy fields, copy
// instance name, etc etc)
SoNode::copyContents(from, copyconnections);
// [..then copy internal data..]
}
Reimplemented from SoNode.
Author
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