Hi, I very like the capability of osg::Node to register any number of update, event and cull callbacks. This allows for a nice modular approach with each module registering callbacks for anything they wish without disturbing others.
I came to a problem that Camera can register just one Initial-,Pre-,Post-, and Final-DrawCallback. Surely, I can register my own "callback container" that would call all my registered callback. But that is not compatible with OSG- registered Callbacks, for instance OcclusionQueryNode would overwrite my callback container. Could we possibly make the similar approach for the camera as for osg::Node? I can volunteer to make the first iteration for osg- submissions, if the community and Robert thinks that it is a good idea. My idea for implementation would be to append ref_ptr<DrawCallback> _nestedCallback into the Camera::DrawCallback structure, append Camera::add*Callback() and Camera::remove*Callback() and make Camera::callCallbacks(DrawCallback *cb) with a parameter giving pointer to the first DrawCallback of Initial-,Pre-,Post-, and Final- DrawCallback list. An alternative would be to let the user call nested callbacks from DrawCallback::operator(), but as we would always want (probably) to call all the callbacks and never stop in the middle of the work, I personally like the first approach more and it is more compatibility-friendly, as users will not need to modify their existing callbacks to get the new multi-callback capability. But I am ok with any approach. Do you think it is a good idea? John _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
