circumstances under which this bug occur are rather specific, but the
basic problem occurs when one translation unit other than libosg.so
constructs an object that is a subclass of osg::Shape and another
translation unit other than libosg.so tries to perform a dynamic_cast or
other RTTI-based operation on that object. Under these circumstances,
the RTTI operation will fail. In my case, the translation units involved
were an application and osgdb_ive.so. The application constructed a
scene graph that included instantiations of subclasses of osg::Shape.
Depending on how the user ran the application, it would write the scene
graph to an IVE file using osgDB::writeNodeFile(). The dynamic_cast
operations in DataOutputStream::writeShape() would fail on the first
subclass of osg::Shape that was encountered. This is because there were
two different RTTI data objects for all osg::Shape subclasses being
compared: one in the application and one in osgdb_ive.so.
The fix for this is simple. We must ensure that at least one member
function of each of the subclasses of the polymorphic type osg::Shape is
compiled into libosg.so so that there is exactly one RTTI object for
that type in libosg.so. Then, all code linking against libosg.so will
use that single RTTI object. The following message from a list archive
sort of explains the issue and the solution:
http://aspn.activestate.com/ASPN/Mail/Message/1688156
While the posting has to do with Boost.Python, the problem applies to
C++ libraries in general."
The fix was to convert the osg::State to use C pointers for the set of applied PerContexProgram objects, and use the osg::Oberver mechanism to avoid dangling pointers for being maintained in osg::State.
methods
getProjectionMatrixAsOrtho()
getProjectionMatrixAsFrustum()
getProjectionMatrixAsPerspective()
getViewMatrixAsLookAt() (2x)
are now const, as they only call const methods of osg::Matrixf/d.
"
returns true if (the extension string is supported or GL version is greater than or equal to a specified version) and
non extension disable is used. This makes it possible to disable extensions that are now
available as parts of the core OpenGL spec.
Updated Texture.cpp is use this method.
/** Convinience method that sets the update callback of the node if it doesn't exist, or nest it into the existing one. */
void addUpdateCallback(NodeCallback* nc);
/** Convinience method that removes a given callback from a node, even if that callback is nested. There is no error return in case the given callback is not found. */
void removeUpdateCallback(NodeCallback* nc);
... and the same for Event and Cull callbacks methods."
