From Martin Lavery and Robert Osfield, added fallbacks for when now command line args are provided.

examples/osgpick/osgpick.cpp

@@ -213,6 +213,9 @@ int main( int argc, char **argv )
 
     // read the scene from the list of file specified commandline args.
     osg::ref_ptr<osg::Node> scene = osgDB::readNodeFiles(arguments);
+     
+    // if not loaded assume no arguments passed in, try use default mode instead.
+    if (!scene) scene = osgDB::readNodeFile("fountain.osg");
 
     osg::ref_ptr<osg::Group> group = dynamic_cast<osg::Group*>(scene.get());
     if (!group)