From Wang Rui, "I'd like to submit my inbuilt schema data support of

the OutputStream/InputStream implementations, which was just finished
last weekend with a few tests on Windows and Ubuntu. Hope it could
work and get more feedbacks soon.

I've added a new option "SchemaData" to the osg2 plugin. Developers
may test the new feature with the command line:

# osgconv cow.osg cow.osgb -O SchemaData

It will record all serializer properties used in the scene graph, at
the beginning of the generated file. And when osgviewer and user
applications is going to read the osgb file, the inbuilt data will be
automatically read and applied first, to keep backwards compatibility
partly. This will not affect osgb files generated with older versions.
"

include/osgDB/InputStream

@@ -161,6 +161,7 @@ protected:
     
     int _byteSwap;
     bool _useFloatMatrix;
+    bool _useSchemaData;
     bool _forceReadingImage;
     std::vector<std::string> _fields;
     osg::ref_ptr<InputIterator> _in;

include/osgDB/OutputStream

@@ -168,6 +168,8 @@ protected:
     ObjectMap _objectMap;
     
     WriteImageHint _writeImageHint;
+    bool _useSchemaData;
+    std::map<std::string, std::string> _inbuiltSchemaMap;
     std::vector<std::string> _fields;
     std::string _schemaName;
     std::string _compressorName;