From Wojciech Lewandowski, VirtualProgram example that illustrates how one can create a custom system for composing shaders within the scene graph.

examples/osgvirtualprogram/osgvirtualprogram.cpp

@@ -0,0 +1,41 @@
+#include <iostream>
+#include <osg/Geode>
+#include <osg/TexGen>
+#include <osg/Texture2D>
+#include <osg/MatrixTransform>
+#include <osgDB/ReadFile>
+#include <osgViewer/Viewer>
+
+extern osg::Node * CreateSimpleHierarchy( const char * file );
+extern osg::Node * CreateAdvancedHierarchy( const char * file );
+
+int main( int argc, char **argv )
+{
+    // construct the viewer.
+    osg::ArgumentParser arguments( &argc, argv );
+    osgViewer::Viewer viewer( arguments );
+
+    std::string filename = "cow.osg";
+    bool useAdvancedTechnique = arguments.read("-a") || arguments.read("--advanced") ;
+
+    if (arguments.argc()>1)
+    {
+        if (!arguments.isOption(1)) filename =  arguments[1];
+    }
+
+    // osg::Node * node = CreateSimpleHierarchy( file );
+    osg::Node * node = useAdvancedTechnique ?
+        CreateAdvancedHierarchy( filename.c_str() ) :
+        CreateSimpleHierarchy( filename.c_str() );
+
+    if ( !node ) {
+        osg::notify( osg::NOTICE ) << "Error, cannot read " << filename << std::endl;
+        return 1;
+    }    
+
+    viewer.setSceneData( node );
+    viewer.realize(  );
+    viewer.run();
+
+    return 0;
+}