From Guillaume Chouvenc, "I have added the file StateAttribute.cpp in src/osgPlugins/osg

to support the reading and writing of StateAttribute Callback
in osg files.
"

src/osgPlugins/osg/CMakeLists.txt

@@ -61,6 +61,7 @@ ShadeModel.cpp
 Shader.cpp
 Shape.cpp
 ShapeDrawable.cpp
+StateAttribute.cpp
 StateSet.cpp
 Stencil.cpp
 Switch.cpp

src/osgPlugins/osg/StateAttribute.cpp

@@ -0,0 +1,81 @@
+#include "osg/StateAttribute"
+
+#include "osgDB/Registry"
+#include "osgDB/Input"
+#include "osgDB/Output"
+
+using namespace osg;
+using namespace osgDB;
+using namespace std;
+
+// forward declare functions to use later.
+bool StateAttribute_readLocalData(Object& obj, Input& fr);
+bool StateAttribute_writeLocalData(const Object& obj, Output& fw);
+
+// register the read and write functions with the osgDB::Registry.
+osg::StateAttribute* g_stateAttribute = 0; 
+RegisterDotOsgWrapperProxy g_StateAttributeProxy
+(
+    g_stateAttribute, // no instance, osg::StateAttribute is an abstract class.
+    "StateAttribute",
+    "Object StateAttribute",
+    &StateAttribute_readLocalData,
+    &StateAttribute_writeLocalData
+);
+
+
+bool StateAttribute_readLocalData(Object& obj, Input& fr)
+{
+    bool iteratorAdvanced = false;
+    StateAttribute& stateAttribute = static_cast<StateAttribute&>(obj);
+
+    static ref_ptr<StateAttribute::Callback> s_callback = new osg::StateAttribute::Callback;
+    while (fr.matchSequence("UpdateCallback {"))
+    {
+        int entry = fr[0].getNoNestedBrackets();
+        fr += 2;
+        StateAttribute::Callback* callback = dynamic_cast<StateAttribute::Callback*>(fr.readObjectOfType(*s_callback));
+        if (callback) {
+            stateAttribute.setUpdateCallback(callback);
+        }
+        iteratorAdvanced = true;
+    }
+
+    while (fr.matchSequence("EventCallback {"))
+    {
+        int entry = fr[0].getNoNestedBrackets();
+        fr += 2;
+        StateAttribute::Callback* callback = dynamic_cast<StateAttribute::Callback*>(fr.readObjectOfType(*s_callback));
+        if (callback) {
+            stateAttribute.setEventCallback(callback);
+        }
+        iteratorAdvanced = true;
+    }
+
+    return iteratorAdvanced;
+}
+
+bool StateAttribute_writeLocalData(const Object& obj,Output& fw)
+{
+    const StateAttribute& stateAttribute = static_cast<const StateAttribute&>(obj);
+
+    if (stateAttribute.getUpdateCallback())
+    {
+        fw.indent() << "UpdateCallback {" << std::endl;
+        fw.moveIn();
+        fw.writeObject(*stateAttribute.getUpdateCallback());
+        fw.moveOut();
+        fw.indent() << "}" << std::endl;
+    }
+
+    if (stateAttribute.getEventCallback())
+    {
+        fw.indent() << "EventCallback {" << std::endl;
+        fw.moveIn();
+        fw.writeObject(*stateAttribute.getEventCallback());
+        fw.moveOut();
+        fw.indent() << "}" << std::endl;
+    }
+
+    return true;
+}