Add a mutex lock around the SharedStateManager

components/resource/scenemanager.cpp

@@ -357,7 +357,9 @@ namespace Resource
             loaded->accept(setFilterSettingsControllerVisitor);
 
             // share state
+            mSharedStateMutex.lock();
             osgDB::Registry::instance()->getOrCreateSharedStateManager()->share(loaded.get());
+            mSharedStateMutex.unlock();
 
             if (mIncrementalCompileOperation)
                 mIncrementalCompileOperation->add(loaded);

components/resource/scenemanager.hpp

@@ -89,6 +89,8 @@ namespace Resource
         void setUnRefImageDataAfterApply(bool unref);
 
     private:
+        OpenThreads::Mutex mSharedStateMutex;
+
         Resource::ImageManager* mImageManager;
         Resource::NifFileManager* mNifFileManager;