Added initial cut of basic scripting support, introducing an osg::Script object to wrap up the individual scripts, osg::ScriptCallback for assigning a Script as node callback and an osg::ScriptEngine base class that plugins implement to provided support for specific scripting languages.

Provided are lua, python and V8 (for javascript) plugins that just open up enough of a link to the respective libs to run a script, there is no scene graph <-> script communication in current implementation.

src/osg/CMakeLists.txt

@@ -137,6 +137,7 @@ SET(TARGET_H
     ${HEADER_PATH}/RenderInfo
     ${HEADER_PATH}/SampleMaski
     ${HEADER_PATH}/Scissor
+    ${HEADER_PATH}/ScriptEngine
     ${HEADER_PATH}/Sequence
     ${HEADER_PATH}/ShadeModel
     ${HEADER_PATH}/Shader
@@ -323,6 +324,7 @@ SET(TARGET_SRC
     Referenced.cpp
     SampleMaski.cpp
     Scissor.cpp
+    ScriptEngine.cpp
     Sequence.cpp
     ShadeModel.cpp
     Shader.cpp

src/osg/ScriptEngine.cpp

@@ -0,0 +1,50 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osg/ScriptEngine>
+#include <osg/UserDataContainer>
+
+using namespace osg;
+
+ScriptEngine* ScriptCallback::getScriptEngine(osg::NodePath& nodePath)
+{
+    if (!_script) return 0;
+
+    for(osg::NodePath::reverse_iterator itr = nodePath.rbegin();
+        itr != nodePath.rend();
+        ++itr)
+    {
+        osg::Node* node = *itr;
+        osg::UserDataContainer* udc = node->getUserDataContainer();
+        if (udc)
+        {
+            ScriptEngine* engine = dynamic_cast<ScriptEngine*>(udc->getUserObject(_script->getLanguage()));
+            if (engine) return engine;
+        }
+    }
+    return 0;
+}
+
+void ScriptCallback::operator()(Node* node, NodeVisitor* nv)
+{
+    ScriptEngine* engine = getScriptEngine(nv->getNodePath());
+    if (engine && _script.valid())
+    {
+        engine->run(_script.get());
+    }
+
+    // note, callback is responsible for scenegraph traversal so
+    // they must call traverse(node,nv) to ensure that the
+    // scene graph subtree (and associated callbacks) are traversed.
+    traverse(node,nv);
+}

src/osgDB/Registry.cpp

@@ -303,6 +303,7 @@ Registry::Registry()
     addFileExtensionAlias("frag", "glsl");
     addFileExtensionAlias("geom", "glsl");
 
+    addFileExtensionAlias("js", "V8");
 
 #if defined(DARWIN_IMAGEIO)
     addFileExtensionAlias("jpg",  "imageio");

src/osgPlugins/CMakeLists.txt

@@ -258,6 +258,23 @@ ADD_SUBDIRECTORY(pvr)
 ADD_SUBDIRECTORY(osc)
 ADD_SUBDIRECTORY(trk)
 
+
+####################################################
+#
+# ScriptEngines
+#
+IF (LUA_LIBRARIES AND LUA_INCLUDE_DIR)
+    ADD_SUBDIRECTORY(lua)
+ENDIF()
+
+IF (V8_FOUND)
+    ADD_SUBDIRECTORY(V8)
+ENDIF()
+
+IF (PYTHONLIBS_FOUND)
+    ADD_SUBDIRECTORY(python)
+ENDIF()
+
 ####################################################
 #
 # Device integration plugins

src/osgPlugins/V8/CMakeLists.txt

@@ -0,0 +1,13 @@
+SET(TARGET_H
+    V8ScriptEngine.h
+)
+SET(TARGET_SRC
+    V8ScriptEngine.cpp
+    ReaderWriterV8.cpp
+)
+
+SET(TARGET_EXTERNAL_LIBRARIES ${TARGET_EXTERNAL_LIBRARIES} ${V8_LIBRARY})
+INCLUDE_DIRECTORIES(${V8_INCLUDE_DIR} )
+
+#### end var setup  ###
+SETUP_PLUGIN(v8)

src/osgPlugins/V8/ReaderWriterV8.cpp

@@ -0,0 +1,72 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osgDB/FileNameUtils>
+#include <osgDB/FileUtils>
+#include <osgDB/Registry>
+
+#include "V8ScriptEngine.h"
+
+class ReaderWriterV8 : public osgDB::ReaderWriter
+{
+    public:
+
+        ReaderWriterV8()
+        {
+            supportsExtension("v8","JavaScript");
+            supportsExtension("js","JavaScript");
+        }
+
+        virtual const char* className() const { return "V8 JavaScript ScriptEngine plugin"; }
+
+        virtual ReadResult readObject(std::istream& fin,const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            osg::ref_ptr<osg::Script> script = new osg::Script;
+            script->setLanguage("js");
+
+            std::string str;
+            while(fin)
+            {
+                int c = fin.get();
+                if (c>=0 && c<=255)
+                {
+                    str.push_back(c);
+                }
+            }
+            script->setScript(str);
+
+            return script.release();
+        }
+
+        virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            if (file=="ScriptEngine.V8") return new v8::V8ScriptEngine();
+            if (file=="ScriptEngine.js") return new v8::V8ScriptEngine();
+
+            std::string ext = osgDB::getLowerCaseFileExtension(file);
+            if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;
+
+            std::string fileName = osgDB::findDataFile( file, options );
+            if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;
+
+            osgDB::ifstream istream(fileName.c_str(), std::ios::in);
+            if(!istream) return ReadResult::FILE_NOT_HANDLED;
+
+            return readObject(istream, options);
+        }
+
+};
+
+// now register with Registry to instantiate the above
+// reader/writer.
+REGISTER_OSGPLUGIN(v8, ReaderWriterV8)

src/osgPlugins/V8/V8ScriptEngine.cpp

@@ -0,0 +1,82 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include "V8ScriptEngine.h"
+
+using namespace v8;
+
+V8ScriptEngine::V8ScriptEngine():
+    osg::ScriptEngine("js"),
+    _isolate(0)
+{
+    initialize();
+}
+
+V8ScriptEngine::V8ScriptEngine(const V8ScriptEngine& rhs, const osg::CopyOp&):
+    osg::ScriptEngine("js"),
+    _isolate(0)
+{
+    initialize();
+}
+
+V8ScriptEngine::~V8ScriptEngine()
+{
+    _isolate->Dispose();
+    _isolate = 0;
+}
+
+void V8ScriptEngine::initialize()
+{
+    _isolate = v8::Isolate::New();
+
+}
+
+void V8ScriptEngine::run(osg::Script* script)
+{
+    if (!script || !_isolate) return;
+
+    v8::Locker locker(_isolate);
+    v8::Isolate::Scope isolate_scope(_isolate);
+
+    // Create a stack-allocated handle scope.
+    v8::HandleScope handle_scope;
+
+    v8::Handle<v8::ObjectTemplate> global = v8::ObjectTemplate::New();
+    _globalContext = v8::Context::New(NULL, global);
+    _globalTemplate = v8::Persistent<v8::ObjectTemplate>::New(global);
+
+    {
+        // Create a nested handle scope
+        v8::HandleScope local_handle_scope;
+
+        // Enter the global context
+        v8::Context::Scope context_scope(_globalContext);
+
+        // Create a string containing the JavaScript source code.
+        v8::Handle<v8::String> source = v8::String::New(script->getScript().c_str());
+
+        // Compile the source code.
+        v8::Handle<v8::Script> v8_script = v8::Script::Compile(source);
+
+        // Run the script to get the result.
+        v8::Handle<v8::Value> result = v8_script->Run();
+
+        // Convert the result to an ASCII string and print it.
+        v8::String::AsciiValue ascii(result);
+        printf("%s\n", *ascii);
+    }
+        
+    _globalTemplate.Dispose();
+    _globalContext.Dispose();
+
+}

src/osgPlugins/V8/V8ScriptEngine.h

@@ -0,0 +1,53 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef V8SCRIPTENGINE_H
+#define V8SCRIPTENGINE_H
+
+#include <osg/ScriptEngine>
+
+#include <v8.h>
+
+namespace v8
+{
+
+class V8ScriptEngine : public osg::ScriptEngine
+{
+    public:
+        V8ScriptEngine();
+        V8ScriptEngine(const V8ScriptEngine& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+
+        META_Object(v8, V8ScriptEngine)
+
+        virtual const std::string& getLanguage() const { return _language; }
+
+        /** run a Script.*/
+        virtual void run(osg::Script* script);
+
+        v8::Isolate* getIsolate() { return _isolate; }
+
+    protected:
+
+        void initialize();
+
+        virtual ~V8ScriptEngine();
+
+        v8::Isolate* _isolate;
+        v8::Persistent<v8::Context> _globalContext;
+        v8::Persistent<v8::ObjectTemplate> _globalTemplate;
+};
+
+
+}
+
+#endif

src/osgPlugins/lua/CMakeLists.txt

@@ -0,0 +1,13 @@
+SET(TARGET_H
+    LuaScriptEngine.h
+)
+SET(TARGET_SRC
+    LuaScriptEngine.cpp
+    ReaderWriterLua.cpp
+)
+
+SET(TARGET_EXTERNAL_LIBRARIES ${TARGET_EXTERNAL_LIBRARIES} ${LUA_LIBRARY})
+INCLUDE_DIRECTORIES(${LUA_INCLUDE_DIR} )
+
+#### end var setup  ###
+SETUP_PLUGIN(lua)

src/osgPlugins/lua/LuaScriptEngine.cpp

@@ -0,0 +1,51 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include "LuaScriptEngine.h"
+
+using namespace lua;
+
+LuaScriptEngine::LuaScriptEngine():
+    osg::ScriptEngine("lua"),
+    _lua(0)
+{
+    initialize();
+}
+
+LuaScriptEngine::LuaScriptEngine(const LuaScriptEngine& rhs, const osg::CopyOp&):
+    osg::ScriptEngine("lua"),
+    _lua(0)
+{
+    initialize();
+}
+
+LuaScriptEngine::~LuaScriptEngine()
+{
+    lua_close(_lua);
+}
+
+void LuaScriptEngine::initialize()
+{
+    _lua = lua_open();
+    luaL_openlibs(_lua);
+}
+
+void LuaScriptEngine::run(osg::Script* script)
+{
+    if (!script || !_lua) return;
+
+    if (luaL_dostring(_lua, script->getScript().c_str()))
+    {
+        OSG_NOTICE << "LuaScriptEngine::run(Script*) error: " << lua_tostring(_lua, -1) << std::endl;
+    }
+}

src/osgPlugins/lua/LuaScriptEngine.h

@@ -0,0 +1,56 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef LUASCRIPTENGINE_H
+#define LUASCRIPTENGINE_H
+
+#include <osg/ScriptEngine>
+
+extern "C" {
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+}
+
+namespace lua
+{
+
+class LuaScriptEngine : public osg::ScriptEngine
+{
+    public:
+        LuaScriptEngine();
+        LuaScriptEngine(const LuaScriptEngine& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+
+        META_Object(lua, LuaScriptEngine)
+
+        virtual const std::string& getLanguage() const { return _language; }
+
+        /** run a Script.*/
+        virtual void run(osg::Script* script);
+
+        /** get the lua_State object.*/
+        lua_State* getLuaState() { return _lua; }
+
+    protected:
+
+        void initialize();
+
+        virtual ~LuaScriptEngine();
+
+        lua_State* _lua;
+};
+
+
+}
+
+#endif

src/osgPlugins/lua/ReaderWriterLua.cpp

@@ -0,0 +1,70 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osgDB/FileNameUtils>
+#include <osgDB/FileUtils>
+#include <osgDB/Registry>
+
+#include "LuaScriptEngine.h"
+
+class ReaderWriterLua : public osgDB::ReaderWriter
+{
+    public:
+
+        ReaderWriterLua()
+        {
+            supportsExtension("lua","lua script");
+        }
+
+        virtual const char* className() const { return "Lua ScriptEngine plugin"; }
+
+        virtual ReadResult readObject(std::istream& fin,const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            osg::ref_ptr<osg::Script> script = new osg::Script;
+            script->setLanguage("lua");
+
+            std::string str;
+            while(fin)
+            {
+                int c = fin.get();
+                if (c>=0 && c<=255)
+                {
+                    str.push_back(c);
+                }
+            }
+            script->setScript(str);
+
+            return script.release();
+        }
+
+        virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            if (file=="ScriptEngine.lua") return new lua::LuaScriptEngine();
+
+            std::string ext = osgDB::getLowerCaseFileExtension(file);
+            if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;
+
+            std::string fileName = osgDB::findDataFile( file, options );
+            if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;
+
+            osgDB::ifstream istream(fileName.c_str(), std::ios::in);
+            if(!istream) return ReadResult::FILE_NOT_HANDLED;
+
+            return readObject(istream, options);
+        }
+
+};
+
+// now register with Registry to instantiate the above
+// reader/writer.
+REGISTER_OSGPLUGIN(lua, ReaderWriterLua)

src/osgPlugins/python/CMakeLists.txt

@@ -0,0 +1,13 @@
+SET(TARGET_H
+    PythonScriptEngine.h
+)
+SET(TARGET_SRC
+    PythonScriptEngine.cpp
+    ReaderWriterPython.cpp
+)
+
+SET(TARGET_EXTERNAL_LIBRARIES ${TARGET_EXTERNAL_LIBRARIES} ${PYTHON_LIBRARY})
+INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_DIR} )
+
+#### end var setup  ###
+SETUP_PLUGIN(python)

src/osgPlugins/python/PythonScriptEngine.cpp

@@ -0,0 +1,58 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include "PythonScriptEngine.h"
+
+using namespace python;
+
+PythonScriptEngine::PythonScriptEngine():
+    osg::ScriptEngine("python"),
+    _py_main(0)
+{
+    initialize();
+}
+
+PythonScriptEngine::PythonScriptEngine(const PythonScriptEngine& rhs, const osg::CopyOp&):
+    osg::ScriptEngine("python"),
+    _py_main(0)
+{
+    initialize();
+}
+
+PythonScriptEngine::~PythonScriptEngine()
+{
+    Py_Finalize();
+}
+
+void PythonScriptEngine::initialize()
+{
+    Py_InitializeEx(0);
+
+    _py_main = PyModule_GetDict(PyImport_AddModule("__main__"));
+}
+
+void PythonScriptEngine::run(osg::Script* script)
+{
+    if (!script || !_py_main) return;
+
+    PyObject* r = PyRun_String(script->getScript().c_str(), Py_file_input, _py_main, _py_main);
+
+    if(!r) {
+        r = PyErr_Occurred();
+
+        if(r) {
+            PyErr_Print();
+            PyErr_Clear();
+        }
+    }
+}

src/osgPlugins/python/PythonScriptEngine.h

@@ -0,0 +1,52 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef PYTHONSCRIPTENGINE_H
+#define PYTHONSCRIPTENGINE_H
+
+#include <osg/ScriptEngine>
+
+#include <Python.h>
+
+namespace python
+{
+
+class PythonScriptEngine : public osg::ScriptEngine
+{
+    public:
+        PythonScriptEngine();
+        PythonScriptEngine(const PythonScriptEngine& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
+
+        META_Object(lua, PythonScriptEngine)
+
+        virtual const std::string& getLanguage() const { return _language; }
+
+        /** run a Script.*/
+        virtual void run(osg::Script* script);
+
+        /** get the Python main object.*/
+        PyObject* getPythonMain() { return _py_main; }
+
+    protected:
+
+        void initialize();
+
+        virtual ~PythonScriptEngine();
+
+        PyObject* _py_main;
+
+};
+
+}
+
+#endif

src/osgPlugins/python/ReaderWriterPython.cpp

@@ -0,0 +1,70 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2013 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osgDB/FileNameUtils>
+#include <osgDB/FileUtils>
+#include <osgDB/Registry>
+
+#include "PythonScriptEngine.h"
+
+class ReaderWriterPython : public osgDB::ReaderWriter
+{
+    public:
+
+        ReaderWriterPython()
+        {
+            supportsExtension("python","python script");
+        }
+
+        virtual const char* className() const { return "Python ScriptEngine plugin"; }
+
+        virtual ReadResult readObject(std::istream& fin,const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            osg::ref_ptr<osg::Script> script = new osg::Script;
+            script->setLanguage("python");
+
+            std::string str;
+            while(fin)
+            {
+                int c = fin.get();
+                if (c>=0 && c<=255)
+                {
+                    str.push_back(c);
+                }
+            }
+            script->setScript(str);
+
+            return script.release();
+        }
+
+        virtual ReadResult readObject(const std::string& file, const osgDB::ReaderWriter::Options* options =NULL) const
+        {
+            if (file=="ScriptEngine.python") return new python::PythonScriptEngine();
+
+            std::string ext = osgDB::getLowerCaseFileExtension(file);
+            if (!acceptsExtension(ext)) return ReadResult::FILE_NOT_HANDLED;
+
+            std::string fileName = osgDB::findDataFile( file, options );
+            if (fileName.empty()) return ReadResult::FILE_NOT_FOUND;
+
+            osgDB::ifstream istream(fileName.c_str(), std::ios::in);
+            if(!istream) return ReadResult::FILE_NOT_HANDLED;
+
+            return readObject(istream, options);
+        }
+
+};
+
+// now register with Registry to instantiate the above
+// reader/writer.
+REGISTER_OSGPLUGIN(python, ReaderWriterPython)