From Jeremy Moles, import of the osgWidget NodeKit, sourced from the original http://osgwidget.googlecode.com/svn/trunk

Notes from Robert Osfield, I've merged osgWidget trunk, and added/changed CMakeLists.txt file to make it suitable for inclusion in the core OSG, and moved imagery/scripts/shaders out into OpenSceneGraph-Data

src/osgWidget/Python.cpp

@@ -0,0 +1,215 @@
+// -*-c++-*- osgWidget - Code by: Jeremy Moles (cubicool) 2007-2008
+// $Id: Python.cpp 59 2008-05-15 20:55:31Z cubicool $
+
+// Python.h needs to be included before anything else.
+#ifdef OSGWIDGET_USEPYTHON
+#include <Python.h>
+#endif
+
+#include <osgDB/FileUtils>
+#include <osgWidget/Python>
+#include <osgWidget/Box>
+#include <osgWidget/WindowManager>
+
+namespace osgWidget {
+
+// Our Python library.
+namespace py {
+#ifdef OSGWIDGET_USEPYTHON
+
+// TODO: Until I can find a way to move data around inside of the context, this will
+// have to do. I don't really like it, but I've got no choice.
+static PyObject* G_ERR = 0;
+
+PyObject* newWindow(PyObject* self, PyObject* args) {
+	PyObject*   buffer = 0;
+	const char* name   = 0;
+	int         width  = 0;
+	int         height = 0;
+
+	/*
+	if(PyArg_ParseTuple(args, "sO!ii", &name, &PyBuffer_Type, &buffer, &width, &height)) {
+		const void* buf = 0;
+		int         len = 0;
+
+		if(!PyObject_AsReadBuffer(buffer, &buf, &len)) {
+			// if(Database::instance().add(name, buf, width, height))
+			return Py_BuildValue("i", len);
+
+			// else PyErr_SetString(G_ERR, "Couldn't add image to database.");
+		}
+
+		else PyErr_SetString(G_ERR, "Couldn't read buffer data.");
+
+		return 0;
+	}
+	*/
+
+	PyErr_SetString(G_ERR, "still testing...");
+
+	return 0;
+}
+
+static PyMethodDef methods[] = {
+	{
+		"newWindow", newWindow, METH_VARARGS,
+		"docstring"
+	},
+	{ 0, 0, 0, 0 }
+};
+
+#endif
+}
+
+// A helper function for all those cases where we need to inform the user that there isn't
+// a LUA engine available.
+bool noPythonFail(const std::string& err) {
+	warn() << err << "; Python not compiled in library." << std::endl;
+
+	return false;
+}
+
+// Our "private", internal data.
+struct PythonEngineData {
+#ifdef OSGWIDGET_USEPYTHON
+	PythonEngineData():
+	mod  (0),
+	err  (0),
+	main (0) {
+	}
+
+	bool valid() const {
+		return mod && err && main;
+	}
+
+	PyObject* mod;
+	PyObject* err;
+	PyObject* main;
+#endif
+};
+
+PythonEngine::PythonEngine(WindowManager* wm):
+_wm(wm) {
+#ifdef OSGWIDGET_USEPYTHON
+	_data = new PythonEngineData();
+
+#else
+	_data = 0;
+#endif
+}
+
+bool PythonEngine::initialize() {
+#ifdef OSGWIDGET_USEPYTHON
+	Py_InitializeEx(0);
+
+	if(!_data->valid()) {
+		_data->mod  = Py_InitModule3("osgwidget", py::methods, "main docstring");
+		_data->err  = PyErr_NewException((char*)("osgwidget.error"), 0, 0);
+		_data->main = PyModule_GetDict(PyImport_AddModule("__main__"));
+
+		Py_INCREF(_data->err);
+
+		// TODO: ...sigh...
+		py::G_ERR = _data->err;
+
+		PyModule_AddObject(_data->mod, "error", _data->err);
+	}
+
+	return true;
+
+#else
+	return noPythonFail("Can't initialize the PythonEngine");
+#endif
+}
+
+bool PythonEngine::close() {
+#ifdef OSGWIDGET_USEPYTHON
+	if(_data->valid()) {
+		Py_DECREF(_data->err);
+
+		Py_Finalize();
+	}
+
+	delete _data;
+
+	return true;
+
+#else
+	return noPythonFail("Can't close the PythonEngine");
+#endif
+}
+
+bool PythonEngine::eval(const std::string& code) {
+#ifdef OSGWIDGET_USEPYTHON
+	PyObject* r = PyRun_String(code.c_str(), Py_file_input, _data->main, _data->main);
+
+	if(!r) {
+		r = PyErr_Occurred();
+
+		if(r) {
+			PyErr_Print();
+			PyErr_Clear();
+		}
+
+		return false;
+	}
+
+	return true;
+
+#else
+	return noPythonFail("Can't evaluate code in PythonEngine");
+#endif
+}
+
+bool PythonEngine::runFile(const std::string& filePath) {
+#ifdef OSGWIDGET_USEPYTHON
+	if(!osgDB::fileExists(filePath)) {
+		warn()
+			<< "Couldn't find file \"" << filePath << "\" for PythonEngine."
+			<< std::endl
+		;
+
+		return false;
+	}
+
+	FILE*     f = fopen(filePath.c_str(), "r");
+	PyObject* r = PyRun_File(f, filePath.c_str(), Py_file_input, _data->main, _data->main);
+
+	fclose(f);
+
+	if(!r) {
+		r = PyErr_Occurred();
+
+		if(r) {
+			// The following snippet lets us get the return code. That is: if the
+			// script is stopped with sys.exit() or similar. We could use this
+			// return code to do something sensible... later.
+			if(PyErr_ExceptionMatches(PyExc_SystemExit)) {
+				PyObject* ty = 0;
+				PyObject* er = 0;
+				PyObject* tr = 0;
+
+				PyErr_Fetch(&ty, &er, &tr);
+
+				Py_DECREF(ty);
+				Py_DECREF(er);
+				Py_DECREF(er);
+			}
+
+			else {
+				PyErr_Print();
+				PyErr_Clear();
+			}
+		}
+
+		return false;
+	}
+
+	return true;
+
+#else
+	return noPythonFail("Can't evaluate code in PythonEngine");
+#endif
+}
+
+}