Experimental option to build blender as a python module, rather then blender embedding python.

CMake build option WITH_PYTHON_MODULE, will build ./bin/bpy.so

This allows 'bpy' to be imported from python or other applications/IDE's which embed python, eg:
   python -c "import bpy ; bpy.ops.render.render(write_still=True)"

This runs in background mode and has similar restrictions to running a script:
   blender --background --python test.py

TODO:
 - install to site-packages with blender scripts
 - add support for imp.reload()

4 files changed, 72 insertions, 8 deletions

diff --git a/source/blender/python/intern/CMakeLists.txt b/source/blender/python/intern/CMakeLists.txt
index 5d1a086bc75..b73c9949ada 100644
--- a/source/blender/python/intern/CMakeLists.txt
+++ b/source/blender/python/intern/CMakeLists.txt
@@ -67,4 +67,8 @@ if(WITH_BUILDINFO)
 	add_definitions(-DBUILD_DATE)
 endif()
 
+if(WITH_PYTHON_MODULE)
+	add_definitions(-DWITH_PYTHON_MODULE)
+endif()
+
 blender_add_lib(bf_python "${SRC}" "${INC}")
diff --git a/source/blender/python/intern/bpy.c b/source/blender/python/intern/bpy.c
index 8076515b94b..02073f368e8 100644
--- a/source/blender/python/intern/bpy.c
+++ b/source/blender/python/intern/bpy.c
@@ -53,6 +53,8 @@
 
 #include "AUD_PyInit.h"
 
+PyObject *bpy_package_py= NULL;
+
 static char bpy_script_paths_doc[] =
 ".. function:: script_paths()\n"
 "\n"
@@ -161,7 +163,7 @@ static PyMethodDef meth_bpy_script_paths = {"script_paths", (PyCFunction)bpy_scr
 static PyMethodDef meth_bpy_blend_paths = {"blend_paths", (PyCFunction)bpy_blend_paths, METH_VARARGS|METH_KEYWORDS, bpy_blend_paths_doc};
 static PyMethodDef meth_bpy_user_resource = {"user_resource", (PyCFunction)bpy_user_resource, METH_VARARGS|METH_KEYWORDS, NULL};
 
-static void bpy_import_test(const char *modname)
+static PyObject *bpy_import_test(const char *modname)
 {
 	PyObject *mod= PyImport_ImportModuleLevel((char *)modname, NULL, NULL, NULL, 0);
 	if(mod) {
@@ -170,7 +172,9 @@ static void bpy_import_test(const char *modname)
 	else {
 		PyErr_Print();
 		PyErr_Clear();
-	}	
+	}
+
+	return mod;
 }
 
 /*****************************************************************************
@@ -235,5 +239,5 @@ void BPy_init_modules( void )
 	PyModule_AddObject(mod, meth_bpy_unregister_class.ml_name, (PyObject *)PyCFunction_New(&meth_bpy_unregister_class, NULL));
 
 	/* add our own modules dir, this is a python package */
-	bpy_import_test("bpy");
+	bpy_package_py= bpy_import_test("bpy");
 }
diff --git a/source/blender/python/intern/bpy.h b/source/blender/python/intern/bpy.h
index 76eef6ea4b9..90f21cb07b1 100644
--- a/source/blender/python/intern/bpy.h
+++ b/source/blender/python/intern/bpy.h
@@ -22,4 +22,4 @@
  * ***** END GPL LICENSE BLOCK ***** */
  
 void BPy_init_modules( void );
- 
+extern PyObject *bpy_package_py;
diff --git a/source/blender/python/intern/bpy_interface.c b/source/blender/python/intern/bpy_interface.c
index 4ae1b41bb89..d1773e5fd7a 100644
--- a/source/blender/python/intern/bpy_interface.c
+++ b/source/blender/python/intern/bpy_interface.c
@@ -157,6 +157,7 @@ void BPY_modules_update(bContext *C)
 }
 
 /* must be called before Py_Initialize */
+#ifndef WITH_PYTHON_MODULE
 static void bpy_python_start_path(void)
 {
 	char *py_path_bundle= BLI_get_folder(BLENDER_PYTHON, NULL);
@@ -195,8 +196,7 @@ static void bpy_python_start_path(void)
 		// printf("found python (wchar_t) '%ls'\n", py_path_bundle_wchar);
 	}
 }
-
-
+#endif
 
 void BPY_context_set(bContext *C)
 {
@@ -219,8 +219,9 @@ static struct _inittab bpy_internal_modules[]= {
 /* call BPY_context_set first */
 void BPY_python_start(int argc, const char **argv)
 {
+#ifndef WITH_PYTHON_MODULE
 	PyThreadState *py_tstate = NULL;
-	
+
 	/* not essential but nice to set our name */
 	static wchar_t bprogname_wchar[FILE_MAXDIR+FILE_MAXFILE]; /* python holds a reference */
 	utf8towchar(bprogname_wchar, bprogname);
@@ -252,8 +253,13 @@ void BPY_python_start(int argc, const char **argv)
 	
 	/* Initialize thread support (also acquires lock) */
 	PyEval_InitThreads();
+#else
+	(void)argc;
+	(void)argv;
 	
-	
+	PyImport_ExtendInittab(bpy_internal_modules);
+#endif
+
 	/* bpy.* and lets us import it */
 	BPy_init_modules();
 
@@ -281,8 +287,10 @@ void BPY_python_start(int argc, const char **argv)
 	
 	pyrna_alloc_types();
 
+#ifndef WITH_PYTHON_MODULE
 	py_tstate = PyGILState_GetThisThreadState();
 	PyEval_ReleaseThread(py_tstate);
+#endif
 }
 
 void BPY_python_end(void)
@@ -659,3 +667,51 @@ int BPY_context_member_get(bContext *C, const char *member, bContextDataResult *
 	return done;
 }
 
+
+#ifdef WITH_PYTHON_MODULE
+/* TODO, reloading the module isnt functional at the moment. */
+
+extern int main_python(int argc, const char **argv);
+static struct PyModuleDef bpy_proxy_def = {
+	PyModuleDef_HEAD_INIT,
+	"bpy",  /* m_name */
+	NULL,  /* m_doc */
+	0,  /* m_size */
+	NULL,  /* m_methods */
+	NULL,  /* m_reload */
+	NULL,  /* m_traverse */
+	NULL,  /* m_clear */
+	NULL,  /* m_free */
+};	
+
+PyMODINIT_FUNC
+PyInit_bpy(void)
+{
+	int argc= 0;
+	const char *argv[]={NULL};
+	
+	main_python(argc, argv);
+
+	/* initialized in BPy_init_modules() */
+	if(bpy_package_py) {
+		/* Problem:
+		 * 1) this init function is expected to have a private member defined - 'md_def'
+		 *    but this is only set for C defined modules (not py packages)
+		 *    so we cant return 'bpy_package_py' as is.
+		 *
+		 * 2) there is a 'bpy' C module for python to load which is basically all of blender,
+		 *    and there is scripts/bpy/__init__.py, 
+		 *    we may end up having to rename this module so there is no naming conflict here eg:
+		 *    'from blender import bpy' */
+		PyObject *bpy_proxy= PyModule_Create(&bpy_proxy_def);
+		PyDict_Update(PyModule_GetDict(bpy_proxy), PyModule_GetDict(bpy_package_py));
+		return bpy_proxy;
+	}
+	else {
+		PyErr_SetString(PyExc_RuntimeError, "could not import internal bpy package");
+		return NULL;
+	}
+	
+	
+}
+#endif