pydrivers: 'frame' is now in the driver namespace,

- no need to link to scenes when using a frame from the pydriver, this made linking rigs for eg, quite messy.
- advantage that we get subframe values (where scenes from was fixed to a whole number).

source/blender/python/intern/bpy_driver.c

@@ -91,6 +91,29 @@ int bpy_pydriver_create_dict(void)
 	return 0;
 }
 
+/* note, this function should do nothing most runs, only when changing frame */
+static PyObject *bpy_pydriver_InternStr__frame= NULL;
+
+static void bpy_pydriver_update_dict(const float evaltime)
+{
+	/* not thread safe but neither is python */
+	static float evaltime_prev= FLT_MAX;
+
+	if (evaltime_prev != evaltime) {
+
+		/* currently only update the frame */
+		if (bpy_pydriver_InternStr__frame == NULL) {
+			bpy_pydriver_InternStr__frame= PyUnicode_FromString("frame");
+		}
+
+		PyDict_SetItem(bpy_pydriver_Dict,
+		               bpy_pydriver_InternStr__frame,
+		               PyFloat_FromDouble(evaltime));
+
+		evaltime_prev= evaltime;
+	}
+}
+
 /* Update function, it gets rid of pydrivers global dictionary, forcing
  * BPY_driver_exec to recreate it. This function is used to force
  * reloading the Blender text module "pydrivers.py", if available, so
@@ -110,6 +133,11 @@ void BPY_driver_reset(void)
 		bpy_pydriver_Dict= NULL;
 	}
 
+	if (bpy_pydriver_InternStr__frame) {
+		Py_DECREF(bpy_pydriver_InternStr__frame);
+		bpy_pydriver_InternStr__frame= NULL;
+	}
+
 	if (use_gil)
 		PyGILState_Release(gilstate);
 
@@ -139,7 +167,7 @@ static void pydriver_error(ChannelDriver *driver)
  * now release the GIL on python operator execution instead, using
  * PyEval_SaveThread() / PyEval_RestoreThread() so we dont lock up blender.
  */
-float BPY_driver_exec(ChannelDriver *driver)
+float BPY_driver_exec(ChannelDriver *driver, const float evaltime)
 {
 	PyObject *driver_vars=NULL;
 	PyObject *retval= NULL;
@@ -183,6 +211,10 @@ float BPY_driver_exec(ChannelDriver *driver)
 		}
 	}
 
+	/* update global namespace */
+	bpy_pydriver_update_dict(evaltime);
+
+
 	if (driver->expr_comp==NULL)
 		driver->flag |= DRIVER_FLAG_RECOMPILE;
 
@@ -246,6 +278,7 @@ float BPY_driver_exec(ChannelDriver *driver)
 		}
 	}
 
+
 #if 0 // slow, with this can avoid all Py_CompileString above.
 	/* execute expression to get a value */
 	retval= PyRun_String(expr, Py_eval_input, bpy_pydriver_Dict, driver_vars);

source/blender/python/intern/bpy_driver.h

@@ -33,7 +33,7 @@ int bpy_pydriver_create_dict(void);
 extern PyObject *bpy_pydriver_Dict;
 
 /* externals */
-float BPY_driver_exec(struct ChannelDriver *driver);
+float BPY_driver_exec(struct ChannelDriver *driver, const float evaltime);
 void BPY_driver_reset(void);
 
 #endif // BPY_DRIVER_H