PyDriver support for all RNA property types

Support for driver variables that don't resolve to numbers, eg:
objects, bones, curves... etc.

Without this, Python expressions to access this data needed to use an absolute path from `bpy.data`,
however this is inconvenient, breaks easily (based on naming) and wouldn't set the dependencies correctly.

4 files changed, 135 insertions, 6 deletions

diff --git a/source/blender/python/intern/CMakeLists.txt b/source/blender/python/intern/CMakeLists.txt
index fa7c94025f7..2715d2c5992 100644
--- a/source/blender/python/intern/CMakeLists.txt
+++ b/source/blender/python/intern/CMakeLists.txt
@@ -71,6 +71,7 @@ set(SRC
 	bpy_rna_anim.c
 	bpy_rna_array.c
 	bpy_rna_callback.c
+	bpy_rna_driver.c
 	bpy_rna_id_collection.c
 	bpy_traceback.c
 	bpy_util.c
@@ -99,6 +100,7 @@ set(SRC
 	bpy_rna.h
 	bpy_rna_anim.h
 	bpy_rna_callback.h
+	bpy_rna_driver.h
 	bpy_rna_id_collection.h
 	bpy_traceback.h
 	bpy_util.h
diff --git a/source/blender/python/intern/bpy_driver.c b/source/blender/python/intern/bpy_driver.c
index dd1b4eae61b..f9c0982a4c3 100644
--- a/source/blender/python/intern/bpy_driver.c
+++ b/source/blender/python/intern/bpy_driver.c
@@ -42,10 +42,13 @@
 #include "BKE_fcurve.h"
 #include "BKE_global.h"
 
+#include "bpy_rna_driver.h"  /* for pyrna_driver_get_variable_value */
+
 #include "bpy_driver.h"
 
 extern void BPY_update_rna_module(void);
 
+#define USE_RNA_AS_PYOBJECT
 
 /* for pydrivers (drivers using one-line Python expressions to express relationships between targets) */
 PyObject *bpy_pydriver_Dict = NULL;
@@ -262,12 +265,24 @@ float BPY_driver_exec(ChannelDriver *driver, const float evaltime)
 	driver_vars = PyDict_New();
 	for (dvar = driver->variables.first, i = 0; dvar; dvar = dvar->next) {
 		PyObject *driver_arg = NULL;
-		float tval = 0.0f;
-		
-		/* try to get variable value */
-		tval = driver_get_variable_value(driver, dvar);
-		driver_arg = PyFloat_FromDouble((double)tval);
-		
+
+	/* support for any RNA data */
+#ifdef USE_RNA_AS_PYOBJECT
+		if (dvar->type == DVAR_TYPE_SINGLE_PROP) {
+			driver_arg = pyrna_driver_get_variable_value(driver, &dvar->targets[0]);
+
+			if (driver_arg == NULL) {
+				driver_arg = PyFloat_FromDouble(0.0);
+			}
+		}
+		else
+#endif
+		{
+			/* try to get variable value */
+			float tval = driver_get_variable_value(driver, dvar);
+			driver_arg = PyFloat_FromDouble((double)tval);
+		}
+
 		/* try to add to dictionary */
 		/* if (PyDict_SetItemString(driver_vars, dvar->name, driver_arg)) { */
 		if (PyDict_SetItem(driver_vars, PyTuple_GET_ITEM(expr_vars, i++), driver_arg) < 0) {
diff --git a/source/blender/python/intern/bpy_rna_driver.c b/source/blender/python/intern/bpy_rna_driver.c
new file mode 100644
index 00000000000..482508a8d85
--- /dev/null
+++ b/source/blender/python/intern/bpy_rna_driver.c
@@ -0,0 +1,79 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_rna_driver.c
+ *  \ingroup pythonintern
+ *
+ * This file defines utility functions that use the RNA API, from PyDrivers.
+ */
+
+#include <Python.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_utildefines.h"
+
+#include "BKE_fcurve.h"
+
+#include "RNA_access.h"
+
+#include "bpy_rna.h"
+
+#include "bpy_rna_driver.h"  /* own include */
+
+
+/**
+ * A version of #driver_get_variable_value which returns a PyObject.
+ */
+PyObject *pyrna_driver_get_variable_value(
+        struct ChannelDriver *driver, struct DriverTarget *dtar)
+{
+	PyObject *driver_arg = NULL;
+	PointerRNA ptr;
+	PropertyRNA *prop = NULL;
+	int index;
+
+	if (driver_get_variable_property(driver, dtar, &ptr, &prop, &index)) {
+		if (prop) {
+			if (index != -1) {
+				if (index < RNA_property_array_length(&ptr, prop) && index >= 0) {
+					/* object, property & index */
+					driver_arg = pyrna_array_index(&ptr, prop, index);
+				}
+				else {
+					/* out of range, pass */
+				}
+			}
+			else {
+				/* object & property */
+				driver_arg = pyrna_prop_to_py(&ptr, prop);
+			}
+		}
+		else {
+			/* object only */
+			driver_arg = pyrna_struct_CreatePyObject(&ptr);
+		}
+	}
+	else {
+		/* can't resolve path, pass */
+	}
+
+	return driver_arg;
+}
diff --git a/source/blender/python/intern/bpy_rna_driver.h b/source/blender/python/intern/bpy_rna_driver.h
new file mode 100644
index 00000000000..8deac2e4384
--- /dev/null
+++ b/source/blender/python/intern/bpy_rna_driver.h
@@ -0,0 +1,33 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#ifndef __BPY_RNA_DRIVER_H__
+#define __BPY_RNA_DRIVER_H__
+
+/** \file blender/python/intern/bpy_rna_driver.h
+ *  \ingroup pythonintern
+ */
+
+struct ChannelDriver;
+struct DriverTarget;
+
+PyObject *pyrna_driver_get_variable_value(struct ChannelDriver *driver, struct DriverTarget *dtar);
+
+#endif  /* __BPY_RNA_DRIVER_H__ */