Drivers: "Scripted Expression" drivers (i.e. PyDrivers) work again

Now it is possible to write a Python Expression using the variable names for driver targets (see mockup from initial commit) to substitute the appropriate values into the expression.

In the __global__ namespace for PyDriver evaluation, the following modules are available:
* __builtins__ - i.e. the builtin Python functions
* bpy - new Python API
* math or m - math module

For example:
Consider a driver with three targets, named: A, B, C
Now, you could write an expression like:
   C if A < 5 else B
or even:
   2*C if A < 5 or A > 20 else m.PI*B

Of course, you don't have to have three targets, the above was just an example.

TODO:
* Bring back way to load pydrivers.py
* Blender.Noise equivalent would be nice to have

P.S.  I hope I haven't made any terrible Python API coding errors here (i.e. mem leaks, etc.)

4 files changed, 9 insertions, 3 deletions

diff --git a/source/blender/blenkernel/BKE_fcurve.h b/source/blender/blenkernel/BKE_fcurve.h
index f973f86972d..3dd083476ce 100644
--- a/source/blender/blenkernel/BKE_fcurve.h
+++ b/source/blender/blenkernel/BKE_fcurve.h
@@ -33,6 +33,8 @@ struct ChannelDriver *fcurve_copy_driver(struct ChannelDriver *driver);
 void driver_free_target(struct ChannelDriver *driver, struct DriverTarget *dtar);
 struct DriverTarget *driver_add_new_target(struct ChannelDriver *driver);
 
+float driver_get_target_value(struct ChannelDriver *driver, struct DriverTarget *dtar);
+
 /* ************** F-Curve Modifiers *************** */
 
 /* F-Curve Modifier Type-Info (fmi):
diff --git a/source/blender/blenkernel/intern/anim_sys.c b/source/blender/blenkernel/intern/anim_sys.c
index 5b10f921d7d..30dcb383ef6 100644
--- a/source/blender/blenkernel/intern/anim_sys.c
+++ b/source/blender/blenkernel/intern/anim_sys.c
@@ -401,12 +401,12 @@ static short animsys_write_rna_setting (PointerRNA *ptr, char *path, int array_i
 					RNA_property_enum_set(&new_ptr, prop, (int)value);
 					break;
 				default:
-					break;
+					/* nothing can be done here... so it is unsuccessful? */
+					return 0;
 			}
 		}
 		
 		/* successful */
-		// XXX should the unhandled case also be successful?
 		return 1;
 	}
 	else {
diff --git a/source/blender/blenkernel/intern/depsgraph.c b/source/blender/blenkernel/intern/depsgraph.c
index a34f99d253f..8bd848ea9e6 100644
--- a/source/blender/blenkernel/intern/depsgraph.c
+++ b/source/blender/blenkernel/intern/depsgraph.c
@@ -326,6 +326,10 @@ static void dag_add_driver_relation(AnimData *adt, DagForest *dag, DagNode *node
 					/* check if bone... */
 					if ((ob->type==OB_ARMATURE) && dtar->rna_path && strstr(dtar->rna_path, "pose.pose_channels["))
 						dag_add_relation(dag, node1, node, isdata?DAG_RL_DATA_DATA:DAG_RL_DATA_OB, "Driver");
+					/* check if ob data */
+					else if (dtar->rna_path && strstr(dtar->rna_path, "data."))
+						dag_add_relation(dag, node1, node, isdata?DAG_RL_DATA_DATA:DAG_RL_DATA_OB, "Driver");
+					/* normal */
 					else
 						dag_add_relation(dag, node1, node, isdata?DAG_RL_OB_DATA:DAG_RL_OB_OB, "Driver");
 				}
diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c
index cce4f3a1217..49100be5216 100644
--- a/source/blender/blenkernel/intern/fcurve.c
+++ b/source/blender/blenkernel/intern/fcurve.c
@@ -650,7 +650,7 @@ ChannelDriver *fcurve_copy_driver (ChannelDriver *driver)
 /* Driver Evaluation -------------------------- */
 
 /* Helper function to obtain a value using RNA from the specified source (for evaluating drivers) */
-static float driver_get_target_value (ChannelDriver *driver, DriverTarget *dtar)
+float driver_get_target_value (ChannelDriver *driver, DriverTarget *dtar)
 {
 	PointerRNA id_ptr, ptr;
 	PropertyRNA *prop;