Driver Scripting:

Added RNA functions for adding and removing Driver Targets. Unfortunately, I couldn't do this by simply adding callbacks for the add/remove of the collection, as I've had to add to extra RNA functions to do that.

Example usage - driving Lamp Distance with Cube LocZ:
myOb= bpy.data.objects["Lamp"]
myOb.driver_add("data.distance")

# drivers is list of F-Curves that have driver data
drivers= myOb.animation_data.drivers
distDriver= drivers[0].driver 

dtar= distDriver.add_target("ctrl1")
dtar.id_type= 'OBJECT'
dtar.id= bpy.data.objects["Cube"]
dtar.rna_path= "location"
dtar.array_index= 2

5 files changed, 99 insertions, 3 deletions

diff --git a/source/blender/editors/space_graph/graph_buttons.c b/source/blender/editors/space_graph/graph_buttons.c
index e2eb40b1137..b5d69934ad5 100644
--- a/source/blender/editors/space_graph/graph_buttons.c
+++ b/source/blender/editors/space_graph/graph_buttons.c
@@ -259,7 +259,7 @@ static void driver_delete_var_cb (bContext *C, void *driver_v, void *dtar_v)
 	ChannelDriver *driver= (ChannelDriver *)driver_v;
 	DriverTarget *dtar= (DriverTarget *)dtar_v;
 	
-	/* add a new var */
+	/* remove the active target */
 	driver_free_target(driver, dtar);
 }
 
@@ -341,7 +341,7 @@ static void graph_panel_drivers(const bContext *C, Panel *pa)
 	/* add driver target variables */
 	col= uiLayoutColumn(pa->layout, 0);
 	block= uiLayoutGetBlock(col);
-		but= uiDefBut(block, BUT, B_IPO_DEPCHANGE, "Add Variable", 0, 0, 10*UI_UNIT_X, UI_UNIT_Y, NULL, 0.0, 0.0, 0, 0, "Add a new target variable for this Driver");
+		but= uiDefBut(block, BUT, B_IPO_DEPCHANGE, "Add Target", 0, 0, 10*UI_UNIT_X, UI_UNIT_Y, NULL, 0.0, 0.0, 0, 0, "Add a new target variable for this Driver");
 		uiButSetFunc(but, driver_add_var_cb, driver, NULL);
 	
 	/* loop over targets, drawing them */
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 3bad6e13453..6f1e61e6869 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -1995,7 +1995,7 @@ RNAProcessItem PROCESS_ITEMS[]= {
 	{"rna_context.c", NULL, RNA_def_context},
 	{"rna_controller.c", NULL, RNA_def_controller},
 	{"rna_curve.c", NULL, RNA_def_curve},
-	{"rna_fcurve.c", NULL, RNA_def_fcurve},
+	{"rna_fcurve.c", "rna_fcurve_api.c", RNA_def_fcurve},
 	{"rna_fluidsim.c", NULL, RNA_def_fluidsim},
 	{"rna_gpencil.c", NULL, RNA_def_gpencil},
 	{"rna_group.c", NULL, RNA_def_group},
diff --git a/source/blender/makesrna/intern/rna_fcurve.c b/source/blender/makesrna/intern/rna_fcurve.c
index e69e2cd0e2c..a914deb37a6 100644
--- a/source/blender/makesrna/intern/rna_fcurve.c
+++ b/source/blender/makesrna/intern/rna_fcurve.c
@@ -83,6 +83,7 @@ static StructRNA *rna_FModifierType_refine(struct PointerRNA *ptr)
 
 /* ****************************** */
 
+#include "BKE_fcurve.h"
 #include "BKE_depsgraph.h"
 
 static void rna_ChannelDriver_update_data(bContext *C, PointerRNA *ptr)
@@ -610,8 +611,12 @@ static void rna_def_channeldriver(BlenderRNA *brna)
 	/* Collections */
 	prop= RNA_def_property(srna, "targets", PROP_COLLECTION, PROP_NONE);
 	RNA_def_property_collection_sdna(prop, NULL, "targets", NULL);
+	RNA_def_property_collection_funcs(prop, NULL, NULL, NULL, NULL, NULL, NULL, NULL, "add_target", "remove_target");
 	RNA_def_property_struct_type(prop, "DriverTarget");
 	RNA_def_property_ui_text(prop, "Target Variables", "Properties acting as targets for this driver.");
+	
+	/* Functions */
+	RNA_api_drivers(srna);
 }
 
 /* *********************** */
diff --git a/source/blender/makesrna/intern/rna_fcurve_api.c b/source/blender/makesrna/intern/rna_fcurve_api.c
new file mode 100644
index 00000000000..12ffb3e26fb
--- /dev/null
+++ b/source/blender/makesrna/intern/rna_fcurve_api.c
@@ -0,0 +1,90 @@
+/**
+ * ***** 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2009 Blender Foundation.
+ * All rights reserved.
+ *
+ * 
+ * Contributor(s): Joshua Leung
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+#include "RNA_define.h"
+#include "RNA_types.h"
+
+#include "DNA_anim_types.h"
+
+#ifdef RNA_RUNTIME
+
+#include <stddef.h>
+
+#include "BLI_blenlib.h"
+
+#include "BKE_animsys.h"
+#include "BKE_fcurve.h"
+
+DriverTarget *rna_Driver_add_target(ChannelDriver *driver, char *name)
+{
+	DriverTarget *dtar= driver_add_new_target(driver);
+	
+	/* set the name if given */
+	if (name && name[0]) {
+		BLI_strncpy(dtar->name, name, 64);
+		BLI_uniquename(&driver->targets, dtar, "var", '_', offsetof(DriverTarget, name), 64);
+	}
+	
+	/* return this target for the users to play with */
+	return dtar;
+}
+
+void rna_Driver_remove_target(ChannelDriver *driver, DriverTarget *dtar)
+{
+	/* call the API function for this */
+	driver_free_target(driver, dtar);
+}
+
+#else
+
+void RNA_api_drivers(StructRNA *srna)
+{
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
+	/* add target */
+	func= RNA_def_function(srna, "add_target", "rna_Driver_add_target");
+	RNA_def_function_ui_description(func, "Add a new target for the driver.");
+		/* return type */
+	parm= RNA_def_pointer(func, "target", "DriverTarget", "", "Newly created Driver Target.");
+		RNA_def_function_return(func, parm);
+		/* optional name parameter */
+	parm= RNA_def_string(func, "name", "", 64, "Name", "Name to use in scripted expressions/functions. (No spaces or dots are allowed. Also, must not start with a symbol or digit)");
+	
+	/* remove target */
+	func= RNA_def_function(srna, "remove_target", "rna_Driver_remove_target");
+		RNA_def_function_ui_description(func, "Remove an existing target from the driver.");
+		/* target to remove*/
+	parm= RNA_def_pointer(func, "target", "DriverTarget", "", "Target to remove from the driver.");
+		RNA_def_property_flag(parm, PROP_REQUIRED);
+}
+
+#endif
diff --git a/source/blender/makesrna/intern/rna_internal.h b/source/blender/makesrna/intern/rna_internal.h
index 0e557b59b22..d90b4f17c85 100644
--- a/source/blender/makesrna/intern/rna_internal.h
+++ b/source/blender/makesrna/intern/rna_internal.h
@@ -204,6 +204,7 @@ char *rna_TextureSlot_path(struct PointerRNA *ptr);
 /* API functions */
 
 void RNA_api_action(StructRNA *srna);
+void RNA_api_drivers(StructRNA *srna);
 void RNA_api_image(struct StructRNA *srna);
 void RNA_api_keyconfig(struct StructRNA *srna);
 void RNA_api_keyingset(struct StructRNA *srna);