From f3b9ea066eeb2b69b81723c24cb5d9ffdbf0556f Mon Sep 17 00:00:00 2001
From: Joshua Leung <aligorith@gmail.com>
Date: Sun, 21 Feb 2010 11:05:52 +0000
Subject: [PATCH] Bugfix #21245: "Track to" (Ctrl + T) operator was missing
 notifier updates

Bugfix #21255: Clear track operator did not remove TrackTo constraints too. This could still be made to do Locked Track and other tracking constraints later too, but for now this will do.
---
 source/blender/blenkernel/BKE_constraint.h    |  1 +
 source/blender/blenkernel/intern/constraint.c | 23 ++++++++++++++++---
 .../blender/editors/object/object_relations.c | 11 +++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/source/blender/blenkernel/BKE_constraint.h b/source/blender/blenkernel/BKE_constraint.h
index 42089e37d63..9c5e89bff76 100644
--- a/source/blender/blenkernel/BKE_constraint.h
+++ b/source/blender/blenkernel/BKE_constraint.h
@@ -136,6 +136,7 @@ struct bConstraint *add_pose_constraint(struct Object *ob, struct bPoseChannel *
 
 int remove_constraint(ListBase *list, struct bConstraint *con);
 int remove_constraint_index(ListBase *list, int index);
+void remove_constraints_type(ListBase *list, short type, short last_only);
 
 /* Constraints + Proxies function prototypes */
 void extract_proxylocal_constraints(struct ListBase *dst, struct ListBase *src);
diff --git a/source/blender/blenkernel/intern/constraint.c b/source/blender/blenkernel/intern/constraint.c
index fe2e009918c..c22510a2527 100644
--- a/source/blender/blenkernel/intern/constraint.c
+++ b/source/blender/blenkernel/intern/constraint.c
@@ -3903,6 +3903,26 @@ int remove_constraint_index (ListBase *list, int index)
 		return 0;
 }
 
+/* Remove all the constraints of the specified type from the given constraint stack */
+void remove_constraints_type (ListBase *list, short type, short last_only)
+{
+	bConstraint *con, *conp;
+	
+	if (list == NULL)
+		return;
+	
+	/* remove from the end of the list to make it faster to find the last instance */
+	for (con= list->last; con; con= conp) {
+		conp= con->prev;
+		
+		if (con->type == type) {
+			remove_constraint(list, con);
+			if (last_only) 
+				return;
+		}
+	}
+}
+
 /* ......... */
 
 /* Creates a new constraint, initialises its data, and returns it */
@@ -4062,9 +4082,6 @@ void copy_constraints (ListBase *dst, const ListBase *src)
 		/* make a new copy of the constraint's data */
 		con->data = MEM_dupallocN(con->data);
 		
-		// NOTE: depreceated... old animation system
-		id_us_plus((ID *)con->ipo);
-		
 		/* only do specific constraints if required */
 		if (cti) {
 			/* perform custom copying operations if needed */
diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index 71b0dd82252..b2ccd96f3a7 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -873,9 +873,17 @@ static int object_track_clear_exec(bContext *C, wmOperator *op)
 		return OPERATOR_CANCELLED;
 	}
 	CTX_DATA_BEGIN(C, Object*, ob, selected_editable_objects) {
+		/* remove track-object for old track */
 		ob->track= NULL;
 		ob->recalc |= OB_RECALC;
 		
+		/* also remove all Track To constraints 
+		 * TODO: 
+		 *	- do we only want to do the last instance (use 1 as last arg instead)
+		 *	- also, what about other forms of tracking?
+		 */
+		remove_constraints_type(&ob->constraints, CONSTRAINT_TYPE_TRACKTO, 0);
+		
 		if(type == 1)
 			ED_object_apply_obmat(ob);
 	}
@@ -883,6 +891,7 @@ static int object_track_clear_exec(bContext *C, wmOperator *op)
 
 	DAG_ids_flush_update(0);
 	DAG_scene_sort(CTX_data_scene(C));
+	WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
 
 	return OPERATOR_FINISHED;
 }
@@ -973,8 +982,10 @@ static int track_set_exec(bContext *C, wmOperator *op)
 		}
 		CTX_DATA_END;
 	}
+	
 	DAG_scene_sort(scene);
 	DAG_ids_flush_update(0);
+	WM_event_add_notifier(C, NC_OBJECT|ND_TRANSFORM, NULL);
 	
 	return OPERATOR_FINISHED;
 }