Action Constraint: Add manual time factor input control

Adds an optional slider to the action constraint so that it can be
driven without a constraint target.

This is very helpful for more complex rigging and mechanical rigs, as it
means the action constraint can be controlled with a driver/custom
property directly, currently if we want to use a driver to control it we
must add a "dummy" bone/object inbetween to act as a control.

Reviewed By: Sebastian Parborg, Sybren A. Stüvel, Demeter Dzadik, Julian Eisel

Differential Revision: http://developer.blender.org/D8022

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/object/object_constraint.c b/source/blender/editors/object/object_constraint.c
index b062ae0c698..af04c4a3263 100644
--- a/source/blender/editors/object/object_constraint.c
+++ b/source/blender/editors/object/object_constraint.c
@@ -387,6 +387,11 @@ static void test_constraint(
       data->act = NULL;
       con->flag |= CONSTRAINT_DISABLE;
     }
+
+    /* Skip target checking if we're not using it */
+    if (data->flag & ACTCON_USE_EVAL_TIME) {
+      check_targets = false;
+    }
   }
   else if (con->type == CONSTRAINT_TYPE_FOLLOWPATH) {
     bFollowPathConstraint *data = con->data;