- add template for defining custom driver functions.

- comment unused assignments.

release/scripts/templates/driver_functions.py

@@ -0,0 +1,34 @@
+# This script defines functions to be used directly in drivers expressions to
+# extend the builtin set of python functions.
+#
+# This can be executed on manually or set to 'Register' to
+# initialize thefunctions on file load.
+
+
+# two sample functions
+def invert(f):
+    """ Simple function call:
+
+            invert(val)
+    """
+    return 1.0 - f
+
+
+uuid_store = {}
+
+def slow_value(value, fac, uuid):
+    """ Delay the value by a factor, use a unique string to allow
+        use in multiple drivers without conflict:
+
+            slow_value(val, 0.5, "my_value")
+    """
+    value_prev = uuid_store.get(uuid, value)
+    uuid_store[uuid] = value_new = (value_prev * fac) + (value * (1.0 - fac))
+    return value_new
+
+
+import bpy
+
+# Add variable defined in this script into the drivers namespace.
+bpy.app.driver_namespace["invert"] = invert
+bpy.app.driver_namespace["slow_value"] = slow_value