Class FunctionController

object --+    
         |    
Controller --+
             |
            FunctionController

Set parameters using a Python function.

This is a very commonly used subclass of Controller, because it is
very intuitive and requires a minimum of code to set up.  Many of
the Vision Egg demo programs create instances of
FunctionController.

A number of parameters are passed to the function depending on the
value of temporal_variables:

The function can make use of temporal variables, which are made
available by passingkeyword argument(s) depending on the
controller's temporal_variables attribute. Note that only the
absolute temporal variables are available when the go loop is not
running.

flag(s) present    argument  description
-----------------  --------  ----------------------------------
TIME_SEC_ABSOLUTE  t_abs     seconds, continuously increasing
TIME_SEC_SINCE_GO  t         seconds, reset to 0.0 each go loop
FRAMES_ABSOLUTE    f_abs     frames, continuously increasing
FRAMES_SINCE_GO    f         frames, reset to 0 each go loop

Create an instance of FunctionController.

Arguments:

during_go_func -- function evaluted during go loop
between_go_func -- function evaluted not during go loop

Called by Presentation. Overrides method in Controller base class.

Called by Presentation. Overrides method in Controller base class.