/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file timedCycle.I
 * @author jason
 * @date 2000-08-01
 */

/**
 *
 */
INLINE TimedCycle::
TimedCycle() :
  _cycle_time(30),
  _inv_cycle_time(1./30),
  _next_switch(-1),
  _current_child(0),
  _element_count(0)
{
  _global_clock = ClockObject::get_global_clock();
}

/**
 *
 */
INLINE TimedCycle::
TimedCycle(PN_stdfloat cycle_time, int element_count) :
  _cycle_time(cycle_time),
  _current_child(0),
  _element_count(element_count)
{
  nassertv(_cycle_time > 0);
  _global_clock = ClockObject::get_global_clock();
  _next_switch = _global_clock->get_frame_time() + _cycle_time;
  _inv_cycle_time = 1. / _cycle_time;
}

/**
 * Set the number of elements being cycled through
 */
INLINE void TimedCycle::
set_element_count(int element_count)
{
  _element_count = element_count;
}

/**
 * Set the number of elements being cycled through
 */
INLINE void TimedCycle::
set_cycle_time(PN_stdfloat cycle_time)
{
  nassertv(cycle_time > 0);
  if (_next_switch == -1)
  {
    _next_switch = _global_clock->get_frame_time() + cycle_time;
  }
  else
  {
    _next_switch = _next_switch - _cycle_time + cycle_time;
  }
  _cycle_time = cycle_time;
  _inv_cycle_time = 1. / _cycle_time;
}


/**
 * Set the number of elements being cycled through
 */
INLINE int TimedCycle::
next_element()
{
  double current_time = _global_clock->get_frame_time();
  unsigned int increment = (unsigned int) ((current_time - _next_switch)
                                           * _inv_cycle_time);

  _next_switch += _cycle_time * increment;
  _current_child = (_current_child + increment) % _element_count;

  return _current_child;
}