hersto:  Library/TimeDependent.cpp

/*
  TimeDependent.cpp
 
  Common base class for CTDamper and CTChaser.
  Forms an object that needs to perform actions
  in a frequent manner, e.g. in an animation
  framework. Provides a Tick(.) method that is
  to be called frequently and can announce when
  it needs thos method calls and when not.

  Author:
      Herbert Stocker

  HomePage:
      http://www.hersto.net/Followers
      (various resources there)

  License:
      You may use this file in any project and
      modify it as long as you keep this comment
      block unchanged.

  Accompanying Files:
      TimeDependent.h

  Documentation:
      See http://www.hersto.net/Followers

 */


#include "TimeDependent.h"

#ifndef NULL
#   define NULL 0
#endif


CTimeDependent::CTimeDependent()
:   mpvNeedTickContext(NULL)
,   mpfNeedTickCB(NULL)
{}


CTimeDependent::~CTimeDependent()
{
    mfUnRegisterFromTimer();
}


void CTimeDependent::Tick(double DeltaT, double Now)
{
    // To be implemented by the derived class.
}


void CTimeDependent::SetNeedTickCB(void* pvContext, double (*pfNeedTickCB) (void* pvContext, CTimeDependent* pCaller, bool bNeedTick))
{
    mpvNeedTickContext= pvContext;
    mpfNeedTickCB= pfNeedTickCB;
}


void CTimeDependent::mfUnRegisterFromTimer()
{
    if(mpfNeedTickCB)
    {
        mpfNeedTickCB(mpvNeedTickContext, this, false);
        mpfNeedTickCB= NULL;
    }
}







/*
In its destructor the timer object should go through
its list of registered CTimeDependent objects and
call their SetNeedTickCB(.) with a NULL pointer for the call-back function,
or the destructor of the CTimeDependent objects will later try to unregister
themselves from the already dead timer object.
*/