/home/marsyas/marsyas/src/marsyas/FM.cpp

/*
** Copyright (C) 1998-2006 George Tzanetakis <gtzan@cs.uvic.ca>
**  
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
** 
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
** 
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software 
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include "FM.h"

using std::ostringstream;
using namespace Marsyas;

#define WAVETABLE_SIZE 8192

// create the wavetable.
FM::FM(mrs_string name)
: MarSystem("FM",name),
  wavetable_(WAVETABLE_SIZE),
  wavetableSize_(WAVETABLE_SIZE)
{
  mrs_real incr = TWOPI / wavetableSize_;
    
  for (mrs_natural t=0; t < wavetableSize_; ++t) {
    wavetable_(t) = (mrs_real)(0.5 * sin(incr * t));
  }
  
    mIndex_ = 0;
    oIndex_ = 0;
    addControls();
}


FM :: ~FM() {}


MarSystem* FM::clone() const 
{
  return new FM(*this);
}


void
FM::addControls() 
{
  addctrl("mrs_natural/nChannels",1);
  
  addctrl("mrs_real/mDepth", 15.0);                     // modulator depth
  setctrlState("mrs_real/mDepth",true);
  
  addctrl("mrs_real/mSpeed", 6.0);                      // modulator speed
  setctrlState("mrs_real/mSpeed", true);
  
  addctrl("mrs_real/cFrequency", 1000.0);           // carrier frequency
  setctrlState("mrs_real/cFrequency", true);
  
  addctrl("mrs_bool/noteon", false);
  setctrlState("mrs_bool/noteon", true);
}   


void FM::myUpdate(MarControlPtr sender) 
{
    (void) sender;
  MRSDIAG("FM.cpp - FM:myUpdate");
  
  setctrl("mrs_natural/onSamples", getctrl("mrs_natural/inSamples"));
  setctrl("mrs_natural/onObservations", getctrl("mrs_natural/inObservations"));
  setctrl("mrs_real/osrate", getctrl("mrs_real/israte"));
  
  // update the controls for the FM  
  cFrequency_ = getctrl("mrs_real/cFrequency")->to<mrs_real>();
  isRate_ = getctrl("mrs_real/israte")->to<mrs_real>();
  mSpeed_ = getctrl("mrs_real/mSpeed")->to<mrs_real>();
  mDepth_ = getctrl("mrs_real/mDepth")->to<mrs_real>();
  mRate_ = (mSpeed_ * wavetableSize_) / getctrl("mrs_real/israte")->to<mrs_real>();
  inSamples_ = getctrl("mrs_natural/inSamples")->to<mrs_natural>();
}   

void FM::myProcess( realvec& in, realvec& out ) 
{
    (void) in;
    mrs_natural t;
  //checkFlow(in,out);
  

  register mrs_real mSample_;
  register mrs_real oFrequency_;                                
                                            
  if (getctrl("mrs_bool/noteon")->to<mrs_bool>() == false) {
    return;
  }
  
  for (t=0; t < inSamples_; t++)  
    {
      
      // calculate the modulator output
      mSample_ = wavetable_((mrs_natural)mIndex_);
      mIndex_ += mRate_;
      mSample_ *= mDepth_;
      
      // calculate any FM and the new output rate
      oFrequency_ = cFrequency_ + mSample_;
      oRate_ = (oFrequency_ * wavetableSize_) / isRate_;
      
      out(0,t) = wavetable_((mrs_natural)oIndex_);
      
      // we are one sample behind in case this index goes off the map
      oIndex_ += oRate_;    
      
      while (mIndex_ >= wavetableSize_)
    mIndex_ -= wavetableSize_;              
      
      while (oIndex_ >= wavetableSize_)
    oIndex_ -= wavetableSize_;  
    }
  
}

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