Marsyas  0.6.0-alpha
/usr/src/RPM/BUILD/marsyas-0.6.0/src/marsyas/marsystems/BlitOsc.cpp
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00001 /*
00002 ** Copyright (C) 1998-2011 George Tzanetakis <gtzan@cs.uvic.ca>
00003 **
00004 ** This program is free software; you can redistribute it and/or modify
00005 ** it under the terms of the GNU General Public License as published by
00006 ** the Free Software Foundation; either version 2 of the License, or
00007 ** (at your option) any later version.
00008 **
00009 ** This program is distributed in the hope that it will be useful,
00010 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
00011 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012 ** GNU General Public License for more details.
00013 **
00014 ** You should have received a copy of the GNU General Public License
00015 ** along with this program; if not, write to the Free Software
00016 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
00017 */
00018 
00019 #include "BlitOsc.h"
00020 #include "math.h"
00021 
00022 using namespace Marsyas;
00023 
00024 BlitOsc::BlitOsc(mrs_string name):MarSystem("BlitOsc", name)
00025 {
00026   addControls();
00027 }
00028 
00029 BlitOsc::BlitOsc(const BlitOsc& a) : MarSystem(a)
00030 {
00031   // For any MarControlPtr in a MarSystem
00032   // it is necessary to perform this getctrl
00033   // in the copy constructor in order for cloning to work
00034 }
00035 
00036 BlitOsc::~BlitOsc()
00037 {
00038 }
00039 
00040 MarSystem*
00041 BlitOsc::clone() const
00042 {
00043   return new BlitOsc(*this);
00044 }
00045 
00046 void BlitOsc::addControls()
00047 {
00048   //Add specific controls needed by this MarSystem.
00049   addctrl("mrs_real/frequency", 440.0);
00050   addctrl("mrs_bool/noteon", false);
00051   addctrl("mrs_natural/type", 0);
00052 
00053   setctrlState("mrs_real/frequency", true);
00054   setctrlState("mrs_natural/type", true);
00055   setctrlState("mrs_bool/noteon", true);
00056 }
00057 
00058 
00059 void BlitOsc::myUpdate(MarControlPtr sender)
00060 {
00061   ap1.set_delay(1.9);
00062   ap2.set_delay(1.3);
00063 
00064   frequency_ = (getctrl("mrs_real/frequency")->to<mrs_real>());
00065   type_ = (getctrl("mrs_natural/type")->to<mrs_natural>());
00066   noteon_ = (getctrl("mrs_bool/noteon")->to<mrs_bool>());
00067   israte_ = (getctrl("mrs_real/israte")->to<mrs_real>());
00068 
00069   phase_ = 0;
00070   inv_ = 1;
00071 
00072   switch (type_)
00073   {
00074   case 0: // Saw
00075     //std::cout << frequency_ << std::endl;
00076     dc_ = frequency_/israte_;
00077     break;
00078   case 1: // Square
00079     // The frequency has to be doubled to compensate for
00080     // the frequency be being halved by the square wave
00081     // being bipolar
00082     frequency_ *= 2;
00083     dc_ = 0;
00084     break;
00085   }
00086 
00087   // d is how many samples to delay
00088   // because it is possible a fractional amount we split it
00089   // into the integer part, and the fractional part.
00090   mrs_real d = israte_/frequency_;
00091   // N_ is the integer part.
00092   N_ = (mrs_natural)floor(d);
00093   // frac_ is the fractional part
00094   frac_ = (d - N_);
00095   // delay is used as an overflow counter for the
00096   // fractional part.
00097   delay_ = frac_;
00098 
00099   // no change to network flow
00100   MarSystem::myUpdate(sender);
00101 }
00102 
00103 void BlitOsc::myProcess(realvec& in, realvec& out)
00104 {
00105   (void) in;
00106   for (mrs_natural t = 0; t < inSamples_; t++)
00107   {
00108     if (phase_ >= N_ - 1)
00109     {
00110       phase_ = 0;
00111 
00112       // The amount of delay is incresed by 1 to optimize the allpass filter.
00113       // N_ is compensated accordingly for this delay at the top of this if
00114       // statement.
00115       ap1.set_delay(delay_ + 1);
00116 
00117       switch (type_)
00118       {
00119       case 0: // Saw
00120         out(0,t) = le(ap2(ap1(1)) - dc_);
00121         break;
00122       case 1: // Square
00123         out(0,t) = le(ap2(ap1(1 * inv_)));
00124         inv_ = (-inv_);
00125         break;
00126       }
00127 
00128       // This is the logic to tune the fractional part of the period.
00129       delay_ += frac_;
00130       if (delay_ >= 1)
00131       {
00132         delay_ -= 1;
00133         phase_ = -1;
00134       }
00135     }
00136     else
00137     {
00138       phase_++;
00139       out(0,t) = le(ap2(ap1(0)) - dc_);
00140     }
00141   }
00142 }