zynaddsubfx

ZynAddSubFX open source synthesizer
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Filter.cpp (2367B)

      1 /*
      2   ZynAddSubFX - a software synthesizer
      3 
      4   Filter.cpp - Filters, uses analog,formant,etc. filters
      5   Copyright (C) 2002-2005 Nasca Octavian Paul
      6   Author: Nasca Octavian Paul
      7 
      8   This program is free software; you can redistribute it and/or
      9   modify it under the terms of the GNU General Public License
     10   as published by the Free Software Foundation; either version 2
     11   of the License, or (at your option) any later version.
     12 */
     13 
     14 #include <cmath>
     15 #include <cstdio>
     16 #include <cassert>
     17 
     18 #include "Filter.h"
     19 #include "AnalogFilter.h"
     20 #include "FormantFilter.h"
     21 #include "SVFilter.h"
     22 #include "MoogFilter.h"
     23 #include "CombFilter.h"
     24 #include "../Params/FilterParams.h"
     25 #include "../Misc/Allocator.h"
     26 
     27 namespace zyn {
     28 
     29 Filter::Filter(unsigned int srate, int bufsize)
     30     : outgain(1.0f),
     31       samplerate(srate),
     32       buffersize(bufsize)
     33 {
     34     alias();
     35 }
     36 
     37 Filter *Filter::generate(Allocator &memory, const FilterParams *pars,
     38         unsigned int srate, int bufsize)
     39 {
     40     assert(srate != 0);
     41     assert(bufsize != 0);
     42 
     43     unsigned char Ftype   = pars->Ptype;
     44     unsigned char Fstages = pars->Pstages;
     45 
     46     Filter *filter;
     47     switch(pars->Pcategory) {
     48         case 1:
     49             filter = memory.alloc<FormantFilter>(pars, &memory, srate, bufsize);
     50             break;
     51         case 2:
     52             filter = memory.alloc<SVFilter>(Ftype, 1000.0f, pars->getq(), Fstages, srate, bufsize);
     53             filter->outgain = dB2rap(pars->getgain());
     54             if(filter->outgain > 1.0f)
     55                 filter->outgain = sqrt(filter->outgain);
     56             break;
     57         case 3:
     58             filter = memory.alloc<MoogFilter>(Ftype, 1000.0f, pars->getq(), srate, bufsize);
     59             filter->setgain(pars->getgain());
     60             break;
     61         case 4:
     62             filter = memory.alloc<CombFilter>(&memory, Ftype, 1000.0f, pars->getq(), srate, bufsize);
     63             filter->setgain(pars->getgain());
     64             break;
     65         default:
     66             filter = memory.alloc<AnalogFilter>(Ftype, 1000.0f, pars->getq(), Fstages, srate, bufsize);
     67             if((Ftype >= 6) && (Ftype <= 8))
     68                 filter->setgain(pars->getgain());
     69             else
     70                 filter->outgain = dB2rap(pars->getgain());
     71             break;
     72     }
     73     return filter;
     74 }
     75 
     76 float Filter::getrealfreq(float freqpitch)
     77 {
     78     return powf(2.0f, freqpitch + 9.96578428f); //log2(1000)=9.95748f
     79 }
     80 
     81 }