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/*
ZynAddSubFX - a software synthesizer
FilterParams.C - Parameters for filter
Copyright (C) 2002-2005 Nasca Octavian Paul
Author: Nasca Octavian Paul
This program is free software; you can redistribute it and/or modify
it under the terms of version 2 of the GNU General Public License
as published by the Free Software Foundation.
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 (version 2) for more details.
You should have received a copy of the GNU General Public License (version 2)
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <math.h>
#include "globals.h"
#include "filter_parameters.h"
void FilterParams::init(
float sample_rate,
unsigned char Ptype_,
unsigned char Pfreq_,
unsigned char Pq_)
{
m_sample_rate = sample_rate;
Dtype=Ptype_;
Dfreq=Pfreq_;
Dq=Pq_;
defaults();
}
void FilterParams::defaults(){
Ptype=Dtype;
Pfreq=Dfreq;
Pq=Dq;
m_additional_stages = 0;
m_frequency_tracking = 0;
m_gain = 0;
m_category = ZYN_FILTER_TYPE_ANALOG;
Pnumformants=3;
Pformantslowness=64;
for (int j=0;j<FF_MAX_VOWELS;j++){
defaults(j);
};
Psequencesize=3;
for (int i=0;i<FF_MAX_SEQUENCE;i++) Psequence[i].nvowel=i%FF_MAX_VOWELS;
Psequencestretch=40;
Psequencereversed=0;
Pcenterfreq=64;//1 kHz
Poctavesfreq=64;
Pvowelclearness=64;
};
void FilterParams::defaults(int n){
int j=n;
for (int i=0;i<FF_MAX_FORMANTS;i++){
Pvowels[j].formants[i].freq=(int)(RND*127.0);//some random freqs
Pvowels[j].formants[i].q=64;
Pvowels[j].formants[i].amp=127;
};
};
/*
* Parameter control
*/
REALTYPE FilterParams::getfreq(){
return((Pfreq/64.0-1.0)*5.0);
};
REALTYPE FilterParams::getq(){
return(exp(pow((REALTYPE) Pq/127.0,2)*log(1000.0))-0.9);
};
REALTYPE FilterParams::getfreqtracking(REALTYPE notefreq)
{
return log(notefreq / 440.0) * m_frequency_tracking / LOG_2;
};
/*
* Get the center frequency of the formant's graph
*/
REALTYPE FilterParams::getcenterfreq(){
return(10000.0*pow(10,-(1.0-Pcenterfreq/127.0)*2.0));
};
/*
* Get the number of octave that the formant functions applies to
*/
REALTYPE FilterParams::getoctavesfreq(){
return(0.25+10.0*Poctavesfreq/127.0);
};
/*
* Get the frequency from x, where x is [0..1]
*/
REALTYPE FilterParams::getfreqx(REALTYPE x){
if (x>1.0) x=1.0;
REALTYPE octf=pow(2.0,getoctavesfreq());
return(getcenterfreq()/sqrt(octf)*pow(octf,x));
};
/*
* Get the x coordinate from frequency (used by the UI)
*/
REALTYPE FilterParams::getfreqpos(REALTYPE freq){
return((log(freq)-log(getfreqx(0.0)))/log(2.0)/getoctavesfreq());
};
/*
* Get the freq. response of the formant filter
*/
void FilterParams::formantfilterH(int nvowel,int nfreqs,REALTYPE *freqs)
{
REALTYPE c[3],d[3];
REALTYPE filter_freq,filter_q,filter_amp;
REALTYPE omega,sn,cs,alpha;
for (int i=0;i<nfreqs;i++) freqs[i]=0.0;
//for each formant...
for (int nformant=0;nformant<Pnumformants;nformant++)
{
//compute formant parameters(frequency,amplitude,etc.)
filter_freq=getformantfreq(Pvowels[nvowel].formants[nformant].freq);
filter_q=getformantq(Pvowels[nvowel].formants[nformant].q)*getq();
if (m_additional_stages > 0)
{
filter_q = (filter_q > 1.0 ? pow(filter_q, 1.0 / (m_additional_stages + 1)) : filter_q);
}
filter_amp=getformantamp(Pvowels[nvowel].formants[nformant].amp);
if (filter_freq <= (m_sample_rate / 2 - 100.0))
{
omega = 2 * PI * filter_freq / m_sample_rate;
sn=sin(omega);
cs=cos(omega);
alpha=sn/(2*filter_q);
REALTYPE tmp=1+alpha;
c[0]=alpha/tmp*sqrt(filter_q+1);
c[1]=0;
c[2]=-alpha/tmp*sqrt(filter_q+1);
d[1]=-2*cs/tmp*(-1);
d[2]=(1-alpha)/tmp*(-1);
}
else
{
continue;
}
for (int i=0;i<nfreqs;i++) {
REALTYPE freq=getfreqx(i/(REALTYPE) nfreqs);
if (freq > m_sample_rate / 2)
{
for (int tmp = i ; tmp < nfreqs ; tmp++)
{
freqs[tmp] = 0.0;
}
break;
}
REALTYPE fr = freq / m_sample_rate * PI * 2.0;
REALTYPE x=c[0],y=0.0;
for (int n=1;n<3;n++){
x+=cos(n*fr)*c[n];
y-=sin(n*fr)*c[n];
};
REALTYPE h=x*x+y*y;
x=1.0;y=0.0;
for (int n=1;n<3;n++){
x-=cos(n*fr)*d[n];
y+=sin(n*fr)*d[n];
};
h=h/(x*x+y*y);
freqs[i] += pow(h, (m_additional_stages + 1.0) / 2.0) * filter_amp;
};
};
for (int i=0;i<nfreqs;i++) {
if (freqs[i]>0.000000001) freqs[i]=rap2dB(freqs[i]) + m_gain;
else freqs[i]=-90.0;
};
};
/*
* Transforms a parameter to the real value
*/
REALTYPE FilterParams::getformantfreq(unsigned char freq){
REALTYPE result=getfreqx(freq/127.0);
return(result);
};
REALTYPE FilterParams::getformantamp(unsigned char amp){
REALTYPE result=pow(0.1,(1.0-amp/127.0)*4.0);
return(result);
};
REALTYPE FilterParams::getformantq(unsigned char q){
//temp
REALTYPE result=pow(25.0,(q-32.0)/64.0);
return(result);
};
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