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/*
* Copyright (c) 1997-1999 Mark Danks.
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt" in this distribution.
*/
/* Original code by Miller Puckette */
/* a non-interpolating reson filter, not very carefully coded... */
/* 11/29/94 modified to do interpolation - M. Danks */
#include "m_pd.h"
#include <stdlib.h>
#define BUFSIZE 4096
typedef struct resonctl
{
float c_freq;
float c_samprate;
float c_feedback;
int c_delayinsamps;
float c_fraction;
int c_phase;
float *c_buf;
} t_resonctl;
typedef struct sigreson
{
t_object x_obj; /* header */
t_resonctl *x_ctl; /* pointer to state */
t_resonctl x_cspace; /* garage for state when not in a chain */
} t_sigreson;
/* the DSP routine -- called for every n samples of input */
static t_int *cu_reson(t_int *w)
{
t_float *in1 = (t_float *)(w[1]);
t_float *in2 = (t_float *)(w[2]);
t_float *out = (t_float *)(w[3]);
t_resonctl *x = (t_resonctl *)(w[4]);
int n = (int)(w[5]);
long i;
int writephase = x->c_phase;
for (i = 0; i < n; i++)
{
/* note two tricks: 1. input is read before output
* is written, because the routine might be called
* in-place;
* 2 - a seed of 1E-20 is thrown in to avoid floating
* underflow which slows the calculation down.
*/
int readphase, phase, delayinsamps;
float fraction, f, g, freq, freqtemp;
float ftemp;
freq = *in2++;
freqtemp = (freq < 1 ? 1 : freq);
ftemp = x->c_samprate/freqtemp;
if (ftemp >= BUFSIZE-1)
ftemp = BUFSIZE - 1.f;
else if (ftemp < 1.0)
ftemp = 1.f;
delayinsamps = (int)ftemp;
fraction = ftemp - delayinsamps;
readphase = writephase - delayinsamps;
phase = readphase & (BUFSIZE-1);
f = x->c_buf[phase] + fraction *
(x->c_buf[(phase-1)& (BUFSIZE-1)] - x->c_buf[phase]);
g = *in1++;
*out++ = x->c_buf[(writephase++) & (BUFSIZE-1)] =
g + x->c_feedback * f + 1E-20f;
}
x->c_phase = writephase & (BUFSIZE-1);
return (w+6);
}
/* sets the reson frequency */
void sigreson_float(t_sigreson *x, t_floatarg f)
{
float ftemp;
x->x_ctl->c_freq = (f < 1 ? 1 : f);
ftemp = x->x_ctl->c_samprate/x->x_ctl->c_freq;
if (ftemp >= BUFSIZE - 1)
ftemp = BUFSIZE - 1.f;
else if (ftemp < 1.0)
ftemp = 1.f;
x->x_ctl->c_delayinsamps = (int)ftemp;
x->x_ctl->c_fraction = ftemp - x->x_ctl->c_delayinsamps;
}
/* routine which FTS calls to put you on the DSP chain or take you off. */
static void sigreson_dsp(t_sigreson *x, t_signal **sp)
{
x->x_ctl->c_samprate = sp[0]->s_sr;
sigreson_float(x, x->x_ctl->c_freq);
dsp_add(cu_reson, 5, sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec,
x->x_ctl, sp[0]->s_n);
}
static void sigreson_ft1(t_sigreson *x, t_floatarg f) /* sets feedback */
{
if (f > .99999) f = .99999f;
else if (f < -.99999) f = -.99999f;
x->x_ctl->c_feedback = (float)f;
}
static void sigreson_ff(t_sigreson *x) /* cleanup on free */
{
free(x->x_ctl->c_buf);
}
static t_class *sigreson_class;
void *sigreson_new(t_floatarg f, t_floatarg g)
{
t_sigreson *x = (t_sigreson *)pd_new(sigreson_class);
outlet_new(&x->x_obj, &s_signal);
/* things in "cspace" are things you'll actually use at DSP time */
x->x_cspace.c_phase = 0;
if (!(x->x_cspace.c_buf = (float *)malloc(BUFSIZE * sizeof(float))))
{
error("buffer alloc failed");
return (0);
}
x->x_cspace.c_samprate = 44100.f; /* just a plausible default */
/* control block is in the garage at startup */
x->x_ctl = &x->x_cspace;
sigreson_float(x, (t_float)f); /* setup params */
sigreson_ft1(x, g);
/* make a "float" inlet */
inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_signal, &s_signal);
inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_float, gensym("ft1"));
return (x);
}
void reson_tilde_setup(void)
{
sigreson_class = class_new(gensym("reson~"), (t_newmethod)sigreson_new,
(t_method)sigreson_ff, sizeof(t_sigreson), 0,
A_DEFFLOAT, A_DEFFLOAT, 0);
class_addfloat(sigreson_class, (t_method)sigreson_float);
class_addmethod(sigreson_class, (t_method)sigreson_ft1, gensym("ft1"), A_FLOAT, 0);
class_addmethod(sigreson_class, (t_method)nullfn, &s_signal, A_NULL);
class_addmethod(sigreson_class, (t_method)sigreson_dsp, gensym("dsp"), A_NULL);
}
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