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/* Copyright (c) 2003 krzYszcz and others.
* For information on usage and redistribution, and for a DISCLAIMER OF ALL
* WARRANTIES, see the file, "LICENSE.txt," in this distribution. */
/* This is Pd's lop~ with signal-controlled cutoff. */
/* CHECKED scalar case: input preserved (not coefs) after changing mode */
/* CHECKME if creation arg (or a default) restored after signal disconnection */
#include <math.h>
#include "m_pd.h"
#include "shared.h"
#include "sickle/sic.h"
#if defined(_WIN32) || defined(__APPLE__)
/* cf pd/src/x_arithmetic.c */
#define sinf sin
#endif
#define ONEPOLE_HZ 0
#define ONEPOLE_LINEAR 1
#define ONEPOLE_RADIANS 2
#define ONEPOLE_MINB0 .0001 /* CHECKED 1st term of ir for b0=0 */
#define ONEPOLE_MAXB0 .99 /* CHECKED 1st term of ir for b0=1 */
#define ONEPOLE_MINOMEGA 0. /* CHECKME */
#define ONEPOLE_MAXOMEGA (SHARED_PI * .5) /* CHECKME */
typedef struct _onepole
{
t_sic x_sic;
int x_mode;
float x_srcoef;
float x_ynm1;
} t_onepole;
static t_class *onepole_class;
static t_symbol *ps_hz;
static t_symbol *ps_linear;
static t_symbol *ps_radians;
static void onepole_clear(t_onepole *x)
{
x->x_ynm1 = 0.;
}
static void onepole_hz(t_onepole *x)
{
x->x_mode = ONEPOLE_HZ;
}
static void onepole_linear(t_onepole *x)
{
x->x_mode = ONEPOLE_LINEAR;
}
static void onepole_radians(t_onepole *x)
{
x->x_mode = ONEPOLE_RADIANS;
}
/* LATER make ready for optional audio-rate modulation
(separate scalar case routine, use sic_makecostable(), etc.) */
static t_int *onepole_perform(t_int *w)
{
t_onepole *x = (t_onepole *)(w[1]);
int nblock = (int)(w[2]);
t_float *xin = (t_float *)(w[3]);
t_float fin0 = *(t_float *)(w[4]);
t_float *out = (t_float *)(w[5]);
int mode = x->x_mode;
float ynm1 = x->x_ynm1;
/* CHECKME sampled once per block */
float b0;
if (mode == ONEPOLE_HZ)
{
float omega = fin0 * x->x_srcoef;
if (omega < ONEPOLE_MINOMEGA)
omega = ONEPOLE_MINOMEGA;
else if (omega > ONEPOLE_MAXOMEGA)
omega = ONEPOLE_MAXOMEGA;
/* The actual solution for a half-power cutoff is:
b0 = sqrt(sqr(2-cos(omega))-1) + cos(omega) - 1.
The sin(omega) below is only slightly better approximation than
Miller's b0=omega, except for the two highest octaves (or so),
where it is much better (but far from good). */
b0 = sinf(omega);
}
else if (mode == ONEPOLE_LINEAR)
b0 = sinf(fin0 * (SHARED_PI * .5)); /* CHECKME actual range of fin0 */
else
b0 = fin0;
if (b0 < ONEPOLE_MINB0)
b0 = ONEPOLE_MINB0;
else if (b0 > ONEPOLE_MAXB0)
b0 = ONEPOLE_MAXB0;
/* b0 is the standard 1-|a1| (where |a1| is pole's radius),
specifically: a1=b0-1 => a1 in [-.9999 .. -.01] => lowpass (stable) */
while (nblock--)
*out++ = ynm1 = b0 * (*xin++ - ynm1) + ynm1;
x->x_ynm1 = (PD_BIGORSMALL(ynm1) ? 0. : ynm1);
return (w + 6);
}
static void onepole_dsp(t_onepole *x, t_signal **sp)
{
x->x_srcoef = SHARED_2PI / sp[0]->s_sr;
onepole_clear(x);
dsp_add(onepole_perform, 5, x, sp[0]->s_n,
sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec);
}
static void *onepole_new(t_symbol *s, t_floatarg f)
{
t_onepole *x = (t_onepole *)pd_new(onepole_class);
x->x_srcoef = SHARED_2PI / sys_getsr();
/* CHECKED no int-to-float conversion (any int bashed to 0.) */
sic_newinlet((t_sic *)x, f);
outlet_new((t_object *)x, &s_signal);
onepole_clear(x);
if (s == ps_linear)
x->x_mode = ONEPOLE_LINEAR;
else if (s == ps_radians)
x->x_mode = ONEPOLE_RADIANS;
else
{
x->x_mode = ONEPOLE_HZ;
if (s && s != &s_ && s != ps_hz && s != gensym("Hz"))
{
/* CHECKED no warning */
}
}
return (x);
}
void onepole_tilde_setup(void)
{
ps_hz = gensym("hz");
ps_linear = gensym("linear");
ps_radians = gensym("radians");
onepole_class = class_new(gensym("onepole~"),
(t_newmethod)onepole_new, 0,
sizeof(t_onepole), 0,
A_DEFFLOAT, A_DEFSYM, 0);
sic_setup(onepole_class, onepole_dsp, SIC_FLOATTOSIGNAL);
class_addmethod(onepole_class, (t_method)onepole_clear, gensym("clear"), 0);
class_addmethod(onepole_class, (t_method)onepole_hz, ps_hz, 0);
class_addmethod(onepole_class, (t_method)onepole_hz, gensym("Hz"), 0);
class_addmethod(onepole_class, (t_method)onepole_linear, ps_linear, 0);
class_addmethod(onepole_class, (t_method)onepole_radians, ps_radians, 0);
}
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