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/******************************************************
*
* zexy - implementation file
*
* copyleft (c) IOhannes m zmölnig
*
* 1999:forum::für::umläute:2004
*
* institute of electronic music and acoustics (iem)
*
******************************************************
*
* license: GNU General Public License v.2
*
******************************************************/
/* ---------------- envrms~ - simple envelope follower. ----------------- */
/* this is exactly the same as msp's env~-object, but does not output dB but RMS !! */
/* i found env~+dbtorms most inconvenient (and expensive...) */
#include "zexy.h"
#include <math.h>
#define MAXOVERLAP 10
#define MAXVSTAKEN 64
t_class *sigenvrms_class;
typedef struct sigenvrms
{
t_object x_obj; /* header */
void *x_outlet; /* a "float" outlet */
void *x_clock; /* a "clock" object */
float *x_buf; /* a Hanning window */
int x_phase; /* number of points since last output */
int x_period; /* requested period of output */
int x_realperiod; /* period rounded up to vecsize multiple */
int x_npoints; /* analysis window size in samples */
float x_result; /* result to output */
float x_sumbuf[MAXOVERLAP]; /* summing buffer */
} t_sigenvrms;
static void sigenvrms_tick(t_sigenvrms *x);
static void *sigenvrms_new(t_floatarg fnpoints, t_floatarg fperiod)
{
int npoints = fnpoints;
int period = fperiod;
t_sigenvrms *x;
float *buf;
int i;
if (npoints < 1) npoints = 1024;
if (period < 1) period = npoints/2;
if (period < npoints / MAXOVERLAP + 1)
period = npoints / MAXOVERLAP + 1;
if (!(buf = getbytes(sizeof(float) * (npoints + MAXVSTAKEN))))
{
error("env: couldn't allocate buffer");
return (0);
}
x = (t_sigenvrms *)pd_new(sigenvrms_class);
x->x_buf = buf;
x->x_npoints = npoints;
x->x_phase = 0;
x->x_period = period;
for (i = 0; i < MAXOVERLAP; i++) x->x_sumbuf[i] = 0;
for (i = 0; i < npoints; i++)
buf[i] = (1. - cos((2 * 3.141592654 * i) / npoints))/npoints;
for (; i < npoints+MAXVSTAKEN; i++) buf[i] = 0;
x->x_clock = clock_new(x, (t_method)sigenvrms_tick);
x->x_outlet = outlet_new(&x->x_obj, gensym("float"));
return (x);
}
static t_int *sigenvrms_perform(t_int *w)
{
t_sigenvrms *x = (t_sigenvrms *)(w[1]);
t_float *in = (t_float *)(w[2]);
int n = (int)(w[3]);
int count;
float *sump;
in += n;
for (count = x->x_phase, sump = x->x_sumbuf;
count < x->x_npoints; count += x->x_realperiod, sump++)
{
float *hp = x->x_buf + count;
float *fp = in;
float sum = *sump;
int i;
for (i = 0; i < n; i++)
{
fp--;
sum += *hp++ * (*fp * *fp);
}
*sump = sum;
}
sump[0] = 0;
x->x_phase -= n;
if (x->x_phase < 0)
{
x->x_result = x->x_sumbuf[0];
for (count = x->x_realperiod, sump = x->x_sumbuf;
count < x->x_npoints; count += x->x_realperiod, sump++)
sump[0] = sump[1];
sump[0] = 0;
x->x_phase = x->x_realperiod - n;
clock_delay(x->x_clock, 0L);
}
return (w+4);
}
static void sigenvrms_dsp(t_sigenvrms *x, t_signal **sp)
{
if (x->x_period % sp[0]->s_n) x->x_realperiod =
x->x_period + sp[0]->s_n - (x->x_period % sp[0]->s_n);
else x->x_realperiod = x->x_period;
dsp_add(sigenvrms_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
if (sp[0]->s_n > MAXVSTAKEN) bug("sigenvrms_dsp");
}
static void sigenvrms_tick(t_sigenvrms *x) /* callback function for the clock */
{
outlet_float(x->x_outlet, sqrtf(x->x_result));
}
static void sigenvrms_ff(t_sigenvrms *x) /* cleanup on free */
{
clock_free(x->x_clock);
freebytes(x->x_buf, (x->x_npoints + MAXVSTAKEN) * sizeof(float));
}
static void sigenvrms_help(void)
{
post("envrms~\t:: envelope follower that does output rms instead of dB");
}
void envrms_tilde_setup(void)
{
sigenvrms_class = class_new(gensym("envrms~"), (t_newmethod)sigenvrms_new,
(t_method)sigenvrms_ff, sizeof(t_sigenvrms), 0, A_DEFFLOAT, A_DEFFLOAT, 0);
class_addmethod(sigenvrms_class, nullfn, gensym("signal"), 0);
class_addmethod(sigenvrms_class, (t_method)sigenvrms_dsp, gensym("dsp"), 0);
class_addmethod(sigenvrms_class, (t_method)sigenvrms_help, gensym("help"), 0);
class_sethelpsymbol(sigenvrms_class, gensym("zexy/envrms~"));
zexy_register("envrms~");
}
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