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/*
* envrms~: simple envelope follower
*
* (c) 1999-2011 IOhannes m zmölnig, forum::für::umläute, institute of electronic music and acoustics (iem)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* 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 for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* ---------------- 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"
#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 */
t_sample *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 */
t_float x_result; /* result to output */
t_sample 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;
t_sample *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(*buf) * (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_sample *in = (t_sample *)(w[2]);
int n = (int)(w[3]);
int count;
t_sample *sump;
in += n;
for (count = x->x_phase, sump = x->x_sumbuf;
count < x->x_npoints; count += x->x_realperiod, sump++)
{
t_sample *hp = x->x_buf + count;
t_sample *fp = in;
t_sample 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(*x->x_buf));
}
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);
zexy_register("envrms~");
}
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