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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
*
******************************************************/
/*
30041999
two bandlimited noise gnerators based on DODGE/JERSE "computer music" c3.9 : RANDI & RANDH
I do not care for copyrights
(all in all, the used noise~-code (in fact, the pseude-random-code) is from Miller Puckette
and I made only very few modifications so look out for the LICENSE.TXT delivered with
puredata for further (c)-information
forum für umläute 1999
this is in fact the very same as the late "NOISE.C", except that I tried to optimize the code a little bit
(by partially removing those very expensive if..then's in about 15 minutes, so there are thousands of new bugs very likely)
14071999
finally added changing seeds, this is to prevent to noise~-units to output the very same, something quite unnatural even for pseudo-random-noise
*/
#include "zexy.h"
/* general */
typedef struct _nois
{
t_object x_obj;
int val;
t_float current;
t_float decrement;
t_float updater;
t_float to_go;
} t_nois;
static void set_noisfreq(t_nois *x, t_floatarg freq)
{
x->updater = (freq > 0) ? sys_getsr() / freq : 1;
if (x->updater < 1)
{
x->updater = 1;
}
x->to_go = 0;
}
/* ------------------------ noisi~ ----------------------------- */
static t_class *noisi_class;
static t_int *noisi_perform(t_int *w){
t_nois *x = (t_nois *)(w[1]);
t_float *out = (t_float *)(w[2]);
int n = (int)(w[3]);
int *vp = (int *)(&x->val); /* what the ... */
int i_value = *vp;
t_float f_value = x->current;
t_float decrement = x->decrement;
t_float all_to_go = x->updater;
t_float still_to_go = x->to_go;
if (all_to_go == 1) {
/* this is "pure white" noise, so we have to calculate each sample */
while (n--) {
i_value *= 435898247;
i_value += 382842987;
*out++ = ((t_sample)((i_value & 0x7fffffff) - 0x40000000)) * (t_sample)(1.0 / 0x40000000);
}
} else if (n < still_to_go) {
/* signal won't change for the next 64 samples */
still_to_go -= n;
while (n--){
*out++ = (f_value -= decrement);
}
} else if (all_to_go + still_to_go > n) {
/* only one update calculation necessary for 64 samples !!! */
while (still_to_go-- > 0) {
n--;
*out++ = (f_value -= decrement);
}
still_to_go += all_to_go + 1;
decrement = (
(f_value =
((t_sample)((i_value & 0x7fffffff)-0x40000000))*(t_sample)(1.0 / 0x40000000)) -
((t_sample)(((i_value = i_value * 435898247 + 382842987) & 0x7fffffff)
- 0x40000000)) * (t_sample)(1.0 / 0x40000000)
) / all_to_go;
while (n--) {
still_to_go--;
*out++ = (f_value -= decrement);
}
} else {
/* anything else */
while (n--) {
if (still_to_go-- <= 0) { /* update only if all time has elapsed */
still_to_go += all_to_go;
decrement = (
(f_value = ((t_sample)((i_value & 0x7fffffff) - 0x40000000)) * (t_sample)(1.0 / 0x40000000)) -
((t_sample)(((i_value = i_value * 435898247 + 382842987) & 0x7fffffff) - 0x40000000)) * (t_sample)(1.0 / 0x40000000)
) / all_to_go;
}
*out++ = (f_value -= decrement);
}
}
*vp = i_value;
x->current = f_value;
x->decrement = decrement;
x->to_go = still_to_go;
return (w+4);
}
static void noisi_dsp(t_nois *x, t_signal **sp){
dsp_add(noisi_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
}
static void noisi_helper(void){
post("\n%c noisi~\t:: a bandlimited interpolating pseudo-noise generator", HEARTSYMBOL);
post("<freq>\t : sampling-frequency (in Hz)\n"
"'help'\t : view this");
post("creation : \"noisi~ [<freq>]\"\t: ('0'(default) will produce 'white' noise)\n");
post("note\t : the seed of the pseudo-noise generator changes from\n"
"\t instance to instance, so two noisi~-objects created at the\n"
"\t same time will produce different signals, something the original\n"
"\t noise~-object misses\n");
post("for further details see DODGE/JERSE \"computer music\" c3.9\n");
}
static void *noisi_new(t_floatarg f){
t_nois *x = (t_nois *)pd_new(noisi_class);
static int init = 4259;
x->val = (init *= 17);
set_noisfreq (x, f);
outlet_new(&x->x_obj, gensym("signal"));
return (x);
}
void noisi_tilde_setup(void){
noisi_class = class_new(gensym("noisi~"), (t_newmethod)noisi_new, 0, sizeof(t_nois), 0, A_DEFFLOAT, 0);
class_addfloat(noisi_class, set_noisfreq);
class_addmethod(noisi_class, (t_method)noisi_dsp, gensym("dsp"), 0);
class_addmethod(noisi_class, (t_method)noisi_helper, gensym("help"), 0);
class_sethelpsymbol(noisi_class, gensym("zexy/noisi~"));
}
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