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Diffstat (limited to 'src/noisi~.c')
| -rw-r--r-- | src/noisi~.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/noisi~.c b/src/noisi~.c new file mode 100644 index 0000000..14fb1be --- /dev/null +++ b/src/noisi~.c @@ -0,0 +1,167 @@ +/****************************************************** + * + * 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~")); +} |