aboutsummaryrefslogtreecommitdiff
path: root/src/noisi~.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/noisi~.c')
-rw-r--r--src/noisi~.c167
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~"));
+}