1 files changed, 113 insertions, 0 deletions
diff --git a/src/dirac~.c b/src/dirac~.c
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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
+ *
+ ******************************************************/
+
+
+/*
+This external makes the two main test-functions available :
+dirac~ : will make a single peak (eg: a 1 in all the 0s) at a desired position in the signal-vector
+			the position can be passed as an argument when creating the object
+step~  : will make a unity step at a desired point in the signal-vector; the second input specifies a 
+			length:	after the so-specified time has elapsed, the step will toggle back to the previous
+			value;
+			the length can be passed as an argument when creating the object
+			with length==1 you might do the dirac~ thing a little bit more complicated
+			with length==0 the output just toggles between 0 and 1 every time you bang the object
+
+NOTE : the inlets do NOT specify any times but sample-NUMBERS; there are 64 samples in a signal-vector,
+		each "lasting" for 1/44100 secs.
+*/
+
+#include "zexy.h"
+
+/* ------------------------ dirac~ ----------------------------- */ 
+
+
+static t_class *dirac_class;
+
+typedef struct _dirac
+{
+    t_object x_obj;
+	t_float position;
+	t_float do_it;
+} t_dirac;
+
+static void dirac_bang(t_dirac *x)
+{
+	x->do_it = x->position;
+}
+
+static void dirac_float(t_dirac *x, t_float where)
+{
+	x->do_it = x->position = where;
+}
+
+static t_int *dirac_perform(t_int *w)
+{
+	t_dirac *x = (t_dirac *)(w[1]);
+	t_float *out = (t_float *)(w[2]);
+	int n = (int)(w[3]);
+
+	int do_it = x->do_it;
+
+	while (n--)
+		{
+		*out++ = (!do_it--);
+		}
+	x->do_it = do_it;
+
+	return (w+4);
+}
+
+static void dirac_dsp(t_dirac *x, t_signal **sp)
+{
+	dsp_add(dirac_perform, 3, x, sp[0]->s_vec, sp[0]->s_n);
+}
+
+static void dirac_helper(void)
+{
+	post("%c dirac~-object :: generates a dirac (unity-pulse)", HEARTSYMBOL);
+	post("creation : \"dirac~ [<position>]\" : create a dirac at specified position (in samples)\n"
+		 "inlet\t: <position>\t: create a dirac at new position\n"
+		 "\t  'bang'\t: create a dirac at specified position\n"
+		 "\t  'help'\t: view this\n"
+		 "outlet\t: signal~");
+}
+
+
+
+static void *dirac_new(t_floatarg where)
+{
+	t_dirac *x = (t_dirac *)pd_new(dirac_class);
+
+	outlet_new(&x->x_obj, gensym("signal"));
+
+	x->do_it = 0;
+	x->position = where;
+	return (x);
+}
+ 
+void dirac_tilde_setup(void)
+{
+	dirac_class = class_new(gensym("dirac~"), (t_newmethod)dirac_new, 0,
+		sizeof(t_dirac), 0, A_DEFFLOAT, 0);
+	class_addfloat(dirac_class, dirac_float); 
+	class_addbang(dirac_class, dirac_bang); 
+	class_addmethod(dirac_class, (t_method)dirac_dsp, gensym("dsp"), 0);
+
+	class_addmethod(dirac_class, (t_method)dirac_helper, gensym("help"), 0);
+    class_sethelpsymbol(dirac_class, gensym("zexy/dirac~"));
+  zexy_register("dirac~");
+}