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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~");
+}