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/* ------------------------- delta ------------------------------------------ */
/* */
/* Claculate 1st or 2nd order difference. */
/* Written by Olaf Matthes (olaf.matthes@gmx.de) */
/* Inspired by code written by Trond Lossius. */
/* Get source at http://www.akustische-kunst.org/puredata/maxlib/ */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU General Public License */
/* as published by the Free Software Foundation; either version 2 */
/* of the License, or (at your option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public License */
/* along with this program; if not, write to the Free Software */
/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* */
/* Based on PureData by Miller Puckette and others. */
/* */
/* ---------------------------------------------------------------------------- */
#include "m_pd.h"
#include <stdio.h>
#define MAXSIZE 32
static char *version = "delta v0.1, written by Olaf Matthes <olaf.matthes@gmx.de>";
typedef struct delta
{
t_object x_ob;
t_outlet *x_out; /* result */
t_int x_order; /* 1st or second order */
t_int x_clearflag;
t_float x_delta; /* the result */
t_float x_prev; /* previous value */
t_float x_prev2; /* value previous to previous value */
} t_delta;
static void delta_clear(t_delta *x)
{
if(x->x_order == 2)
x->x_clearflag = 2;
else
x->x_clearflag = 1;
x->x_delta = 0;
}
static void delta_bang(t_delta *x)
{
outlet_float(x->x_out, x->x_delta);
}
static void delta_float(t_delta *x, t_floatarg f)
{
if(x->x_order != 2) /* first order */
{
if(x->x_clearflag)
{
x->x_prev = f;
x->x_delta = 0;
x->x_clearflag = 0;
}
else
{
x->x_delta = f - x->x_prev;
x->x_prev = f;
}
}
else
{
switch(x->x_clearflag)
{
case 0:
x->x_delta = f - 2*x->x_prev + x->x_prev2;
x->x_prev2 = x->x_prev;
x->x_prev = f;
break;
case 1:
x->x_prev = f;
x->x_clearflag--;
break;
case 2:
x->x_prev2 = f;
x->x_clearflag--;
break;
}
}
delta_bang(x);
}
static t_class *delta_class;
static void *delta_new(t_floatarg f)
{
int i;
t_delta *x = (t_delta *)pd_new(delta_class);
x->x_out = outlet_new(&x->x_ob, gensym("float"));
x->x_order = (int)f;
if(x->x_order == 2)
x->x_clearflag = 2;
else
x->x_clearflag = 1;
x->x_delta = 0;
#ifndef MAXLIB
post(version);
#endif
return (void *)x;
}
void delta_setup(void)
{
delta_class = class_new(gensym("delta"), (t_newmethod)delta_new,
0, sizeof(t_delta), 0, A_DEFFLOAT, 0);
class_addfloat(delta_class, delta_float);
class_addbang(delta_class, (t_method)delta_bang);
class_addmethod(delta_class, (t_method)delta_clear, gensym("clear"), 0);
class_sethelpsymbol(delta_class, gensym("maxlib/help-delta.pd"));
}
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