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/*
* sbosc.c - smallband oscillator. periodic, linear interpolated
* frequency center.
*
* Copyright (c) 2000-2003 by Tom Schouten
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "m_pd.h"
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define LOGTABSIZE 10
#define TABSIZE (1<<LOGTABSIZE)
#define MASKTABSIZE (TABSIZE-1)
#define SHIFTTABSIZE ((sizeof(unsigned int) * 8) - LOGTABSIZE)
#define FRACTABSIZE (1<<SHIFTTABSIZE)
#define INVFRACTABSIZE (1.0f / (float)(FRACTABSIZE))
#define MASKFRACTABSIZE (FRACTABSIZE-1)
#define PITCHLIMIT 20.0f
static float costable[TABSIZE];
static inline void _exp_j2pi(unsigned int t, float *real, float *imag)
{
unsigned int i1 = t >> SHIFTTABSIZE;
float f2 = (t & MASKFRACTABSIZE) * INVFRACTABSIZE;
unsigned int i2 = (i1+1) & MASKTABSIZE;
unsigned int i3 = (i1 - (TABSIZE>>2)) & MASKTABSIZE;
unsigned int i4 = (i2 + 1 - (TABSIZE>>2)) & MASKTABSIZE;
float f1 = 1.0f - f2;
float a1 = f1 * costable[i1];
float a2 = f2 * costable[i2];
float b1 = f1 * costable[i3];
float b2 = f2 * costable[i4];
*real = a1 + a2;
*imag = b1 + b2;
}
static t_class *sbosc_tilde_class;
typedef struct _sbosc_tilde
{
t_object x_obj;
float x_f;
/* state vars */
unsigned int x_phase; // phase of main pitch osc
unsigned int x_phase_inc; // frequency of main pitch osc
unsigned int x_harmonic; // first harmonic
float x_frac; // fraction of first harmonic
} t_sbosc_tilde;
static void *sbosc_tilde_new(void)
{
t_sbosc_tilde *x = (t_sbosc_tilde *)pd_new(sbosc_tilde_class);
x->x_phase = 0;
inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("signal"), gensym("signal"));
inlet_new(&x->x_obj, &x->x_obj.ob_pd, gensym("float"), gensym("phase"));
outlet_new(&x->x_obj, gensym("signal"));
outlet_new(&x->x_obj, gensym("signal"));
x->x_f = 0;
return (x);
}
static t_int *sbosc_tilde_perform(t_int *w)
{
t_sbosc_tilde *x = (t_sbosc_tilde *)(w[1]);
t_float *pitch = (t_float *)(w[2]);
t_float *center= (t_float *)(w[3]);
t_float *out_real = (t_float *)(w[4]);
t_float *out_imag = (t_float *)(w[5]);
int n = (int)(w[6]);
int i;
t_float pitch_to_phase = 4294967295.0f / sys_getsr();
for (i = 0; i < n; i++)
{
float p = *pitch++;
float c = *center++;
float r1,r2,i1,i2;
/* compute harmonic mixture */
unsigned int h1 = x->x_phase * x->x_harmonic;
unsigned int h2 = h1 + x->x_phase;
_exp_j2pi(h1, &r1, &i1);
_exp_j2pi(h2, &r2, &i2);
r1 *= x->x_frac;
i1 *= x->x_frac;
r2 *= 1.0f - x->x_frac;
i2 *= 1.0f - x->x_frac;
*out_real++ = r1 + r2;
*out_imag++ = i1 + i2;
x->x_phase += x->x_phase_inc;
/* check for phase wrap & update osc */
if ((x->x_phase <= x->x_phase_inc))
{
float p_plus = (p < 0.0f) ? -p : p;
float p_limit = (p_plus < PITCHLIMIT) ? PITCHLIMIT : p_plus;
float c_plus = (c < 0.0f) ? -c : c;
float harmonic = c_plus/p_limit;
x->x_phase_inc = pitch_to_phase * p_limit;
x->x_harmonic = harmonic;
x->x_frac = 1.0f - (harmonic - x->x_harmonic);
}
}
return (w+7);
}
static void sbosc_tilde_dsp(t_sbosc_tilde *x, t_signal **sp)
{
dsp_add(sbosc_tilde_perform, 6, x,
sp[0]->s_vec, sp[1]->s_vec, sp[2]->s_vec, sp[3]->s_vec, sp[0]->s_n);
}
static void sbosc_tilde_free(t_sbosc_tilde *x)
{
}
static void sbosc_tilde_phase(t_sbosc_tilde *x, t_floatarg f)
{
x->x_phase = f * (1.0f / 4294967295.0f);
}
void sbosc_tilde_setup(void)
{
int i;
// init tables
for (i=0; i<TABSIZE; i++)
costable[i] = cos(2.0 * M_PI * (double)i / (double)TABSIZE);
// class setup
sbosc_tilde_class = class_new(gensym("sbosc~"),
(t_newmethod)sbosc_tilde_new, (t_method)sbosc_tilde_free,
sizeof(t_sbosc_tilde), 0, A_DEFSYM, 0);
CLASS_MAINSIGNALIN(sbosc_tilde_class, t_sbosc_tilde, x_f);
class_addmethod(sbosc_tilde_class, (t_method)sbosc_tilde_dsp,
gensym("dsp"), 0);
class_addmethod(sbosc_tilde_class, (t_method)sbosc_tilde_phase,
gensym("phase"), A_FLOAT, 0);
}
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