/* $Id: flange.c,v 1.4 1999/03/10 07:58:03 boyns Exp $ */
/*
* Copyright (C) 1993-99 Mark R. Boyns <boyns@doit.org>
*
* This file is part of rplay.
*
* rplay 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.
*
* rplay 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 rplay; see the file COPYING. If not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
#include "rplayd.h"
#ifdef TEST_FLANGE
typedef struct
{
float rate; /* rate of delay change (-1.0 - 1.0) */
float sweep; /* sweep range in milliseconds */
float delay; /* fixed additional delay in milliseconds */
float dry_mix; /* mix of unaffected signal (-1.0 - 1.0) */
float wet_mix; /* mix of affected signal (-1.0 - 1.0) */
float feedback; /* amount of recirculation (-1.0 - 1.0) */
float depth;
}
parameters;
parameters p =
{2.0, 20.0, 0.0, 0.5, 0.5, 0.0, 10};
#define SPMS 8
#define SPS 8000
#define BFSZ 1024
float Buf[BFSZ];
typedef union
{
unsigned char b[2];
unsigned short w;
}
bw;
typedef union
{
unsigned short w[2];
long l;
}
wl;
void
flange(char *native_buf, int nsamples, int nchannels)
{
short *sample = (short *) native_buf;
short *flanged = (short *) native_buf;
int size = nsamples * nchannels;
static int first = 1;
static int i, fp, ep1, ep2;
static int step, depth, delay, min_sweep, max_sweep;
static float inval, outval, ifac = 65536.0;
static wl sweep;
if (first)
{
first = 0;
step = (int) (p.rate * 65.536);
depth = (int) (p.depth * (float) SPMS);
delay = (int) (p.delay * (float) SPMS);
max_sweep = BFSZ - 2 - delay;
min_sweep = max_sweep - depth;
if (min_sweep < 0)
{
exit(1);
}
sweep.w[0] = (min_sweep + max_sweep) / 2;
sweep.w[1] = 0;
fp = ep1 = ep2 = 0;
}
#if 0
printf("step = %d, depth = %d, delay = %d\n", step, depth, delay);
printf("max_sweep = %d, min_sweep = %d\n", max_sweep, min_sweep);
#endif
for (i = 0; i < size; i++)
{
outval = (Buf[ep1] * sweep.w[1] + Buf[ep2] * (ifac - sweep.w[1])) / ifac;
Buf[fp] = (inval = (float) sample[i]) + outval * p.feedback;
outval = outval * p.wet_mix + inval * p.dry_mix;
if (outval > 32000)
flanged[i] = 32000;
else if (outval < -32000)
flanged[i] = -32000;
else
flanged[i] = (int) outval;
fp = (fp + 1) & (BFSZ - 1);
sweep.l += step;
ep1 = (fp + sweep.w[0]) & (BFSZ - 1);
ep2 = (ep1 - 1) & (BFSZ - 1);
if (sweep.w[0] > max_sweep)
step = -step;
else if (sweep.w[0] < min_sweep)
step = -step;
}
}
#endif /* TEST_FLANGE */