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/*
** Copyright (C) 2007-2011 Erik de Castro Lopo <erikd@mega-nerd.com>
**
** 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <sndfile.h>
#include "utils.h"
#include "generate.h"
#define SF_MAX(x,y) ((x) > (y) ? (x) : (y))
static float crappy_snare (float *output, int len, int offset, float gain, float maxabs) ;
void
generate_file (const char * filename, int format, int len)
{ float * output ;
float maxabs = 0.0 ;
output = calloc (len, sizeof (float)) ;
maxabs = crappy_snare (output, len, 0, 0.95, maxabs) ;
maxabs = crappy_snare (output, len, len / 4, 0.85, maxabs) ;
maxabs = crappy_snare (output, len, 2 * len / 4, 0.85, maxabs) ;
crappy_snare (output, len, 3 * len / 4, 0.85, maxabs) ;
write_mono_file (filename, format, 44100, output, len) ;
free (output) ;
} /* generate_file */
static inline float
rand_float (void)
{ return rand () / (0.5 * RAND_MAX) - 1.0 ;
} /* rand_float */
static float
crappy_snare (float *output, int len, int offset, float gain, float maxabs)
{ int k ;
float env = 0.0 ;
for (k = offset ; k < len && env < gain ; k++)
{ env += 0.03 ;
output [k] += env * rand_float () ;
maxabs = SF_MAX (maxabs, fabs (output [k])) ;
} ;
for ( ; k < len && env > 1e-8 ; k++)
{ env *= 0.995 ;
output [k] += env * rand_float () ;
maxabs = SF_MAX (maxabs, fabs (output [k])) ;
} ;
return maxabs ;
} /* crappy_snare */
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