cannam@85: /*
cannam@85: ** Copyright (C) 2007-2011 Erik de Castro Lopo <erikd@mega-nerd.com>
cannam@85: **
cannam@85: ** This program is free software; you can redistribute it and/or modify
cannam@85: ** it under the terms of the GNU General Public License as published by
cannam@85: ** the Free Software Foundation; either version 2 of the License, or
cannam@85: ** (at your option) any later version.
cannam@85: **
cannam@85: ** This program is distributed in the hope that it will be useful,
cannam@85: ** but WITHOUT ANY WARRANTY; without even the implied warranty of
cannam@85: ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
cannam@85: ** GNU General Public License for more details.
cannam@85: **
cannam@85: ** You should have received a copy of the GNU General Public License
cannam@85: ** along with this program; if not, write to the Free Software
cannam@85: ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
cannam@85: */
cannam@85: 
cannam@85: #include <stdio.h>
cannam@85: #include <stdlib.h>
cannam@85: #include <string.h>
cannam@85: #include <math.h>
cannam@85: 
cannam@85: #include <sndfile.h>
cannam@85: 
cannam@85: #include "utils.h"
cannam@85: #include "generate.h"
cannam@85: 
cannam@85: #define	SF_MAX(x,y)		((x) > (y) ? (x) : (y))
cannam@85: 
cannam@85: static float crappy_snare (float *output, int len, int offset, float gain, float maxabs) ;
cannam@85: 
cannam@85: void
cannam@85: generate_file (const char * filename, int format, int len)
cannam@85: {	float * output ;
cannam@85: 	float maxabs = 0.0 ;
cannam@85: 
cannam@85: 	output = calloc (len, sizeof (float)) ;
cannam@85: 
cannam@85: 	maxabs = crappy_snare (output, len, 0, 0.95, maxabs) ;
cannam@85: 	maxabs = crappy_snare (output, len, len / 4, 0.85, maxabs) ;
cannam@85: 	maxabs = crappy_snare (output, len, 2 * len / 4, 0.85, maxabs) ;
cannam@85: 	crappy_snare (output, len, 3 * len / 4, 0.85, maxabs) ;
cannam@85: 
cannam@85: 	write_mono_file (filename, format, 44100, output, len) ;
cannam@85: 
cannam@85: 	free (output) ;
cannam@85: } /* generate_file */
cannam@85: 
cannam@85: static inline float
cannam@85: rand_float (void)
cannam@85: {	return rand () / (0.5 * RAND_MAX) - 1.0 ;
cannam@85: } /* rand_float */
cannam@85: 
cannam@85: static float
cannam@85: crappy_snare (float *output, int len, int offset, float gain, float maxabs)
cannam@85: {	int k ;
cannam@85: 	float env = 0.0 ;
cannam@85: 
cannam@85: 	for (k = offset ; k < len && env < gain ; k++)
cannam@85: 	{	env += 0.03 ;
cannam@85: 		output [k] += env * rand_float () ;
cannam@85: 		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
cannam@85: 		} ;
cannam@85: 
cannam@85: 	for ( ; k < len && env > 1e-8 ; k++)
cannam@85: 	{	env *= 0.995 ;
cannam@85: 		output [k] += env * rand_float () ;
cannam@85: 		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
cannam@85: 		} ;
cannam@85: 
cannam@85: 	return maxabs ;
cannam@85: } /* crappy_snare */