Chris@40: /*
Chris@40: ** Copyright (C) 2007-2012 Erik de Castro Lopo <erikd@mega-nerd.com>
Chris@40: **
Chris@40: ** This program is free software; you can redistribute it and/or modify
Chris@40: ** it under the terms of the GNU General Public License as published by
Chris@40: ** the Free Software Foundation; either version 2 of the License, or
Chris@40: ** (at your option) any later version.
Chris@40: **
Chris@40: ** This program is distributed in the hope that it will be useful,
Chris@40: ** but WITHOUT ANY WARRANTY; without even the implied warranty of
Chris@40: ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
Chris@40: ** GNU General Public License for more details.
Chris@40: **
Chris@40: ** You should have received a copy of the GNU General Public License
Chris@40: ** along with this program; if not, write to the Free Software
Chris@40: ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Chris@40: */
Chris@40: 
Chris@40: #include <stdio.h>
Chris@40: #include <stdlib.h>
Chris@40: #include <string.h>
Chris@40: #include <math.h>
Chris@40: 
Chris@40: #include <sndfile.h>
Chris@40: 
Chris@40: #include "utils.h"
Chris@40: #include "generate.h"
Chris@40: 
Chris@40: #define	SF_MAX(x, y)		((x) > (y) ? (x) : (y))
Chris@40: 
Chris@40: static float crappy_snare (float *output, int len, int offset, float gain, float maxabs) ;
Chris@40: 
Chris@40: void
Chris@40: generate_file (const char * filename, int format, int len)
Chris@40: {	float * output ;
Chris@40: 	float maxabs = 0.0 ;
Chris@40: 
Chris@40: 	output = calloc (len, sizeof (float)) ;
Chris@40: 
Chris@40: 	maxabs = crappy_snare (output, len, 0, 0.95, maxabs) ;
Chris@40: 	maxabs = crappy_snare (output, len, len / 4, 0.85, maxabs) ;
Chris@40: 	maxabs = crappy_snare (output, len, 2 * len / 4, 0.85, maxabs) ;
Chris@40: 	crappy_snare (output, len, 3 * len / 4, 0.85, maxabs) ;
Chris@40: 
Chris@40: 	write_mono_file (filename, format, 44100, output, len) ;
Chris@40: 
Chris@40: 	free (output) ;
Chris@40: } /* generate_file */
Chris@40: 
Chris@40: static inline float
Chris@40: rand_float (void)
Chris@40: {	return rand () / (0.5 * RAND_MAX) - 1.0 ;
Chris@40: } /* rand_float */
Chris@40: 
Chris@40: static float
Chris@40: crappy_snare (float *output, int len, int offset, float gain, float maxabs)
Chris@40: {	int k ;
Chris@40: 	float env = 0.0 ;
Chris@40: 
Chris@40: 	for (k = offset ; k < len && env < gain ; k++)
Chris@40: 	{	env += 0.03 ;
Chris@40: 		output [k] += env * rand_float () ;
Chris@40: 		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
Chris@40: 		} ;
Chris@40: 
Chris@40: 	for ( ; k < len && env > 1e-8 ; k++)
Chris@40: 	{	env *= 0.995 ;
Chris@40: 		output [k] += env * rand_float () ;
Chris@40: 		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
Chris@40: 		} ;
Chris@40: 
Chris@40: 	return maxabs ;
Chris@40: } /* crappy_snare */