91 lines
2.0 KiB
C
91 lines
2.0 KiB
C
/*
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* simple-tone-generator.c
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*
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* Copyright (C) 2011 Kamal Mostafa <kamal@whence.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <math.h>
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#include <strings.h>
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#include <malloc.h>
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#include <assert.h>
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#include "simpleaudio.h"
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/* "current" phase state of the tone generator */
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static float sa_tone_cphase = 0.0;
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void
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simpleaudio_tone_reset()
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{
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sa_tone_cphase = 0.0;
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}
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void
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simpleaudio_tone(simpleaudio *sa_out, float tone_freq, size_t nsamples_dur)
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{
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unsigned int framesize = simpleaudio_get_framesize(sa_out);
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void *buf = malloc(nsamples_dur * framesize);
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assert(buf);
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if ( tone_freq != 0 ) {
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float wave_nsamples = simpleaudio_get_rate(sa_out) / tone_freq;
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size_t i;
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#define SINE_PHASE_ANGLE ( M_PI*2.0*(i/wave_nsamples + sa_tone_cphase) )
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switch ( simpleaudio_get_format(sa_out) ) {
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case SA_SAMPLE_FORMAT_FLOAT:
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{
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float *float_buf = buf;
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for ( i=0; i<nsamples_dur; i++ )
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float_buf[i] = sinf(SINE_PHASE_ANGLE);
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}
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break;
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case SA_SAMPLE_FORMAT_S16:
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{
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short *float_buf = buf;
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for ( i=0; i<nsamples_dur; i++ )
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float_buf[i] = 32767 * sinf(SINE_PHASE_ANGLE);
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}
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break;
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default:
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assert(0);
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break;
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}
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sa_tone_cphase
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= fmodf(sa_tone_cphase + (float)nsamples_dur/wave_nsamples, 1.0);
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} else {
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bzero(buf, nsamples_dur * framesize);
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sa_tone_cphase = 0.0;
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}
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assert ( simpleaudio_write(sa_out, buf, nsamples_dur) > 0 );
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free(buf);
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}
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