58 lines
1.1 KiB
C
58 lines
1.1 KiB
C
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/*
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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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* NO LICENSE HAS BEEN SPECIFIED OR GRANTED FOR THIS WORK.
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*
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*/
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#include <math.h>
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#include <strings.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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#define TONE_GEN_BUFSIZE (10*48000) // FIXME
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float buf[TONE_GEN_BUFSIZE];
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assert ( nsamples_dur <= TONE_GEN_BUFSIZE );
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if ( tone_freq != 0 ) {
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float wave_nsamples = 48000.0 / tone_freq; // FIXME rate
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size_t i;
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for ( i=0; i<nsamples_dur; i++ ) {
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buf[i] = sinf( M_PI*2.0*( i/wave_nsamples + sa_tone_cphase) );
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buf[i] /= 2.0; // normalize (for pulseaudio?) */
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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*sizeof(float));
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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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}
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