105 lines
2.2 KiB
C
105 lines
2.2 KiB
C
/*
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* arngment - random music generator
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*
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* Written in 2020 by Lucas
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*
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* To the extent possible under law, the author(s) have dedicated all
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* copyright and related and neighboring rights to this software to the
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* public domain worldwide. This software is distributed without any
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* warranty.
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*
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* You should have received a copy of the CC0 Public Domain Dedication
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* along with this software. If not, see
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* <http://creativecommons.org/publicdomain/zero/1.0/>.
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*/
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/* getopt, srand48, visibility for glibc */
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#if !defined(__OpenBSD__)
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#define _DEFAULT_SOURCE
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#endif
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#include <limits.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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#include "err.h"
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#include "lrand48_uniform.h"
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#include "note.h"
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#include "synth.h"
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#define nelems(_a) (sizeof(_a) / sizeof((_a)[0]))
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#define GAIN 1.4
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#define RATE 48000
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static void
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usage(void)
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{
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fprintf(stderr, "Usage: %s base_note\n", __progname);
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exit(1);
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}
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int
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main(int argc, char *argv[])
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{
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int16_t buf[RATE];
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int scale[] = {
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0, 2, 3, 5, 7, 8, 10, 12,
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0, 2, 3, 5, 7, 8, 10, 12,
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12, 14, 15, 17, 19, 20, 22, 24,
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};
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struct note base_note, note;
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double l, r, t;
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size_t i;
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uint32_t k;
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int ch;
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while ((ch = getopt(argc, argv, "")) != -1)
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switch (ch) {
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default:
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usage();
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}
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argc -= optind;
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argv += optind;
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if (argc != 1)
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usage();
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if (!note_parse(&base_note, argv[0]))
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errx(1, "Invalid note %s", argv[0]);
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srand48(time(NULL));
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for (;;) {
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k = lrand48_uniform(nelems(scale));
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note = base_note;
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note.offset += scale[k];
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for (i = 0; i < RATE / 2; i += 2) {
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t = i / (double)RATE;
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l = synth_distortion(GAIN,
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synth_sinewave(t, note_pitch(note)));
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r = synth_distortion(GAIN,
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synth_trianglewave(t, note_pitch(note)));
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buf[i] = l * INT16_MAX;
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buf[i + 1] = r * INT16_MAX;
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}
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k = lrand48_uniform(nelems(scale));
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note = base_note;
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note.offset += scale[k];
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for (; i < RATE; i += 2) {
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t = i / (double)RATE;
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l = synth_distortion(GAIN,
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synth_sinewave(t, note_pitch(note)));
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r = synth_distortion(GAIN,
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synth_trianglewave(t, note_pitch(note)));
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buf[i] = l * INT16_MAX;
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buf[i + 1] = r * INT16_MAX;
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}
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fwrite(buf, sizeof(buf[0]), RATE, stdout);
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}
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return 0;
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}
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