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#include <stdio.h>
#include <alsa/asoundlib.h>
#include <math.h>
#include <raylib.h>
#include <pthread.h>
#include <stdbool.h>
#define SAMPLE_RATE 48000
#define PERIOD_SIZE 480
#define AMPLITUDE 10000
#define check(ret) \
do { \
int res = (ret); \
if (res < 0) { \
fprintf(stderr, "%s:%d ERROR: %s (%d)\n", \
__FILE__, __LINE__, snd_strerror(res), res); \
exit(1); \
} \
} while (0)
typedef struct {
snd_pcm_t * pcm;
float *freqs;
size_t freqs_count;
bool should_stop;
} sound_thread_meta;
int set_hw_params(snd_pcm_t *pcm) {
snd_pcm_hw_params_t *hw_params;
snd_pcm_hw_params_alloca(&hw_params);
check(snd_pcm_hw_params_any(pcm, hw_params));
unsigned int resample = 1;
check(snd_pcm_hw_params_set_rate_resample(pcm, hw_params, resample));
check(snd_pcm_hw_params_set_access(pcm, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED));
check(snd_pcm_hw_params_set_format(pcm, hw_params, SND_PCM_FORMAT_S16_LE));
check(snd_pcm_hw_params_set_channels(pcm, hw_params, 1));
check(snd_pcm_hw_params_set_rate(pcm, hw_params, SAMPLE_RATE, 0));
snd_pcm_uframes_t period_size = PERIOD_SIZE;
check(snd_pcm_hw_params_set_period_size_near(pcm, hw_params, &period_size, 0));
snd_pcm_uframes_t buffer_size = period_size * 3;
check(snd_pcm_hw_params_set_buffer_size_near(pcm, hw_params, &buffer_size));
check(snd_pcm_hw_params(pcm, hw_params));
return 0;
}
short *gen_sine(short *buffer, size_t sample_count, float freq, float *phase) {
for (size_t i = 0; i < sample_count; i++) {
buffer[i] = AMPLITUDE * sinf(*phase);
*phase += 2 * M_PI * freq / SAMPLE_RATE;
if (*phase >= 2 * M_PI) *phase -= 2 * M_PI;
}
return buffer;
}
short *gen_square(short *buffer, size_t sample_count, float freq, float *phase) {
int samples_full_cycle = (float)SAMPLE_RATE / freq;
int samples_half_cycle = samples_full_cycle / 2.0f;
for (size_t i = 0; i < sample_count; i++) {
buffer[i] = *phase < samples_half_cycle ? AMPLITUDE : -AMPLITUDE;
*phase = (((int)*phase + 1) % samples_full_cycle);
}
return buffer;
}
short *gen_saw(short *buffer, size_t sample_count, float freq, float *phase) {
int samples_full_cycle = (float)SAMPLE_RATE / freq;
int step = AMPLITUDE / samples_full_cycle;
for (size_t i = 0; i < sample_count; i++) {
buffer[i] = *phase;
*phase += step;
if (*phase >= AMPLITUDE) {
*phase = -AMPLITUDE;
}
}
return buffer;
}
void *sound_thread_generate(void *ptr) {
sound_thread_meta *meta = ptr;
short buffer[PERIOD_SIZE];
float phase = 0.0f;
float prev_freq = meta->freqs[0];
while (!meta->should_stop) {
if (meta->freqs_count <= 0) {
continue;
}
float freq = meta->freqs[0];
if (freq != prev_freq) {
printf("%f\n", freq);
prev_freq = freq;
}
gen_saw(buffer, PERIOD_SIZE, freq, &phase);
snd_pcm_sframes_t written = snd_pcm_writei(meta->pcm, buffer, PERIOD_SIZE);
if (written < 0) {
snd_pcm_prepare(meta->pcm); // recover from xrun
}
}
return NULL;
}
typedef struct {
char key;
float freq;
} freq_map;
int main() {
snd_pcm_t *sound_device;
int err;
err = snd_pcm_open(&sound_device, "default", SND_PCM_STREAM_PLAYBACK, 0);
if (err < 0) {
printf("error: failed to open device: %s", snd_strerror(err));
return 1;
}
err = set_hw_params(sound_device);
if (err < 0) {
printf("error: failed to set parameters: %s", snd_strerror(err));
return 1;
}
SetConfigFlags(FLAG_WINDOW_RESIZABLE);
InitWindow(800, 800, "crynth");
SetTargetFPS(60);
float freqs[10];
freqs[0] = 220;
sound_thread_meta soundgen = {
.pcm = sound_device,
.freqs = freqs,
.freqs_count = 1,
.should_stop = false,
};
pthread_t sound_thread;
pthread_create(&sound_thread, NULL, sound_thread_generate, &soundgen);
while (!WindowShouldClose()) {
if (IsKeyDown(KEY_SPACE)) {
soundgen.freqs[0] = 900;
} else {
soundgen.freqs[0] = 500;
}
BeginDrawing();
ClearBackground(RAYWHITE);
EndDrawing();
}
soundgen.should_stop = true;
CloseWindow();
pthread_join(sound_thread, NULL);
check(snd_pcm_drop(sound_device));
check(snd_pcm_close(sound_device));
return 0;
}
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