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/* Recreate exstream.c from A4. */
#include <stdio.h>
#include <math.h>
#include "allegro5/allegro.h"
#include "allegro5/allegro_audio.h"
#include "common.c"
#define SAMPLES_PER_BUFFER 1024
static void saw(ALLEGRO_AUDIO_STREAM *stream)
{
ALLEGRO_EVENT_QUEUE *queue;
int8_t *buf;
int pitch = 0x10000;
int val = 0;
int i;
int n = 200;
queue = al_create_event_queue();
al_register_event_source(queue, al_get_audio_stream_event_source(stream));
#ifdef ALLEGRO_POPUP_EXAMPLES
if (textlog) {
al_register_event_source(queue, al_get_native_text_log_event_source(textlog));
}
#endif
log_printf("Generating saw wave...\n");
while (n > 0) {
ALLEGRO_EVENT event;
al_wait_for_event(queue, &event);
if (event.type == ALLEGRO_EVENT_AUDIO_STREAM_FRAGMENT) {
buf = al_get_audio_stream_fragment(stream);
if (!buf) {
/* This is a normal condition you must deal with. */
continue;
}
for (i = 0; i < SAMPLES_PER_BUFFER; i++) {
/* Crude saw wave at maximum amplitude. Please keep this compatible
* to the A4 example so we know when something has broken for now.
*
* It would be nice to have a better example with user interface
* and some simple synth effects.
*/
buf[i] = ((val >> 16) & 0xff);
val += pitch;
pitch++;
}
if (!al_set_audio_stream_fragment(stream, buf)) {
log_printf("Error setting stream fragment.\n");
}
n--;
if ((n % 10) == 0) {
log_printf(".");
fflush(stdout);
}
}
#ifdef ALLEGRO_POPUP_EXAMPLES
if (event.type == ALLEGRO_EVENT_NATIVE_DIALOG_CLOSE) {
break;
}
#endif
}
al_drain_audio_stream(stream);
log_printf("\n");
al_destroy_event_queue(queue);
}
int main(int argc, char **argv)
{
ALLEGRO_AUDIO_STREAM *stream;
void *buf;
(void)argc;
(void)argv;
if (!al_init()) {
abort_example("Could not init Allegro.\n");
}
if (!al_install_audio()) {
abort_example("Could not init sound.\n");
}
al_reserve_samples(0);
stream = al_create_audio_stream(8, SAMPLES_PER_BUFFER, 22050,
ALLEGRO_AUDIO_DEPTH_UINT8, ALLEGRO_CHANNEL_CONF_1);
while ((buf = al_get_audio_stream_fragment(stream))) {
al_fill_silence(buf, SAMPLES_PER_BUFFER, ALLEGRO_AUDIO_DEPTH_UINT8,
ALLEGRO_CHANNEL_CONF_1);
al_set_audio_stream_fragment(stream, buf);
}
if (!stream) {
abort_example("Could not create stream.\n");
}
if (!al_attach_audio_stream_to_mixer(stream, al_get_default_mixer())) {
abort_example("Could not attach stream to mixer.\n");
}
open_log();
saw(stream);
close_log(false);
al_destroy_audio_stream(stream);
al_uninstall_audio();
return 0;
}
/* vim: set sts=3 sw=3 et: */
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