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/*
* Example program for the Allegro library, by Peter Wang.
*
* This program demonstrates a simple use of mixer postprocessing callbacks.
*/
#include <math.h>
#include "allegro5/allegro.h"
#include "allegro5/allegro_audio.h"
#include "allegro5/allegro_acodec.h"
#include "allegro5/allegro_image.h"
#include "allegro5/allegro_primitives.h"
#include "common.c"
#define FPS 60
static volatile float rms_l = 0.0;
static volatile float rms_r = 0.0;
static ALLEGRO_DISPLAY *display;
static ALLEGRO_BITMAP *dbuf;
static ALLEGRO_BITMAP *bmp;
static float theta;
static void update_meter(void *buf, unsigned int samples, void *data)
{
float *fbuf = (float *)buf;
float sum_l = 0.0;
float sum_r = 0.0;
unsigned int i;
(void)data;
for (i = samples; i > 0; i--) {
sum_l += fbuf[0] * fbuf[0];
sum_r += fbuf[1] * fbuf[1];
fbuf += 2;
}
rms_l = sqrt(sum_l / samples);
rms_r = sqrt(sum_r / samples);
}
static void draw(void)
{
const float sw = al_get_bitmap_width(bmp);
const float sh = al_get_bitmap_height(bmp);
const float dw = al_get_bitmap_width(dbuf);
const float dh = al_get_bitmap_height(dbuf);
const float dx = dw / 2.0;
const float dy = dh / 2.0;
float db_l;
float db_r;
float db;
float scale;
float disp;
/* Whatever looks okay. */
if (rms_l > 0.0 && rms_r > 0.0) {
db_l = 20 * log10(rms_l / 20e-6);
db_r = 20 * log10(rms_r / 20e-6);
db = (db_l + db_r) / 2.0;
scale = db / 20.0;
disp = (rms_l + rms_r) * 200.0;
}
else {
db_l = db_r = db = scale = disp = 0.0;
}
al_set_target_bitmap(dbuf);
al_set_blender(ALLEGRO_ADD, ALLEGRO_ALPHA, ALLEGRO_INVERSE_ALPHA);
al_draw_filled_rectangle(0, 0, al_get_bitmap_width(dbuf), al_get_bitmap_height(dbuf),
al_map_rgba_f(0.8, 0.3, 0.1, 0.06));
al_set_blender(ALLEGRO_ADD, ALLEGRO_ONE, ALLEGRO_INVERSE_ALPHA);
al_draw_tinted_scaled_rotated_bitmap(bmp,
al_map_rgba_f(0.8, 0.3, 0.1, 0.2),
sw/2.0, sh/2.0, dx, dy - disp, scale, scale, theta, 0);
al_set_blender(ALLEGRO_ADD, ALLEGRO_ONE, ALLEGRO_ZERO);
al_set_target_backbuffer(display);
al_draw_bitmap(dbuf, 0, 0, 0);
al_set_blender(ALLEGRO_ADD, ALLEGRO_ALPHA, ALLEGRO_INVERSE_ALPHA);
al_draw_line(10, dh - db_l, 10, dh, al_map_rgb_f(1, 0.6, 0.2), 6);
al_draw_line(20, dh - db_r, 20, dh, al_map_rgb_f(1, 0.6, 0.2), 6);
al_flip_display();
theta -= (rms_l + rms_r) * 0.1;
}
static void main_loop(void)
{
ALLEGRO_EVENT_QUEUE *queue;
ALLEGRO_EVENT event;
bool redraw = true;
queue = al_create_event_queue();
al_register_event_source(queue, al_get_keyboard_event_source());
al_register_event_source(queue, al_get_display_event_source(display));
theta = 0.0;
for (;;) {
if (redraw && al_is_event_queue_empty(queue)) {
draw();
redraw = false;
}
if (!al_wait_for_event_timed(queue, &event, 1.0/FPS)) {
redraw = true;
continue;
}
if (event.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
break;
}
if (event.type == ALLEGRO_EVENT_KEY_DOWN &&
event.keyboard.keycode == ALLEGRO_KEY_ESCAPE) {
break;
}
}
al_destroy_event_queue(queue);
}
int main(int argc, char **argv)
{
const char *filename = "../demos/cosmic_protector/data/sfx/title_music.ogg";
ALLEGRO_VOICE *voice;
ALLEGRO_MIXER *mixer;
ALLEGRO_AUDIO_STREAM *stream;
if (argc > 1) {
filename = argv[1];
}
if (!al_init()) {
abort_example("Could not init Allegro.\n");
}
al_init_primitives_addon();
al_init_image_addon();
al_init_acodec_addon();
init_platform_specific();
al_install_keyboard();
display = al_create_display(640, 480);
if (!display) {
abort_example("Could not create display.\n");
}
dbuf = al_create_bitmap(640, 480);
bmp = al_load_bitmap("data/mysha.pcx");
if (!bmp) {
abort_example("Could not load data/mysha.pcx\n");
}
if (!al_install_audio()) {
abort_example("Could not init sound.\n");
}
voice = al_create_voice(44100, ALLEGRO_AUDIO_DEPTH_INT16,
ALLEGRO_CHANNEL_CONF_2);
if (!voice) {
abort_example("Could not create voice.\n");
}
mixer = al_create_mixer(44100, ALLEGRO_AUDIO_DEPTH_FLOAT32,
ALLEGRO_CHANNEL_CONF_2);
if (!mixer) {
abort_example("Could not create mixer.\n");
}
if (!al_attach_mixer_to_voice(mixer, voice)) {
abort_example("al_attach_mixer_to_voice failed.\n");
}
stream = al_load_audio_stream(filename, 4, 2048);
if (!stream) {
/* On Android we only pack this into the APK. */
stream = al_load_audio_stream("data/welcome.wav", 4, 2048);
}
if (!stream) {
abort_example("Could not load '%s'\n", filename);
}
al_set_audio_stream_playmode(stream, ALLEGRO_PLAYMODE_LOOP);
al_attach_audio_stream_to_mixer(stream, mixer);
al_set_mixer_postprocess_callback(mixer, update_meter, NULL);
main_loop();
al_destroy_audio_stream(stream);
al_destroy_mixer(mixer);
al_destroy_voice(voice);
al_uninstall_audio();
al_destroy_bitmap(dbuf);
al_destroy_bitmap(bmp);
return 0;
}
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