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#include <allegro5/allegro.h>
#include <stdio.h>
#include "common.c"
#define WIDTH 640
#define HEIGHT 480
#define NUM_STARS 300
#define TARGET_FPS 9999
typedef struct Point
{
float x, y;
} Point;
int main(int argc, char **argv)
{
ALLEGRO_DISPLAY *display;
ALLEGRO_KEYBOARD_STATE key_state;
Point stars[3][NUM_STARS/3];
float speeds[3] = { 0.0001f, 0.05f, 0.15f };
ALLEGRO_COLOR colors[3];
long start, now, elapsed, frame_count;
int total_frames = 0;
double program_start;
double length;
int layer, star;
(void)argc;
(void)argv;
if (!al_init()) {
abort_example("Could not init Allegro.\n");
}
open_log();
al_install_keyboard();
display = al_create_display(WIDTH, HEIGHT);
if (!display) {
abort_example("Could not create display.\n");
}
colors[0] = al_map_rgba(255, 100, 255, 128);
colors[1] = al_map_rgba(255, 100, 100, 255);
colors[2] = al_map_rgba(100, 100, 255, 255);
for (layer = 0; layer < 3; layer++) {
for (star = 0; star < NUM_STARS/3; star++) {
Point *p = &stars[layer][star];
p->x = rand() % WIDTH;
p->y = rand() % HEIGHT;
}
}
start = al_get_time() * 1000;
now = start;
elapsed = 0;
frame_count = 0;
program_start = al_get_time();
while (1) {
if (frame_count < (1000/TARGET_FPS)) {
frame_count += elapsed;
}
else {
int X, Y;
frame_count -= (1000/TARGET_FPS);
al_clear_to_color(al_map_rgb(0, 0, 0));
for (star = 0; star < NUM_STARS/3; star++) {
Point *p = &stars[0][star];
al_draw_pixel(p->x, p->y, colors[0]);
}
al_lock_bitmap(al_get_backbuffer(display), ALLEGRO_PIXEL_FORMAT_ANY, 0);
for (layer = 1; layer < 3; layer++) {
for (star = 0; star < NUM_STARS/3; star++) {
Point *p = &stars[layer][star];
// put_pixel ignores blending
al_put_pixel(p->x, p->y, colors[layer]);
}
}
/* Check that dots appear at the window extremes. */
X = WIDTH - 1;
Y = HEIGHT - 1;
al_put_pixel(0, 0, al_map_rgb_f(1, 1, 1));
al_put_pixel(X, 0, al_map_rgb_f(1, 1, 1));
al_put_pixel(0, Y, al_map_rgb_f(1, 1, 1));
al_put_pixel(X, Y, al_map_rgb_f(1, 1, 1));
al_unlock_bitmap(al_get_backbuffer(display));
al_flip_display();
total_frames++;
}
now = al_get_time() * 1000;
elapsed = now - start;
start = now;
for (layer = 0; layer < 3; layer++) {
for (star = 0; star < NUM_STARS/3; star++) {
Point *p = &stars[layer][star];
p->y -= speeds[layer] * elapsed;
if (p->y < 0) {
p->x = rand() % WIDTH;
p->y = HEIGHT;
}
}
}
al_rest(0.001);
al_get_keyboard_state(&key_state);
if (al_key_down(&key_state, ALLEGRO_KEY_ESCAPE))
break;
}
length = al_get_time() - program_start;
if (length != 0) {
log_printf("%d FPS\n", (int)(total_frames / length));
}
al_destroy_display(display);
close_log(true);
return 0;
}
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