ex_fluid.c

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#define ALLEGRO_UNSTABLE 1
 
#include <locale.h>
 
#include "nilorea/n_common.h"
#include "nilorea/n_log.h"
#include "nilorea/n_list.h"
#include "nilorea/n_str.h"
#include "nilorea/n_time.h"
#include "nilorea/n_fluids.h"
 
#include <allegro5/allegro.h>
#include <allegro5/allegro_ttf.h>
#include "allegro5/allegro_audio.h"
#include "allegro5/allegro_acodec.h"
#include <allegro5/allegro_font.h>
#include <allegro5/allegro_image.h>
#include <allegro5/allegro_primitives.h>
 
#include "ex_fluid_config.h"
 
#define RESERVED_SAMPLES 16
#define MAX_SAMPLE_DATA 10
 
ALLEGRO_DISPLAY* display = NULL;
 
/******************************************************************************
 *                           VARIOUS DECLARATIONS                             *
 ******************************************************************************/
 
int DONE = 0,            /* Flag to check if we are always running */
    getoptret = 0,       /* launch parameter check */
    log_level = LOG_ERR; /* default LOG_LEVEL */
 
double drawFPS = 60.0;
double logicFPS = 120.0;
 
ALLEGRO_TIMER* fps_timer = NULL;
ALLEGRO_TIMER* logic_timer = NULL;
N_TIME logic_chrono;
N_TIME drawing_chrono;
 
N_FLUID* fluid_sim = NULL;
size_t WIDTH = 800,
       HEIGHT = 600;
bool fullscreen = 0;
char* bgmusic = NULL;
 
THREAD_POOL* thread_pool = NULL;
 
int main(int argc, char* argv[]) {
    /* Set the locale to the POSIX C environment */
    setlocale(LC_ALL, "POSIX");
 
    set_log_level(LOG_ERR);
 
    N_STR* log_file = NULL;
    nstrprintf(log_file, "%s.log", argv[0]);
    /*set_log_file( _nstr( log_file ) );*/
    free_nstr(&log_file);
 
    char ver_str[128] = "";
 
    while ((getoptret = getopt(argc, argv, "hvV:L:")) != EOF) {
        switch (getoptret) {
            case 'h':
                n_log(LOG_NOTICE, "\n    %s -h help -v version -V DEBUGLEVEL (NOLOG,VERBOSE,NOTICE,ERROR,DEBUG)\n", argv[0]);
                exit(TRUE);
            case 'v':
                sprintf(ver_str, "%s %s", __DATE__, __TIME__);
                exit(TRUE);
                break;
            case 'V':
                if (!strncmp("INFO", optarg, 6)) {
                    log_level = LOG_INFO;
                } else {
                    if (!strncmp("NOTICE", optarg, 6)) {
                        log_level = LOG_NOTICE;
                    } else {
                        if (!strncmp("VERBOSE", optarg, 7)) {
                            log_level = LOG_NOTICE;
                        } else {
                            if (!strncmp("ERROR", optarg, 5)) {
                                log_level = LOG_ERR;
                            } else {
                                if (!strncmp("DEBUG", optarg, 5)) {
                                    log_level = LOG_DEBUG;
                                } else {
                                    n_log(LOG_ERR, "%s is not a valid log level", optarg);
                                    exit(FALSE);
                                }
                            }
                        }
                    }
                }
                n_log(LOG_NOTICE, "LOG LEVEL UP TO: %d", log_level);
                set_log_level(log_level);
                break;
            case 'L':
                n_log(LOG_NOTICE, "LOG FILE: %s", optarg);
                set_log_file(optarg);
                break;
            case '?': {
                switch (optopt) {
                    case 'V':
                        n_log(LOG_ERR, "\nPlease specify a log level after -V. \nAvailable values: NOLOG,VERBOSE,NOTICE,ERROR,DEBUG");
                        break;
                    case 'L':
                        n_log(LOG_ERR, "\nPlease specify a log file after -L");
                    default:
                        break;
                }
            }
                __attribute__((fallthrough));
            default:
                n_log(LOG_ERR, "\n    %s -h help -v version -V DEBUGLEVEL (NOLOG,VERBOSE,NOTICE,ERROR,DEBUG) -L logfile", argv[0]);
                exit(FALSE);
        }
    }
    /*
     * INITIALISATION
     */
    int threadedProcessing = 0;
    N_FLUID* fluid_data = NULL;
    Malloc(fluid_data, N_FLUID, 1);
    if (load_app_state("CONFIGS/ex_fluid.cfg", &WIDTH, &HEIGHT, &fullscreen, &bgmusic, &drawFPS, &logicFPS, fluid_data, &threadedProcessing) != TRUE) {
        n_log(LOG_ERR, "couldn't load CONFIGS/ex_fluid.cfg !");
        exit(1);
    }
    double fluid_factor = fluid_data->cScale;
    n_log(LOG_DEBUG, "%s starting with params: %dx%d fullscreen(%d), music: %s", argv[0], WIDTH, HEIGHT, fullscreen, _str(bgmusic));
 
    /* allegro 5 + addons loading */
    if (!al_init()) {
        n_abort("Could not init Allegro.\n");
    }
    if (!al_init_acodec_addon()) {
        n_abort("Could not register addons.\n");
    }
    if (!al_install_audio()) {
        n_log(LOG_ERR, "Unable to initialize audio addon, disabling bgmusic\n");
        Free(bgmusic);
    }
    if (!al_init_acodec_addon()) {
        n_abort("Unable to initialize acoded addon\n");
    }
    if (!al_init_image_addon()) {
        n_abort("Unable to initialize image addon\n");
    }
    if (!al_init_primitives_addon()) {
        n_abort("Unable to initialize primitives addon\n");
    }
    if (!al_init_font_addon()) {
        n_abort("Unable to initialize font addon\n");
    }
    if (!al_init_ttf_addon()) {
        n_abort("Unable to initialize ttf_font addon\n");
    }
    if (!al_install_keyboard()) {
        n_abort("Unable to initialize keyboard handler\n");
    }
    if (!al_install_mouse()) {
        n_abort("Unable to initialize mouse handler\n");
    }
 
    if (bgmusic && !al_reserve_samples(RESERVED_SAMPLES)) {
        n_abort("Could not set up voice and mixer.\n");
    }
 
    ALLEGRO_SAMPLE* sample_data[MAX_SAMPLE_DATA] = {NULL};
    memset(sample_data, 0, sizeof(sample_data));
 
    ALLEGRO_EVENT_QUEUE* event_queue = NULL;
 
    event_queue = al_create_event_queue();
    if (!event_queue) {
        fprintf(stderr, "failed to create event_queue!\n");
        return -1;
    }
 
    if (fullscreen) {
        al_set_new_display_flags(ALLEGRO_OPENGL | ALLEGRO_FULLSCREEN_WINDOW);
    } else {
        al_set_new_display_flags(ALLEGRO_OPENGL | ALLEGRO_WINDOWED);
    }
 
#ifdef __windows__
    al_set_new_bitmap_flags(ALLEGRO_VIDEO_BITMAP | ALLEGRO_NO_PRESERVE_TEXTURE);
#endif
 
    display = al_create_display(WIDTH, HEIGHT);
    if (!display) {
        n_abort("Unable to create display\n");
    }
 
    al_set_window_title(display, argv[0]);
 
    ALLEGRO_FONT* font = al_load_font("DATAS/2Dumb.ttf", 18, 0);
    if (!font) {
        n_abort("Unable to load font DATAS/2Dumb.ttf\n");
    }
 
    DONE = 0;
    fps_timer = al_create_timer(1.0 / drawFPS);
    logic_timer = al_create_timer(1.0 / logicFPS);
 
    al_register_event_source(event_queue, al_get_display_event_source(display));
    al_start_timer(fps_timer);
    al_start_timer(logic_timer);
    al_register_event_source(event_queue, al_get_timer_event_source(fps_timer));
    al_register_event_source(event_queue, al_get_timer_event_source(logic_timer));
 
    al_register_event_source(event_queue, al_get_keyboard_event_source());
    al_register_event_source(event_queue, al_get_mouse_event_source());
 
    bool backbuffer = 1;
    ALLEGRO_BITMAP* scrbuf = NULL;
    ALLEGRO_BITMAP* bitmap = al_create_bitmap(WIDTH, HEIGHT);
 
    al_hide_mouse_cursor(display);
 
    enum APP_KEYS {
        KEY_UP,
        KEY_DOWN,
        KEY_LEFT,
        KEY_RIGHT,
        KEY_ESC,
        KEY_SPACE,
        KEY_CTRL,
        KEY_SHIFT,
        KEY_PAD_MINUS,
        KEY_PAD_PLUS,
        KEY_PAD_ENTER,
        KEY_M,
        KEY_W,
        KEY_F1,
        KEY_F2,
        KEY_F3,
        KEY_F4,
        KEY_F5,
        KEY_F6
    };
    int key[19] = {false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false};
 
    if (bgmusic) {
        if (!(sample_data[0] = al_load_sample(bgmusic))) {
            n_log(LOG_ERR, "Could not load %s", bgmusic);
            exit(1);
        }
        al_play_sample(sample_data[0], 1, 0, 1, ALLEGRO_PLAYMODE_LOOP, NULL);
    }
 
    thread_pool = new_thread_pool(get_nb_cpu_cores(), 0);
 
    /* set fluid */
    fluid_sim = new_n_fluid(fluid_data->density, fluid_data->gravity, fluid_data->numIters, fluid_data->fluid_production_percentage, fluid_data->overRelaxation, WIDTH / fluid_factor, HEIGHT / fluid_factor);
 
    fluid_sim->density = fluid_data->density;
    fluid_sim->gravity = fluid_data->gravity;
    fluid_sim->numIters = fluid_data->numIters;
    fluid_sim->fluid_production_percentage = fluid_data->fluid_production_percentage;
    fluid_sim->overRelaxation = fluid_data->overRelaxation;
    fluid_sim->cScale = fluid_data->cScale;
    Free(fluid_data);
 
    fluid_sim->dt = 1.0 / logicFPS;
 
    size_t n = fluid_sim->numY;
    double inVel = 2.0;
    for (size_t i = 0; i < fluid_sim->numX; i++) {
        for (size_t j = 0; j < fluid_sim->numY; j++) {
            double s = 1.0;  // fluid
            if (i == 0 || j == 0 || j == fluid_sim->numY - 1)
                s = 0.0;  // solid
                          //
            fluid_sim->s[i * n + j] = s;
 
            if (i == 1) {
                fluid_sim->u[i * n + j] = inVel;
            }
        }
    }
    double pipeH = fluid_sim->fluid_production_percentage * fluid_sim->numY;
    size_t minJ = floor(0.5 * fluid_sim->numY - 0.5 * pipeH);
    size_t maxJ = floor(0.5 * fluid_sim->numY + 0.5 * pipeH);
    for (size_t j = 0; j < minJ; j++)
        fluid_sim->m[j] = 1.0;
    for (size_t j = minJ; j < maxJ; j++)
        fluid_sim->m[j] = 0.0;
    for (size_t j = maxJ; j < fluid_sim->numY; j++)
        fluid_sim->m[j] = 1.0;
 
    bool do_draw = 1, do_logic = 1;
    int mx = WIDTH / 3, my = HEIGHT / 2, mouse_button = 0, mouse_b1 = 0, mouse_b2 = 0;
 
    n_fluid_resetObstacles(fluid_sim);
 
    al_flush_event_queue(event_queue);
    al_set_mouse_xy(display, WIDTH / 3, HEIGHT / 2);
 
    int w = al_get_display_width(display);
    int h = al_get_display_height(display);
 
    bitmap = al_create_bitmap(WIDTH, HEIGHT);
 
    size_t logic_duration = 0;
    size_t drawing_duration = 0;
    do {
        do {
            ALLEGRO_EVENT ev;
 
            al_wait_for_event(event_queue, &ev);
 
            if (ev.type == ALLEGRO_EVENT_KEY_DOWN) {
                switch (ev.keyboard.keycode) {
                    case ALLEGRO_KEY_UP:
                        key[KEY_UP] = 1;
                        break;
                    case ALLEGRO_KEY_DOWN:
                        key[KEY_DOWN] = 1;
                        break;
                    case ALLEGRO_KEY_LEFT:
                        key[KEY_LEFT] = 1;
                        break;
                    case ALLEGRO_KEY_RIGHT:
                        key[KEY_RIGHT] = 1;
                        break;
                    case ALLEGRO_KEY_ESCAPE:
                        key[KEY_ESC] = 1;
                        break;
                    case ALLEGRO_KEY_SPACE:
                        key[KEY_SPACE] = 1;
                        break;
                    case ALLEGRO_KEY_LSHIFT:
                    case ALLEGRO_KEY_RSHIFT:
                        key[KEY_SHIFT] = 1;
                        break;
                    case ALLEGRO_KEY_PAD_MINUS:
                        key[KEY_PAD_MINUS] = 1;
                        break;
                    case ALLEGRO_KEY_PAD_PLUS:
                        key[KEY_PAD_PLUS] = 1;
                        break;
                    case ALLEGRO_KEY_PAD_ENTER:
                        key[KEY_PAD_ENTER] = 1;
                        break;
                    case ALLEGRO_KEY_M:
                        key[KEY_M] = 1;
                        break;
                    case ALLEGRO_KEY_W:
                        key[KEY_W] = 1;
                        break;
                    case ALLEGRO_KEY_LCTRL:
                    case ALLEGRO_KEY_RCTRL:
                        key[KEY_CTRL] = 1;
                        break;
                    case ALLEGRO_KEY_F1:
                        key[KEY_F1] = 1;
                        break;
                    case ALLEGRO_KEY_F2:
                        key[KEY_F2] = 1;
                        break;
                    case ALLEGRO_KEY_F3:
                        key[KEY_F3] = 1;
                        break;
                    case ALLEGRO_KEY_F4:
                        key[KEY_F4] = 1;
                        break;
                    case ALLEGRO_KEY_F5:
                        key[KEY_F5] = 1;
                        break;
                    case ALLEGRO_KEY_F6:
                        key[KEY_F6] = 1;
                        break;
                    default:
                        break;
                }
            } else if (ev.type == ALLEGRO_EVENT_KEY_UP) {
                switch (ev.keyboard.keycode) {
                    case ALLEGRO_KEY_UP:
                        key[KEY_UP] = 0;
                        break;
                    case ALLEGRO_KEY_DOWN:
                        key[KEY_DOWN] = 0;
                        break;
                    case ALLEGRO_KEY_LEFT:
                        key[KEY_LEFT] = 0;
                        break;
                    case ALLEGRO_KEY_RIGHT:
                        key[KEY_RIGHT] = 0;
                        break;
                    case ALLEGRO_KEY_ESCAPE:
                        key[KEY_ESC] = 0;
                        break;
                    case ALLEGRO_KEY_SPACE:
                        key[KEY_SPACE] = 0;
                        break;
                    case ALLEGRO_KEY_LSHIFT:
                    case ALLEGRO_KEY_RSHIFT:
                        key[KEY_SHIFT] = 0;
                        break;
                    case ALLEGRO_KEY_PAD_MINUS:
                        key[KEY_PAD_MINUS] = 0;
                        break;
                    case ALLEGRO_KEY_PAD_PLUS:
                        key[KEY_PAD_PLUS] = 0;
                        break;
                    case ALLEGRO_KEY_PAD_ENTER:
                        key[KEY_PAD_ENTER] = 0;
                        break;
                    case ALLEGRO_KEY_M:
                        key[KEY_M] = 0;
                        break;
                    case ALLEGRO_KEY_W:
                        key[KEY_W] = 0;
                        break;
                    case ALLEGRO_KEY_LCTRL:
                    case ALLEGRO_KEY_RCTRL:
                        key[KEY_CTRL] = 0;
                        break;
                    case ALLEGRO_KEY_F1:
                        key[KEY_F1] = 0;
                        break;
                    case ALLEGRO_KEY_F2:
                        key[KEY_F2] = 0;
                        break;
                    case ALLEGRO_KEY_F3:
                        key[KEY_F3] = 0;
                        break;
                    case ALLEGRO_KEY_F4:
                        key[KEY_F4] = 0;
                        break;
                    case ALLEGRO_KEY_F5:
                        key[KEY_F5] = 0;
                        break;
                    case ALLEGRO_KEY_F6:
                        key[KEY_F6] = 0;
                        break;
 
                    default:
                        break;
                }
            } else if (ev.type == ALLEGRO_EVENT_TIMER) {
                if (al_get_timer_event_source(fps_timer) == ev.any.source) {
                    do_draw = 1;
                } else if (al_get_timer_event_source(logic_timer) == ev.any.source) {
                    do_logic = 1;
                }
            } else if (ev.type == ALLEGRO_EVENT_MOUSE_AXES) {
                mx = ev.mouse.x;
                my = ev.mouse.y;
            } else if (ev.type == ALLEGRO_EVENT_MOUSE_BUTTON_DOWN) {
                if (ev.mouse.button == 1)
                    mouse_b1 = 1;
                if (ev.mouse.button == 2)
                    mouse_b2 = 1;
            } else if (ev.type == ALLEGRO_EVENT_MOUSE_BUTTON_UP) {
                if (ev.mouse.button == 1)
                    mouse_b1 = 0;
                if (ev.mouse.button == 2)
                    mouse_b2 = 0;
            }
 
            /* Processing inputs */
            mouse_button = -1;
            if (mouse_b1 == 1)
                mouse_button = 1;
            if (mouse_b2 == 1)
                mouse_button = 2;
            else if (ev.type == ALLEGRO_EVENT_DISPLAY_SWITCH_IN || ev.type == ALLEGRO_EVENT_DISPLAY_SWITCH_OUT) {
                al_clear_keyboard_state(display);
                al_flush_event_queue(event_queue);
            } else {
                // Processing inputs
                // get_keyboard( chat_line , ev );
                if (key[KEY_F1]) {
                    fluid_sim->showSmoke = 1;
                }
                if (key[KEY_F2]) {
                    fluid_sim->showSmoke = 0;
                }
                if (key[KEY_F3]) {
                    fluid_sim->showPressure = 1;
                }
                if (key[KEY_F4]) {
                    fluid_sim->showPressure = 0;
                }
                if (key[KEY_F5]) {
                    fluid_sim->showPaint = 1;
                }
                if (key[KEY_F6]) {
                    fluid_sim->showPaint = 0;
                }
                if (key[KEY_UP]) {
                    fluid_sim->density += 100.0;
                }
                if (key[KEY_DOWN]) {
                    fluid_sim->density -= 100.0;
                    if (fluid_sim->density < 1.0) fluid_sim->density = 1.0;
                }
                if (key[KEY_LEFT]) {
                    fluid_sim->numIters++;
                }
                if (key[KEY_RIGHT]) {
                    fluid_sim->numIters--;
                    if (fluid_sim->numIters < 1.0) fluid_sim->numIters = 1.0;
                }
                if (key[KEY_PAD_PLUS]) {
                    fluid_sim->fluid_production_percentage += 0.01;
                    if (fluid_sim->fluid_production_percentage > 1.0) fluid_sim->fluid_production_percentage = 1.0;
                }
                if (key[KEY_PAD_MINUS]) {
                    fluid_sim->fluid_production_percentage -= 0.01;
                    if (fluid_sim->fluid_production_percentage < 0.1) fluid_sim->fluid_production_percentage = 0.1;
                }
                if (mouse_button != -1) {
                    n_log(LOG_DEBUG, "mouse button: %d", mouse_button);
                }
            }
        } while (!al_is_event_queue_empty(event_queue));
 
        if (do_logic == 1) {
            start_HiTimer(&logic_chrono);
            static int old_mx = -1, old_my = -1;
            double vx = 0.0, vy = 0.0;
            if (old_mx != mx || old_my != my) {
                if (old_mx != -1 && old_my != -1) {
                    vx = (old_mx - mx) / logicFPS;
                    vy = (old_my - my) / logicFPS;
                }
                old_mx = mx;
                old_my = my;
                n_fluid_resetObstacles(fluid_sim);
                n_fluid_setObstacle(fluid_sim, mx / fluid_factor, (my / fluid_factor) - 20.0, vx, vy, fluid_factor / 2);
                n_fluid_setObstacle(fluid_sim, (mx / fluid_factor) - 15, my / fluid_factor, vx, vy, fluid_factor / 2 + fluid_factor / 3);
                n_fluid_setObstacle(fluid_sim, (mx / fluid_factor) + 15, my / fluid_factor - 10.0, vx, vy, fluid_factor / 2 + fluid_factor / 2);
                n_fluid_setObstacle(fluid_sim, (mx / fluid_factor) + 15, my / fluid_factor + 10.0, vx, vy, fluid_factor / 2 + fluid_factor / 2);
                n_fluid_setObstacle(fluid_sim, mx / fluid_factor, (my / fluid_factor) + 20.0, vx, vy, fluid_factor / 2);
            }
 
            pipeH = fluid_sim->fluid_production_percentage * fluid_sim->numY;
            minJ = floor(0.5 * fluid_sim->numY - 0.5 * pipeH);
            maxJ = floor(0.5 * fluid_sim->numY + 0.5 * pipeH);
            for (size_t j = 0; j < minJ; j++)
                fluid_sim->m[j] = 1.0;
            for (size_t j = minJ; j < maxJ; j++)
                fluid_sim->m[j] = 0.0;
            for (size_t j = maxJ; j < fluid_sim->numY; j++)
                fluid_sim->m[j] = 1.0;
            for (size_t j = minJ; j < maxJ; j++)
                fluid_sim->m[j] = 0.0;
 
            if (threadedProcessing == 1)
                n_fluid_simulate_threaded(fluid_sim, thread_pool);
            else
                n_fluid_simulate(fluid_sim);
 
            logic_duration = (logic_duration + get_usec(&logic_chrono)) / 2;
            do_logic = 0;
        }
        if (do_draw == 1) {
            start_HiTimer(&drawing_chrono);
 
            if (backbuffer)
                scrbuf = al_get_backbuffer(display);
            else
                scrbuf = bitmap;
 
            al_set_target_bitmap(scrbuf);
 
            if (!backbuffer)
                al_lock_bitmap(scrbuf, al_get_bitmap_format(scrbuf), ALLEGRO_LOCK_READWRITE);
 
            n_fluid_draw(fluid_sim);
 
            al_draw_circle(mx, my - 20 * fluid_factor, fluid_factor * fluid_factor / 2, al_map_rgb(255, 0, 0), 2.0);
            al_draw_circle(mx - 15 * fluid_factor, my, fluid_factor * fluid_factor / 2 + (fluid_factor * fluid_factor) / 3, al_map_rgb(255, 0, 0), 2.0);
            al_draw_circle(mx + 15 * fluid_factor, my + 10.0 * fluid_factor, fluid_factor * fluid_factor / 2 + (fluid_factor * fluid_factor) / 2, al_map_rgb(255, 0, 0), 2.0);
            al_draw_circle(mx + 15 * fluid_factor, my - 10.0 * fluid_factor, fluid_factor * fluid_factor / 2 + (fluid_factor * fluid_factor) / 2, al_map_rgb(255, 0, 0), 2.0);
            al_draw_circle(mx, my + 20 * fluid_factor, fluid_factor * fluid_factor / 2, al_map_rgb(255, 0, 0), 2.0);
 
            static N_STR* textout = NULL;
            nstrprintf(textout, "[F1/F2]:showSmoke:%d [F3/F4]:showPressure:%d [F5/F6]:showPaint:%d", fluid_sim->showSmoke, fluid_sim->showPressure, fluid_sim->showPaint);
            al_draw_text(font, al_map_rgb(0, 0, 255), WIDTH, 10, ALLEGRO_ALIGN_RIGHT, _nstr(textout));
 
            nstrprintf(textout, "numIters: %zd production: %3.3g density: %3.3g", fluid_sim->numIters, fluid_sim->fluid_production_percentage, fluid_sim->density);
            al_draw_text(font, al_map_rgb(0, 0, 255), WIDTH, 25, ALLEGRO_ALIGN_RIGHT, _nstr(textout));
 
            nstrprintf(textout, "logic(max %zd): %zd usecs", (size_t)(1000000.0 / logicFPS), logic_duration);
            al_draw_text(font, al_map_rgb(0, 0, 255), 5, 10, ALLEGRO_ALIGN_LEFT, _nstr(textout));
 
            nstrprintf(textout, "drawing(max %zd): %zd usecs", (size_t)(1000000.0 / drawFPS), drawing_duration);
            al_draw_text(font, al_map_rgb(0, 0, 255), 5, 30, ALLEGRO_ALIGN_LEFT, _nstr(textout));
 
            if (!backbuffer) {
                al_unlock_bitmap(scrbuf);
                al_set_target_bitmap(al_get_backbuffer(display));
                al_draw_bitmap(scrbuf, w / 2 - al_get_bitmap_width(scrbuf) / 2, h / 2 - al_get_bitmap_height(scrbuf) / 2, 0);
            }
 
            drawing_duration = (drawing_duration + get_usec(&drawing_chrono)) / 2;
 
            al_flip_display();
 
            do_draw = 0;
        }
 
    } while (!key[KEY_ESC] && !DONE);
 
    al_uninstall_system();
 
    return 0;
}