Some code not working.

Some code not working.

Amaz1ng

Member #12,865

May 2011

What's wrong with this code? It seems be crashing.

#SelectExpand
  1#include <stdio.h>
  2#include <allegro5/allegro.h>
  3#include <allegro5/allegro5.h>
  4#include <allegro5/allegro_image.h>
  5#include <allegro5/allegro_primitives.h>
  6#include <allegro5/allegro_font.h>
  7#include <allegro5/allegro_ttf.h>
  8
  9ALLEGRO_DISPLAY *display = NULL;
 10ALLEGRO_EVENT_QUEUE *events = NULL;
 11ALLEGRO_EVENT ev;
 12ALLEGRO_BITMAP *bmp, *bmp2, *bmp3;
 13ALLEGRO_EVENT_SOURCE * timesrc = NULL;
 14ALLEGRO_TIMEOUT *timeout = NULL;
 15ALLEGRO_TIMER *timer = NULL;
 16const int SCREEN_W = 1024;
 17const int SCREEN_H = 768;
 18const float FPS = 60;
 19const char* title = "Fantasy Land Redemption";
 20
 21void init_allegro();
 22void load_sounds();
 23void load_images();
 24void redraw();
 25
 26int main(int argc, char **argv)
 27{
 28  //LOAD CONTENT
 29  init_allegro();
 30  load_images();
 31  load_sounds();
 32
 33  //timer
 34  timer = al_create_timer(1 / 60);
 35  timesrc = al_get_timer_event_source(timer);
 36  al_start_timer(timer);
 37
 38   //events
 39   events = al_create_event_queue();
 40   al_register_event_source(events, al_get_display_event_source(display));
 41   al_register_event_source(events, timesrc);
 42
 43   while(1)
 44   {
 45     al_wait_for_event(events, &ev);
 46
 47     if(ev.type == ALLEGRO_EVENT_TIMER)
 48     {
 49     redraw();
 50     }
 51   }
 52
 53   //destroy
 54   al_destroy_display(display);
 55   al_destroy_event_queue(events);
 56   return 0;
 57}
 58
 59void init_allegro()
 60{
 61  //initiailize, create window
 62   al_init();
 63   display = al_create_display(SCREEN_W, SCREEN_H);
 64   al_set_window_title(display, title);
 65}
 66
 67void load_sounds()
 68{
 69}
 70
 71void load_images()
 72{
 73  //images?
 74   al_init_image_addon();
 75   bmp = al_load_bitmap("hero_stand.png");
 76   al_set_target_bitmap(al_get_backbuffer(display));
 77}
 78
 79void gametickupdate()
 80{
 81
 82}
 83
 84void redraw()
 85{
 86  al_draw_bitmap(bmp, SCREEN_W / 2, SCREEN_H / 2, NULL);
 87}

Edgar Reynaldo

Major Reynaldo

May 2007

What's wrong with your debugger? You seem to not be using it.

Try checking the return values of functions that could fail.

Amaz1ing said:

   while(1)
   {
     al_wait_for_event_until(events, &ev, timeout);

     if(ev.type == ALLEGRO_EVENT_TIMER)
     {
     redraw();
     }
   }

If al_wait_for_event_until times out, then the value of ev is most likely unchanged since the last time that it was altered. Check the return value of al_wait_for_event_until and if it timed out, don't check the event value.

Amaz1ing said:

   al_register_event_source(events, timesrc);

You never initialized timesrc to a value other than NULL, I don't know if that would crash or not.

You also never created an ALLEGRO_TIMER, nor did you register it with

al_register_event_source(event , al_get_timer_event_source(timer));

so you'll never get any ALLEGRO_EVENT_TIMER events either.

Eagle and Allegro 5 binaries | Older Allegro 4 and 5 binaries | Allegro 5 compile guide
King Piccolo will make it so Then I could just flip it with some sweet, sweet matrix math. In either case, I’ll ride this wagon until the wheels fall off. Thanks to those that keep it running

Karadoc ~~

Member #2,749

September 2002

My suggestion is to put printf statements all through the code so that you can see how far it gets before it crashes. like this:

void main(..)
{
  printf("start of main\n");
  init_allegro();
  ...
  printf("checkpoint 1\n");
  events = al_create_event_queue();
  ...
  printf("and so on\n");
  ...
}

... or just run it through a debugger to see where it crashes. Once you find the exact line that makes it crash, it will probably be more clear what the problem is.

-----------

Arthur Kalliokoski

Second in Command

February 2005

If you use printf(), you probably want to follow it with an fflush(stdout) to make sure it's printed regardless of crashes.

They all watch too much MSNBC... they get ideas.

Karadoc ~~

Member #2,749

September 2002

I think printf to stdout automatically flushes when there is a newline ('\n'). doesn't it? Maybe I'm wrong, but I use this method of debugging frequently and I've only had flush problems when I make it write to a log file instead of stdout.

-----------

Arthur Kalliokoski

Second in Command

February 2005

Karadoc ~~ said:

I think printf to stdout automatically flushes when there is a newline ('\n'). doesn't it?

I think it depends on the compiler. DJGPP always flushed printf() to avoid confusing the n00bs, but if you wanted more speed due to buffering, you had to use fprintf().

They all watch too much MSNBC... they get ideas.

Amaz1ng

Member #12,865

May 2011

Yeah I looked w/ the debugger and found the problems. But a new problem is that when I use strcat to get a filename, it strips the slashes off.

void load_images()
{
  //images?
  path = al_get_current_directory();
  strcat(path, "\sprites\hero\hero_stand.png");
   al_init_image_addon();
   hero_stand = al_load_bitmap(path);
   
   al_set_target_bitmap(al_get_backbuffer(display));
}

Karadoc ~~

Member #2,749

September 2002

Backslash is the escape character. If you actually want the backslash character, you put to put two of them. eg. "\\sprites\\hero\\hero_stand.png"

-----------

Arthur Kalliokoski

Second in Command

February 2005

Since the C preprocessor sees a backslash as an escape character (e.g. '\n') you have to put two backslashes in a row, such as "\\sprites\\hero\\hero_stand.png" or use forward slashes "/sprites/hero/hero_stand.png".

They all watch too much MSNBC... they get ideas.

Edgar Reynaldo

Major Reynaldo

May 2007

If you compiled your code with all warnings enabled, your compiler would have told you about unrecognized escape sequences. gcc -Wall FTW.