Allegro 4 Functions Errors

Question

I've been learning some game programming with allegro lately and I've run into a problem. My "game" is a compile type of the many tutorials I learnt uptil now. Anyway, I ran into a function problem with Allegro. My first code was this:

#include <allegro.h>
#include <sstream>
#include <string>
#include <cstring>
#include <fstream>
volatile bool Close = false;
void handler(){
     Close = true;}
/*timer*/
volatile long speed_counter = 0;
void increment_speed_counter(){
     speed_counter++;
     }
END_OF_FUNCTION(increment_speed_counter);

using namespace std;


int main() 
{   
if(!allegro_init()){
                    fstream error;
                    error.open("error_log.txt", ios::ate);
                    error << "ERROR: Failed to initialized allegro!!\n";
                    error.close();
                    }
    install_keyboard();
    install_timer();

    LOCK_VARIABLE(speed_counter);
    LOCK_FUNCTION(increment_speed_counter);
 install_int_ex(increment_speed_counter, BPS_TO_TIMER(120));

    set_color_depth(24);
    set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);

    BITMAP *buffer = create_bitmap(640, 480);
    BITMAP *spaceship = load_bitmap("ship.bmp", NULL); //up
    BITMAP *spaceship2 = load_bitmap("ship2.bmp", NULL); //down
    BITMAP *spaceship3 = load_bitmap("ship3.bmp", NULL); //right
    BITMAP *spaceship4 = load_bitmap("ship4.bmp", NULL); //left
    FONT *myriad = load_font("myriad.pcx", NULL, NULL);
    BITMAP *meteor = load_bitmap("meteor.bmp", NULL);
    BITMAP *options = create_bitmap(640, 480);

//srand(time(NULL));
LOCK_FUNCTION(handler);
//int mx = rand() % 100;
//int my = rand() % 100;
long int ship_x = 300;
long int ship_y = 200;
int Bx [1000];
int By [1000];
    bool done = false;
set_close_button_callback(handler);




    while(!Close){                 
  while(speed_counter > 0){
textprintf_ex(screen, font, 200,10, makecol(255,100,200), -1, "Space Void: Asonomia"); 

                 if(ship_x >= 620){
                           ship_x = 620;
                           }
                 if(ship_y >= 460){
                           ship_y = 460;
                           }
                 if(ship_x <= 0){
                           ship_x = 0;
                           }
                 if(ship_y <= 0){
                           ship_y = 0;
                           }

                 if(key[KEY_ESC]){
                                 Close = true;
                                  }
                 if(key[KEY_LEFT]){

                                   ship_x -=5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship4, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                   }
                 if(key[KEY_RIGHT]){
                                    ship_x +=5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship3, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                    }
                 if(key[KEY_UP]){
                                 ship_y -= 5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                 }
                 if(key[KEY_DOWN]){
                                   ship_y += 5;
                                   clear(buffer);
                                 draw_sprite(buffer, spaceship2, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                   }

speed_counter--;
                }
}



   destroy_bitmap(spaceship);
    destroy_bitmap(spaceship2);
    destroy_bitmap(spaceship3);
    destroy_bitmap(spaceship4);
    destroy_bitmap(buffer);

    return 0;
}
END_OF_MAIN()

It was very messy so I decided to clean it up a bit by adding functions.

So now it's this:

#include <allegro.h>
#include <sstream>
#include <string>
#include <cstring>
#include <fstream>

//X Button
volatile bool Close = false;
void handler(){
     Close = true;}
//FPS 
volatile long speed_counter = 0;
void increment_speed_counter(){
    speed_counter++;
}

void initialize(){
    if(!allegro_init()){
    allegro_message("Error Initializing Allegro");
    }
    install_keyboard();
    install_timer();
    LOCK_VARIABLE(speed_counter);
    LOCK_FUNCTION(increment_speed_counter);
    install_int_ex(increment_speed_counter, BPS_TO_TIMER(60));

    //Video Mode

    set_color_depth(24);
    set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0,0);

}


void load_externs(){
    BITMAP *buffer = create_bitmap(640, 480);
    BITMAP *spaceship = load_bitmap("ship.bmp", NULL); //up
    BITMAP *spaceship2 = load_bitmap("ship2.bmp", NULL); //down
    BITMAP *spaceship3 = load_bitmap("ship3.bmp", NULL); //right
    BITMAP *spaceship4 = load_bitmap("ship4.bmp", NULL); //left
    BITMAP *meteor = load_bitmap("meteor.bmp", NULL);
    BITMAP *options = create_bitmap(640, 480);
}

int main(){
initialize();
load_externs();

    long int ship_x = 300;
    long int ship_y = 200;
    bool done = false;
    set_close_button_callback(handler);

    while(!Close){                 
while(speed_counter > 0){
textprintf_ex(screen, font, 200,10, makecol(255,100,200), -1, "Space Void: Asonomia"); 

                 if(ship_x >= 620){
                           ship_x = 620;
                           }
                 if(ship_y >= 460){
                           ship_y = 460;
                           }
                 if(ship_x <= 0){
                           ship_x = 0;
                           }
                 if(ship_y <= 0){
                           ship_y = 0;
                           }

                 if(key[KEY_ESC]){
                                 Close = true;
                                  }
                 if(key[KEY_LEFT]){

                                   ship_x -=5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship4, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                   }
                 if(key[KEY_RIGHT]){
                                    ship_x +=5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship3, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                    }
                 if(key[KEY_UP]){
                                 ship_y -= 5;
                                 clear(buffer);
                                 draw_sprite(buffer, spaceship, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                 }
                 if(key[KEY_DOWN]){
                                   ship_y += 5;
                                   clear(buffer);
                                 draw_sprite(buffer, spaceship2, ship_x, ship_y);
                                 blit(buffer, screen, 0,0,0,0, 640, 480);
                                 rest(20);
                                   }

speed_counter--;
                }
}



   destroy_bitmap(spaceship);
    destroy_bitmap(spaceship2);
    destroy_bitmap(spaceship3);
    destroy_bitmap(spaceship4);
    destroy_bitmap(buffer);
    return 0;

}
END_OF_MAIN()

I added two new functions which were "load_externs" which would load the bitmaps and "initialize" which would initialize allegro, graphics etc. Now, when I compiled it it game me the error that there were no define BITMAPs, like spaceship, buffer etc. Although, I had added the function in int main: load_externs(); and top of that it wasnt initializing allegro, which meant that it wasn't reading the functions I added in int main(), but why? I'm probably missing something out here, I'd appreciate some help, thanks. :)

EDIT: I couldn't ask this on allegro.cc as well as I already made an account there and I couldn't log in with it, same happened when I made another account. I keep getting login errors... :/ But... I know stackoverflow's awesome members are always here to help. :D

Answer 1

You have made the bitmaps local variables in load_externs, they won't be be visible in other functions like main.

The quickest solution is to make buffer, spaceship etc global.