Sprite Not Moving

Hello!
I have made my script and it is using allegro, The only thing that isn't working is moving the sprite. Why doesn't my sprite move?

Code:

---

#include <allegro.h>



void myAllegroSetup()
{
    allegro_init();
    install_keyboard();
    set_color_depth(32);
    set_gfx_mode( GFX_AUTODETECT_WINDOWED, 600, 400, 0, 0);
   




}


void displayIntro()
{
          BITMAP *introImage;   
          introImage = load_bitmap("open.bmp",NULL);
         
          stretch_blit(introImage, screen, 0, 0, introImage->w, introImage->h, 0, 0, 600, 400); // Draws the stretched image onto the screen
          textout_ex(screen, font, "Press any key to continue", 380, 380, makecol(255, 255, 255), -1);
          readkey();

          stretch_blit(introImage, screen, 0, 0, introImage->w, introImage->h, 0, 0, 600, 400); // Draws the stretched image onto the screen
          textout_ex(screen, font, "How to play", 400, 220, makecol(255, 255, 255), -1);     
          textout_ex(screen, font, "___________", 400, 223, makecol(255, 255, 255), -1);       
         
          textout_ex(screen, font, "        z  =  Talk/Action", 300, 247, makecol(255, 255, 255), -1);       
          textout_ex(screen, font, "        x  =  Cancel", 300, 257, makecol(255, 255, 255), -1);       
          textout_ex(screen, font, "Arrow Keys  =  Move/Navigate Menus'", 300, 267, makecol(255, 255, 255), -1);             
          textout_ex(screen, font, "Press any key to continue", 380, 380, makecol(255, 255, 255), -1);
         
          readkey();       
}

void movePlayer(){
   
    int playerX = 100;
    int playerY = 100;
   
    BITMAP *player;   
    player = load_bitmap("sprite/walk_none.bmp",NULL);
   
    if( key[KEY_LEFT]){
        playerX - 20;
        draw_sprite( screen, player, playerX, playerY);
    } else if( key[KEY_RIGHT]){
        playerX + 20;
        draw_sprite( screen, player, playerX, playerY);
    } else if( key[KEY_UP]){
        playerY + 20;
        draw_sprite( screen, player, playerX, playerY);
    } else if( key[KEY_DOWN]){
        playerY - 20;
        draw_sprite( screen, player, playerX, playerY);
    }
}
}
       


int main(){
 

 
    myAllegroSetup();
    displayIntro();

   
    movePlayer();

    return 0;
} 
END_OF_MAIN();

---

Check your operators in your movePlayer() function. It is a very obvious mistake.

You need loops.

You only call the function once, and if a key isn't pressed at that moment, nothing will happen.

Edit: good catch by Desolation as well :)

Also, I might suggest you another way to code this that I think is much cleaner:

Code:

---

if( key[KEY_LEFT]) playerX - 20;
else if( key[KEY_RIGHT]) playerX + 20;
else if( key[KEY_UP]) playerY + 20;
else if( key[KEY_DOWN]) playerY - 20;

draw_sprite( screen, player, playerX, playerY);

---

Quote:

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Originally Posted by Salem

You need loops.

You only call the function once, and if a key isn't pressed at that moment, nothing will happen.

---

Even if keys are pressed when the function is executed, the sprite will not move. There is another error.

Sorry, I changed the script to what I wanted it to be (Hence why I was always drawing the sprite).

Code:

---

#include <allegro.h>
#include <string>



void myAllegroSetup()
{
    allegro_init();
    install_keyboard();
    set_color_depth(32);
    set_gfx_mode( GFX_AUTODETECT_WINDOWED, 600, 400, 0, 0);
}


void displayIntro()
{
          BITMAP *introImage;   
          introImage = load_bitmap("bg/open.bmp",NULL);
         
          stretch_blit(introImage, screen, 0, 0, introImage->w, introImage->h, 0, 0, 600, 400); // Draws the stretched image onto the screen
          textout_ex(screen, font, "Press any key to continue", 380, 380, makecol(255, 255, 255), -1);
          readkey();

          stretch_blit(introImage, screen, 0, 0, introImage->w, introImage->h, 0, 0, 600, 400); // Draws the stretched image onto the screen
          textout_ex(screen, font, "How to play", 400, 220, makecol(255, 255, 255), -1);     
          textout_ex(screen, font, "___________", 400, 223, makecol(255, 255, 255), -1);       
         
          textout_ex(screen, font, "        z  =  Talk/Action", 300, 247, makecol(255, 255, 255), -1);       
          textout_ex(screen, font, "        x  =  Cancel", 300, 257, makecol(255, 255, 255), -1);       
          textout_ex(screen, font, "Arrow Keys  =  Move/Navigate Menus'", 300, 267, makecol(255, 255, 255), -1);             
          textout_ex(screen, font, "Press any key to continue", 380, 380, makecol(255, 255, 255), -1);
         
          readkey();       
}

void movePlayer(){
   
    int playerX;
    int playerY;
    int abc;
       
    BITMAP *walk_left  = load_bitmap( "sprite/walk_left.bmp", NULL);
    BITMAP *walk_right = load_bitmap( "sprite/walk_right.bmp", NULL);
    BITMAP *walk_up    = load_bitmap( "sprite/walk_up.bmp", NULL);
    BITMAP *walk_down  = load_bitmap( "sprite/walk_down.bmp", NULL);
    BITMAP *walk_none  = load_bitmap( "sprite/walk_none.bmp", NULL);
         
     
    while(!key[KEY_ESC]) {
   
    if( key[KEY_LEFT]){
        playerX - 20;
        draw_sprite( screen, walk_left, playerX, playerY);
    } else if( key[KEY_RIGHT]){
        playerX + 20;
        draw_sprite( screen, walk_right, playerX, playerY);
    } else if( key[KEY_UP]){
        playerY + 20;
        draw_sprite( screen, walk_up, playerX, playerY);
    } else if( key[KEY_DOWN]){
        playerY - 20;
        draw_sprite( screen, walk_down, playerX, playerY);
    }
    else draw_sprite( screen, walk_none, playerX, playerY);
}
}
       


int main(){
 

 
    myAllegroSetup();
    displayIntro();
 
    rectfill( screen, 0, 0, 600, 400, makecol( 0, 0, 0));    // Temporary background

    movePlayer();

    return 0;
} 
END_OF_MAIN();

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I know I need to say where playerX and playerY should go but I cant include this in the function as it is repeated, So where would I declare them?

Sorry if this sounds stupid or w/e but I havent slept for 37 hours

> Sorry if this sounds stupid or w/e but I havent slept for 37 hours
Well there's your problem!
Get some sleep, and enjoy the "OMG what was I thinking moment in the morning"