clearing the screen

umm... i want to animate a bitmap according to what key the user is pressing. But when I use no clear screen functions the old bitmap is left behind. When I use a clear screen function then it is really sketchy. I used man different types of clear screen such as clear_to_color etc. I am not sure what I am doing wrong. Oh and I am using the allegro library with Dev C++ and windows 98 (if that matters)

Code:

---

#include <allegro.h>


int main()
{

 allegro_init();     


 set_gfx_mode(GFX_SAFE, 640, 480, 0, 0);
 set_color_depth(16); // Set the color depth

 install_keyboard();

 BITMAP *pic;
 pic = load_bitmap("plane.bmp", NULL); // Load our picture

 int x=0, y=0;
acquire_screen();

while(!key[KEY_ESC])
{if (key[KEY_UP])
  {y++;}
 if (key[KEY_DOWN])
  {y--;}
 clear_bitmap(screen);
 for (int i=0 ; i < 1; i++) { clear_bitmap(screen);
 vsync();
 blit(pic, screen, x, y, 0, 0, 640, 480);
  }
}

release_screen();
destroy_bitmap(pic);//Release the bitmap data
 allegro_exit();
 return 0;   
}   


END_OF_MAIN();

---

try this clear screen function:

Code:

---

void cls()
{
  union REGS i,o;

  i.h.ah = 6;
  i.h.bh = 7;
  i.h.ch = 0;
  i.h.dh = 24;
  i.h.al = 0;
  i.h.cl = 0;
  i.h.dl = 79;

  int86(16,&i,&o);
  gotoxy(1,1);
}

---

if your compiler doesn't have gotoxy(x,y) then add this function too:

Code:

---

void gotoxy(int x, int y)
{
        HANDLE hConsoleOutput;
        COORD dwCursorPosition;

        dwCursorPosition.X = x;
        dwCursorPosition.Y = y;
        hConsoleOutput = GetStdHandle(STD_OUTPUT_HANDLE);
        SetConsoleCursorPosition(hConsoleOutput,dwCursorPosition);
}

---

dont forget to include windows.h for the gotoxy function

will that code work for clearing text too?

i belive it clears the whole screen doesn't matter whats on it. (i hope :D )