#include <gba.h> 

void WaitForVBlank(void)
{
   while(! (REG_DISPSTAT & DISPSTAT_VB));
   while(REG_DISPSTAT & DISPSTAT_VB);
}

int main()
{
    SetMode(MODE_3 | BG2_ENABLE);   
    unsigned char x,y,ballx,bally,paddley;
	signed char ballvspeed, ballhspeed;
	ballx=SCREEN_WIDTH/2;
	bally=SCREEN_HEIGHT/2;
	ballhspeed=2;
	ballvspeed=2;
	paddley=SCREEN_HEIGHT/2;
    while(1)
	{
		if(((bally+ballvspeed)>0)&&(bally+ballvspeed)<SCREEN_HEIGHT)
			bally+=ballvspeed;
		else
			ballvspeed=-ballvspeed;
		if(((ballx+ballhspeed)>0)&&(ballx+ballhspeed)<SCREEN_WIDTH)
			ballx+=ballhspeed;
		else
			ballhspeed=-ballhspeed;
		
		for(x=0;x<SCREEN_WIDTH;x++)
			for(y=0;y<SCREEN_HEIGHT;y++)
					if(!((x==ballx)&&(y==bally)))
						VideoBuffer[x+y*SCREEN_WIDTH]=RGB16(0,0,0);
					else
						VideoBuffer[x+y*SCREEN_WIDTH]=RGB16(31,31,31);

		WaitForVBlank();
	}  
 }