/* Fly saucer */

#ifdef __TINY__
#error BGIDEMO will not run in the tiny model.
#endif

#include <dos.h>
#include <math.h>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#include <graphics.h>


int main (void)
{
	clrscr ();
	int gdriver = DETECT, gmode, errorcode;
	initgraph (&gdriver, &gmode, "c:\\tclite\\bgi");
	errorcode = graphresult ();

	if (errorcode != grOk)
		{
		printf ("Graphics error: %s\n", grapherrormsg (errorcode));
		printf ("Press Anykey to halt: ");
		getch ();
		exit (1);
		}

	int MaxX, MaxY, MaxColors;
	MaxX = getmaxx();
	MaxY = getmaxy();

  static int r	    = 20;
  static int StartX = 100;
  static int StartY = 50;

  struct viewporttype vp;
  int PauseTime, x, y, ulx, uly, lrx, lry, size, i, width, height, step;
  void *Saucer;

  getviewsettings( &vp );

  setfillstyle( SOLID_FILL, getmaxcolor() );
  fillellipse(StartX, StartY, r, (r/3)+2);
  ellipse(StartX, StartY-4, 190, 357, r, r/3);

  line(StartX+7, StartY-6, StartX+10, StartY-12);
  circle(StartX+10, StartY-12, 2);
  line(StartX-7, StartY-6, StartX-10, StartY-12);
  circle(StartX-10, StartY-12, 2);


  /* Read saucer image */
  ulx = StartX-(r+1);
  uly = StartY-14;
  lrx = StartX+(r+1);
  lry = StartY+(r/3)+3;
  width = lrx - ulx + 1;
  height = lry - uly + 1;
  size = imagesize(ulx, uly, lrx, lry);

  Saucer = malloc( size );
  getimage(ulx, uly, lrx, lry, Saucer);
  putimage(ulx, uly, Saucer, XOR_PUT);

/* Plot some "stars"  */

  //for ( i=0 ; i<1000; ++i )
    //putpixel(random(MaxX), random(MaxY), random( MaxColors-1 )+1);
  x = MaxX / 2;
  y = MaxY / 2;
  PauseTime = 70;

  x = getmaxx();
  y = getmaxy()/2;

  /* until a key is hit */
  while ( !kbhit() ) {

    /* Draw the Saucer */
    putimage(x, y, Saucer, XOR_PUT);		     /*  draw image  */
    delay(PauseTime);
    putimage(x, y, Saucer, XOR_PUT);		     /* erase image  */

    /* Move Saucer */

    x--;

    //for (i=0; i<1; i++ )
    //delay (1);

    if (x == 0)
    {
    x = getmaxx();
    }

    /*
    step = random( 2*r );
    if ((step/2) % 2 != 0 )
      step = -1 * step;
    x = x + step;
    step = random( r );
    if ((step/2) % 2 != 0 )
      step = -1 * step;
    y = y + step;
    */

    if (vp.left + x + width - 1 > vp.right)
      x = vp.right-vp.left-width + 1;
    else
      if (x < 0)
	x = 0;
    if (vp.top + y + height - 1 > vp.bottom)
      y = vp.bottom-vp.top-height + 1;
    else
      if (y < 0)
	y = 0;

  }
  free( Saucer );

  return 0;
}