#include <exec/types.h>
 #include <exec/memory.h>
 #include <intuition/intuition.h>
 #include <graphics/sprite.h>
 
 #define REV		0L
 #define FRAMES		6
 #define SPRHEIGHT	16
 #define WORDSPERSPR	(2 * SPRHEIGHT + 4)
 #define MAXX		(640-32)
 #define MAXY		(200-16)
 #define MAGIC1		33
 #define MAGIC2		21
 #define ever		(;;)
 
 extern UWORD	ballmask[], ball0[];
 extern void	*OpenLibrary(), *OpenWindow(), *AllocMem(), *GetMsg(),
 		*ViewPortAddress();
 extern long	GetSprite(), VBeamPos();
 
 
 struct NewWindow windef = {
 	0, 15, 300, 10,
 	-1, -1,
 	CLOSEWINDOW,
 	WINDOWCLOSE | WINDOWDEPTH | WINDOWDRAG | ACTIVATE,
 	NULL, NULL,
 	(UBYTE *) "One moment....",
 	NULL, NULL, 0, 0, 0, 0,
 	WBENCHSCREEN
 };
 /*	Doing it this way is faster than saying  (i+offset) % 6  */
 UBYTE		idx[] = { 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4 };
 
 struct SimpleSprite	spr[FRAMES];
 struct Window	*win;
 struct ViewPort	*vp;
 UWORD		*sprbuf;
 UWORD		*sprites[FRAMES];
 int		vx[FRAMES], vy[FRAMES];
 void		*GfxBase, *IntuitionBase;
 
 
 main ()
 {
 	int i, offset = 0, flag = 0;
 	void *msg;
 
 	openstuff ();
 	setupsprites ();
 	rnd ((short) -VBeamPos());	/*  Plant a seed  */
 
 	for (i=0; i<FRAMES; i++) {
 		if (GetSprite (&spr[i], (long) i+2) < 0)
 			die ("Sprite allocation failed.");
 		spr[i].x = 640 / 2;
 		spr[i].y = 10;
 		spr[i].height = SPRHEIGHT;
 		ChangeSprite (vp, &spr[i], sprites[i]);
 	}
 
 	SetWindowTitles (win, "  \253\253<< Oing! >>\273\273  ", "Oing!");
 	for ever {
 		/*
 		 * WaitTOF()'s presence way up here is significant.  I used
 		 * have it down by the ChangeSprite() loop, but it flickered.
 		 * When it's up here, I get just the right amount of delay
 		 * after top-of-frame so that nothing glitches.
 		 */
 		WaitTOF ();
 		if (msg = GetMsg (win -> UserPort)) {
 			ReplyMsg (msg);
 			closestuff ();
 			return;
 		}
 		for (i=0; i<FRAMES; i++) {
 			spr[i].x += vx[i];
 			if (spr[i].x > MAXX) {
 				/*  spr.x is unsigned, so we have to cheat  */
 				spr[i].x = (spr[i].x & 0x8000) ? 0 : MAXX;
 				vx[i] = -vx[i];
 			}
 
 			/* The shift by 2 is to slow vertical motion a bit */
 			if ((spr[i].y += (vy[i] >> 2)) > MAXY) {
 				spr[i].y = MAXY;
 				vx[i] = rnd (MAGIC2) - MAGIC2 / 2;
 				vy[i] = -rnd (MAGIC1) - 5;
 			}
 			vy[i]++;	/*  Gravity  */
 		}
 
 		for (i=0; i<FRAMES; i++) 
 			ChangeSprite (vp, &spr[i], sprites[idx[i+offset]]);
 
 		/*  Rotate balls every other loop  */
 		if (flag = !flag)
 			offset = (offset + 1) % 6;
 	}
 }
 
 openstuff ()
 {
 	register int i;
 
 	if (!(IntuitionBase = OpenLibrary ("intuition.library", REV)))
 		die ("Intuition open failed.");
 
 	if (!(GfxBase = OpenLibrary ("graphics.library", REV)))
 		die ("Art shop closed.");
 
 	if (!(win = OpenWindow (&windef)))
 		die ("Window painted shut.");
 	vp = ViewPortAddress (win);
 
 	for (i=20; i<32; i += 4) {
 		SetRGB4 (vp, i+1L, 15L, 0L, 0L);
 		SetRGB4 (vp, i+3L, 15L, 14L, 13L);
 	}
 }
 
 closestuff ()
 {
 	register int i;
 
 	for (i=0; i<FRAMES; i++)
 		if (spr[i].num)
 			FreeSprite ((long) spr[i].num);
 
 	if (sprbuf)
 		FreeMem (sprbuf, 2L * WORDSPERSPR * FRAMES);
 	if (win)
 		CloseWindow (win);
 	if (GfxBase)
 		CloseLibrary (GfxBase);
 	if (IntuitionBase)
 		CloseLibrary (IntuitionBase);
 }
 
 die (str)
 char *str;
 {
 	if (win) {
 		SetWindowTitles (win, str, -1L);
 		WaitPort (win -> UserPort);
 	} else
 		puts (str);
 	closestuff ();
 	exit (100);
 }
 
 /*
  * The following code segment was lifted (nearly) intact from the Alpha-9
  * 1.2 README disk.  Thanks to Jim Mackraz for the code, and also for
  * drawing all those ball sprites.
  */
 setupsprites ()
 {
 	UWORD *cw;	/* current position in buffer of sprite images */
 	UWORD *maskp;	/* current position in ballmask             */
 	UWORD *ballp;	/* current position in ball0 data           */
 	int frame, scan;
 
 	if (!(sprbuf = AllocMem (2L * WORDSPERSPR * FRAMES, MEMF_CHIP)))
 		die ("Can't allocate sprite buffer.");
 
 	cw = sprbuf;	/* current position at top of buffer */
 	ballp = ball0;	/* ... top of data to be interleaved */
 
 	for (frame=0; frame<FRAMES; frame++) {
 		maskp = ballmask;	/* one mask for all frames */
 		sprites[frame] = cw;
 		*cw++ = 0;		/* poscntl */
 		*cw++ = 0;
 
 		/* one word from ball0, one word from ballmask */
 		for (scan=0; scan<SPRHEIGHT; scan++) {
 			*cw++ = *maskp++;
 			*cw++ = *ballp++;
 		}
 		*cw++ = 0;	/* termination */
 		*cw++ = 0;
 	}
 }