/* : ts=8

  DEMOlition - Un piccolo scherzo da Workbench ispirato da un micro BBC.

    Questo programma usa "Melt" di Stephen Coy per fare una copia dello
  schermo del Workbench e gestire l'handle di chiusura. Ho cambiato solo
   il codice di azione. Stephen non aveva posto restrizioni sul suo uso,
         sicche' neanche io ne ho poste: abusatene sinche' volete!

         Autore: Kriton Krimis - Distribuzione: EnigmA Amiga Disk

  Compilato con ""Aztec C" della Manx V3.6a - Adattamento di L.Callegari

*/

#include <exec/types.h>
#include <intuition/intuition.h>

#define DEPTH	(SHORT) 2

#define NE 0
#define SE 1
#define SW 2
#define NW 3

#define rndcol(c)	SetRGB4 (vp, (long)(c), (long)(RangeRand(16)-1), \
						(long)(RangeRand(16)-1), \
						(long)(RangeRand(16)-1))

extern void	*OpenLibrary(), *OpenWindow(), *OpenScreen(), *GetMsg();
extern long	RangeRand(), ReadPixel();

struct NewScreen scrdef = {
	(SHORT)0, (SHORT)0, (SHORT)0, (SHORT)0, DEPTH,
	(UBYTE)0, (UBYTE)1,
	(USHORT) 0,
	CUSTOMSCREEN,
	NULL,
	(UBYTE *) "Kriton",
	NULL,
	NULL
};

struct NewWindow windef = {
	(SHORT) 0, (SHORT) 30,
	(SHORT) 180, (SHORT) 10,
	(UBYTE) -1, (UBYTE) -1,
	CLOSEWINDOW,
	WINDOWCLOSE|WINDOWDRAG|WINDOWDEPTH|SMART_REFRESH|ACTIVATE,
	NULL,
	NULL,
	(UBYTE *) "DEMOlition",
	NULL,
	NULL,
	(SHORT) 0, (SHORT) 0,
	(SHORT) 0, (SHORT) 0,
	WBENCHSCREEN
};

struct Screen	*scr;
struct Window	*win;
struct TmpRas	tmpras;
struct RastPort	*rp;
struct ViewPort *vp;
void		*IntuitionBase, *GfxBase;
int		x, y,
		dx, dy,
		newx, newy,
		maxx, maxy;

demo()
{
	int	class;
	struct	IntuiMessage	*message;
	int	dir;
	int	c;

	maxx = scr->Width - 2;
	maxy = scr->Height - 2;
	x = newx = RangeRand((long)(maxx));
	y = newy = RangeRand((long)(maxy));
	dir = RangeRand(3L);
	dx = 1;
	dy = 1;
	SetAPen(rp, 3L);
	show();

	FOREVER {
	  message = (struct IntuiMessage *)GetMsg(win->UserPort);
	  if(message != (struct IntuiMessage *)NULL) {
	    class = message->Class;
	    ReplyMsg(message);
	    if(class == CLOSEWINDOW) {
	      return;
	    }
	  }

	  hide();
	  switch (dir) {
	    case NE:
	      newx = x + dx;
	      newy = y - dy;
	      if (newx > maxx){
		dir = NW;
		rndcol(0);
	      }
	      else
		if (newy < 0){
		  dir = SE;
		  rndcol(0);
		}
		else
		  if( (c = ReadPixel(rp, (long)newx, (long)newy)) != 0L) {
		    explode(c);
		    rndcol(c);
		    dir = NW;
		  }
	      break;
	    case SE:
	      newx = x + dx;
	      newy = y + dy;
	      if (newx > maxx){
	        dir = SW;
		rndcol(0);
	      }
	      else
	        if (newy > maxy){
		  dir = NE;
		  rndcol(0);
		}
		else
		  if( (c = ReadPixel(rp, (long)newx, (long)newy)) != 0L) {
		    explode(c);
		    rndcol(c);
		    dir = NE;
		  }
	      break;
	    case SW:
	      newx = x - dx;
	      newy = y + dy;
	      if (newx < 0){
	        dir = SE;
		rndcol(0);
	      }
	      else
	        if (newy > maxy){
		  dir = NW;
		  rndcol(0);
		}
		else
		  if( (c = ReadPixel(rp, (long)newx, (long)newy)) != 0L) {
		    explode(c);
		    rndcol(c);
		    dir = SE;
		  }
	      break;
	    case NW:
	      newx = x - dx;
	      newy = y - dy;
	      if (newx < 0){
	        dir = NE;
		rndcol(0);
	      }
	      else
	        if (newy < 0){
		  dir = SW;
		  rndcol(0);
		}
		else
		  if( (c = ReadPixel(rp, (long)newx, (long)newy)) != 0L) {
		    explode(c);
		    rndcol(c);
		    dir = SW;
		  }
	      break;
	  }
	  show();
	}
}

show()
{
  static int do_delay = 0;
  x = newx;
  y = newy;

  SetAPen(rp, 3L);
  SetDrMd(rp, JAM1);
  WritePixel(rp, (long)x    , (long)y);

  SetDrMd(rp, COMPLEMENT);
  WritePixel(rp, (long)(x+1), (long)y);
  WritePixel(rp, (long)x    , (long)(y+1));
  WritePixel(rp, (long)(x+1), (long)(y+1));

  if (do_delay) {
    Delay(1L);
    do_delay = 0;
  }else{
    do_delay = 1;
  }
}

hide()
{
  SetAPen(rp, 0L);
  SetDrMd(rp, JAM1);
  WritePixel(rp, (long)x    , (long)y);

  SetDrMd(rp, COMPLEMENT);
  WritePixel(rp, (long)(x+1), (long)y);
  WritePixel(rp, (long)x    , (long)(y+1));
  WritePixel(rp, (long)(x+1), (long)(y+1)); 
}

#define DELIM 0xff

explode(c)
  int c;
{
  static int ex[] = {-3,  0,  1,  4,		DELIM,
		     -2,  0,  1,  3,		DELIM,
		     -1,  0,  1,  2,		DELIM,
		     -3, -2, -1,  0,  1,	DELIM,
		      0,  1,  2,  3,  4,	DELIM,
		     -1,  0,  1,  2,		DELIM,
		     -2,  0,  1,  3,		DELIM,
		     -3,  0,  1,  4,		DELIM};
  int ey;
  int i;
  int xx, yy;

  SetAPen(rp, 0L);
  SetDrMd(rp, JAM1);

  ey = -3;
  i = 0;
  while (ey < 5) {
    if( ex[i] == DELIM) {
      i++;
      ey++;
      continue;
    }
    xx = newx + ex[i];
    yy = newy + ey;
    if( (xx >= 0) && (yy >= 0) && (xx <= maxx) && (yy <= maxy) )
      WritePixel(rp, (long)(xx), (long)yy);
    i++;
  }
  SetRGB4 (vp, (long)c, (long)(RangeRand(16)-1),
			(long)(RangeRand(16)-1),
			(long)(RangeRand(16)-1));
}

openstuff()
{
	if(!(IntuitionBase = OpenLibrary("intuition.library", 0L))) {
	  puts("Manca Intuition!");
	  exit(100);
	}

	if(!(GfxBase = OpenLibrary("graphics.library", 0L))) {
	  puts("Manca grafica!");
	  exit(100);
	}

	if(!(win = OpenWindow(&windef))) {
	  puts("Non si apre la finestra!");
	  closestuff();
	  exit(100);
	}
}

die(str)
char	*str;
{
	puts(str);
	closestuff();
	exit(100);
}

closestuff()
{
	if(tmpras.RasPtr) FreeRaster(tmpras.RasPtr, 320L, 200L);
	if(scr)           CloseScreen(scr);
	if(win)           CloseWindow(win);
	if(GfxBase)       CloseLibrary(GfxBase);
	if(IntuitionBase) CloseLibrary(IntuitionBase);
}

void main()
{
	struct Screen	*wb;
	struct BitMap	*wbm, *mbm;
	long		x, y, n;
	register int	i;

	openstuff();

	wb = win->WScreen;
	scrdef.LeftEdge  = wb->LeftEdge;
	scrdef.TopEdge   = wb->TopEdge;
	scrdef.Width     = wb->Width;
	scrdef.Height    = wb->Height;
	scrdef.ViewModes = wb->ViewPort.Modes;
	if(!(scr = OpenScreen(&scrdef)))
	  die("Fallita apertura schermo!");
	ScreenToBack(scr);

	rp = &scr->RastPort;
	vp = &scr->ViewPort;
	mbm = rp->BitMap;
	wbm = win->WScreen->RastPort.BitMap;
	BltBitMap(wbm, 0L, 0L, mbm, 0L, 0L,
		  (long)scrdef.Width, (long)scrdef.Height,
		  0xc0L, 0xffL, NULL);
	ScreenToFront(scr);
	demo();
	closestuff();
}

/*********************** FINE DEL FILE ****************************/