Aphs.243
net.games.pacman
utzoo!decvax!duke!phs!dennis
Sun Feb 21 16:59:31 1982
pacman magic passage bug fixed
There's a bug in the distributed pacman which allows the monsters
to get one free move as they go through the magic passage.  This
caused me great pain until I fixed it, as I often get chased
through there.  The fixes are as follows.

Add to pacdefs.h:

#define	xleft(x)	((x)+LEFTINT>=0?(x)+LEFTINT:XWRAP)
#define	xright(x)	((x)+RIGHTINT<=XWRAP?(x)+RIGHTINT:0)

Then, make these changes to monster.c:

108c108
< 			newx = tmpx + LEFTINT;
---
> 			newx = xleft(tmpx);
110,111d109
< 			if (newx <= 0)
< 				newx = XWRAP;	/* wrap around */
115c113
< 			newx = tmpx + RIGHTINT;
---
> 			newx = xright(tmpx);
117,118d114
< 			if (newx >= XWRAP)
< 				newx = 0;	/* wrap around */
119a116,118
> 		default:
> 			errgen("bad which");
> 			break;
184d182
< 	char *brdptr;
192d189
< 	brdptr = &(brd[y][x]);
194c191
< 		((next = *(brdptr + (BRDX * UPINT))) != WALL) &&
---
> 		((next = brd[y+UPINT][x]) != WALL) &&
200c197
< 		((next = *(brdptr + (BRDX * DOWNINT))) != WALL) &&
---
> 		((next = brd[y+DOWNINT][x]) != WALL) &&
206c203
< 		((next = *(brdptr + LEFTINT)) != WALL) &&
---
> 		((next = brd[y][xleft(x)]) != WALL) &&
212c209
< 		((next = *(brdptr + RIGHTINT)) != WALL) &&
---
> 		((next = brd[y][xright(x)]) != WALL) &&
234,235c231,232
< 				if ((*(brdptr + (BRDX * DOWNINT)) != WALL) &&
< 					(*(brdptr + (BRDX * DOWNINT)) != GATE))
---
> 				if (((next = brd[y+DOWNINT][x]) != WALL) &&
> 					(next != GATE))
242,243c239,240
< 				if ((*(brdptr + (BRDX * UPINT)) != WALL) &&
< 					(*(brdptr + (BRDX * UPINT)) != GATE))
---
> 				if (((next = brd[y+UPINT][x]) != WALL) &&
> 					(next != GATE))
250,251c247,248
< 				if ((*(brdptr + LEFTINT) != WALL) &&
< 					(*(brdptr + LEFTINT) != GATE))
---
> 				if ((next = brd[y][xleft(x)]) != WALL &&
> 					(next != GATE))
258,259c255,256
< 				if ((*(brdptr + RIGHTINT) != WALL) &&
< 					(*(brdptr + RIGHTINT) != GATE))
---
> 				if ((next = brd[y][xright(x)]) != WALL &&
> 					(next != GATE))