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fix #H30 - rn2(0) from off by 1 bug in special level door creation

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From a bug report, the placement
of random doors by the code that loads special levels would attempt to
evaluate rn2(0) and either get a divide by zero crash (normal build) or an
impossible warning (DEBUG enabled when compiing rnd.c, done automatically
when BETA is defined).  The problem was only noticable for random door in
a 1x1 room; none of our distributed levels specify such a thing so regular
users won't have encountered this bug.  It's a one line fix.

     Altar placement in temples also had a quirk of a similar nature.  It
wouldn't trigger rn2(0) problems but would always place the altar to left
of mid-point in rooms with even width and above the center point in ones
with even height.  Now the placement is randomized so that sometimes it'll
be to the right and/or below mid-point in such cases.

     This also simplifies a couple other instances of similar expressions
that I spotted.
This commit is contained in:
nethack.rankin
2006-01-29 04:32:04 +00:00
parent 0a52d1879f
commit e2dd0a12ae
4 changed files with 22 additions and 11 deletions
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20
src/mkroom.c
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@@ -1,4 +1,4 @@
/* SCCS Id: @(#)mkroom.c 3.5 2005/03/12 */
/* SCCS Id: @(#)mkroom.c 3.5 2006/01/28 */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/* NetHack may be freely redistributed. See license for details. */
@@ -483,11 +483,19 @@ shrine_pos(roomno)
int roomno;
{
static coord buf;
int delta;
struct mkroom *troom = &rooms[roomno - ROOMOFFSET];
buf.x = troom->lx + ((troom->hx - troom->lx) / 2);
buf.y = troom->ly + ((troom->hy - troom->ly) / 2);
return(&buf);
/* if width and height are odd, placement will be the exact center;
if either or both are even, center point is a hypothetical spot
between map locations and placement will be adjacent to that */
delta = troom->hx - troom->lx;
buf.x = troom->lx + delta / 2;
if ((delta % 2) && rn2(2)) buf.x++;
delta = troom->hy - troom->ly;
buf.y = troom->ly + delta / 2;
if ((delta % 2) && rn2(2)) buf.y++;
return &buf;
}
STATIC_OVL void
@@ -555,14 +563,14 @@ int
somex(croom)
register struct mkroom *croom;
{
return rn2(croom->hx-croom->lx+1) + croom->lx;
return rn1(croom->hx - croom->lx + 1, croom->lx);
}
int
somey(croom)
register struct mkroom *croom;
{
return rn2(croom->hy-croom->ly+1) + croom->ly;
return rn1(croom->hy - croom->ly + 1, croom->ly);
}
boolean