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[aNetHack.git] / src / mklev.c

/* NetHack 3.6  mklev.c $NHDT-Date: 1446191876 2015/10/30 07:57:56 $  $NHDT-Branch: master $:$NHDT-Revision: 1.44 $ */
/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
/* NetHack may be freely redistributed.  See license for details. */

#include "hack.h"

/* for UNIX, Rand #def'd to (long)lrand48() or (long)random() */
/* croom->lx etc are schar (width <= int), so % arith ensures that */
/* conversion of result to int is reasonable */

STATIC_DCL void FDECL(mkfount, (int, struct mkroom *));
STATIC_DCL void FDECL(mksink, (struct mkroom *));
STATIC_DCL void FDECL(mkaltar, (struct mkroom *));
STATIC_DCL void FDECL(mkgrave, (struct mkroom *));
STATIC_DCL void NDECL(makevtele);
STATIC_DCL void NDECL(clear_level_structures);
STATIC_DCL void NDECL(makelevel);
STATIC_DCL boolean FDECL(bydoor, (XCHAR_P, XCHAR_P));
STATIC_DCL struct mkroom *FDECL(find_branch_room, (coord *));
STATIC_DCL struct mkroom *FDECL(pos_to_room, (XCHAR_P, XCHAR_P));
STATIC_DCL boolean FDECL(place_niche, (struct mkroom *, int *, int *, int *));
STATIC_DCL void FDECL(makeniche, (int));
STATIC_DCL void NDECL(make_niches);
STATIC_PTR int FDECL(CFDECLSPEC do_comp, (const genericptr,
                                          const genericptr));
STATIC_DCL void FDECL(dosdoor, (XCHAR_P, XCHAR_P, struct mkroom *, int));
STATIC_DCL void FDECL(join, (int, int, BOOLEAN_P));
STATIC_DCL void FDECL(do_room_or_subroom, (struct mkroom *, int, int,
                                           int, int, BOOLEAN_P,
                                           SCHAR_P, BOOLEAN_P, BOOLEAN_P));
STATIC_DCL void NDECL(makerooms);
STATIC_DCL void FDECL(finddpos, (coord *, XCHAR_P, XCHAR_P,
                                 XCHAR_P, XCHAR_P));
STATIC_DCL void FDECL(mkinvpos, (XCHAR_P, XCHAR_P, int));
STATIC_DCL void FDECL(mk_knox_portal, (XCHAR_P, XCHAR_P));

#define create_vault() create_room(-1, -1, 2, 2, -1, -1, VAULT, TRUE)
#define init_vault() vault_x = -1
#define do_vault() (vault_x != -1)
static xchar vault_x, vault_y;
static boolean made_branch; /* used only during level creation */

/* Args must be (const genericptr) so that qsort will always be happy. */

STATIC_PTR int CFDECLSPEC
do_comp(vx, vy)
const genericptr vx;
const genericptr vy;
{
#ifdef LINT
    /* lint complains about possible pointer alignment problems, but we know
       that vx and vy are always properly aligned. Hence, the following
       bogus definition:
    */
    return (vx == vy) ? 0 : -1;
#else
    register const struct mkroom *x, *y;

    x = (const struct mkroom *) vx;
    y = (const struct mkroom *) vy;
    if (x->lx < y->lx)
        return -1;
    return (x->lx > y->lx);
#endif /* LINT */
}

STATIC_OVL void
finddpos(cc, xl, yl, xh, yh)
coord *cc;
xchar xl, yl, xh, yh;
{
    register xchar x, y;

    x = rn1(xh - xl + 1, xl);
    y = rn1(yh - yl + 1, yl);
    if (okdoor(x, y))
        goto gotit;

    for (x = xl; x <= xh; x++)
        for (y = yl; y <= yh; y++)
            if (okdoor(x, y))
                goto gotit;

    for (x = xl; x <= xh; x++)
        for (y = yl; y <= yh; y++)
            if (IS_DOOR(levl[x][y].typ) || levl[x][y].typ == SDOOR)
                goto gotit;
    /* cannot find something reasonable -- strange */
    x = xl;
    y = yh;
gotit:
    cc->x = x;
    cc->y = y;
    return;
}

void
sort_rooms()
{
#if defined(SYSV) || defined(DGUX)
    qsort((genericptr_t) rooms, (unsigned) nroom, sizeof(struct mkroom),
          do_comp);
#else
    qsort((genericptr_t) rooms, nroom, sizeof(struct mkroom), do_comp);
#endif
}

STATIC_OVL void
do_room_or_subroom(croom, lowx, lowy, hix, hiy, lit, rtype, special, is_room)
register struct mkroom *croom;
int lowx, lowy;
register int hix, hiy;
boolean lit;
schar rtype;
boolean special;
boolean is_room;
{
    register int x, y;
    struct rm *lev;

    /* locations might bump level edges in wall-less rooms */
    /* add/subtract 1 to allow for edge locations */
    if (!lowx)
        lowx++;
    if (!lowy)
        lowy++;
    if (hix >= COLNO - 1)
        hix = COLNO - 2;
    if (hiy >= ROWNO - 1)
        hiy = ROWNO - 2;

    if (lit) {
        for (x = lowx - 1; x <= hix + 1; x++) {
            lev = &levl[x][max(lowy - 1, 0)];
            for (y = lowy - 1; y <= hiy + 1; y++)
                lev++->lit = 1;
        }
        croom->rlit = 1;
    } else
        croom->rlit = 0;

    croom->lx = lowx;
    croom->hx = hix;
    croom->ly = lowy;
    croom->hy = hiy;
    croom->rtype = rtype;
    croom->doorct = 0;
    /* if we're not making a vault, doorindex will still be 0
     * if we are, we'll have problems adding niches to the previous room
     * unless fdoor is at least doorindex
     */
    croom->fdoor = doorindex;
    croom->irregular = FALSE;

    croom->nsubrooms = 0;
    croom->sbrooms[0] = (struct mkroom *) 0;
    if (!special) {
        for (x = lowx - 1; x <= hix + 1; x++)
            for (y = lowy - 1; y <= hiy + 1; y += (hiy - lowy + 2)) {
                levl[x][y].typ = HWALL;
                levl[x][y].horizontal = 1; /* For open/secret doors. */
            }
        for (x = lowx - 1; x <= hix + 1; x += (hix - lowx + 2))
            for (y = lowy; y <= hiy; y++) {
                levl[x][y].typ = VWALL;
                levl[x][y].horizontal = 0; /* For open/secret doors. */
            }
        for (x = lowx; x <= hix; x++) {
            lev = &levl[x][lowy];
            for (y = lowy; y <= hiy; y++)
                lev++->typ = ROOM;
        }
        if (is_room) {
            levl[lowx - 1][lowy - 1].typ = TLCORNER;
            levl[hix + 1][lowy - 1].typ = TRCORNER;
            levl[lowx - 1][hiy + 1].typ = BLCORNER;
            levl[hix + 1][hiy + 1].typ = BRCORNER;
        } else { /* a subroom */
            wallification(lowx - 1, lowy - 1, hix + 1, hiy + 1);
        }
    }
}

void
add_room(lowx, lowy, hix, hiy, lit, rtype, special)
int lowx, lowy, hix, hiy;
boolean lit;
schar rtype;
boolean special;
{
    register struct mkroom *croom;

    croom = &rooms[nroom];
    do_room_or_subroom(croom, lowx, lowy, hix, hiy, lit, rtype, special,
                       (boolean) TRUE);
    croom++;
    croom->hx = -1;
    nroom++;
}

void
add_subroom(proom, lowx, lowy, hix, hiy, lit, rtype, special)
struct mkroom *proom;
int lowx, lowy, hix, hiy;
boolean lit;
schar rtype;
boolean special;
{
    register struct mkroom *croom;

    croom = &subrooms[nsubroom];
    do_room_or_subroom(croom, lowx, lowy, hix, hiy, lit, rtype, special,
                       (boolean) FALSE);
    proom->sbrooms[proom->nsubrooms++] = croom;
    croom++;
    croom->hx = -1;
    nsubroom++;
}

STATIC_OVL void
makerooms()
{
    boolean tried_vault = FALSE;

    /* make rooms until satisfied */
    /* rnd_rect() will returns 0 if no more rects are available... */
    while (nroom < MAXNROFROOMS && rnd_rect()) {
        if (nroom >= (MAXNROFROOMS / 6) && rn2(2) && !tried_vault) {
            tried_vault = TRUE;
            if (create_vault()) {
                vault_x = rooms[nroom].lx;
                vault_y = rooms[nroom].ly;
                rooms[nroom].hx = -1;
            }
        } else if (!create_room(-1, -1, -1, -1, -1, -1, OROOM, -1))
            return;
    }
    return;
}

STATIC_OVL void
join(a, b, nxcor)
register int a, b;
boolean nxcor;
{
    coord cc, tt, org, dest;
    register xchar tx, ty, xx, yy;
    register struct mkroom *croom, *troom;
    register int dx, dy;

    croom = &rooms[a];
    troom = &rooms[b];

    /* find positions cc and tt for doors in croom and troom
       and direction for a corridor between them */

    if (troom->hx < 0 || croom->hx < 0 || doorindex >= DOORMAX)
        return;
    if (troom->lx > croom->hx) {
        dx = 1;
        dy = 0;
        xx = croom->hx + 1;
        tx = troom->lx - 1;
        finddpos(&cc, xx, croom->ly, xx, croom->hy);
        finddpos(&tt, tx, troom->ly, tx, troom->hy);
    } else if (troom->hy < croom->ly) {
        dy = -1;
        dx = 0;
        yy = croom->ly - 1;
        finddpos(&cc, croom->lx, yy, croom->hx, yy);
        ty = troom->hy + 1;
        finddpos(&tt, troom->lx, ty, troom->hx, ty);
    } else if (troom->hx < croom->lx) {
        dx = -1;
        dy = 0;
        xx = croom->lx - 1;
        tx = troom->hx + 1;
        finddpos(&cc, xx, croom->ly, xx, croom->hy);
        finddpos(&tt, tx, troom->ly, tx, troom->hy);
    } else {
        dy = 1;
        dx = 0;
        yy = croom->hy + 1;
        ty = troom->ly - 1;
        finddpos(&cc, croom->lx, yy, croom->hx, yy);
        finddpos(&tt, troom->lx, ty, troom->hx, ty);
    }
    xx = cc.x;
    yy = cc.y;
    tx = tt.x - dx;
    ty = tt.y - dy;
    if (nxcor && levl[xx + dx][yy + dy].typ)
        return;
    if (okdoor(xx, yy) || !nxcor)
        dodoor(xx, yy, croom);

    org.x = xx + dx;
    org.y = yy + dy;
    dest.x = tx;
    dest.y = ty;

    if (!dig_corridor(&org, &dest, nxcor, level.flags.arboreal ? ROOM : CORR,
                      STONE))
        return;

    /* we succeeded in digging the corridor */
    if (okdoor(tt.x, tt.y) || !nxcor)
        dodoor(tt.x, tt.y, troom);

    if (smeq[a] < smeq[b])
        smeq[b] = smeq[a];
    else
        smeq[a] = smeq[b];
}

void
makecorridors()
{
    int a, b, i;
    boolean any = TRUE;

    for (a = 0; a < nroom - 1; a++) {
        join(a, a + 1, FALSE);
        if (!rn2(50))
            break; /* allow some randomness */
    }
    for (a = 0; a < nroom - 2; a++)
        if (smeq[a] != smeq[a + 2])
            join(a, a + 2, FALSE);
    for (a = 0; any && a < nroom; a++) {
        any = FALSE;
        for (b = 0; b < nroom; b++)
            if (smeq[a] != smeq[b]) {
                join(a, b, FALSE);
                any = TRUE;
            }
    }
    if (nroom > 2)
        for (i = rn2(nroom) + 4; i; i--) {
            a = rn2(nroom);
            b = rn2(nroom - 2);
            if (b >= a)
                b += 2;
            join(a, b, TRUE);
        }
}

void
add_door(x, y, aroom)
register int x, y;
register struct mkroom *aroom;
{
    register struct mkroom *broom;
    register int tmp;
    int i;

    if (aroom->doorct == 0)
        aroom->fdoor = doorindex;

    aroom->doorct++;

    for (tmp = doorindex; tmp > aroom->fdoor; tmp--)
        doors[tmp] = doors[tmp - 1];

    for (i = 0; i < nroom; i++) {
        broom = &rooms[i];
        if (broom != aroom && broom->doorct && broom->fdoor >= aroom->fdoor)
            broom->fdoor++;
    }
    for (i = 0; i < nsubroom; i++) {
        broom = &subrooms[i];
        if (broom != aroom && broom->doorct && broom->fdoor >= aroom->fdoor)
            broom->fdoor++;
    }

    doorindex++;
    doors[aroom->fdoor].x = x;
    doors[aroom->fdoor].y = y;
}

STATIC_OVL void
dosdoor(x, y, aroom, type)
register xchar x, y;
struct mkroom *aroom;
int type;
{
    boolean shdoor = *in_rooms(x, y, SHOPBASE) ? TRUE : FALSE;

    if (!IS_WALL(levl[x][y].typ)) /* avoid SDOORs on already made doors */
        type = DOOR;
    levl[x][y].typ = type;
    if (type == DOOR) {
        if (!rn2(3)) { /* is it a locked door, closed, or a doorway? */
            if (!rn2(5))
                levl[x][y].doormask = D_ISOPEN;
            else if (!rn2(6))
                levl[x][y].doormask = D_LOCKED;
            else
                levl[x][y].doormask = D_CLOSED;

            if (levl[x][y].doormask != D_ISOPEN && !shdoor
                && level_difficulty() >= 5 && !rn2(25))
                levl[x][y].doormask |= D_TRAPPED;
        } else {
#ifdef STUPID
            if (shdoor)
                levl[x][y].doormask = D_ISOPEN;
            else
                levl[x][y].doormask = D_NODOOR;
#else
            levl[x][y].doormask = (shdoor ? D_ISOPEN : D_NODOOR);
#endif
        }

        /* also done in roguecorr(); doing it here first prevents
           making mimics in place of trapped doors on rogue level */
        if (Is_rogue_level(&u.uz))
            levl[x][y].doormask = D_NODOOR;

        if (levl[x][y].doormask & D_TRAPPED) {
            struct monst *mtmp;

            if (level_difficulty() >= 9 && !rn2(5)
                && !((mvitals[PM_SMALL_MIMIC].mvflags & G_GONE)
                     && (mvitals[PM_LARGE_MIMIC].mvflags & G_GONE)
                     && (mvitals[PM_GIANT_MIMIC].mvflags & G_GONE))) {
                /* make a mimic instead */
                levl[x][y].doormask = D_NODOOR;
                mtmp = makemon(mkclass(S_MIMIC, 0), x, y, NO_MM_FLAGS);
                if (mtmp)
                    set_mimic_sym(mtmp);
            }
        }
        /* newsym(x,y); */
    } else { /* SDOOR */
        if (shdoor || !rn2(5))
            levl[x][y].doormask = D_LOCKED;
        else
            levl[x][y].doormask = D_CLOSED;

        if (!shdoor && level_difficulty() >= 4 && !rn2(20))
            levl[x][y].doormask |= D_TRAPPED;
    }

    add_door(x, y, aroom);
}

STATIC_OVL boolean
place_niche(aroom, dy, xx, yy)
register struct mkroom *aroom;
int *dy, *xx, *yy;
{
    coord dd;

    if (rn2(2)) {
        *dy = 1;
        finddpos(&dd, aroom->lx, aroom->hy + 1, aroom->hx, aroom->hy + 1);
    } else {
        *dy = -1;
        finddpos(&dd, aroom->lx, aroom->ly - 1, aroom->hx, aroom->ly - 1);
    }
    *xx = dd.x;
    *yy = dd.y;
    return (boolean) ((isok(*xx, *yy + *dy)
                       && levl[*xx][*yy + *dy].typ == STONE)
                      && (isok(*xx, *yy - *dy)
                          && !IS_POOL(levl[*xx][*yy - *dy].typ)
                          && !IS_FURNITURE(levl[*xx][*yy - *dy].typ)));
}

/* there should be one of these per trap, in the same order as trap.h */
static NEARDATA const char *trap_engravings[TRAPNUM] = {
    (char *) 0,      (char *) 0,    (char *) 0,    (char *) 0, (char *) 0,
    (char *) 0,      (char *) 0,    (char *) 0,    (char *) 0, (char *) 0,
    (char *) 0,      (char *) 0,    (char *) 0,    (char *) 0,
    /* 14..16: trap door, teleport, level-teleport */
    "Vlad was here", "ad aerarium", "ad aerarium", (char *) 0, (char *) 0,
    (char *) 0,      (char *) 0,    (char *) 0,    (char *) 0, (char *) 0,
};

STATIC_OVL void
makeniche(trap_type)
int trap_type;
{
    register struct mkroom *aroom;
    struct rm *rm;
    int vct = 8;
    int dy, xx, yy;
    struct trap *ttmp;

    if (doorindex < DOORMAX) {
        while (vct--) {
            aroom = &rooms[rn2(nroom)];
            if (aroom->rtype != OROOM)
                continue; /* not an ordinary room */
            if (aroom->doorct == 1 && rn2(5))
                continue;
            if (!place_niche(aroom, &dy, &xx, &yy))
                continue;

            rm = &levl[xx][yy + dy];
            if (trap_type || !rn2(4)) {
                rm->typ = SCORR;
                if (trap_type) {
                    if ((trap_type == HOLE || trap_type == TRAPDOOR)
                        && !Can_fall_thru(&u.uz))
                        trap_type = ROCKTRAP;
                    ttmp = maketrap(xx, yy + dy, trap_type);
                    if (ttmp) {
                        if (trap_type != ROCKTRAP)
                            ttmp->once = 1;
                        if (trap_engravings[trap_type]) {
                            make_engr_at(xx, yy - dy,
                                         trap_engravings[trap_type], 0L,
                                         DUST);
                            wipe_engr_at(xx, yy - dy, 5,
                                         FALSE); /* age it a little */
                        }
                    }
                }
                dosdoor(xx, yy, aroom, SDOOR);
            } else {
                rm->typ = CORR;
                if (rn2(7))
                    dosdoor(xx, yy, aroom, rn2(5) ? SDOOR : DOOR);
                else {
                    /* inaccessible niches occasionally have iron bars */
                    if (!rn2(5) && IS_WALL(levl[xx][yy].typ)) {
                        levl[xx][yy].typ = IRONBARS;
                        if (rn2(3))
                            (void) mkcorpstat(CORPSE, (struct monst *) 0,
                                              mkclass(S_HUMAN, 0), xx,
                                              yy + dy, TRUE);
                    }
                    if (!level.flags.noteleport)
                        (void) mksobj_at(SCR_TELEPORTATION, xx, yy + dy, TRUE,
                                         FALSE);
                    if (!rn2(3))
                        (void) mkobj_at(0, xx, yy + dy, TRUE);
                }
            }
            return;
        }
    }
}

STATIC_OVL void
make_niches()
{
    int ct = rnd((nroom >> 1) + 1), dep = depth(&u.uz);
    boolean ltptr = (!level.flags.noteleport && dep > 15),
            vamp = (dep > 5 && dep < 25);

    while (ct--) {
        if (ltptr && !rn2(6)) {
            ltptr = FALSE;
            makeniche(LEVEL_TELEP);
        } else if (vamp && !rn2(6)) {
            vamp = FALSE;
            makeniche(TRAPDOOR);
        } else
            makeniche(NO_TRAP);
    }
}

STATIC_OVL void
makevtele()
{
    makeniche(TELEP_TRAP);
}

/* clear out various globals that keep information on the current level.
 * some of this is only necessary for some types of levels (maze, normal,
 * special) but it's easier to put it all in one place than make sure
 * each type initializes what it needs to separately.
 */
STATIC_OVL void
clear_level_structures()
{
    static struct rm zerorm = { cmap_to_glyph(S_stone),
                                0, 0, 0, 0, 0, 0, 0, 0, 0 };
    register int x, y;
    register struct rm *lev;

    for (x = 0; x < COLNO; x++) {
        lev = &levl[x][0];
        for (y = 0; y < ROWNO; y++) {
            *lev++ = zerorm;
            /*
             * These used to be '#if MICROPORT_BUG',
             * with use of memset(0) for '#if !MICROPORT_BUG' below,
             * but memset is not appropriate for initializing pointers,
             * so do these level.objects[][] and level.monsters[][]
             * initializations unconditionally.
             */
            level.objects[x][y] = (struct obj *) 0;
            level.monsters[x][y] = (struct monst *) 0;
        }
    }
    level.objlist = (struct obj *) 0;
    level.buriedobjlist = (struct obj *) 0;
    level.monlist = (struct monst *) 0;
    level.damagelist = (struct damage *) 0;
    level.bonesinfo = (struct cemetery *) 0;

    level.flags.nfountains = 0;
    level.flags.nsinks = 0;
    level.flags.has_shop = 0;
    level.flags.has_vault = 0;
    level.flags.has_zoo = 0;
    level.flags.has_court = 0;
    level.flags.has_morgue = level.flags.graveyard = 0;
    level.flags.has_beehive = 0;
    level.flags.has_barracks = 0;
    level.flags.has_temple = 0;
    level.flags.has_swamp = 0;
    level.flags.noteleport = 0;
    level.flags.hardfloor = 0;
    level.flags.nommap = 0;
    level.flags.hero_memory = 1;
    level.flags.shortsighted = 0;
    level.flags.sokoban_rules = 0;
    level.flags.is_maze_lev = 0;
    level.flags.is_cavernous_lev = 0;
    level.flags.arboreal = 0;
    level.flags.wizard_bones = 0;
    level.flags.corrmaze = 0;

    nroom = 0;
    rooms[0].hx = -1;
    nsubroom = 0;
    subrooms[0].hx = -1;
    doorindex = 0;
    init_rect();
    init_vault();
    xdnstair = ydnstair = xupstair = yupstair = 0;
    sstairs.sx = sstairs.sy = 0;
    xdnladder = ydnladder = xupladder = yupladder = 0;
    made_branch = FALSE;
    clear_regions();
}

STATIC_OVL void
makelevel()
{
    register struct mkroom *croom, *troom;
    register int tryct;
    register int x, y;
    struct monst *tmonst; /* always put a web with a spider */
    branch *branchp;
    int room_threshold;

    if (wiz1_level.dlevel == 0)
        init_dungeons();
    oinit(); /* assign level dependent obj probabilities */
    clear_level_structures();

    {
        register s_level *slev = Is_special(&u.uz);

        /* check for special levels */
        if (slev && !Is_rogue_level(&u.uz)) {
            makemaz(slev->proto);
            return;
        } else if (dungeons[u.uz.dnum].proto[0]) {
            makemaz("");
            return;
        } else if (In_mines(&u.uz)) {
            makemaz("minefill");
            return;
        } else if (In_quest(&u.uz)) {
            char fillname[9];
            s_level *loc_lev;

            Sprintf(fillname, "%s-loca", urole.filecode);
            loc_lev = find_level(fillname);

            Sprintf(fillname, "%s-fil", urole.filecode);
            Strcat(fillname,
                   (u.uz.dlevel < loc_lev->dlevel.dlevel) ? "a" : "b");
            makemaz(fillname);
            return;
        } else if (In_hell(&u.uz)
                   || (rn2(5) && u.uz.dnum == medusa_level.dnum
                       && depth(&u.uz) > depth(&medusa_level))) {
            makemaz("");
            return;
        }
    }

    /* otherwise, fall through - it's a "regular" level. */

    if (Is_rogue_level(&u.uz)) {
        makeroguerooms();
        makerogueghost();
    } else
        makerooms();
    sort_rooms();

    /* construct stairs (up and down in different rooms if possible) */
    croom = &rooms[rn2(nroom)];
    if (!Is_botlevel(&u.uz))
        mkstairs(somex(croom), somey(croom), 0, croom); /* down */
    if (nroom > 1) {
        troom = croom;
        croom = &rooms[rn2(nroom - 1)];
        if (croom == troom)
            croom++;
    }

    if (u.uz.dlevel != 1) {
        xchar sx, sy;
        do {
            sx = somex(croom);
            sy = somey(croom);
        } while (occupied(sx, sy));
        mkstairs(sx, sy, 1, croom); /* up */
    }

    branchp = Is_branchlev(&u.uz);    /* possible dungeon branch */
    room_threshold = branchp ? 4 : 3; /* minimum number of rooms needed
                                         to allow a random special room */
    if (Is_rogue_level(&u.uz))
        goto skip0;
    makecorridors();
    make_niches();

    /* make a secret treasure vault, not connected to the rest */
    if (do_vault()) {
        xchar w, h;
        debugpline0("trying to make a vault...");
        w = 1;
        h = 1;
        if (check_room(&vault_x, &w, &vault_y, &h, TRUE)) {
        fill_vault:
            add_room(vault_x, vault_y, vault_x + w, vault_y + h, TRUE, VAULT,
                     FALSE);
            level.flags.has_vault = 1;
            ++room_threshold;
            fill_room(&rooms[nroom - 1], FALSE);
            mk_knox_portal(vault_x + w, vault_y + h);
            if (!level.flags.noteleport && !rn2(3))
                makevtele();
        } else if (rnd_rect() && create_vault()) {
            vault_x = rooms[nroom].lx;
            vault_y = rooms[nroom].ly;
            if (check_room(&vault_x, &w, &vault_y, &h, TRUE))
                goto fill_vault;
            else
                rooms[nroom].hx = -1;
        }
    }

    {
        register int u_depth = depth(&u.uz);

        if (wizard && nh_getenv("SHOPTYPE"))
            mkroom(SHOPBASE);
        else if (u_depth > 1 && u_depth < depth(&medusa_level)
                 && nroom >= room_threshold && rn2(u_depth) < 3)
            mkroom(SHOPBASE);
        else if (u_depth > 4 && !rn2(6))
            mkroom(COURT);
        else if (u_depth > 5 && !rn2(8)
                 && !(mvitals[PM_LEPRECHAUN].mvflags & G_GONE))
            mkroom(LEPREHALL);
        else if (u_depth > 6 && !rn2(7))
            mkroom(ZOO);
        else if (u_depth > 8 && !rn2(5))
            mkroom(TEMPLE);
        else if (u_depth > 9 && !rn2(5)
                 && !(mvitals[PM_KILLER_BEE].mvflags & G_GONE))
            mkroom(BEEHIVE);
        else if (u_depth > 11 && !rn2(6))
            mkroom(MORGUE);
        else if (u_depth > 12 && !rn2(8) && antholemon())
            mkroom(ANTHOLE);
        else if (u_depth > 14 && !rn2(4)
                 && !(mvitals[PM_SOLDIER].mvflags & G_GONE))
            mkroom(BARRACKS);
        else if (u_depth > 15 && !rn2(6))
            mkroom(SWAMP);
        else if (u_depth > 16 && !rn2(8)
                 && !(mvitals[PM_COCKATRICE].mvflags & G_GONE))
            mkroom(COCKNEST);
    }

skip0:
    /* Place multi-dungeon branch. */
    place_branch(branchp, 0, 0);

    /* for each room: put things inside */
    for (croom = rooms; croom->hx > 0; croom++) {
        if (croom->rtype != OROOM)
            continue;

        /* put a sleeping monster inside */
        /* Note: monster may be on the stairs. This cannot be
           avoided: maybe the player fell through a trap door
           while a monster was on the stairs. Conclusion:
           we have to check for monsters on the stairs anyway. */

        if (u.uhave.amulet || !rn2(3)) {
            x = somex(croom);
            y = somey(croom);
            tmonst = makemon((struct permonst *) 0, x, y, NO_MM_FLAGS);
            if (tmonst && tmonst->data == &mons[PM_GIANT_SPIDER]
                && !occupied(x, y))
                (void) maketrap(x, y, WEB);
        }
        /* put traps and mimics inside */
        x = 8 - (level_difficulty() / 6);
        if (x <= 1)
            x = 2;
        while (!rn2(x))
            mktrap(0, 0, croom, (coord *) 0);
        if (!rn2(3))
            (void) mkgold(0L, somex(croom), somey(croom));
        if (Is_rogue_level(&u.uz))
            goto skip_nonrogue;
        if (!rn2(10))
            mkfount(0, croom);
        if (!rn2(60))
            mksink(croom);
        if (!rn2(60))
            mkaltar(croom);
        x = 80 - (depth(&u.uz) * 2);
        if (x < 2)
            x = 2;
        if (!rn2(x))
            mkgrave(croom);

        /* put statues inside */
        if (!rn2(20))
            (void) mkcorpstat(STATUE, (struct monst *) 0,
                              (struct permonst *) 0, somex(croom),
                              somey(croom), CORPSTAT_INIT);
        /* put box/chest inside;
         *  40% chance for at least 1 box, regardless of number
         *  of rooms; about 5 - 7.5% for 2 boxes, least likely
         *  when few rooms; chance for 3 or more is negligible.
         */
        if (!rn2(nroom * 5 / 2))
            (void) mksobj_at((rn2(3)) ? LARGE_BOX : CHEST, somex(croom),
                             somey(croom), TRUE, FALSE);

        /* maybe make some graffiti */
        if (!rn2(27 + 3 * abs(depth(&u.uz)))) {
            char buf[BUFSZ];
            const char *mesg = random_engraving(buf);
            if (mesg) {
                do {
                    x = somex(croom);
                    y = somey(croom);
                } while (levl[x][y].typ != ROOM && !rn2(40));
                if (!(IS_POOL(levl[x][y].typ)
                      || IS_FURNITURE(levl[x][y].typ)))
                    make_engr_at(x, y, mesg, 0L, MARK);
            }
        }

    skip_nonrogue:
        if (!rn2(3)) {
            (void) mkobj_at(0, somex(croom), somey(croom), TRUE);
            tryct = 0;
            while (!rn2(5)) {
                if (++tryct > 100) {
                    impossible("tryct overflow4");
                    break;
                }
                (void) mkobj_at(0, somex(croom), somey(croom), TRUE);
            }
        }
    }
}

/*
 *      Place deposits of minerals (gold and misc gems) in the stone
 *      surrounding the rooms on the map.
 *      Also place kelp in water.
 *      mineralize(-1, -1, -1, -1, FALSE); => "default" behaviour
 */
void
mineralize(kelp_pool, kelp_moat, goldprob, gemprob, skip_lvl_checks)
int kelp_pool, kelp_moat, goldprob, gemprob;
boolean skip_lvl_checks;
{
    s_level *sp;
    struct obj *otmp;
    int x, y, cnt;

    if (kelp_pool < 0)
        kelp_pool = 10;
    if (kelp_moat < 0)
        kelp_moat = 30;

    /* Place kelp, except on the plane of water */
    if (!skip_lvl_checks && In_endgame(&u.uz))
        return;
    for (x = 2; x < (COLNO - 2); x++)
        for (y = 1; y < (ROWNO - 1); y++)
            if ((kelp_pool && levl[x][y].typ == POOL && !rn2(kelp_pool))
                || (kelp_moat && levl[x][y].typ == MOAT && !rn2(kelp_moat)))
                (void) mksobj_at(KELP_FROND, x, y, TRUE, FALSE);

    /* determine if it is even allowed;
       almost all special levels are excluded */
    if (!skip_lvl_checks
        && (In_hell(&u.uz) || In_V_tower(&u.uz) || Is_rogue_level(&u.uz)
            || level.flags.arboreal
            || ((sp = Is_special(&u.uz)) != 0 && !Is_oracle_level(&u.uz)
                && (!In_mines(&u.uz) || sp->flags.town))))
        return;

    /* basic level-related probabilities */
    if (goldprob < 0)
        goldprob = 20 + depth(&u.uz) / 3;
    if (gemprob < 0)
        gemprob = goldprob / 4;

    /* mines have ***MORE*** goodies - otherwise why mine? */
    if (!skip_lvl_checks) {
        if (In_mines(&u.uz)) {
            goldprob *= 2;
            gemprob *= 3;
        } else if (In_quest(&u.uz)) {
            goldprob /= 4;
            gemprob /= 6;
        }
    }

    /*
     * Seed rock areas with gold and/or gems.
     * We use fairly low level object handling to avoid unnecessary
     * overhead from placing things in the floor chain prior to burial.
     */
    for (x = 2; x < (COLNO - 2); x++)
        for (y = 1; y < (ROWNO - 1); y++)
            if (levl[x][y + 1].typ != STONE) { /* <x,y> spot not eligible */
                y += 2; /* next two spots aren't eligible either */
            } else if (levl[x][y].typ != STONE) { /* this spot not eligible */
                y += 1; /* next spot isn't eligible either */
            } else if (!(levl[x][y].wall_info & W_NONDIGGABLE)
                       && levl[x][y - 1].typ == STONE
                       && levl[x + 1][y - 1].typ == STONE
                       && levl[x - 1][y - 1].typ == STONE
                       && levl[x + 1][y].typ == STONE
                       && levl[x - 1][y].typ == STONE
                       && levl[x + 1][y + 1].typ == STONE
                       && levl[x - 1][y + 1].typ == STONE) {
                if (rn2(1000) < goldprob) {
                    if ((otmp = mksobj(GOLD_PIECE, FALSE, FALSE)) != 0) {
                        otmp->ox = x, otmp->oy = y;
                        otmp->quan = 1L + rnd(goldprob * 3);
                        otmp->owt = weight(otmp);
                        if (!rn2(3))
                            add_to_buried(otmp);
                        else
                            place_object(otmp, x, y);
                    }
                }
                if (rn2(1000) < gemprob) {
                    for (cnt = rnd(2 + dunlev(&u.uz) / 3); cnt > 0; cnt--)
                        if ((otmp = mkobj(GEM_CLASS, FALSE)) != 0) {
                            if (otmp->otyp == ROCK) {
                                dealloc_obj(otmp); /* discard it */
                            } else {
                                otmp->ox = x, otmp->oy = y;
                                if (!rn2(3))
                                    add_to_buried(otmp);
                                else
                                    place_object(otmp, x, y);
                            }
                        }
                }
            }
}

void
mklev()
{
    struct mkroom *croom;
    int ridx;

    init_mapseen(&u.uz);
    if (getbones())
        return;

    in_mklev = TRUE;
    makelevel();
    bound_digging();
    mineralize(-1, -1, -1, -1, FALSE);
    in_mklev = FALSE;
    /* has_morgue gets cleared once morgue is entered; graveyard stays
       set (graveyard might already be set even when has_morgue is clear
       [see fixup_special()], so don't update it unconditionally) */
    if (level.flags.has_morgue)
        level.flags.graveyard = 1;
    if (!level.flags.is_maze_lev) {
        for (croom = &rooms[0]; croom != &rooms[nroom]; croom++)
#ifdef SPECIALIZATION
            topologize(croom, FALSE);
#else
            topologize(croom);
#endif
    }
    set_wall_state();
    /* for many room types, rooms[].rtype is zeroed once the room has been
       entered; rooms[].orig_rtype always retains original rtype value */
    for (ridx = 0; ridx < SIZE(rooms); ridx++)
        rooms[ridx].orig_rtype = rooms[ridx].rtype;
}

void
#ifdef SPECIALIZATION
topologize(croom, do_ordinary)
struct mkroom *croom;
boolean do_ordinary;
#else
topologize(croom)
struct mkroom *croom;
#endif
{
    register int x, y, roomno = (int) ((croom - rooms) + ROOMOFFSET);
    int lowx = croom->lx, lowy = croom->ly;
    int hix = croom->hx, hiy = croom->hy;
#ifdef SPECIALIZATION
    schar rtype = croom->rtype;
#endif
    int subindex, nsubrooms = croom->nsubrooms;

    /* skip the room if already done; i.e. a shop handled out of order */
    /* also skip if this is non-rectangular (it _must_ be done already) */
    if ((int) levl[lowx][lowy].roomno == roomno || croom->irregular)
        return;
#ifdef SPECIALIZATION
    if (Is_rogue_level(&u.uz))
        do_ordinary = TRUE; /* vision routine helper */
    if ((rtype != OROOM) || do_ordinary)
#endif
        {
        /* do innards first */
        for (x = lowx; x <= hix; x++)
            for (y = lowy; y <= hiy; y++)
#ifdef SPECIALIZATION
                if (rtype == OROOM)
                    levl[x][y].roomno = NO_ROOM;
                else
#endif
                    levl[x][y].roomno = roomno;
        /* top and bottom edges */
        for (x = lowx - 1; x <= hix + 1; x++)
            for (y = lowy - 1; y <= hiy + 1; y += (hiy - lowy + 2)) {
                levl[x][y].edge = 1;
                if (levl[x][y].roomno)
                    levl[x][y].roomno = SHARED;
                else
                    levl[x][y].roomno = roomno;
            }
        /* sides */
        for (x = lowx - 1; x <= hix + 1; x += (hix - lowx + 2))
            for (y = lowy; y <= hiy; y++) {
                levl[x][y].edge = 1;
                if (levl[x][y].roomno)
                    levl[x][y].roomno = SHARED;
                else
                    levl[x][y].roomno = roomno;
            }
    }
    /* subrooms */
    for (subindex = 0; subindex < nsubrooms; subindex++)
#ifdef SPECIALIZATION
        topologize(croom->sbrooms[subindex], (boolean) (rtype != OROOM));
#else
        topologize(croom->sbrooms[subindex]);
#endif
}

/* Find an unused room for a branch location. */
STATIC_OVL struct mkroom *
find_branch_room(mp)
coord *mp;
{
    struct mkroom *croom = 0;

    if (nroom == 0) {
        mazexy(mp); /* already verifies location */
    } else {
        /* not perfect - there may be only one stairway */
        if (nroom > 2) {
            int tryct = 0;

            do
                croom = &rooms[rn2(nroom)];
            while ((croom == dnstairs_room || croom == upstairs_room
                    || croom->rtype != OROOM) && (++tryct < 100));
        } else
            croom = &rooms[rn2(nroom)];

        do {
            if (!somexy(croom, mp))
                impossible("Can't place branch!");
        } while (occupied(mp->x, mp->y)
                 || (levl[mp->x][mp->y].typ != CORR
                     && levl[mp->x][mp->y].typ != ROOM));
    }
    return croom;
}

/* Find the room for (x,y).  Return null if not in a room. */
STATIC_OVL struct mkroom *
pos_to_room(x, y)
xchar x, y;
{
    int i;
    struct mkroom *curr;

    for (curr = rooms, i = 0; i < nroom; curr++, i++)
        if (inside_room(curr, x, y))
            return curr;
    ;
    return (struct mkroom *) 0;
}

/* If given a branch, randomly place a special stair or portal. */
void
place_branch(br, x, y)
branch *br; /* branch to place */
xchar x, y; /* location */
{
    coord m;
    d_level *dest;
    boolean make_stairs;
    struct mkroom *br_room;

    /*
     * Return immediately if there is no branch to make or we have
     * already made one.  This routine can be called twice when
     * a special level is loaded that specifies an SSTAIR location
     * as a favored spot for a branch.
     */
    if (!br || made_branch)
        return;

    if (!x) { /* find random coordinates for branch */
        br_room = find_branch_room(&m);
        x = m.x;
        y = m.y;
    } else {
        br_room = pos_to_room(x, y);
    }

    if (on_level(&br->end1, &u.uz)) {
        /* we're on end1 */
        make_stairs = br->type != BR_NO_END1;
        dest = &br->end2;
    } else {
        /* we're on end2 */
        make_stairs = br->type != BR_NO_END2;
        dest = &br->end1;
    }

    if (br->type == BR_PORTAL) {
        mkportal(x, y, dest->dnum, dest->dlevel);
    } else if (make_stairs) {
        sstairs.sx = x;
        sstairs.sy = y;
        sstairs.up =
            (char) on_level(&br->end1, &u.uz) ? br->end1_up : !br->end1_up;
        assign_level(&sstairs.tolev, dest);
        sstairs_room = br_room;

        levl[x][y].ladder = sstairs.up ? LA_UP : LA_DOWN;
        levl[x][y].typ = STAIRS;
    }
    /*
     * Set made_branch to TRUE even if we didn't make a stairwell (i.e.
     * make_stairs is false) since there is currently only one branch
     * per level, if we failed once, we're going to fail again on the
     * next call.
     */
    made_branch = TRUE;
}

STATIC_OVL boolean
bydoor(x, y)
register xchar x, y;
{
    register int typ;

    if (isok(x + 1, y)) {
        typ = levl[x + 1][y].typ;
        if (IS_DOOR(typ) || typ == SDOOR)
            return TRUE;
    }
    if (isok(x - 1, y)) {
        typ = levl[x - 1][y].typ;
        if (IS_DOOR(typ) || typ == SDOOR)
            return TRUE;
    }
    if (isok(x, y + 1)) {
        typ = levl[x][y + 1].typ;
        if (IS_DOOR(typ) || typ == SDOOR)
            return TRUE;
    }
    if (isok(x, y - 1)) {
        typ = levl[x][y - 1].typ;
        if (IS_DOOR(typ) || typ == SDOOR)
            return TRUE;
    }
    return FALSE;
}

/* see whether it is allowable to create a door at [x,y] */
int
okdoor(x, y)
xchar x, y;
{
    boolean near_door = bydoor(x, y);

    return ((levl[x][y].typ == HWALL || levl[x][y].typ == VWALL)
            && doorindex < DOORMAX && !near_door);
}

void
dodoor(x, y, aroom)
int x, y;
struct mkroom *aroom;
{
    if (doorindex >= DOORMAX) {
        impossible("DOORMAX exceeded?");
        return;
    }

    dosdoor(x, y, aroom, rn2(8) ? DOOR : SDOOR);
}

boolean
occupied(x, y)
register xchar x, y;
{
    return (boolean) (t_at(x, y) || IS_FURNITURE(levl[x][y].typ)
                      || is_lava(x, y) || is_pool(x, y)
                      || invocation_pos(x, y));
}

/* make a trap somewhere (in croom if mazeflag = 0 && !tm) */
/* if tm != null, make trap at that location */
void
mktrap(num, mazeflag, croom, tm)
int num, mazeflag;
struct mkroom *croom;
coord *tm;
{
    register int kind;
    coord m;

    /* no traps in pools */
    if (tm && is_pool(tm->x, tm->y))
        return;

    if (num > 0 && num < TRAPNUM) {
        kind = num;
    } else if (Is_rogue_level(&u.uz)) {
        switch (rn2(7)) {
        default:
            kind = BEAR_TRAP;
            break; /* 0 */
        case 1:
            kind = ARROW_TRAP;
            break;
        case 2:
            kind = DART_TRAP;
            break;
        case 3:
            kind = TRAPDOOR;
            break;
        case 4:
            kind = PIT;
            break;
        case 5:
            kind = SLP_GAS_TRAP;
            break;
        case 6:
            kind = RUST_TRAP;
            break;
        }
    } else if (Inhell && !rn2(5)) {
        /* bias the frequency of fire traps in Gehennom */
        kind = FIRE_TRAP;
    } else {
        unsigned lvl = level_difficulty();

        do {
            kind = rnd(TRAPNUM - 1);
            /* reject "too hard" traps */
            switch (kind) {
            case MAGIC_PORTAL:
            case VIBRATING_SQUARE:
                kind = NO_TRAP;
                break;
            case ROLLING_BOULDER_TRAP:
            case SLP_GAS_TRAP:
                if (lvl < 2)
                    kind = NO_TRAP;
                break;
            case LEVEL_TELEP:
                if (lvl < 5 || level.flags.noteleport)
                    kind = NO_TRAP;
                break;
            case SPIKED_PIT:
                if (lvl < 5)
                    kind = NO_TRAP;
                break;
            case LANDMINE:
                if (lvl < 6)
                    kind = NO_TRAP;
                break;
            case WEB:
                if (lvl < 7)
                    kind = NO_TRAP;
                break;
            case STATUE_TRAP:
            case POLY_TRAP:
                if (lvl < 8)
                    kind = NO_TRAP;
                break;
            case FIRE_TRAP:
                if (!Inhell)
                    kind = NO_TRAP;
                break;
            case TELEP_TRAP:
                if (level.flags.noteleport)
                    kind = NO_TRAP;
                break;
            case HOLE:
                /* make these much less often than other traps */
                if (rn2(7))
                    kind = NO_TRAP;
                break;
            }
        } while (kind == NO_TRAP);
    }

    if ((kind == TRAPDOOR || kind == HOLE) && !Can_fall_thru(&u.uz))
        kind = ROCKTRAP;

    if (tm)
        m = *tm;
    else {
        register int tryct = 0;
        boolean avoid_boulder = (kind == PIT || kind == SPIKED_PIT
                                 || kind == TRAPDOOR || kind == HOLE);

        do {
            if (++tryct > 200)
                return;
            if (mazeflag)
                mazexy(&m);
            else if (!somexy(croom, &m))
                return;
        } while (occupied(m.x, m.y)
                 || (avoid_boulder && sobj_at(BOULDER, m.x, m.y)));
    }

    (void) maketrap(m.x, m.y, kind);
    if (kind == WEB)
        (void) makemon(&mons[PM_GIANT_SPIDER], m.x, m.y, NO_MM_FLAGS);
}

void
mkstairs(x, y, up, croom)
xchar x, y;
char up;
struct mkroom *croom;
{
    if (!x) {
        impossible("mkstairs:  bogus stair attempt at <%d,%d>", x, y);
        return;
    }

    /*
     * We can't make a regular stair off an end of the dungeon.  This
     * attempt can happen when a special level is placed at an end and
     * has an up or down stair specified in its description file.
     */
    if ((dunlev(&u.uz) == 1 && up)
        || (dunlev(&u.uz) == dunlevs_in_dungeon(&u.uz) && !up))
        return;

    if (up) {
        xupstair = x;
        yupstair = y;
        upstairs_room = croom;
    } else {
        xdnstair = x;
        ydnstair = y;
        dnstairs_room = croom;
    }

    levl[x][y].typ = STAIRS;
    levl[x][y].ladder = up ? LA_UP : LA_DOWN;
}

STATIC_OVL void
mkfount(mazeflag, croom)
int mazeflag;
struct mkroom *croom;
{
    coord m;
    register int tryct = 0;

    do {
        if (++tryct > 200)
            return;
        if (mazeflag)
            mazexy(&m);
        else if (!somexy(croom, &m))
            return;
    } while (occupied(m.x, m.y) || bydoor(m.x, m.y));

    /* Put a fountain at m.x, m.y */
    levl[m.x][m.y].typ = FOUNTAIN;
    /* Is it a "blessed" fountain? (affects drinking from fountain) */
    if (!rn2(7))
        levl[m.x][m.y].blessedftn = 1;

    level.flags.nfountains++;
}

STATIC_OVL void
mksink(croom)
struct mkroom *croom;
{
    coord m;
    register int tryct = 0;

    do {
        if (++tryct > 200)
            return;
        if (!somexy(croom, &m))
            return;
    } while (occupied(m.x, m.y) || bydoor(m.x, m.y));

    /* Put a sink at m.x, m.y */
    levl[m.x][m.y].typ = SINK;

    level.flags.nsinks++;
}

STATIC_OVL void
mkaltar(croom)
struct mkroom *croom;
{
    coord m;
    register int tryct = 0;
    aligntyp al;

    if (croom->rtype != OROOM)
        return;

    do {
        if (++tryct > 200)
            return;
        if (!somexy(croom, &m))
            return;
    } while (occupied(m.x, m.y) || bydoor(m.x, m.y));

    /* Put an altar at m.x, m.y */
    levl[m.x][m.y].typ = ALTAR;

    /* -1 - A_CHAOTIC, 0 - A_NEUTRAL, 1 - A_LAWFUL */
    al = rn2((int) A_LAWFUL + 2) - 1;
    levl[m.x][m.y].altarmask = Align2amask(al);
}

static void
mkgrave(croom)
struct mkroom *croom;
{
    coord m;
    register int tryct = 0;
    register struct obj *otmp;
    boolean dobell = !rn2(10);

    if (croom->rtype != OROOM)
        return;

    do {
        if (++tryct > 200)
            return;
        if (!somexy(croom, &m))
            return;
    } while (occupied(m.x, m.y) || bydoor(m.x, m.y));

    /* Put a grave at m.x, m.y */
    make_grave(m.x, m.y, dobell ? "Saved by the bell!" : (char *) 0);

    /* Possibly fill it with objects */
    if (!rn2(3))
        (void) mkgold(0L, m.x, m.y);
    for (tryct = rn2(5); tryct; tryct--) {
        otmp = mkobj(RANDOM_CLASS, TRUE);
        if (!otmp)
            return;
        curse(otmp);
        otmp->ox = m.x;
        otmp->oy = m.y;
        add_to_buried(otmp);
    }

    /* Leave a bell, in case we accidentally buried someone alive */
    if (dobell)
        (void) mksobj_at(BELL, m.x, m.y, TRUE, FALSE);
    return;
}

/* maze levels have slightly different constraints from normal levels */
#define x_maze_min 2
#define y_maze_min 2

/*
 * Major level transmutation: add a set of stairs (to the Sanctum) after
 * an earthquake that leaves behind a a new topology, centered at inv_pos.
 * Assumes there are no rooms within the invocation area and that inv_pos
 * is not too close to the edge of the map.  Also assume the hero can see,
 * which is guaranteed for normal play due to the fact that sight is needed
 * to read the Book of the Dead.
 */
void
mkinvokearea()
{
    int dist;
    xchar xmin = inv_pos.x, xmax = inv_pos.x;
    xchar ymin = inv_pos.y, ymax = inv_pos.y;
    register xchar i;

    pline_The("floor shakes violently under you!");
    pline_The("walls around you begin to bend and crumble!");
    display_nhwindow(WIN_MESSAGE, TRUE);

    /* any trap hero is stuck in will be going away now */
    if (u.utrap) {
        u.utrap = 0;
        if (u.utraptype == TT_BURIEDBALL)
            buried_ball_to_punishment();
    }
    mkinvpos(xmin, ymin, 0); /* middle, before placing stairs */

    for (dist = 1; dist < 7; dist++) {
        xmin--;
        xmax++;

        /* top and bottom */
        if (dist != 3) { /* the area is wider that it is high */
            ymin--;
            ymax++;
            for (i = xmin + 1; i < xmax; i++) {
                mkinvpos(i, ymin, dist);
                mkinvpos(i, ymax, dist);
            }
        }

        /* left and right */
        for (i = ymin; i <= ymax; i++) {
            mkinvpos(xmin, i, dist);
            mkinvpos(xmax, i, dist);
        }

        flush_screen(1); /* make sure the new glyphs shows up */
        delay_output();
    }

    You("are standing at the top of a stairwell leading down!");
    mkstairs(u.ux, u.uy, 0, (struct mkroom *) 0); /* down */
    newsym(u.ux, u.uy);
    vision_full_recalc = 1; /* everything changed */
}

/* Change level topology.  Boulders in the vicinity are eliminated.
 * Temporarily overrides vision in the name of a nice effect.
 */
STATIC_OVL void
mkinvpos(x, y, dist)
xchar x, y;
int dist;
{
    struct trap *ttmp;
    struct obj *otmp;
    boolean make_rocks;
    register struct rm *lev = &levl[x][y];

    /* clip at existing map borders if necessary */
    if (!within_bounded_area(x, y, x_maze_min + 1, y_maze_min + 1,
                             x_maze_max - 1, y_maze_max - 1)) {
        /* only outermost 2 columns and/or rows may be truncated due to edge
         */
        if (dist < (7 - 2))
            panic("mkinvpos: <%d,%d> (%d) off map edge!", x, y, dist);
        return;
    }

    /* clear traps */
    if ((ttmp = t_at(x, y)) != 0)
        deltrap(ttmp);

    /* clear boulders; leave some rocks for non-{moat|trap} locations */
    make_rocks = (dist != 1 && dist != 4 && dist != 5) ? TRUE : FALSE;
    while ((otmp = sobj_at(BOULDER, x, y)) != 0) {
        if (make_rocks) {
            fracture_rock(otmp);
            make_rocks = FALSE; /* don't bother with more rocks */
        } else {
            obj_extract_self(otmp);
            obfree(otmp, (struct obj *) 0);
        }
    }
    unblock_point(x, y); /* make sure vision knows this location is open */

    /* fake out saved state */
    lev->seenv = 0;
    lev->doormask = 0;
    if (dist < 6)
        lev->lit = TRUE;
    lev->waslit = TRUE;
    lev->horizontal = FALSE;
    /* short-circuit vision recalc */
    viz_array[y][x] = (dist < 6) ? (IN_SIGHT | COULD_SEE) : COULD_SEE;

    switch (dist) {
    case 1: /* fire traps */
        if (is_pool(x, y))
            break;
        lev->typ = ROOM;
        ttmp = maketrap(x, y, FIRE_TRAP);
        if (ttmp)
            ttmp->tseen = TRUE;
        break;
    case 0: /* lit room locations */
    case 2:
    case 3:
    case 6: /* unlit room locations */
        lev->typ = ROOM;
        break;
    case 4: /* pools (aka a wide moat) */
    case 5:
        lev->typ = MOAT;
        /* No kelp! */
        break;
    default:
        impossible("mkinvpos called with dist %d", dist);
        break;
    }

    /* display new value of position; could have a monster/object on it */
    newsym(x, y);
}

/*
 * The portal to Ludios is special.  The entrance can only occur within a
 * vault in the main dungeon at a depth greater than 10.  The Ludios branch
 * structure reflects this by having a bogus "source" dungeon:  the value
 * of n_dgns (thus, Is_branchlev() will never find it).
 *
 * Ludios will remain isolated until the branch is corrected by this function.
 */
STATIC_OVL void
mk_knox_portal(x, y)
xchar x, y;
{
    extern int n_dgns; /* from dungeon.c */
    d_level *source;
    branch *br;
    schar u_depth;

    br = dungeon_branch("Fort Ludios");
    if (on_level(&knox_level, &br->end1)) {
        source = &br->end2;
    } else {
        /* disallow Knox branch on a level with one branch already */
        if (Is_branchlev(&u.uz))
            return;
        source = &br->end1;
    }

    /* Already set or 2/3 chance of deferring until a later level. */
    if (source->dnum < n_dgns || (rn2(3) && !wizard))
        return;

    if (!(u.uz.dnum == oracle_level.dnum      /* in main dungeon */
          && !at_dgn_entrance("The Quest")    /* but not Quest's entry */
          && (u_depth = depth(&u.uz)) > 10    /* beneath 10 */
          && u_depth < depth(&medusa_level))) /* and above Medusa */
        return;

    /* Adjust source to be current level and re-insert branch. */
    *source = u.uz;
    insert_branch(br, TRUE);

    debugpline0("Made knox portal.");
    place_branch(br, x, y);
}

/*mklev.c*/