Source:NetHack 3.6.0/src/dbridge.c

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/* NetHack 3.6	dbridge.c	$NHDT-Date: 1449269914 2015/12/04 22:58:34 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.35 $ */
/*      Copyright (c) 1989 by Jean-Christophe Collet              */
/* NetHack may be freely redistributed.  See license for details. */

/*
* This file contains the drawbridge manipulation (create, open, close,
* destroy).
*
* Added comprehensive monster-handling, and the "entity" structure to
* deal with players as well. - 11/89
*
* Any traps and/or engravings at either the portcullis or span location
* are destroyed whenever the bridge is lowered, raised, or destroyed.
* (Engraving handling could be extended to flag whether an engraving on
* the DB_UNDER surface is hidden by the lowered bridge, or one on the
* bridge itself is hidden because the bridge has been raised, but that
* seems like an awful lot of effort for very little gain.)
*/

#include "hack.h"

STATIC_DCL void FDECL(get_wall_for_db, (int *, int *));
STATIC_DCL struct entity *FDECL(e_at, (int, int));
STATIC_DCL void FDECL(m_to_e, (struct monst *, int, int, struct entity *));
STATIC_DCL void FDECL(u_to_e, (struct entity *));
STATIC_DCL void FDECL(set_entity, (int, int, struct entity *));
STATIC_DCL const char *FDECL(e_nam, (struct entity *));
STATIC_DCL const char *FDECL(E_phrase, (struct entity *, const char *));
STATIC_DCL boolean FDECL(e_survives_at, (struct entity *, int, int));
STATIC_DCL void FDECL(e_died, (struct entity *, int, int));
STATIC_DCL boolean FDECL(automiss, (struct entity *));
STATIC_DCL boolean FDECL(e_missed, (struct entity *, BOOLEAN_P));
STATIC_DCL boolean FDECL(e_jumps, (struct entity *));
STATIC_DCL void FDECL(do_entity, (struct entity *));

boolean
is_pool(x, y)
int x, y;
{
schar ltyp;

if (!isok(x, y))
return FALSE;
ltyp = levl[x][y].typ;
/* The ltyp == MOAT is not redundant with is_moat, because the
* Juiblex level does not have moats, although it has MOATs. There
* is probably a better way to express this. */
if (ltyp == POOL || ltyp == MOAT || ltyp == WATER || is_moat(x, y))
return TRUE;
return FALSE;
}

boolean
is_lava(x, y)
int x, y;
{
schar ltyp;

if (!isok(x, y))
return FALSE;
ltyp = levl[x][y].typ;
if (ltyp == LAVAPOOL
|| (ltyp == DRAWBRIDGE_UP
&& (levl[x][y].drawbridgemask & DB_UNDER) == DB_LAVA))
return TRUE;
return FALSE;
}

boolean
is_pool_or_lava(x, y)
int x, y;
{
if (is_pool(x, y) || is_lava(x, y))
return TRUE;
else
return FALSE;
}

boolean
is_ice(x, y)
int x, y;
{
schar ltyp;

if (!isok(x, y))
return FALSE;
ltyp = levl[x][y].typ;
if (ltyp == ICE || (ltyp == DRAWBRIDGE_UP
&& (levl[x][y].drawbridgemask & DB_UNDER) == DB_ICE))
return TRUE;
return FALSE;
}

boolean
is_moat(x, y)
int x, y;
{
schar ltyp;

if (!isok(x, y))
return FALSE;
ltyp = levl[x][y].typ;
if (!Is_juiblex_level(&u.uz)
&& (ltyp == MOAT
|| (ltyp == DRAWBRIDGE_UP
&& (levl[x][y].drawbridgemask & DB_UNDER) == DB_MOAT)))
return TRUE;
return FALSE;
}

schar
db_under_typ(mask)
int mask;
{
switch (mask & DB_UNDER) {
case DB_ICE:
return ICE;
break;
case DB_LAVA:
return LAVAPOOL;
break;
case DB_MOAT:
return MOAT;
break;
default:
return STONE;
break;
}
}

/*
* We want to know whether a wall (or a door) is the portcullis (passageway)
* of an eventual drawbridge.
*
* Return value:  the direction of the drawbridge.
*/

int
is_drawbridge_wall(x, y)
int x, y;
{
struct rm *lev;

lev = &levl[x][y];
if (lev->typ != DOOR && lev->typ != DBWALL)
return -1;

if (IS_DRAWBRIDGE(levl[x + 1][y].typ)
&& (levl[x + 1][y].drawbridgemask & DB_DIR) == DB_WEST)
return DB_WEST;
if (IS_DRAWBRIDGE(levl[x - 1][y].typ)
&& (levl[x - 1][y].drawbridgemask & DB_DIR) == DB_EAST)
return DB_EAST;
if (IS_DRAWBRIDGE(levl[x][y - 1].typ)
&& (levl[x][y - 1].drawbridgemask & DB_DIR) == DB_SOUTH)
return DB_SOUTH;
if (IS_DRAWBRIDGE(levl[x][y + 1].typ)
&& (levl[x][y + 1].drawbridgemask & DB_DIR) == DB_NORTH)
return DB_NORTH;

return -1;
}

/*
* Use is_db_wall where you want to verify that a
* drawbridge "wall" is UP in the location x, y
* (instead of UP or DOWN, as with is_drawbridge_wall).
*/
boolean
is_db_wall(x, y)
int x, y;
{
return (boolean) (levl[x][y].typ == DBWALL);
}

/*
* Return true with x,y pointing to the drawbridge if x,y initially indicate
* a drawbridge or drawbridge wall.
*/
boolean
find_drawbridge(x, y)
int *x, *y;
{
int dir;

if (IS_DRAWBRIDGE(levl[*x][*y].typ))
return TRUE;
dir = is_drawbridge_wall(*x, *y);
if (dir >= 0) {
switch (dir) {
case DB_NORTH:
(*y)++;
break;
case DB_SOUTH:
(*y)--;
break;
case DB_EAST:
(*x)--;
break;
case DB_WEST:
(*x)++;
break;
}
return TRUE;
}
return FALSE;
}

/*
* Find the drawbridge wall associated with a drawbridge.
*/
STATIC_OVL void
get_wall_for_db(x, y)
int *x, *y;
{
switch (levl[*x][*y].drawbridgemask & DB_DIR) {
case DB_NORTH:
(*y)--;
break;
case DB_SOUTH:
(*y)++;
break;
case DB_EAST:
(*x)++;
break;
case DB_WEST:
(*x)--;
break;
}
}

/*
* Creation of a drawbridge at pos x,y.
*     dir is the direction.
*     flag must be put to TRUE if we want the drawbridge to be opened.
*/

boolean
create_drawbridge(x, y, dir, flag)
int x, y, dir;
boolean flag;
{
int x2, y2;
boolean horiz;
boolean lava = levl[x][y].typ == LAVAPOOL; /* assume initialized map */

x2 = x;
y2 = y;
switch (dir) {
case DB_NORTH:
horiz = TRUE;
y2--;
break;
case DB_SOUTH:
horiz = TRUE;
y2++;
break;
case DB_EAST:
horiz = FALSE;
x2++;
break;
default:
impossible("bad direction in create_drawbridge");
/*FALLTHRU*/
case DB_WEST:
horiz = FALSE;
x2--;
break;
}
if (!IS_WALL(levl[x2][y2].typ))
return FALSE;
if (flag) { /* We want the bridge open */
levl[x][y].typ = DRAWBRIDGE_DOWN;
levl[x2][y2].typ = DOOR;
levl[x2][y2].doormask = D_NODOOR;
} else {
levl[x][y].typ = DRAWBRIDGE_UP;
levl[x2][y2].typ = DBWALL;
/* Drawbridges are non-diggable. */
levl[x2][y2].wall_info = W_NONDIGGABLE;
}
levl[x][y].horizontal = !horiz;
levl[x2][y2].horizontal = horiz;
levl[x][y].drawbridgemask = dir;
if (lava)
levl[x][y].drawbridgemask |= DB_LAVA;
return  TRUE;
}

struct entity {
struct monst *emon;     /* youmonst for the player */
struct permonst *edata; /* must be non-zero for record to be valid */
int ex, ey;
};

#define ENTITIES 2

static NEARDATA struct entity occupants[ENTITIES];

STATIC_OVL
struct entity *
e_at(x, y)
int x, y;
{
int entitycnt;

for (entitycnt = 0; entitycnt < ENTITIES; entitycnt++)
if ((occupants[entitycnt].edata) && (occupants[entitycnt].ex == x)
&& (occupants[entitycnt].ey == y))
break;
debugpline1("entitycnt = %d", entitycnt);
#ifdef D_DEBUG
wait_synch();
#endif
return (entitycnt == ENTITIES) ? (struct entity *) 0
: &(occupants[entitycnt]);
}

STATIC_OVL void
m_to_e(mtmp, x, y, etmp)
struct monst *mtmp;
int x, y;
struct entity *etmp;
{
etmp->emon = mtmp;
if (mtmp) {
etmp->ex = x;
etmp->ey = y;
if (mtmp->wormno && (x != mtmp->mx || y != mtmp->my))
etmp->edata = &mons[PM_LONG_WORM_TAIL];
else
etmp->edata = mtmp->data;
} else
etmp->edata = (struct permonst *) 0;
}

STATIC_OVL void
u_to_e(etmp)
struct entity *etmp;
{
etmp->emon = &youmonst;
etmp->ex = u.ux;
etmp->ey = u.uy;
etmp->edata = youmonst.data;
}

STATIC_OVL void
set_entity(x, y, etmp)
int x, y;
struct entity *etmp;
{
if ((x == u.ux) && (y == u.uy))
u_to_e(etmp);
else if (MON_AT(x, y))
m_to_e(m_at(x, y), x, y, etmp);
else
etmp->edata = (struct permonst *) 0;
}

#define is_u(etmp) (etmp->emon == &youmonst)
#define e_canseemon(etmp) \
(is_u(etmp) ? (boolean) TRUE : canseemon(etmp->emon))

/*
* e_strg is a utility routine which is not actually in use anywhere, since
* the specialized routines below suffice for all current purposes.
*/

/* #define e_strg(etmp, func) (is_u(etmp)? (char *)0 : func(etmp->emon)) */

STATIC_OVL const char *
e_nam(etmp)
struct entity *etmp;
{
return is_u(etmp) ? "you" : mon_nam(etmp->emon);
}

/*
* Generates capitalized entity name, makes 2nd -> 3rd person conversion on
* verb, where necessary.
*/

STATIC_OVL const char *
E_phrase(etmp, verb)
struct entity *etmp;
const char *verb;
{
static char wholebuf[80];

Strcpy(wholebuf, is_u(etmp) ? "You" : Monnam(etmp->emon));
if (!verb || !*verb)
return wholebuf;
Strcat(wholebuf, " ");
if (is_u(etmp))
Strcat(wholebuf, verb);
else
Strcat(wholebuf, vtense((char *) 0, verb));
return wholebuf;
}

/*
* Simple-minded "can it be here?" routine
*/

STATIC_OVL boolean
e_survives_at(etmp, x, y)
struct entity *etmp;
int x, y;
{
if (noncorporeal(etmp->edata))
return TRUE;
if (is_pool(x, y))
return (boolean) ((is_u(etmp) && (Wwalking || Amphibious || Swimming
|| Flying || Levitation))
|| is_swimmer(etmp->edata)
|| is_flyer(etmp->edata)
|| is_floater(etmp->edata));
/* must force call to lava_effects in e_died if is_u */
if (is_lava(x, y))
return (boolean) ((is_u(etmp) && (Levitation || Flying))
|| likes_lava(etmp->edata)
|| is_flyer(etmp->edata));
if (is_db_wall(x, y))
return (boolean) (is_u(etmp) ? Passes_walls
: passes_walls(etmp->edata));
return TRUE;
}

STATIC_OVL void
e_died(etmp, dest, how)
struct entity *etmp;
int dest, how;
{
if (is_u(etmp)) {
if (how == DROWNING) {
killer.name[0] = 0; /* drown() sets its own killer */
(void) drown();
} else if (how == BURNING) {
killer.name[0] = 0; /* lava_effects() sets own killer */
(void) lava_effects();
} else {
coord xy;

/* use more specific killer if specified */
if (!killer.name[0]) {
killer.format = KILLED_BY_AN;
Strcpy(killer.name, "falling drawbridge");
}
done(how);
/* So, you didn't die */
if (!e_survives_at(etmp, etmp->ex, etmp->ey)) {
if (enexto(&xy, etmp->ex, etmp->ey, etmp->edata)) {
pline("A %s force teleports you away...",
Hallucination ? "normal" : "strange");
teleds(xy.x, xy.y, FALSE);
}
/* otherwise on top of the drawbridge is the
* only viable spot in the dungeon, so stay there
*/
}
}
/* we might have crawled out of the moat to survive */
etmp->ex = u.ux, etmp->ey = u.uy;
} else {
int entitycnt;

killer.name[0] = 0;
/* fake "digested to death" damage-type suppresses corpse */
#define mk_message(dest) ((dest & 1) ? "" : (char *) 0)
#define mk_corpse(dest) ((dest & 2) ? AD_DGST : AD_PHYS)
/* if monsters are moving, one of them caused the destruction */
if (context.mon_moving)
monkilled(etmp->emon, mk_message(dest), mk_corpse(dest));
else /* you caused it */
xkilled(etmp->emon, dest);
etmp->edata = (struct permonst *) 0;

/* dead long worm handling */
for (entitycnt = 0; entitycnt < ENTITIES; entitycnt++) {
if (etmp != &(occupants[entitycnt])
&& etmp->emon == occupants[entitycnt].emon)
occupants[entitycnt].edata = (struct permonst *) 0;
}
#undef mk_message
#undef mk_corpse
}
}

/*
* These are never directly affected by a bridge or portcullis.
*/

STATIC_OVL boolean
automiss(etmp)
struct entity *etmp;
{
return (boolean) ((is_u(etmp) ? Passes_walls : passes_walls(etmp->edata))
|| noncorporeal(etmp->edata));
}

/*
* Does falling drawbridge or portcullis miss etmp?
*/

STATIC_OVL boolean
e_missed(etmp, chunks)
struct entity *etmp;
boolean chunks;
{
int misses;

if (chunks) {
debugpline0("Do chunks miss?");
}
if (automiss(etmp))
return TRUE;

if (is_flyer(etmp->edata)
&& (is_u(etmp) ? !Unaware
: (etmp->emon->mcanmove && !etmp->emon->msleeping)))
/* flying requires mobility */
misses = 5; /* out of 8 */
else if (is_floater(etmp->edata)
|| (is_u(etmp) && Levitation)) /* doesn't require mobility */
misses = 3;
else if (chunks && is_pool(etmp->ex, etmp->ey))
misses = 2; /* sitting ducks */
else
misses = 0;

if (is_db_wall(etmp->ex, etmp->ey))
misses -= 3; /* less airspace */

debugpline1("Miss chance = %d (out of 8)", misses);

return (misses >= rnd(8)) ? TRUE : FALSE;
}

/*
* Can etmp jump from death?
*/

STATIC_OVL boolean
e_jumps(etmp)
struct entity *etmp;
{
int tmp = 4; /* out of 10 */

if (is_u(etmp) ? (Unaware || Fumbling)
: (!etmp->emon->mcanmove || etmp->emon->msleeping
|| !etmp->edata->mmove || etmp->emon->wormno))
return FALSE;

if (is_u(etmp) ? Confusion : etmp->emon->mconf)
tmp -= 2;

if (is_u(etmp) ? Stunned : etmp->emon->mstun)
tmp -= 3;

if (is_db_wall(etmp->ex, etmp->ey))
tmp -= 2; /* less room to maneuver */

debugpline2("%s to jump (%d chances in 10)", E_phrase(etmp, "try"), tmp);
return (tmp >= rnd(10)) ? TRUE : FALSE;
}

STATIC_OVL void
do_entity(etmp)
struct entity *etmp;
{
int newx, newy, at_portcullis, oldx, oldy;
boolean must_jump = FALSE, relocates = FALSE, e_inview;
struct rm *crm;

if (!etmp->edata)
return;

e_inview = e_canseemon(etmp);
oldx = etmp->ex;
oldy = etmp->ey;
at_portcullis = is_db_wall(oldx, oldy);
crm = &levl[oldx][oldy];

if (automiss(etmp) && e_survives_at(etmp, oldx, oldy)) {
if (e_inview && (at_portcullis || IS_DRAWBRIDGE(crm->typ)))
pline_The("%s passes through %s!",
at_portcullis ? "portcullis" : "drawbridge",
e_nam(etmp));
if (is_u(etmp))
spoteffects(FALSE);
return;
}
if (e_missed(etmp, FALSE)) {
if (at_portcullis) {
pline_The("portcullis misses %s!", e_nam(etmp));
} else {
debugpline1("The drawbridge misses %s!", e_nam(etmp));
}
if (e_survives_at(etmp, oldx, oldy)) {
return;
} else {
debugpline0("Mon can't survive here");
if (at_portcullis)
must_jump = TRUE;
else
relocates = TRUE; /* just ride drawbridge in */
}
} else {
if (crm->typ == DRAWBRIDGE_DOWN) {
pline("%s crushed underneath the drawbridge.",
E_phrase(etmp, "are"));             /* no jump */
e_died(etmp, e_inview ? 3 : 2, CRUSHING); /* no corpse */
return;       /* Note: Beyond this point, we know we're  */
}                 /* not at an opened drawbridge, since all  */
must_jump = TRUE; /* *missable* creatures survive on the     */
}                     /* square, and all the unmissed ones die.  */
if (must_jump) {
if (at_portcullis) {
if (e_jumps(etmp)) {
relocates = TRUE;
debugpline0("Jump succeeds!");
} else {
if (e_inview)
pline("%s crushed by the falling portcullis!",
E_phrase(etmp, "are"));
else if (!Deaf)
You_hear("a crushing sound.");
e_died(etmp, e_inview ? 3 : 2, CRUSHING);
/* no corpse */
return;
}
} else { /* tries to jump off bridge to original square */
relocates = !e_jumps(etmp);
debugpline1("Jump %s!", (relocates) ? "fails" : "succeeds");
}
}

/*
* Here's where we try to do relocation.  Assumes that etmp is not
* arriving
* at the portcullis square while the drawbridge is falling, since this
* square
* would be inaccessible (i.e. etmp started on drawbridge square) or
* unnecessary (i.e. etmp started here) in such a situation.
*/
debugpline0("Doing relocation.");
newx = oldx;
newy = oldy;
(void) find_drawbridge(&newx, &newy);
if ((newx == oldx) && (newy == oldy))
get_wall_for_db(&newx, &newy);
debugpline0("Checking new square for occupancy.");
if (relocates && (e_at(newx, newy))) {
/*
* Standoff problem:  one or both entities must die, and/or both
* switch
* places.  Avoid infinite recursion by checking first whether the
* other
* entity is staying put.  Clean up if we happen to move/die in
* recursion.
*/
struct entity *other;

other = e_at(newx, newy);
debugpline1("New square is occupied by %s", e_nam(other));
if (e_survives_at(other, newx, newy) && automiss(other)) {
relocates = FALSE; /* "other" won't budge */
debugpline1("%s suicide.", E_phrase(etmp, "commit"));
} else {
debugpline1("Handling %s", e_nam(other));
while ((e_at(newx, newy) != 0) && (e_at(newx, newy) != etmp))
do_entity(other);
debugpline1("Checking existence of %s", e_nam(etmp));
#ifdef D_DEBUG
wait_synch();
#endif
if (e_at(oldx, oldy) != etmp) {
debugpline1("%s moved or died in recursion somewhere",
E_phrase(etmp, "have"));
#ifdef D_DEBUG
wait_synch();
#endif
return;
}
}
}
if (relocates && !e_at(newx, newy)) { /* if e_at() entity = worm tail */
debugpline1("Moving %s", e_nam(etmp));
if (!is_u(etmp)) {
remove_monster(etmp->ex, etmp->ey);
place_monster(etmp->emon, newx, newy);
update_monster_region(etmp->emon);
} else {
u.ux = newx;
u.uy = newy;
}
etmp->ex = newx;
etmp->ey = newy;
e_inview = e_canseemon(etmp);
}
debugpline1("Final disposition of %s", e_nam(etmp));
#ifdef D_DEBUG
wait_synch();
#endif
if (is_db_wall(etmp->ex, etmp->ey)) {
debugpline1("%s in portcullis chamber", E_phrase(etmp, "are"));
#ifdef D_DEBUG
wait_synch();
#endif
if (e_inview) {
if (is_u(etmp)) {
You("tumble towards the closed portcullis!");
if (automiss(etmp))
You("pass through it!");
else
pline_The("drawbridge closes in...");
} else
pline("%s behind the drawbridge.",
E_phrase(etmp, "disappear"));
}
if (!e_survives_at(etmp, etmp->ex, etmp->ey)) {
killer.format = KILLED_BY_AN;
Strcpy(killer.name, "closing drawbridge");
e_died(etmp, 0, CRUSHING); /* no message */
return;
}
debugpline1("%s in here", E_phrase(etmp, "survive"));
} else {
debugpline1("%s on drawbridge square", E_phrase(etmp, "are"));
if (is_pool(etmp->ex, etmp->ey) && !e_inview)
if (!Deaf)
You_hear("a splash.");
if (e_survives_at(etmp, etmp->ex, etmp->ey)) {
if (e_inview && !is_flyer(etmp->edata)
&& !is_floater(etmp->edata))
pline("%s from the bridge.", E_phrase(etmp, "fall"));
return;
}
debugpline1("%s cannot survive on the drawbridge square",
E_phrase(etmp, NULL));
if (is_pool(etmp->ex, etmp->ey) || is_lava(etmp->ex, etmp->ey))
if (e_inview && !is_u(etmp)) {
/* drown() will supply msgs if nec. */
boolean lava = is_lava(etmp->ex, etmp->ey);

if (Hallucination)
pline("%s the %s and disappears.",
E_phrase(etmp, "drink"), lava ? "lava" : "moat");
else
pline("%s into the %s.", E_phrase(etmp, "fall"),
lava ? "lava" : "moat");
}
killer.format = NO_KILLER_PREFIX;
Strcpy(killer.name, "fell from a drawbridge");
e_died(etmp, e_inview ? 3 : 2, /* CRUSHING is arbitrary */
(is_pool(etmp->ex, etmp->ey))
? DROWNING
: (is_lava(etmp->ex, etmp->ey)) ? BURNING
: CRUSHING); /*no corpse*/
return;
}
}

/*
* Close the drawbridge located at x,y
*/

void
close_drawbridge(x, y)
int x, y;
{
register struct rm *lev1, *lev2;
struct trap *t;
int x2, y2;

lev1 = &levl[x][y];
if (lev1->typ != DRAWBRIDGE_DOWN)
return;
x2 = x;
y2 = y;
get_wall_for_db(&x2, &y2);
if (cansee(x, y) || cansee(x2, y2))
You_see("a drawbridge %s up!",
(((u.ux == x || u.uy == y) && !Underwater)
|| distu(x2, y2) < distu(x, y))
? "coming"
: "going");
else /* "5 gears turn" for castle drawbridge tune */
You_hear("chains rattling and gears turning.");
lev1->typ = DRAWBRIDGE_UP;
lev2 = &levl[x2][y2];
lev2->typ = DBWALL;
switch (lev1->drawbridgemask & DB_DIR) {
case DB_NORTH:
case DB_SOUTH:
lev2->horizontal = TRUE;
break;
case DB_WEST:
case DB_EAST:
lev2->horizontal = FALSE;
break;
}
lev2->wall_info = W_NONDIGGABLE;
set_entity(x, y, &(occupants[0]));
set_entity(x2, y2, &(occupants[1]));
do_entity(&(occupants[0]));          /* Do set_entity after first */
set_entity(x2, y2, &(occupants[1])); /* do_entity for worm tail */
do_entity(&(occupants[1]));
if (OBJ_AT(x, y) && !Deaf)
You_hear("smashing and crushing.");
(void) revive_nasty(x, y, (char *) 0);
(void) revive_nasty(x2, y2, (char *) 0);
delallobj(x, y);
delallobj(x2, y2);
if ((t = t_at(x, y)) != 0)
deltrap(t);
if ((t = t_at(x2, y2)) != 0)
deltrap(t);
del_engr_at(x, y);
del_engr_at(x2, y2);
newsym(x, y);
newsym(x2, y2);
block_point(x2, y2); /* vision */
}

/*
* Open the drawbridge located at x,y
*/

void
open_drawbridge(x, y)
int x, y;
{
register struct rm *lev1, *lev2;
struct trap *t;
int x2, y2;

lev1 = &levl[x][y];
if (lev1->typ != DRAWBRIDGE_UP)
return;
x2 = x;
y2 = y;
get_wall_for_db(&x2, &y2);
if (cansee(x, y) || cansee(x2, y2))
You_see("a drawbridge %s down!",
(distu(x2, y2) < distu(x, y)) ? "going" : "coming");
else /* "5 gears turn" for castle drawbridge tune */
You_hear("gears turning and chains rattling.");
lev1->typ = DRAWBRIDGE_DOWN;
lev2 = &levl[x2][y2];
lev2->typ = DOOR;
lev2->doormask = D_NODOOR;
set_entity(x, y, &(occupants[0]));
set_entity(x2, y2, &(occupants[1]));
do_entity(&(occupants[0]));          /* do set_entity after first */
set_entity(x2, y2, &(occupants[1])); /* do_entity for worm tails */
do_entity(&(occupants[1]));
(void) revive_nasty(x, y, (char *) 0);
delallobj(x, y);
if ((t = t_at(x, y)) != 0)
deltrap(t);
if ((t = t_at(x2, y2)) != 0)
deltrap(t);
del_engr_at(x, y);
del_engr_at(x2, y2);
newsym(x, y);
newsym(x2, y2);
unblock_point(x2, y2); /* vision */
if (Is_stronghold(&u.uz))
u.uevent.uopened_dbridge = TRUE;
}

/*
* Let's destroy the drawbridge located at x,y
*/

void
destroy_drawbridge(x, y)
int x, y;
{
register struct rm *lev1, *lev2;
struct trap *t;
struct obj *otmp;
int x2, y2, i;
boolean e_inview;
struct entity *etmp1 = &(occupants[0]), *etmp2 = &(occupants[1]);

lev1 = &levl[x][y];
if (!IS_DRAWBRIDGE(lev1->typ))
return;
x2 = x;
y2 = y;
get_wall_for_db(&x2, &y2);
lev2 = &levl[x2][y2];
if ((lev1->drawbridgemask & DB_UNDER) == DB_MOAT
|| (lev1->drawbridgemask & DB_UNDER) == DB_LAVA) {
struct obj *otmp2;
boolean lava = (lev1->drawbridgemask & DB_UNDER) == DB_LAVA;
if (lev1->typ == DRAWBRIDGE_UP) {
if (cansee(x2, y2))
pline_The("portcullis of the drawbridge falls into the %s!",
lava ? "lava" : "moat");
else if (!Deaf)
You_hear("a loud *SPLASH*!");
} else {
if (cansee(x, y))
pline_The("drawbridge collapses into the %s!",
lava ? "lava" : "moat");
else if (!Deaf)
You_hear("a loud *SPLASH*!");
}
lev1->typ = lava ? LAVAPOOL : MOAT;
lev1->drawbridgemask = 0;
if ((otmp2 = sobj_at(BOULDER, x, y)) != 0) {
obj_extract_self(otmp2);
(void) flooreffects(otmp2, x, y, "fall");
}
} else {
if (cansee(x, y))
pline_The("drawbridge disintegrates!");
else
You_hear("a loud *CRASH*!");
lev1->typ = ((lev1->drawbridgemask & DB_ICE) ? ICE : ROOM);
lev1->icedpool = ((lev1->drawbridgemask & DB_ICE) ? ICED_MOAT : 0);
}
wake_nearto(x, y, 500);
lev2->typ = DOOR;
lev2->doormask = D_NODOOR;
if ((t = t_at(x, y)) != 0)
deltrap(t);
if ((t = t_at(x2, y2)) != 0)
deltrap(t);
del_engr_at(x, y);
del_engr_at(x2, y2);
for (i = rn2(6); i > 0; --i) { /* scatter some debris */
/* doesn't matter if we happen to pick <x,y2> or <x2,y>;
since drawbridges are never placed diagonally, those
pairings will always match one of <x,y> or <x2,y2> */
otmp = mksobj_at(IRON_CHAIN, rn2(2) ? x : x2, rn2(2) ? y : y2, TRUE,
FALSE);
/* a force of 5 here would yield a radius of 2 for
iron chain; anything less produces a radius of 1 */
(void) scatter(otmp->ox, otmp->oy, 1, MAY_HIT, otmp);
}
newsym(x, y);
newsym(x2, y2);
if (!does_block(x2, y2, lev2))
unblock_point(x2, y2); /* vision */
if (Is_stronghold(&u.uz))
u.uevent.uopened_dbridge = TRUE;

set_entity(x2, y2, etmp2); /* currently only automissers can be here */
if (etmp2->edata) {
e_inview = e_canseemon(etmp2);
if (!automiss(etmp2)) {
if (e_inview)
pline("%s blown apart by flying debris.",
E_phrase(etmp2, "are"));
killer.format = KILLED_BY_AN;
Strcpy(killer.name, "exploding drawbridge");
e_died(etmp2, e_inview ? 3 : 2, CRUSHING); /*no corpse*/
} /* nothing which is vulnerable can survive this */
}
set_entity(x, y, etmp1);
if (etmp1->edata) {
e_inview = e_canseemon(etmp1);
if (e_missed(etmp1, TRUE)) {
debugpline1("%s spared!", E_phrase(etmp1, "are"));
/* if there is water or lava here, fall in now */
if (is_u(etmp1))
spoteffects(FALSE);
else
(void) minliquid(etmp1->emon);
} else {
if (e_inview) {
if (!is_u(etmp1) && Hallucination)
pline("%s into some heavy metal!",
E_phrase(etmp1, "get"));
else
pline("%s hit by a huge chunk of metal!",
E_phrase(etmp1, "are"));
} else {
if (!Deaf && !is_u(etmp1) && !is_pool(x, y)) {
You_hear("a crushing sound.");
} else {
debugpline1("%s from shrapnel", E_phrase(etmp1, "die"));
}
}
killer.format = KILLED_BY_AN;
Strcpy(killer.name, "collapsing drawbridge");
e_died(etmp1, e_inview ? 3 : 2, CRUSHING); /*no corpse*/
if (levl[etmp1->ex][etmp1->ey].typ == MOAT)
do_entity(etmp1);
}
}
}

/*dbridge.c*/