view xrogue/chase.c @ 296:000b1c5b8d63

UltraRogue: fix inventory collision after save and restore. Inventory letters are based on "identifiers" stored in objects' o_ident field. Identifiers are allocated by get_ident(), which keeps a list of objects that have them, to avoid giving the same identifier to multiple objects. The list is not stored in the savefile, so after restore, get_ident() was not aware of existing identifiers. This resulted in picked-up objects having the same inventory letters as objects restored from the file. The restore code now adds all objects with identifiers to the list.
author John "Elwin" Edwards
date Mon, 15 Jan 2018 20:20:35 -0500
parents f54901b9c39b
children e52a8a7ad4c5
line wrap: on
line source

/*
    chase.c  -  Code for one object to chase another

    XRogue: Expeditions into the Dungeons of Doom
    Copyright (C) 1991 Robert Pietkivitch
    All rights reserved.
    
    Based on "Advanced Rogue"
    Copyright (C) 1984, 1985 Michael Morgan, Ken Dalka and AT&T
    All rights reserved.

    Based on "Rogue: Exploring the Dungeons of Doom"
    Copyright (C) 1980, 1981 Michael Toy, Ken Arnold and Glenn Wichman
    All rights reserved.
    
    See the file LICENSE.TXT for full copyright and licensing information.
*/

#include <ctype.h>
#include <curses.h>
#include <limits.h>
#include <stdlib.h>
#include "rogue.h"

bool straight_shot(int ery, int erx, int eey, int eex, coord *shooting);

/*
 * Canblink checks if the monster can teleport (blink).  If so, it will
 * try to blink the monster next to the player.
 */

bool
can_blink(struct thing *tp)
{
    register int y, x, index=9;
    coord tryp; /* To hold the coordinates for use in diag_ok */
    bool spots[9], found_one=FALSE;

    /*
     * First, can the monster even blink?  And if so, there is only a 50%
     * chance that it will do so.  And it won't blink if it is running or
     * held.
     */
    if (off(*tp, CANBLINK) || (on(*tp, ISHELD)) ||
        on(*tp, ISFLEE) ||
        tp->t_action == A_FREEZE ||
        (rnd(12) < 6)) return(FALSE);


    /* Initialize the spots as illegal */
    do {
        spots[--index] = FALSE;
    } while (index > 0);

    /* Find a suitable spot next to the player */
    for (y=hero.y-1; y<hero.y+2; y++)
        for (x=hero.x-1; x<hero.x+2; x++, index++) {
            /* Make sure x coordinate is in range and that we are
             * not at the player's position
             */
            if (x<0 || x >= cols || index == 4) continue;

            /* Is it OK to move there? */
            if (step_ok(y, x, NOMONST, tp) &&
                (!isatrap(mvwinch(cw, y, x)) ||
                  rnd(10) >= tp->t_stats.s_intel ||
                  on(*tp, ISFLY))) {
                /* OK, we can go here.  But don't go there if
                 * monster can't get at player from there
                 */
                tryp.y = y;
                tryp.x = x;
                if (diag_ok(&tryp, &hero, tp)) {
                    spots[index] = TRUE;
                    found_one = TRUE;
                }
            }
        }

    /* If we found one, go to it */
    if (found_one) {
        unsigned char rch;       /* What's really where the creatures moves to */

        /* Find a legal spot */
        while (spots[index=rnd(9)] == FALSE) continue;

        /* Get the coordinates */
        y = hero.y + (index/3) - 1;
        x = hero.x + (index % 3) - 1;

        /* Move the monster from the old space */
        mvwaddch(cw, tp->t_pos.y, tp->t_pos.x, tp->t_oldch);

        /* Move it to the new space */
        tp->t_oldch = mvwinch(cw, y, x);

        /* Display the creature if our hero can see it */
        if (cansee(y, x) &&
            off(*tp, ISINWALL) &&
            !invisible(tp))
            mvwaddch(cw, y, x, tp->t_type);

        /* Fix the monster window */
        mvwaddch(mw, tp->t_pos.y, tp->t_pos.x, ' '); /* Clear old position */
        mvwaddch(mw, y, x, tp->t_type);

        /* Record the new position */
        tp->t_pos.y = y;
        tp->t_pos.x = x;

        /* If the monster is on a trap, trap it */
        rch = mvinch(y, x);
        if (isatrap(rch)) {
            if (cansee(y, x)) tp->t_oldch = rch;
            be_trapped(tp, &(tp->t_pos));
        }
    }

    return(found_one);
}

/* 
 * Can_shoot determines if the monster (er) has a direct line of shot 
 * at the prey (ee).  If so, it returns the direction in which to shoot.
 */

int
can_shoot(coord *er, coord *ee, coord *shoot_dir)
{
    /* 
     * They must be in the same room or very close (at door)
     */
    if (roomin(er) != roomin(ee) && DISTANCE(er->y,er->x,ee->y,ee->x) > 1)
    {
        shoot_dir->x = shoot_dir->y = 0;
        return(-1);
    }

    /* Do we have a straight shot? */
    if (!straight_shot(er->y, er->x, ee->y, ee->x, shoot_dir)) 
    {
        shoot_dir->x = shoot_dir->y = 0;
        return(-2);
    }
    else 
        return(0);
}

/*
 * chase:
 *      Find the spot for the chaser(er) to move closer to the
 *      chasee(ee).  Rer is the room of the chaser, and ree is the
 *      room of the creature being chased (chasee).
 * 	flee: True if destination (ee) is player and monster is running away
 *	or the player is in a wall and the monster can't get to it
 */

void
chase(struct thing *tp, coord *ee, struct room *rer, struct room *ree, 
      bool flee)
{
    int dist, thisdist, monst_dist = INT_MAX; 
    register coord *er = &tp->t_pos; 
    struct thing *prey;                 /* What we are chasing */
    coord ch_ret;                       /* Where chasing takes you */
    unsigned char ch, mch;
    bool next_player = FALSE;

    /* 
     * set the distance from the chas(er) to the chas(ee) here and then
     * we won't have to reset it unless the chas(er) moves (instead of shoots)
     */
    dist = DISTANCE(er->y, er->x, ee->y, ee->x);

    /*
     * See if our destination is a monster or player.  If so, make "prey" point
     * to it.
     */
    if (ce(hero, *ee)) prey = &player;  /* Is it the player? */
    else if (tp->t_dest && ce(*(tp->t_dest), *ee)) {    /* Is it a monster? */
        struct linked_list *item;

        /* What is the monster we're chasing? */
        item = find_mons(ee->y, ee->x);
        if (item != NULL) prey = THINGPTR(item);
        else prey = NULL;
    }
    else prey = NULL;

    /* We will use at least one movement period */
    tp->t_no_move = movement(tp);
    if (on(*tp, ISFLY)) /* If the creature is flying, speed it up */
        tp->t_no_move /= 2;

    /*
     * If the thing is confused or it can't see the player,
     * let it move randomly. 
     */
    if ((on(*tp, ISHUH) && rnd(10) < 8) ||
        (prey && on(*prey, ISINVIS) && off(*tp, CANSEE))) { /* invisible prey */
        /*
         * get a valid random move
         */
        tp->t_newpos = rndmove(tp);
        dist = DISTANCE(tp->t_newpos.y, tp->t_newpos.x, ee->y, ee->x);
    }

    /*
     * Otherwise, find the empty spot next to the chaser that is
     * closest to the chasee.
     */
    else {
        register int ey, ex, x, y;
        int dist_to_old = INT_MIN; /* Dist from goal to old position */

        /*
         * This will eventually hold where we move to get closer
         * If we can't find an empty spot, we stay where we are.
         */
        dist = flee ? 0 : INT_MAX;
        ch_ret = *er;

        /* Are we at our goal already? */
        if (!flee && ce(ch_ret, *ee)) {
            turn_off(*tp, ISRUN);       /* So stop running! */
            return;
        }

        ey = er->y + 1;
        ex = er->x + 1;

        /* Check all possible moves */
        for (x = er->x - 1; x <= ex; x++) {
            if (x < 0 || x >= cols) /* Don't try off the board */
                continue;
            for (y = er->y - 1; y <= ey; y++) {
                coord tryp;

                if ((y < 1) || (y >= lines - 2)) /* Don't try off the board */
                    continue;

                /* Don't try the player if not going after the player */
                if ((flee || !ce(hero, *ee) || on(*tp, ISFRIENDLY)) &&
                    x == hero.x && y == hero.y) {
                    next_player = TRUE;
                    continue;
                }

                tryp.x = x;
                tryp.y = y;

                /* Is there a monster on this spot closer to our goal?
                 * Don't look in our spot or where we were.
                 */
                if (!ce(tryp, *er) && !ce(tryp, tp->t_oldpos) &&
                    isalpha(mch = mvwinch(mw, y, x))) {
                    int test_dist;

                    test_dist = DISTANCE(y, x, ee->y, ee->x);
                    if (test_dist <= 25 &&   /* Let's be fairly close */
                        test_dist < monst_dist) {
                        /* Could we really move there? */
                        mvwaddch(mw, y, x, ' '); /* Temporarily blank monst */
                        if (diag_ok(er, &tryp, tp)) monst_dist = test_dist;
                        mvwaddch(mw, y, x, mch); /* Restore monster */
                    }
                }

                /* Can we move onto the spot? */        
                if (!diag_ok(er, &tryp, tp)) continue;

                ch = mvwinch(cw, y, x); /* Screen character */

                /*
                 * Stepping on player is NOT okay if we are fleeing.
                 * If we are friendly to the player and there is a monster
                 * in the way that is not of our race, it is okay to move
                 * there.
                 */
                if (step_ok(y, x, FIGHTOK, tp) &&
                    (off(*tp, ISFLEE) || ch != PLAYER))
                {
                    /*
                     * If it is a trap, an intelligent monster may not
                     * step on it (unless our hero is on top!)
                     */
                    if ((isatrap(ch))                   && 
                        (rnd(10) < tp->t_stats.s_intel) &&
                        (!on(*tp, ISFLY))               &&
                        (y != hero.y || x != hero.x)) 
                            continue;

                    /*
                     * OK -- this place counts
                     */
                    thisdist = DISTANCE(y, x, ee->y, ee->x);

                    /* Adjust distance if we are being shot at */
                    if (tp->t_wasshot && tp->t_stats.s_intel > 5 &&
                        prey != NULL) {
                        /* Move out of line of sight */
                        if (straight_shot(tryp.y, tryp.x, ee->y, ee->x, (coord *)NULL)) {
                            if (flee) thisdist -= SHOTPENALTY;
                            else thisdist += SHOTPENALTY;
                        }

                        /* But do we want to leave the room? */
                        else if (rer && rer == ree && ch == DOOR)
                            thisdist += DOORPENALTY;
                    }

                    /* Don't move to the last position if we can help it
                     * (unless out prey just moved there)
                     */
                    if (ce(tryp, tp->t_oldpos) && (flee || !ce(tryp, hero)))
                        dist_to_old = thisdist;

                    else if ((flee && (thisdist > dist)) ||
                        (!flee && (thisdist < dist)))
                    {
                        ch_ret = tryp;
                        dist = thisdist;
                    }
                }
            }
        }

        /* If we aren't trying to get the player, but he is in our way,
         * hit him (unless we have been turned or are friendly).  next_player
         * being TRUE -> we are next to the player but don't want to hit him.
         *
         * If we are friendly to the player, following him, and standing next
         * to him, we will try to help him out in battle.
         */
        if (next_player && off(*tp, WASTURNED)) {
            if (off(*tp, ISFRIENDLY) &&
                ((flee && ce(ch_ret, *er)) ||
                 (!flee && DISTANCE(er->y, er->x, ee->y, ee->x) < dist)) &&
                step_ok(tp->t_dest->y, tp->t_dest->x, NOMONST, tp)) {
                /* Okay to hit player */
                debug("Switching to hero.");
                tp->t_newpos = hero;
                tp->t_action = A_MOVE;
                return;
            }
            else if (on(*tp, ISFRIENDLY) && !flee && ce(*ee, hero)) {
                /*
                 * Look all around the player.  If there is a fightable
                 * creature next to both of us, hit it.  Otherwise, if
                 * there is a fightable creature next to the player, try
                 * to move next to it.
                 */
                dist = INT_MAX;
                for (x = hero.x - 1; x <= hero.x + 1; x++) {
                    if (x < 0 || x >= cols) /* Don't try off the board */
                        continue;
                    for (y = hero.y - 1; y <= hero.y + 1; y++) {
                        if ((y < 1) || (y >= lines - 2)) /* Stay on the board */
                            continue;

                        /* Is there a fightable monster here? */
                        if (isalpha(mvwinch(mw, y, x)) &&
                            step_ok(y, x, FIGHTOK, tp) &&
                            off(*tp, ISSTONE)) {
                            thisdist = DISTANCE(er->y, er->x, y, x);
                            if (thisdist < dist) {
                                dist = thisdist;
                                ch_ret.y = y;
                                ch_ret.x = x;
                            }
                        }
                    }
                }

                /* Are we next to a bad guy? */
                if (dist <= 2) {        /* Get him! */
                    tp->t_newpos = ch_ret;
                    tp->t_action = A_MOVE;
                }

                /* Try to move to the bad guy */
                else if (dist < INT_MAX)
                    chase(tp, &ch_ret,
                          roomin(&tp->t_pos), roomin(&ch_ret), FALSE);

                else tp->t_action = A_NIL;

                return;
            }
        }

        /*
         * If we have decided that we can move onto a monster (we are
         * friendly to the player, go to it.
         */
        if (!ce(ch_ret, *er) && isalpha(mvwinch(mw, ch_ret.y, ch_ret.x))) {
            debug("Attack monster");
            tp->t_newpos = ch_ret;
            tp->t_action = A_MOVE;
            return;
        }

        /* If we can't get closer to the player (if that's our goal)
         * because other monsters are in the way, just stay put
         */
        if (!flee && ce(hero, *ee) && monst_dist < INT_MAX &&
            DISTANCE(er->y, er->x, hero.y, hero.x) < dist) {
                tp->t_action = A_NIL; /* do nothing for awhile */
                return;
        }

        /* Do we want to go back to the last position? */
        else if (dist_to_old != INT_MIN &&      /* It is possible to move back */
            ((flee && dist == 0) ||     /* No other possible moves */
             (!flee && dist == INT_MAX))) {
            /* Do we move back or just stay put (default)? */
            dist = DISTANCE(er->y, er->x, ee->y, ee->x); /* Current distance */
            if (!flee || (flee && (dist_to_old > dist))) ch_ret = tp->t_oldpos;
        }

        /* Record the new destination */
        tp->t_newpos = ch_ret;
    }

    /*
     * Do we want to fight or move?  If our selected destination (ch_ret)
     * is our hero, then we want to fight.  Otherwise, we want to move.
     */
    if (ce(tp->t_newpos, hero)) {
        /* Fight! (or sell) */
        if (on(*tp, CANSELL)) {
            tp->t_action = A_SELL;
            tp->t_no_move += movement(tp); /* takes a little time to sell */
        }
        else {
            tp->t_action = A_ATTACK;

            /*
             * Try to find a weapon to wield.  Wield_weap will return a
             * projector if weapon is a projectile (eg. bow for arrow).
             * If weapon is NULL (the case here), it will try to find
             * a suitable weapon.
             *
             *          Add in rest of time. Fight is 
             *          movement() + weap_move() + FIGHTBASE
             */
            tp->t_using = wield_weap((struct object *)NULL, tp);
            if (tp->t_using == NULL)
                tp->t_no_move += weap_move(tp, (struct object *)NULL);
            else
                tp->t_no_move += weap_move(tp, OBJPTR(tp->t_using));

            if (on(*tp, ISHASTE))
                    tp->t_no_move += FIGHTBASE/2;
            else if (on(*tp, ISSLOW))
                    tp->t_no_move += FIGHTBASE*2;
            else
                    tp->t_no_move += FIGHTBASE;
        }
    }
    else {
        /* Move */
        tp->t_action = A_MOVE;

        /*
         * Check if the creature is not next to the player.  If it
         * is not and has held or suffocated the player, then stop it!
         * Note that this code should more appropriately appear in
         * the area that actually moves the monster, but for now it
         * is okay here because the player can't move while held or
         * suffocating.
         */
        if (dist > 2) {
            if (on(*tp, DIDHOLD)) {
                 turn_off(*tp, DIDHOLD);
                 turn_on(*tp, CANHOLD);
                 if (--hold_count == 0) 
                     turn_off(player, ISHELD);
            }

            /* If monster was suffocating, stop it */
            if (on(*tp, DIDSUFFOCATE)) {
                turn_off(*tp, DIDSUFFOCATE);
                turn_on(*tp, CANSUFFOCATE);
                extinguish(suffocate);
                msg("You can breathe again.....Whew!");
            }
        }
    }
}

/*
 * do_chase:
 *      Make one thing chase another.
 */

void
do_chase(struct thing *th)
{
    register struct room *orig_rer,     /* Original room of chaser */
                         *new_room;     /* new room of monster */
    unsigned char floor, rch, sch;
    coord old_pos,                      /* Old position of monster */
          ch_ret;                       /* Where we want to go */

    if (on(*th, NOMOVE)) return;

    ch_ret = th->t_newpos;      /* Record our desired new position */

    /*
     * Make sure we have an open spot (no other monster's gotten in our way,
     * someone didn't just drop a scare monster there, our prey didn't just
     * get there, etc.)
     */
    if (!step_ok(th->t_newpos.y, th->t_newpos.x, FIGHTOK, th)) {
        /*
         * Most monsters get upset now.  Guardians are all friends,
         * and we don't want to see 50 messages in a row!
         */
        if (th->t_stats.s_intel > 4 &&
            off(*th, ISUNDEAD)      &&
            off(*th, ISGUARDIAN)    &&
            off(*th, AREMANY)       &&
            off(*th, ISHUH)         &&
            off(*th, ISCHARMED)     &&
            off(player, ISBLIND)    &&
            cansee(unc(th->t_pos))  &&
        !invisible(th) && (rnd(15) < 5)) {
            switch (rnd(10)) {
              case 0: case 1:
            msg("%s lashes out at you! ",prname(monster_name(th),TRUE));
          when 2: case 3:
            msg("%s scrambles around. ",prname(monster_name(th), TRUE));
                  otherwise:
            msg("%s motions angrily. ", prname(monster_name(th), TRUE));
            }
    }
        return;
    }
    else if (ce(th->t_newpos, hero) ||  /* Player just got in our way */
             isalpha(mvwinch(mw, th->t_newpos.y, th->t_newpos.x))) {
        bool fightplayer = ce(th->t_newpos, hero);

        /* If we were turned or are friendly, we just have to sit here! */
        if (fightplayer && (on(*th, WASTURNED) || on(*th, ISFRIENDLY))) return;

        /* Do we want to sell something? */
        if (fightplayer && on(*th, CANSELL)) {
            th->t_action = A_SELL;
            th->t_no_move += movement(th); /* takes a little time to sell */
            return;
        }

        /* Let's hit him */
        th->t_action = A_ATTACK;

        /*
         * Try to find a weapon to wield.  Wield_weap will return a
         * projector if weapon is a projectile (eg. bow for arrow).
         * If weapon is NULL (the case here), it will try to find
         * a suitable weapon.
         */
        th->t_using = wield_weap((struct object *)NULL, th);
        /*
         * add in rest of time
         */
        if (th->t_using == NULL)
            th->t_no_move += weap_move(th, (struct object *)NULL);
        else
            th->t_no_move += weap_move(th, OBJPTR(th->t_using));
        if (on(*th, ISHASTE))
                th->t_no_move += FIGHTBASE/2;
        else if (on(*th, ISSLOW))
                th->t_no_move += FIGHTBASE*2;
        else
                th->t_no_move += FIGHTBASE;
        return;
    }

    /*
     * Blank out the old position and record the new position --
     * the blanking must be done first in case the positions are the same.
     */
    mvwaddch(mw, th->t_pos.y, th->t_pos.x, ' ');
    mvwaddch(mw, ch_ret.y, ch_ret.x, th->t_type);

    /* Get new and old rooms of monster */
    new_room = roomin(&ch_ret);
    orig_rer = roomin(&th->t_pos);

    /* Store the critter's old position and update the current one */
    old_pos = th->t_pos;
    th->t_pos = ch_ret;
    floor = (roomin(&ch_ret) == NULL) ? PASSAGE : FLOOR;

    /* If we have a scavenger, it can pick something up */
    if (off(*th, ISGUARDIAN)) {
        register struct linked_list *n_item, *o_item;
        register int item_count = 0;
        bool want_something = FALSE;

        while ((n_item = find_obj(ch_ret.y, ch_ret.x)) != NULL) {
            register struct object *n_obj, *o_obj;
            bool wants_it;

            /* Does this monster want anything? */
            if (want_something == FALSE) {
                if (on(*th, ISSCAVENGE)  || on(*th, CARRYFOOD)   ||
                    on(*th, CARRYGOLD)   || on(*th, CARRYSCROLL) ||
                    on(*th, CARRYPOTION) || on(*th, CARRYRING)   ||
                    on(*th, CARRYSTICK)  || on(*th, CARRYMISC)   ||
                    on(*th, CARRYWEAPON) || on(*th, CARRYARMOR)  ||
                    on(*th, CARRYDAGGER))  {
                        want_something = TRUE;

                        /*
                         * Blank the area.  We have to do it only before the
                         * first item in case an item gets dropped in same
                         * place.  We don't want to blank it out after it get
                         * dropped.
                         */
                        mvaddch(ch_ret.y, ch_ret.x, floor);

                        /* Were we specifically after something here? */
                        if (ce(*th->t_dest, ch_ret)) {
                            /* If we're mean, we go after the hero */
                            if (on(*th, ISMEAN)) runto(th, &hero);

                            /* Otherwise just go back to sleep */
                            else {
                                turn_off(*th, ISRUN);
                                th->t_dest = NULL;
                            }
                        }
                }
                else break;
            }

            item_count++;       /* Count the number of items */

            /*
             * see if he's got one of this group already
             */
            o_item = NULL;
            n_obj = OBJPTR(n_item);
            detach(lvl_obj, n_item);

            /* See if he wants it */
            if (n_obj->o_type == SCROLL && n_obj->o_which == S_SCARE &&
                th->t_stats.s_intel < 16)
                wants_it = FALSE; /* Most monsters don't want a scare monster */
            else if (on(*th, ISSCAVENGE)) wants_it = TRUE;
            else {
                wants_it = FALSE;       /* Default case */
                switch (n_obj->o_type) {
                    case FOOD:  if(on(*th, CARRYFOOD))   wants_it = TRUE;
                    when GOLD:  if(on(*th, CARRYGOLD))   wants_it = TRUE;
                    when SCROLL:if(on(*th, CARRYSCROLL)) wants_it = TRUE;
                    when POTION:if(on(*th, CARRYPOTION)) wants_it = TRUE;
                    when RING:  if(on(*th, CARRYRING))   wants_it = TRUE;
                    when STICK: if(on(*th, CARRYSTICK))  wants_it = TRUE;
                    when MM:    if(on(*th, CARRYMISC))   wants_it = TRUE;
                    when ARMOR: if(on(*th, CARRYARMOR))  wants_it = TRUE;
                    when WEAPON:if(on(*th, CARRYWEAPON) ||
                                  (on(*th,CARRYDAGGER)&&n_obj->o_which==DAGGER))
                                        wants_it = TRUE;
                }
            }
            /*
             * The quartermaster doesn't sell cursed stuff so he won't
             * pick it up
             */
            if (on(*th, CANSELL) && (n_obj->o_flags & ISCURSED))
                wants_it = FALSE;

            /* If he doesn't want it, throw it away */
            if (wants_it == FALSE) {
                fall(n_item, FALSE);
                continue;
            }

            /* Otherwise, let's pick it up */
            if (n_obj->o_group) {
                for(o_item = th->t_pack; o_item != NULL; o_item = next(o_item)){
                    o_obj = OBJPTR(o_item);
                    if (o_obj->o_group == n_obj->o_group) {
                        o_obj->o_count += n_obj->o_count;
                        o_discard(n_item);
                        break;
                    }
                }
            }
            if (o_item == NULL) {       /* didn't find it */
                attach(th->t_pack, n_item);
            }
        }

        /* If there was anything here, we may have to update the screen */
        if (item_count) {
            if (cansee(ch_ret.y, ch_ret.x))
                mvwaddch(cw, ch_ret.y, ch_ret.x, mvinch(ch_ret.y, ch_ret.x));
            updpack(TRUE, th); /* Update the monster's encumberance, too */
        }
    }

    rch = mvwinch(stdscr, old_pos.y, old_pos.x); 
    if (th->t_oldch == floor && rch != floor && !isatrap(rch))
        mvwaddch(cw, old_pos.y, old_pos.x, rch);
    else
        mvwaddch(cw, old_pos.y, old_pos.x, th->t_oldch);
    sch = mvwinch(cw, ch_ret.y, ch_ret.x); /* What player sees */
    rch = mvwinch(stdscr, ch_ret.y, ch_ret.x); /* What's really there */

    /* If we have a tunneling monster, it may be making a tunnel */
    if (on(*th, CANTUNNEL)      &&
        (rch==SECRETDOOR || rch==WALL || rch==VERTWALL || rch==HORZWALL)) {
        unsigned char nch;       /* The new look to the tunnel */

        if (rch == WALL && levtype == OUTSIDE) nch = FLOOR;
        else if (rch == WALL) nch = PASSAGE;
        else if (levtype == MAZELEV || levtype == OUTSIDE) nch = FLOOR;
        else nch = DOOR;
        addch(nch);

        if (cansee(ch_ret.y, ch_ret.x)) sch = nch; /* Can player see this? */

        /* Does this make a new exit? */
        if (rch == VERTWALL || rch == HORZWALL) {
            struct linked_list *newroom;
            coord *exit;

            newroom = new_item(sizeof(coord));
            exit = DOORPTR(newroom);
            *exit = ch_ret;
            attach(new_room->r_exit, newroom);
        }
    }

    /* Mark if the monster is inside a wall */
    if (isrock(mvinch(ch_ret.y, ch_ret.x))) turn_on(*th, ISINWALL);
    else turn_off(*th, ISINWALL);

    /* If the monster can illuminate rooms, check for a change */
    if (on(*th, HASFIRE)) {
        register struct linked_list *fire_item;

        /* Is monster entering a room? */
        if (orig_rer != new_room && new_room != NULL) {
            fire_item = creat_item();   /* Get an item-only structure */
            ldata(fire_item) = (char *) th;

            attach(new_room->r_fires, fire_item);
            new_room->r_flags |= HASFIRE;