view rogue3/chase.c @ 233:0990adf580ee

Declare some function arguments as const. Some functions, mostly in fight.c, declared variables as pointers to const char but passed them to functions that took pointers to ordinary char. The strings did not actually get modified, so adding 'const' to the function definitions removed the warnings.
author John "Elwin" Edwards
date Sun, 06 Mar 2016 19:32:47 -0500
parents d9e44e18eeec
children
line wrap: on
line source

/*
 * Code for one object to chase another
 *
 * @(#)chase.c	3.17 (Berkeley) 6/15/81
 *
 * 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 "curses.h"
#include "rogue.h"

coord ch_ret;				/* Where chasing takes you */

/*
 * runners:
 *	Make all the running monsters move.
 */

void
runners()
{
    struct linked_list *item;
    struct thing *tp;

    for (item = mlist; item != NULL;)
    {
	tp = (struct thing *) ldata(item);
        item = next(item);
	if (off(*tp, ISHELD) && on(*tp, ISRUN))
	{
	    if (off(*tp, ISSLOW) || tp->t_turn)
		if (do_chase(tp) == -1)
                    continue;
	    if (on(*tp, ISHASTE))
		if (do_chase(tp) == -1)
                    continue;
	    tp->t_turn ^= TRUE;
	}
    }
}

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

int
do_chase(struct thing *th)
{
    struct room *rer, *ree;	/* room of chaser, room of chasee */
    int mindist = 32767, i, dist;
    int stoprun = FALSE;	/* TRUE means we are there */
    int sch;
    coord this;				/* Temporary destination for chaser */

    rer = roomin(&th->t_pos);	/* Find room of chaser */
    ree = roomin(th->t_dest);	/* Find room of chasee */
    /*
     * We don't count doors as inside rooms for this routine
     */
    if (mvwinch(stdscr, th->t_pos.y, th->t_pos.x) == DOOR)
	rer = NULL;
    this = *th->t_dest;
    /*
     * If the object of our desire is in a different room, 
     * than we are and we ar not in a corridor, run to the
     * door nearest to our goal.
     */
    if (rer != NULL && rer != ree)
	for (i = 0; i < rer->r_nexits; i++)	/* loop through doors */
	{
	    dist = DISTANCE(th->t_dest->y, th->t_dest->x,
			    rer->r_exit[i].y, rer->r_exit[i].x);
	    if (dist < mindist)			/* minimize distance */
	    {
		this = rer->r_exit[i];
		mindist = dist;
	    }
	}
    /*
     * this now contains what we want to run to this time
     * so we run to it.  If we hit it we either want to fight it
     * or stop running
     */
    if (!chase(th, &this))
    {
	if (ce(this, hero))
	{
	    return( attack(th) );
	}
	else if (th->t_type != 'F')
	    stoprun = TRUE;
    }
    else if (th->t_type == 'F')
	return(0);
    mvwaddch(cw, th->t_pos.y, th->t_pos.x, th->t_oldch);
    sch = mvwinch(cw, ch_ret.y, ch_ret.x);
    if (rer != NULL && (rer->r_flags & ISDARK) && sch == FLOOR
	&& DISTANCE(ch_ret.y, ch_ret.x, th->t_pos.y, th->t_pos.x) < 3
	&& off(player, ISBLIND))
	    th->t_oldch = ' ';
    else
	th->t_oldch = sch;

    if (cansee(unc(ch_ret)) && !on(*th, ISINVIS))
        mvwaddch(cw, ch_ret.y, ch_ret.x, th->t_type);
    mvwaddch(mw, th->t_pos.y, th->t_pos.x, ' ');
    mvwaddch(mw, ch_ret.y, ch_ret.x, th->t_type);
    th->t_pos = ch_ret;
    /*
     * And stop running if need be
     */
    if (stoprun && ce(th->t_pos, *(th->t_dest)))
	th->t_flags &= ~ISRUN;

    return(0);
}

/*
 * runto:
 *	Set a mosnter running after something
 *	or stop it from running (for when it dies)
 */

void
runto(coord *runner, coord *spot)
{
    struct linked_list *item;
    struct thing *tp;

    /*
     * If we couldn't find him, something is funny
     */
    if ((item = find_mons(runner->y, runner->x)) == NULL)
    {
	msg("CHASER '%s'", unctrl(winat(runner->y, runner->x)));
	return;
    }
    tp = (struct thing *) ldata(item);
    /*
     * Start the beastie running
     */
    tp->t_dest = spot;
    tp->t_flags |= ISRUN;
    tp->t_flags &= ~ISHELD;
}

/*
 * chase:
 *	Find the spot for the chaser(er) to move closer to the
 *	chasee(ee).  Returns TRUE if we want to keep on chasing later
 *	FALSE if we reach the goal.
 */

int
chase(struct thing *tp, coord *ee)
{
    int x, y;
    int dist, thisdist;
    struct linked_list *item;
    struct object *obj = NULL;
    coord *er = &tp->t_pos;
    int ch;

    /*
     * If the thing is confused, let it move randomly. Invisible
     * Stalkers are slightly confused all of the time, and bats are
     * quite confused all the time
     */
    if ((on(*tp, ISHUH) && rnd(10) < 8) || (tp->t_type == 'I' && rnd(100) < 20)
	|| (tp->t_type == 'B' && rnd(100) < 50))
    {
	/*
	 * get a valid random move
	 */
	ch_ret = *rndmove(tp);
	dist = DISTANCE(ch_ret.y, ch_ret.x, ee->y, ee->x);
	/*
	 * Small chance that it will become un-confused 
	 */
	if (rnd(1000) < 50)
	    tp->t_flags &= ~ISHUH;
    }
    /*
     * Otherwise, find the empty spot next to the chaser that is
     * closest to the chasee.
     */
    else
    {
	int ey, ex;
	/*
	 * This will eventually hold where we move to get closer
	 * If we can't find an empty spot, we stay where we are.
	 */
	dist = DISTANCE(er->y, er->x, ee->y, ee->x);
	ch_ret = *er;

	ey = er->y + 1;
	ex = er->x + 1;
	for (x = er->x - 1; x <= ex; x++)
	    for (y = er->y - 1; y <= ey; y++)
	    {
		coord tryp;

		tryp.x = x;
		tryp.y = y;
		if (!diag_ok(er, &tryp))
		    continue;
		ch = winat(y, x);
		if (step_ok(ch))
		{
		    /*
		     * If it is a scroll, it might be a scare monster scroll
		     * so we need to look it up to see what type it is.
		     */
		    if (ch == SCROLL)
		    {
			for (item = lvl_obj; item != NULL; item = next(item))
			{
			    obj = (struct object *) ldata(item);
			    if (y == obj->o_pos.y && x == obj->o_pos.x)
				break;
			}
			if (item != NULL && obj->o_which == S_SCARE)
			    continue;
		    }
		    /*
		     * If we didn't find any scrolls at this place or it
		     * wasn't a scare scroll, then this place counts
		     */
		    thisdist = DISTANCE(y, x, ee->y, ee->x);
		    if (thisdist < dist)
		    {
			ch_ret = tryp;
			dist = thisdist;
		    }
		}
	    }
    }
    return (dist != 0);
}

/*
 * roomin:
 *	Find what room some coordinates are in. NULL means they aren't
 *	in any room.
 */

struct room *
roomin(coord *cp)
{
    struct room *rp;

    for (rp = rooms; rp <= &rooms[MAXROOMS-1]; rp++)
	if (inroom(rp, cp))
	    return rp;
    return NULL;
}

/*
 * find_mons:
 *	Find the monster from his corrdinates
 */

struct linked_list *
find_mons(int y, int x)
{
    struct linked_list *item;
    struct thing *th;

    for (item = mlist; item != NULL; item = next(item))
    {
	th = (struct thing *) ldata(item);
	if (th->t_pos.y == y && th->t_pos.x == x)
	    return item;
    }
    return NULL;
}

/*
 * diag_ok:
 *	Check to see if the move is legal if it is diagonal
 */

int
diag_ok(coord *sp, coord *ep)
{
    if (ep->x == sp->x || ep->y == sp->y)
	return TRUE;
    return (step_ok(mvinch(ep->y, sp->x)) && step_ok(mvinch(sp->y, ep->x)));
}

/*
 * cansee:
 *	returns true if the hero can see a certain coordinate.
 */

int
cansee(int y, int x)
{
    struct room *rer;
    coord tp;

    if (on(player, ISBLIND))
	return FALSE;
    tp.y = y;
    tp.x = x;
    rer = roomin(&tp);
    /*
     * We can only see if the hero in the same room as
     * the coordinate and the room is lit or if it is close.
     */
    return (rer != NULL && rer == roomin(&hero) && !(rer->r_flags&ISDARK)) ||
	    DISTANCE(y, x, hero.y, hero.x) < 3;
}