server/server/monster.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008,2009,2010 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 2002 Mark Wedel & Crossfire Development Team
 * Copyright (©) 1992 Frank Tore Johansen
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

//+GPL

#include <global.h>
#include <sproto.h>
#include <spells.h>
#include <skills.h>

#define MIN_MON_RADIUS 3        /* minimum monster detection radius */

/* checks npc->enemy and returns that enemy if still valid,
 * NULL otherwise.
 * this is map tile aware.
 * If this returns an enemy, the range vector rv should also be
 * set to sane values.
 */
object *
check_enemy (object *npc, rv_vector * rv)
{
  /* if this is pet, let him attack the same enemy as his owner
   * TODO: when there is no ower enemy, try to find a target,
   * which CAN attack the owner. */
  if ((npc->attack_movement & HI4) == PETMOVE)
    {
      if (npc->owner == NULL)
        npc->enemy = NULL;
      else if (npc->enemy == NULL)
        npc->enemy = npc->owner->enemy;
    }

  /* periodically, a monster may change its target.  Also, if the object
   * has been destroyed, etc, clear the enemy.
   * TODO: this should be changed, because it invokes to attack forced or 
   * attacked monsters to leave the attacker alone, before it is destroyed 
   */
  /* I had removed the random target leave, this invokes problems with friendly
   * objects, getting attacked and defending herself - they don't try to attack
   * again then but perhaps get attack on and on 
   * If we include a aggravated flag in , we can handle evil vs evil and good vs good
   * too. */

  if (npc->enemy)
    {
      /* I broke these if's apart to better be able to see what
       * the grouping checks are.  Code is the same.
       */
      if (npc->enemy->flag [FLAG_REMOVED] ||
          npc->enemy->flag [FLAG_FREED] ||
          !on_same_map (npc, npc->enemy) || npc == npc->enemy || npc->flag [FLAG_NEUTRAL] || npc->enemy->flag [FLAG_NEUTRAL])
        npc->enemy = 0;

      else if (npc->flag [FLAG_FRIENDLY] && ((npc->enemy->flag [FLAG_FRIENDLY]
                                                    && !(should_arena_attack (npc, npc->owner, npc->enemy)))
                                                   || ((npc->enemy->type == PLAYER) && !(should_arena_attack (npc, npc->owner, npc->enemy)))
                                                   || npc->enemy == npc->owner))
        npc->enemy = 0;


      else if (!npc->flag [FLAG_FRIENDLY] && (!npc->enemy->flag [FLAG_FRIENDLY] && npc->enemy->type != PLAYER))
        npc->enemy = 0;

      /* I've noticed that pets could sometimes get an arrow as the
       * target enemy - this code below makes sure the enemy is something
       * that should be attacked.  My guess is that the arrow hits
       * the creature/owner, and so the creature then takes that
       * as the enemy to attack.
       */
      else if (!npc->enemy->flag [FLAG_MONSTER]
               && !npc->enemy->flag [FLAG_GENERATOR]
               && npc->enemy->type != PLAYER
               && npc->enemy->type != GOLEM)
        npc->enemy = 0;
    }

  return can_detect_enemy (npc, npc->enemy, rv) ? npc->enemy : 0;
}

/* Returns the nearest living creature (monster or generator).
 * Modified to deal with tiled maps properly.
 * Also fixed logic so that monsters in the lower directions were more
 * likely to be skipped - instead of just skipping the 'start' number
 * of direction, revisit them after looking at all the other spaces.
 *
 * Note that being this may skip some number of spaces, it will
 * not necessarily find the nearest living creature - it basically
 * chooses one from within a 3 space radius, and since it skips
 * the first few directions, it could very well choose something 
 * 3 spaces away even though something directly north is closer.
 *
 * this function is map tile aware.
 */
object *
find_nearest_living_creature (object *npc)
{
  int i, mflags;
  sint16 nx, ny;
  maptile *m;
  int search_arr[SIZEOFFREE];

  get_search_arr (search_arr);

  for (i = 0; i < SIZEOFFREE; i++)
    {
      /* modified to implement smart searching using search_arr
       * guidance array to determine direction of search order
       */
      nx = npc->x + freearr_x[search_arr[i]];
      ny = npc->y + freearr_y[search_arr[i]];
      m = npc->map;

      mflags = get_map_flags (m, &m, nx, ny, &nx, &ny);

      if (mflags & P_OUT_OF_MAP)
        continue;

      if (mflags & P_IS_ALIVE)
        {
          for (object *tmp = m->at (nx, ny).top; tmp; tmp = tmp->below)
            if (tmp->flag [FLAG_MONSTER] || tmp->flag [FLAG_GENERATOR] || tmp->type == PLAYER)
              if (can_see_monsterP (m, nx, ny, i))
                return tmp;
        }
    }

  return 0;
}

/* Tries to find an enemy for npc.  We pass the range vector since
 * our caller will find the information useful.
 * Currently, only move_monster calls this function.
 * Fix function so that we always make calls to get_rangevector
 * if we have a valid target - function as not doing so in
 * many cases.
 */
static object *
find_enemy (object *npc, rv_vector * rv)
{
  object *attacker, *tmp = NULL;

  attacker = npc->attacked_by;  /* save this for later use. This can be a attacker. */
  npc->attacked_by = 0;         /* always clear the attacker entry */

  /* if we berserk, we don't care about others - we attack all we can find */
  if (npc->flag [FLAG_BERSERK])
    {
      tmp = find_nearest_living_creature (npc);

      if (tmp)
        get_rangevector (npc, tmp, rv, 0);

      return tmp;
    }

  /* Here is the main enemy selection.
   * We want this: if there is an enemy, attack him until its not possible or 
   * one of both is dead.
   * If we have no enemy and we are...
   * a monster: try to find a player, a pet or a friendly monster
   * a friendly: only target a monster which is targeting you first or targeting a player
   * a neutral: fight a attacker (but there should be none), then do nothing
   * a pet: attack player enemy or a monster
   */

  /* pet move */
  if ((npc->attack_movement & HI4) == PETMOVE)
    {
      tmp = get_pet_enemy (npc, rv);

      if (tmp)
        get_rangevector (npc, tmp, rv, 0);

      return tmp;
    }

  /* we check our old enemy. */
  if (!(tmp = check_enemy (npc, rv)))
    {
      if (attacker)             /* if we have an attacker, check him */
        {
          /* TODO: that's not finished */
          /* we don't want a fight evil vs evil or good against non evil */

          if (npc->flag [FLAG_NEUTRAL] || attacker->flag [FLAG_NEUTRAL] ||      /* neutral */
              (npc->flag [FLAG_FRIENDLY] && attacker->flag [FLAG_FRIENDLY]) ||
              (!npc->flag [FLAG_FRIENDLY] && (!attacker->flag [FLAG_FRIENDLY] && attacker->type != PLAYER)))
            npc->clr_flag (FLAG_SLEEP);   /* skip it, but lets wakeup */
          else if (on_same_map (npc, attacker))     /* that's the only thing we must know... */
            {
              npc->clr_flag (FLAG_SLEEP); /* well, NOW we really should wake up! */
              npc->enemy = attacker;
              return attacker;      /* yes, we face our attacker! */
            }
        }

      /* we have no legal enemy or attacker, so we try to target a new one */
      if (!npc->flag [FLAG_UNAGGRESSIVE] && !npc->flag [FLAG_FRIENDLY] && !npc->flag [FLAG_NEUTRAL])
        {
          npc->enemy = get_nearest_player (npc);
          if (npc->enemy)
            tmp = check_enemy (npc, rv);
        }

    }

  return tmp;
}

/* Sees if this monster should wake up.
 * Currently, this is only called from move_monster, and
 * if enemy is set, then so should be rv.
 * returns 1 if the monster should wake up, 0 otherwise.
 */
static int
check_wakeup (object *op, object *enemy, rv_vector *rv)
{
  /* Trim work - if no enemy, no need to do anything below */
  if (!enemy)
    return 0;

  if (!op->flag [FLAG_SLEEP])
    return 1;

  int radius = max (op->stats.Wis, MIN_MON_RADIUS);

  if (op->flag [FLAG_BLIND])
    /* blinded monsters can only find nearby objects to attack */
    radius = MIN_MON_RADIUS;
  else if (op->map
           && !enemy->invisible
           && !stand_in_light (enemy)
           && (!op->flag[FLAG_SEE_IN_DARK] || !op->flag [FLAG_SEE_INVISIBLE]))
    /* This covers the situation where the monster is in the dark 
     * and has an enemy. If the enemy has no carried light (or isnt 
     * glowing!) then the monster has trouble finding the enemy. 
     * Remember we already checked to see if the monster can see in 
     * the dark. */
    radius = min (radius, MIN_MON_RADIUS + MAX_DARKNESS - op->map->darklevel ());

  if (enemy->flag [FLAG_STEALTH])
    radius = radius / 2 + 1;

  /* enemy should already be on this map, so don't really need to check
   * for that.
   */
  if (rv->distance <= radius)
    {
      op->clr_flag (FLAG_SLEEP);
      return 1;
    }

  return 0;
}

static int
move_randomly (object *op)
{
  /* Give up to 15 chances for a monster to move randomly */
  for (int i = 0; i < 15; i++)
    if (op->move (rndm (8) + 1))
      return 1;

  return 0;
}

/*
 * monster_can_pick(): If the monster is interested in picking up
 * the item, then return 0.  Otherwise 0.
 * Instead of pick_up, flags for "greed", etc, should be used.
 * I've already utilized flags for bows, wands, rings, etc, etc. -Frank.
 */
static int
monster_can_pick (object *monster, object *item)
{
  int flag = 0;
  int i;

  if (!can_pick (monster, item))
    return 0;

  if (item->flag [FLAG_UNPAID])
    return 0;

  if (monster->pick_up & 64)    /* All */
    flag = 1;

  else
    switch (item->type)
      {
        case MONEY:
        case GEM:
          flag = monster->pick_up & 2;
          break;

        case FOOD:
          flag = monster->pick_up & 4;
          break;

        case WEAPON:
          flag = (monster->pick_up & 8) || monster->flag [FLAG_USE_WEAPON];
          break;

        case ARMOUR:
        case SHIELD:
        case HELMET:
        case BOOTS:
        case GLOVES:
        case GIRDLE:
          flag = (monster->pick_up & 16) || monster->flag [FLAG_USE_ARMOUR];
          break;

        case SKILL:
          flag = monster->flag [FLAG_CAN_USE_SKILL];
          break;

        case RING:
          flag = monster->flag [FLAG_USE_RING];
          break;

        case WAND:
        case HORN:
        case ROD:
          flag = monster->flag [FLAG_USE_RANGE];
          break;

        case SPELLBOOK:
          flag = monster->arch && monster->arch->flag [FLAG_CAST_SPELL];
          break;

        case SCROLL:
          flag = monster->flag [FLAG_USE_SCROLL];
          break;

        case BOW:
        case ARROW:
          flag = monster->flag [FLAG_USE_BOW];
          break;
      }

  /* Simplistic check - if the monster has a location to equip it, he will
   * pick it up.  Note that this doesn't handle cases where an item may
   * use several locations.
   */
  for (i = 0; i < NUM_BODY_LOCATIONS; i++)
    {
      if (monster->slot[i].info && item->slot[i].info)
        {
          flag = 1;
          break;
        }
    }

  if (((!(monster->pick_up & 32)) && flag) || ((monster->pick_up & 32) && (!flag)))
    return 1;

  return 0;
}

/*
 * monster_check_pickup(): checks for items that monster can pick up.
 *
 * Vick's (vick@bern.docs.uu.se) fix 921030 for the sweeper blob.
 * Each time the blob passes over some treasure, it will
 * grab it a.s.a.p.
 *
 * Eneq(@csd.uu.se): This can now be defined in the archetypes, added code
 * to handle this.
 *
 * This function was seen be continueing looping at one point (tmp->below
 * became a recursive loop.  It may be better to call monster_check_apply
 * after we pick everything up, since that function may call others which
 * affect stacking on this space.
 */
static void
monster_check_pickup (object *monster)
{
  object *tmp, *next;

  for (tmp = monster->below; tmp != NULL; tmp = next)
    {
      next = tmp->below;
      if (monster_can_pick (monster, tmp))
        {
          tmp->remove ();
          tmp = insert_ob_in_ob (tmp, monster);
          monster_check_apply (monster, tmp);
        }

      /* We could try to re-establish the cycling, of the space, but probably
       * not a big deal to just bail out.
       */
      if (next && next->destroyed ())
        return;
    }
}

/*
 * monster_apply_below():
 * Vick's (vick@bern.docs.uu.se) @921107 -> If a monster who's
 * eager to apply things, encounters something apply-able,
 * then make him apply it
 */
static void
monster_apply_below (object *monster)
{
  object *tmp, *next;

  for (tmp = monster->below; tmp != NULL; tmp = next)
    {
      next = tmp->below;
      switch (tmp->type)
        {
            case T_HANDLE:
            case TRIGGER:
              if (monster->will_apply & 1)
                monster->apply (tmp);
              break;

            case TREASURE:
              if (monster->will_apply & 2)
                monster->apply (tmp);
              break;

        }
      if (tmp->flag [FLAG_IS_FLOOR])
        break;
    }
}

/* Returns 1 is monster should cast spell sp at an enemy
 * Returns 0 if the monster should not cast this spell.
 *
 * Note that this function does not check to see if the monster can
 * in fact cast the spell (sp dependencies and what not.)  That is because
 * this function is also sued to see if the monster should use spell items
 * (rod/horn/wand/scroll).
 * Note that there are certainly other offensive spells that could be
 * included, but I decided to leave out the spells that may kill more
 * monsters than players (eg, disease).
 *
 * This could be a lot smarter - if there are few monsters around,
 * then disease might not be as bad. Likewise, if the monster is damaged,
 * the right type of healing spell could be useful.
 */
static int
monster_should_cast_spell (object *monster, object *spell_ob)
{
  if (spell_ob->subtype == SP_BOLT || spell_ob->subtype == SP_BULLET ||
      spell_ob->subtype == SP_EXPLOSION || spell_ob->subtype == SP_CONE ||
      spell_ob->subtype == SP_BOMB || spell_ob->subtype == SP_SMITE ||
      spell_ob->subtype == SP_MAGIC_MISSILE || spell_ob->subtype == SP_SUMMON_GOLEM ||
      spell_ob->subtype == SP_MAGIC_WALL || spell_ob->subtype == SP_SUMMON_MONSTER ||
      spell_ob->subtype == SP_MOVING_BALL || spell_ob->subtype == SP_SWARM || spell_ob->subtype == SP_INVISIBLE)
    return 1;

  return 0;
}

/* Checks if putting on 'item' will make 'who' do more
 * damage. This is a very simplistic check - also checking things
 * like speed and ac are also relevant.
 *
 * return true if item is a better object.
 */
static int
check_good_weapon (object *who, object *item)
{
  object *other_weap;
  int val = 0, i;

  for (other_weap = who->inv; other_weap; other_weap = other_weap->below)
    if (other_weap->type == item->type && other_weap->flag [FLAG_APPLIED])
      break;

  if (!other_weap)       /* No other weapons */
    return 1;

  /* Rather than go through and apply the new one, and see if it is
   * better, just do some simple checks
   * Put some multipliers for things that hvae several effects,
   * eg, magic affects both damage and wc, so it has more weight
   */

  val = item->stats.dam - other_weap->stats.dam;
  val += (item->magic - other_weap->magic) * 3;
  /* Monsters don't really get benefits from things like regen rates
   * from items.  But the bonus for their stats are very important.
   */
  for (i = 0; i < NUM_STATS; i++)
    val += item->stats.stat (i) - other_weap->stats.stat (i) * 2;

  if (val > 0)
    return 1;
  else
    return 0;
}

static int
check_good_armour (object *who, object *item)
{
  object *other_armour;
  int val = 0, i;

  for (other_armour = who->inv; other_armour; other_armour = other_armour->below)
    if (other_armour->type == item->type && other_armour->flag [FLAG_APPLIED])
      break;

  if (other_armour == NULL)     /* No other armour, use the new */
    return 1;

  /* Like above function , see which is better */
  val = item->stats.ac - other_armour->stats.ac;
  val = (item->resist[ATNR_PHYSICAL] - other_armour->resist[ATNR_PHYSICAL]) / 5;
  val += (item->magic - other_armour->magic) * 3;

  /* for the other protections, do weigh them very much in the equation -
   * it is the armor protection which is most important, because there is
   * no good way to know what the player may attack the monster with. 
   * So if the new item has better protection than the old, give that higher
   * value.  If the reverse, then decrease the value of this item some.
   */
  for (i = 1; i < NROFATTACKS; i++)
    {
      if (item->resist[i] > other_armour->resist[i])
        val++;
      else if (item->resist[i] < other_armour->resist[i])
        val--;
    }

  /* Very few armours have stats, so not much need to worry about those. */

  if (val > 0)
    return 1;
  else
    return 0;
}

/*
 * monster_check_apply() is meant to be called after an item is
 * inserted in a monster.
 * If an item becomes outdated (monster found a better item),
 * a pointer to that object is returned, so it can be dropped.
 * (so that other monsters can pick it up and use it)
 * Note that as things are now, monsters never drop something -
 * they can pick up all that they can use.
 */
/* Sept 96, fixed this so skills will be readied -b.t.*/
void
monster_check_apply (object *mon, object *item)
{
  int flag = 0;

  if (item->type == SPELLBOOK && mon->arch && (mon->arch->flag [FLAG_CAST_SPELL]))
    {
      mon->set_flag (FLAG_CAST_SPELL);
      return;
    }

  /* If for some reason, this item is already applied, no more work to do */
  if (item->flag [FLAG_APPLIED])
    return;

  /* Might be better not to do this - if the monster can fire a bow,
   * it is possible in his wanderings, he will find one to use.  In
   * which case, it would be nice to have ammo for it.
   */
  if (mon->flag [FLAG_USE_BOW] && item->type == ARROW)
    {
      /* Check for the right kind of bow */
      object *bow;

      for (bow = mon->inv; bow; bow = bow->below)
        if (bow->type == BOW && bow->race == item->race)
          {
            mon->set_flag (FLAG_READY_BOW);
            LOG (llevTrace, "Found correct bow for arrows.\n");
            return;             /* nothing more to do for arrows */
          }
    }

  if (item->type == TREASURE && mon->will_apply & WILL_APPLY_TREASURE)
    flag = 1;
  /* Eating food gets hp back */
  else if (item->type == FOOD && mon->will_apply & WILL_APPLY_FOOD)
    flag = 1;
  else if (item->type == SCROLL && mon->flag [FLAG_USE_SCROLL])
    {
      if (!item->inv)
        LOG (llevDebug, "Monster %d having scroll %d with empty inventory!", mon->count, item->count);
      else if (monster_should_cast_spell (mon, item->inv))
        mon->set_flag (FLAG_READY_SCROLL);
      /* Don't use it right now */
      return;
    }
  else if (item->type == WEAPON)
    flag = check_good_weapon (mon, item);
  else if (item->is_armor ())
    flag = check_good_armour (mon, item);
  /* Should do something more, like make sure this is a better item */
  else if (item->type == RING)
    flag = 1;
  else if (item->type == WAND || item->type == ROD || item->type == HORN)
    {
      /* We never really 'ready' the wand/rod/horn, because that would mean the
       * weapon would get undone.
       */
      if (!(can_apply_object (mon, item) & CAN_APPLY_NOT_MASK))
        {
          mon->set_flag (FLAG_READY_RANGE);
          item->set_flag (FLAG_APPLIED);
        }
      return;
    }
  else if (item->type == BOW)
    {
      /* We never really 'ready' the bow, because that would mean the
       * weapon would get undone.
       */
      if (!(can_apply_object (mon, item) & CAN_APPLY_NOT_MASK))
        mon->set_flag (FLAG_READY_BOW);
      return;
    }
  else if (item->type == SKILL)
    {
      /*
       * skills are specials: monsters must have the 'FLAG_READY_SKILL' flag set,
       * else they can't use the skill...
       * Skills also don't need to get applied, so return now.
       */
      mon->set_flag (FLAG_READY_SKILL);
      return;
    }

  /* if we don't match one of the above types, return now.
   * can_apply_object will say that we can apply things like flesh, 
   * bolts, and whatever else, because it only checks against the
   * body_info locations.
   */
  if (!flag)
    return;

  /* Check to see if the monster can use this item.  If not, no need
   * to do further processing.  Note that can_apply_object already checks
   * for the CAN_USE flags.
   */
  if (can_apply_object (mon, item) & CAN_APPLY_NOT_MASK)
    return;

  /* should only be applying this item, not unapplying it.
   * also, ignore status of curse so they can take off old armour.
   * monsters have some advantages after all.
   */
  mon->apply (item, AP_APPLY | AP_IGNORE_CURSE);
}

static int
can_hit (object *ob1, object *ob2, rv_vector * rv)
{
  object *more;
  rv_vector rv1;

  if (ob1->flag [FLAG_CONFUSED] && !(rndm (3)))
    return 0;

  if (abs (rv->distance_x) < 2 && abs (rv->distance_y) < 2)
    return 1;

  /* check all the parts of ob2 - just because we can't get to
   * its head doesn't mean we don't want to pound its feet
   */
  for (more = ob2->more; more; more = more->more)
    {
      get_rangevector (ob1, more, &rv1, 0);
      if (abs (rv1.distance_x) < 2 && abs (rv1.distance_y) < 2)
        return 1;
    }

  return 0;
}

static int
dist_att (int dir, object *ob, object *enemy, object *part, rv_vector *rv)
{
  if (can_hit (part, enemy, rv))
    return dir;

  if (rv->distance < 10)
    return absdir (dir + 4);
  else if (rv->distance > 18)
    return dir;

  return 0;
}

static int
run_att (int dir, object *ob, object *enemy, object *part, rv_vector *rv)
{
  if (can_hit (part, enemy, rv))
    return dir;
  else
    return absdir (dir + 4);
}

static int
hitrun_att (int dir, object *ob, object *enemy)
{
  if (ob->move_status++ < 25)
    return dir;
  else if (ob->move_status < 50)
    return absdir (dir + 4);
  else
    ob->move_status = 0;

  return absdir (dir + 4);
}

static int
wait_att (int dir, object *ob, object *enemy, object *part, rv_vector * rv)
{
  int inrange = can_hit (part, enemy, rv);

  if (ob->move_status || inrange)
    ob->move_status++;

  if (ob->move_status == 0)
    return 0;
  else if (ob->move_status < 10)
    return dir;
  else if (ob->move_status < 15)
    return absdir (dir + 4);

  ob->move_status = 0;
  return 0;
}

static int
disthit_att (int dir, object *ob, object *enemy, object *part, rv_vector * rv)
{
  /* The logic below here looked plain wrong before.  Basically, what should
   * happen is that if the creatures hp percentage falls below run_away,
   * the creature should run away (dir+4)
   * I think its wrong for a creature to have a zero maxhp value, but
   * at least one map has this set, and whatever the map contains, the
   * server should try to be resilant enough to avoid the problem
   */
  if (ob->stats.hp * 100 < ob->stats.maxhp * ob->run_away)
    return absdir (dir + 4);

  return dist_att (dir, ob, enemy, part, rv);
}

static int
wait_att2 (int dir, object *ob, object *enemy, object *part, rv_vector * rv)
{
  if (rv->distance < 9)
    return absdir (dir + 4);

  return 0;
}

static void
circ1_move (object *ob)
{
  static int circle[12] = { 3, 3, 4, 5, 5, 6, 7, 7, 8, 1, 1, 2 };

  if (++ob->move_status > 11)
    ob->move_status = 0;

  if (!(ob->move (circle[ob->move_status])))
    ob->move (rndm (8) + 1);
}

static void
circ2_move (object *ob)
{
  static int circle[20] = { 3, 3, 3, 4, 4, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 1, 1, 1, 2, 2 };

  if (++ob->move_status > 19)
    ob->move_status = 0;

  if (!(ob->move (circle[ob->move_status])))
    ob->move (rndm (8) + 1);
}

static void
pace_movev (object *ob)
{
  if (ob->move_status++ > 6)
    ob->move_status = 0;

  if (ob->move_status < 4)
    ob->move (5);
  else
    ob->move (1);
}

static void
pace_moveh (object *ob)
{
  if (ob->move_status++ > 6)
    ob->move_status = 0;

  if (ob->move_status < 4)
    ob->move (3);
  else
    ob->move (7);
}

static void
pace2_movev (object *ob)
{
  if (ob->move_status++ > 16)
    ob->move_status = 0;

  if (ob->move_status < 6)
    ob->move (5);
  else if (ob->move_status < 8)
    return;
  else if (ob->move_status < 13)
    ob->move (1);
  else
    return;
}

static void
pace2_moveh (object *ob)
{
  if (ob->move_status++ > 16)
    ob->move_status = 0;

  if (ob->move_status < 6)
    ob->move (3);
  else if (ob->move_status < 8)
    return;
  else if (ob->move_status < 13)
    ob->move (7);
  else
    return;
}

static void
rand_move (object *ob)
{
  if (ob->move_status < 1 || ob->move_status > 8 || !(ob->move (ob->move_status || !(rndm (9)))))
    for (int i = 0; i < 5; i++)
      if (ob->move (ob->move_status = rndm (8) + 1))
        return;
}

#define MAX_KNOWN_SPELLS 20

/* Returns a randomly selected spell.    This logic is still
 * less than ideal.  This code also only seems to deal with
 * wizard spells, as the check is against sp, and not grace.
 * can mosnters know cleric spells?
 */
static object *
monster_choose_random_spell (object *monster)
{
  object *altern[MAX_KNOWN_SPELLS];
  int i = 0;

  for (object *tmp = monster->inv; tmp; tmp = tmp->below)
    if (tmp->type == SPELLBOOK || tmp->type == SPELL)
      {
        /* Check and see if it's actually a useful spell.
         * If its a spellbook, the spell is actually the inventory item.
         * if it is a spell, then it is just the object itself.
         */
        if (monster_should_cast_spell (monster, (tmp->type == SPELLBOOK) ? tmp->inv : tmp))
          {
            altern [i++] = tmp;

            if (i == MAX_KNOWN_SPELLS)
              break;
          }
      }

  return i ? altern [rndm (i)] : 0;
}

/* This checks to see if the monster should cast a spell/ability.
 * it returns true if the monster casts a spell, 0 if he doesn't.
 * head is the head of the monster.
 * part is the part of the monster we are checking against.
 * pl is the target.
 * dir is the direction to case.
 * rv is the vector which describes where the enemy is.
 */
static int
monster_cast_spell (object *head, object *part, object *pl, int dir, rv_vector * rv)
{
  object *spell_item;
  object *owner;
  rv_vector rv1;

  /* If you want monsters to cast spells over friends, this spell should
   * be removed.  It probably should be in most cases, since monsters still
   * don't care about residual effects (ie, casting a cone which may have a 
   * clear path to the player, the side aspects of the code will still hit
   * other monsters)
   */
  if (!(dir = path_to_player (part, pl, 0)))
    return 0;

  if (head->flag [FLAG_FRIENDLY] && (owner = head->owner) != NULL)
    {
      get_rangevector (head, owner, &rv1, 0x1);
      if (dirdiff (dir, rv1.direction) < 2)
        return 0;             /* Might hit owner with spell */
    }

  if (head->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  /* If the monster hasn't already chosen a spell, choose one
   * I'm not sure if it really make sense to pre-select spells (events
   * could be different by the time the monster goes again).
   */
  if (head->spellitem == NULL)
    {
      if ((spell_item = monster_choose_random_spell (head)) == NULL)
        {
          LOG (llevTrace, "Turned off spells in %s\n", &head->name);
          head->clr_flag (FLAG_CAST_SPELL);   /* Will be turned on when picking up book */
          return 0;
        }

      if (spell_item->type == SPELLBOOK)
        {
          if (!spell_item->inv)
            {
              LOG (llevError, "spellbook %s does not contain a spell?\n", &spell_item->name);
              return 0;
            }

          spell_item = spell_item->inv;
        }
    }
  else
    spell_item = head->spellitem;

  if (!spell_item)
    return 0;

  /* Best guess this is a defensive/healing spell */
  if (spell_item->range <= 1 || spell_item->stats.dam < 0)
    dir = 0;

  /* Monster doesn't have enough spell-points */
  if (head->stats.sp < SP_level_spellpoint_cost (head, spell_item, SPELL_MANA))
    return 0;

  if (head->stats.grace < SP_level_spellpoint_cost (head, spell_item, SPELL_GRACE))
    return 0;

  head->stats.sp -= SP_level_spellpoint_cost (head, spell_item, SPELL_MANA);
  head->stats.grace -= SP_level_spellpoint_cost (head, spell_item, SPELL_GRACE);

  /* set this to null, so next time monster will choose something different */
  head->spellitem = NULL;

  return cast_spell (part, part, dir, spell_item, NULL);
}

static int
monster_use_scroll (object *head, object *part, object *pl, int dir, rv_vector * rv)
{
  object *scroll;
  object *owner;
  rv_vector rv1;

  /* If you want monsters to cast spells over friends, this spell should
   * be removed.  It probably should be in most cases, since monsters still
   * don't care about residual effects (ie, casting a cone which may have a 
   * clear path to the player, the side aspects of the code will still hit
   * other monsters)
   */
  if (!(dir = path_to_player (part, pl, 0)))
    return 0;

  if (head->flag [FLAG_FRIENDLY] && (owner = head->owner) != NULL)
    {
      get_rangevector (head, owner, &rv1, 0x1);
      if (dirdiff (dir, rv1.direction) < 2)
        {
          return 0;             /* Might hit owner with spell */
        }
    }

  if (head->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  for (scroll = head->inv; scroll; scroll = scroll->below)
    if (scroll->type == SCROLL && monster_should_cast_spell (head, scroll->inv))
      break;

  /* Used up all his scrolls, so nothing do to */
  if (!scroll)
    {
      head->clr_flag (FLAG_READY_SCROLL);
      return 0;
    }

  /* Spell should be cast on caster (ie, heal, strength) */
  if (scroll->inv->range == 0)
    dir = 0;

  apply_scroll (part, scroll, dir);
  return 1;
}

/* monster_use_skill()-implemented 95-04-28 to allow monster skill use.
 * Note that monsters do not need the skills SK_MELEE_WEAPON and
 * SK_MISSILE_WEAPON to make those respective attacks, if we
 * required that we would drastically increase the memory
 * requirements of CF!! 
 *
 * The skills we are treating here are all but those. -b.t. 
 *
 * At the moment this is only useful for throwing, perhaps for
 * stealing. TODO: This should be more integrated in the game. -MT, 25.11.01
 */
static int
monster_use_skill (object *head, object *part, object *pl, int dir)
{
  object *skill, *owner;

  if (!(dir = path_to_player (part, pl, 0)))
    return 0;

  if (head->flag [FLAG_FRIENDLY] && (owner = head->owner) != NULL)
    {
      int dir2 = find_dir_2 (owner->x - head->x, owner->y - head->y);

      if (dirdiff (dir, dir2) < 1)
        return 0;               /* Might hit owner with skill -thrown rocks for example ? */
    }

  if (head->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  object *new_skill = 0;

  // skill selection - monster will use the last unused skill
  // and rotate, eventually cycling through all skills.
  for (skill = head->inv; skill; skill = skill->below)
    if (skill->type == SKILL && skill != head->chosen_skill)
      new_skill = skill;

  if (new_skill)
    splay (head->chosen_skill = new_skill);
  else if (!head->chosen_skill)
    {
      LOG (llevDebug, "Error: Monster %s (%d) has FLAG_READY_SKILL without skill.\n", &head->name, head->count);
      head->clr_flag (FLAG_READY_SKILL);
      return 0;
    }

  /* use skill */
  return do_skill (head, part, head->chosen_skill, dir, NULL);
}

/* Monster will use a ranged spell attack. */
static int
monster_use_range (object *head, object *part, object *pl, int dir)
{
  object *wand, *owner;
  int at_least_one = 0;

  if (!(dir = path_to_player (part, pl, 0)))
    return 0;

  if (head->flag [FLAG_FRIENDLY] && (owner = head->owner) != NULL)
    {
      int dir2 = find_dir_2 (owner->x - head->x, owner->y - head->y);

      if (dirdiff (dir, dir2) < 2)
        return 0;               /* Might hit owner with spell */
    }

  if (head->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  for (wand = head->inv; wand; wand = wand->below)
    {
      if (wand->type == WAND)
        {
          /* Found a wand, let's see if it has charges left */
          at_least_one = 1;
          if (wand->stats.food <= 0)
            continue;

          cast_spell (head, wand, dir, wand->inv, NULL);

          if (!(--wand->stats.food))
            {
              if (wand->arch)
                {
                  wand->clr_flag (FLAG_ANIMATE);
                  wand->face = wand->arch->face;
                  wand->set_speed (0);
                }
            }
          /* Success */
          return 1;
        }
      else if (wand->type == ROD || wand->type == HORN)
        {
          /* Found rod/horn, let's use it if possible */
          at_least_one = 1;
          if (wand->stats.hp < max (wand->inv->stats.sp, wand->inv->stats.grace))
            continue;

          /* drain charge before casting spell - can be a case where the
           * spell destroys the monster, and rod, so if done after, results
           * in crash.
           */
          drain_rod_charge (wand);
          cast_spell (head, wand, dir, wand->inv, NULL);

          /* Success */
          return 1;
        }
    }

  if (at_least_one)
    return 0;

  LOG (llevError, "Error: Monster %s (%d) HAS_READY_RANGE() without wand/horn/rod.\n", &head->name, head->count);
  head->clr_flag (FLAG_READY_RANGE);
  return 0;
}

static int
monster_use_bow (object *head, object *part, object *pl, int dir)
{
  object *owner;

  if (!(dir = path_to_player (part, pl, 0)))
    return 0;

  if (head->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  if (head->flag [FLAG_FRIENDLY] && (owner = head->owner) != NULL)
    {
      int dir2 = find_dir_2 (owner->x - head->x, owner->y - head->y);

      if (dirdiff (dir, dir2) < 1)
        return 0;               /* Might hit owner with arrow */
    }

  /* in server/player.c */
  return fire_bow (head, part, NULL, dir, 0, part->x, part->y);

}

void
npc_call_help (object *op)
{
  unordered_mapwalk (mapwalk_buf, op, -7, -7, 7, 7)
    {
      mapspace &ms = m->at (nx, ny);

      /* If nothing alive on this space, no need to search the space. */
      if (!(ms.flags () & P_IS_ALIVE))
        continue;

      for (object *npc = ms.bot; npc; npc = npc->above)
        if (npc->flag [FLAG_ALIVE] && npc->flag [FLAG_UNAGGRESSIVE])
          npc->enemy = op->enemy;
    }
}

void
check_earthwalls (object *op, maptile *m, int x, int y)
{
  for (object *tmp = GET_MAP_OB (m, x, y); tmp; tmp = tmp->above)
    if (tmp->type == EARTHWALL)
      {
        hit_player (tmp, op->stats.dam, op, AT_PHYSICAL, 1);
        return;
      }
}

void
check_doors (object *op, maptile *m, int x, int y)
{
  for (object *tmp = GET_MAP_OB (m, x, y); tmp; tmp = tmp->above)
    if (tmp->type == DOOR)
      {
        hit_player (tmp, 1000, op, AT_PHYSICAL, 1);
        return;
      }
}

/* find_mon_throw_ob() - modeled on find_throw_ob
 * This is probably overly simplistic as it is now - We want
 * monsters to throw things like chairs and other pieces of
 * furniture, even if they are not good throwable objects.
 * Probably better to have the monster throw a throwable object
 * first, then throw any non equipped weapon.
 */
object *
find_mon_throw_ob (object *op)
{
  object *tmp = NULL;

  if (op->head)
    tmp = op->head;
  else
    tmp = op;

  /* New throw code: look through the inventory. Grap the first legal is_thrown
   * marked item and throw it to the enemy.
   */
  for (tmp = op->inv; tmp; tmp = tmp->below)
    {
      /* Can't throw invisible objects or items that are applied */
      if (tmp->invisible || tmp->flag [FLAG_APPLIED])
        continue;

      if (tmp->flag [FLAG_IS_THROWN])
        break;

    }

#ifdef DEBUG_THROW
  LOG (llevDebug, "%s chooses to throw: %s (%d)\n", op->name, !(tmp) ? "(nothing)" : query_name (tmp), tmp ? tmp->count : -1);
#endif

  return tmp;
}

/*
 * Move-monster returns 1 if the object has been freed, otherwise 0.
 */
int
move_monster (object *op)
{
  int dir, diff, pre_att_dir;   /* elmex: pre_att_dir remembers the direction before attack movement */
  object *owner, *enemy, *part, *oph = op;
  rv_vector rv;

  /* Monsters not on maps don't do anything.  These monsters are things
   * Like royal guards in city dwellers inventories.
   */
  if (!op->map)
    return 0;

  /* for target facing, we copy this value here for fast access */
  if (oph->head)                /* force update the head - one arch one pic */
    oph = oph->head;

  if (op->flag [FLAG_NO_ATTACK])  /* we never ever attack */
    enemy = op->enemy = NULL;
  else if ((enemy = find_enemy (op, &rv)))
    /* we have an enemy, just tell him we want him dead */
    enemy->attacked_by = op;  /* our ptr */

  /*  generate hp, if applicable */
  if (op->stats.Con > 0 && op->stats.hp < op->stats.maxhp)
    {
      /* last heal is in funny units.  Dividing by speed puts
       * the regeneration rate on a basis of time instead of
       * #moves the monster makes.  The scaling by 8 is
       * to capture 8th's of a hp fraction regens 
       */
      uint32_t last_heal = op->last_heal + op->stats.Con * 8 / op->speed;
      op->stats.hp = min (op->stats.hp + last_heal / 32, op->stats.maxhp); /* causes Con/4 hp/tick */
      op->last_heal = last_heal % 32;

      /* So if the monster has gained enough HP that they are no longer afraid */
      if (op->flag [FLAG_RUN_AWAY] && op->stats.hp * 100 >= op->stats.maxhp * op->run_away)
        op->flag [FLAG_RUN_AWAY] = false;
    }

  /* generate sp, if applicable */
  if (op->stats.Pow > 0 && op->stats.sp < op->stats.maxsp)
    {
      /* last_sp is in funny units. Dividing by speed puts
       * the regeneration rate on a basis of time instead of
       * #moves the monster makes. The scaling by 8 is
       * to capture 8th's of a sp fraction regens 
       */

      uint32_t last_sp = op->last_sp + op->stats.Pow * 8 / op->speed;
      op->stats.sp = min (op->stats.sp + last_sp / 128, op->stats.maxsp);   /* causes Pow/16 sp/tick */
      op->last_sp = last_sp % 128;
    }

  /* this should probably get modified by many more values.
   * (eg, creatures resistance to fear, level, etc. )
   */
  if (op->flag [FLAG_SCARED] && !(rndm (20)))
    op->clr_flag (FLAG_SCARED);     /* Time to regain some "guts"... */

  if (INVOKE_OBJECT (MONSTER_MOVE, op, ARG_OBJECT (op->enemy)))
    return op->flag [FLAG_FREED];

  if (op->flag [FLAG_SLEEP] || op->flag [FLAG_BLIND] ||
      ((op->map->darklevel () > 0) && !op->flag [FLAG_SEE_IN_DARK] && !op->flag [FLAG_SEE_INVISIBLE]))
    if (!check_wakeup (op, enemy, &rv))
      return 0;

  /* check if monster pops out of hidden spot */
  if (op->flag [FLAG_HIDDEN])
    do_hidden_move (op);

  if (op->pick_up)
    monster_check_pickup (op);

  if (op->will_apply)
    monster_apply_below (op);   /* Check for items to apply below */

  /* If we don't have an enemy, do special movement or the like */
  if (!enemy)
    {
      if (op->flag [FLAG_ONLY_ATTACK])
        {
          op->drop_and_destroy ();
          return 1;
        }

      /* Probably really a bug for a creature to have both
       * stand still and a movement type set.
       */
      if (!op->flag [FLAG_STAND_STILL])
        {
          if (op->attack_movement & HI4)
            {
              switch (op->attack_movement & HI4)
                {
                  case PETMOVE:
                    pet_move (op);
                    break;

                  case CIRCLE1:
                    circ1_move (op);
                    break;

                  case CIRCLE2:
                    circ2_move (op);
                    break;

                  case PACEV:
                    pace_movev (op);
                    break;

                  case PACEH:
                    pace_moveh (op);
                    break;

                  case PACEV2:
                    pace2_movev (op);
                    break;

                  case PACEH2:
                    pace2_moveh (op);
                    break;

                  case RANDO:
                    rand_move (op);
                    break;

                  case RANDO2:
                    move_randomly (op);
                    break;
                }

              return 0;
            }
          else if (op->flag [FLAG_RANDOM_MOVE])
            move_randomly (op);
        }                       /* stand still */

      return 0;
    }                           /* no enemy */

  /* We have an enemy.  Block immediately below is for pets */
  if ((op->attack_movement & HI4) == PETMOVE
      && (owner = op->owner) != NULL
      && !on_same_map (op, owner)
      && !owner->flag [FLAG_REMOVED])
    return follow_owner (op, owner);

  /* doppleganger code to change monster facing to that of the nearest
   * player. Hmm. The code is here, but no monster in the current
   * arch set uses it.
   */
  if (op->race == shstr_doppleganger)
    {
      op->face = enemy->face;
      op->name = enemy->name;
    }

  /* Calculate range information for closest body part - this
   * is used for the 'skill' code, which isn't that smart when
   * it comes to figuring it out - otherwise, giants throw boulders
   * into themselves.
   */
  get_rangevector (op, enemy, &rv, 0);

  /* Move the check for scared up here - if the monster was scared,
   * we were not doing any of the logic below, so might as well save
   * a few cpu cycles.
   */
  if (!op->flag [FLAG_SCARED])
    {
      rv_vector rv1;

      /* now we test every part of an object .... this is a real ugly piece of code */
      for (part = op; part; part = part->more)
        {
          get_rangevector (part, enemy, &rv1, 0x1);
          dir = rv1.direction;

          /* hm, not sure about this part - in original was a scared flag here too
           * but that we test above... so can be old code here 
           */
          if (op->flag [FLAG_RUN_AWAY])
            dir = absdir (dir + 4);

          if (op->flag [FLAG_CONFUSED])
            dir = absdir (dir + rndm (3) + rndm (3) - 2);

          if (op->flag [FLAG_CAST_SPELL] && !(rndm (3)))
            if (monster_cast_spell (op, part, enemy, dir, &rv1))
              return 0;

          if (op->flag [FLAG_READY_SCROLL] && !(rndm (3)))
            if (monster_use_scroll (op, part, enemy, dir, &rv1))
              return 0;

          if (op->flag [FLAG_READY_RANGE] && !(rndm (3)))
            if (monster_use_range (op, part, enemy, dir))
              return 0;

          if (op->flag [FLAG_READY_SKILL] && !(rndm (3)))
            if (monster_use_skill (op, rv.part, enemy, rv.direction))
              return 0;

          if (op->flag [FLAG_READY_BOW] && !(rndm (2)))
            if (monster_use_bow (op, part, enemy, dir))
              return 0;
        }                       /* for processing of all parts */
    }                           /* If not scared */

  part = rv.part;
  dir = rv.direction;

//-GPL

  // if the enemy is a player, we have los. if los says we
  // can directly reach the player, we do not deviate.
  // for non-players, we never deviate
  if (op->stats.Wis >= 8
      && enemy->contr && enemy->contr->darkness_at (op->map, op->x, op->y) == LOS_BLOCKED)
    {
      int sdir = 0;
      uint32_t &smell = op->ms ().smell;

      for (int ndir = 1; ndir <= 8; ++ndir)
        {
          mapxy pos (op); pos.move (ndir);

          if (pos.normalise ())
            {
              mapspace &ms = pos.ms ();

              if (ms.smell > smell)
                {
                  //printf ("%s: found smell, following it, apparently (%d, %d)\n",& op->name,op->ms().smell,ms.smell);//D
                  if (op->stats.Wis >= 10)
                    smell = ms.smell - 1; // smarter: tell others

                  sdir = ndir;
                  
                  // perturbing the path might let the monster lose track,
                  // but it will also widen the actual path, spreading information
                  if (op->stats.Wis >= 15 && !rndm (20)) // even smarter, deviate and spread?
                    sdir = absdir (sdir + 1 - rndm (2) * 2);
                }
            }
        }

      if (sdir)
        dir = sdir;
      else if (smell)
        {
          // no better smell found, so assume the player jumped, and erase this smell
          //printf ("erasing smell %d\n", op->ms ().smell);//D
          unordered_mapwalk (mapwalk_buf, op, -1, -1, 1, 1)
            m->at (nx, ny).smell = 0;
        }
    }

//+GPL

  if (op->flag [FLAG_SCARED] || op->flag [FLAG_RUN_AWAY])
    dir = absdir (dir + 4);

  if (op->flag [FLAG_CONFUSED])
    dir = absdir (dir + rndm (3) + rndm (3) - 2);

  pre_att_dir = dir;            /* remember the original direction */

  if ((op->attack_movement & LO4) && !op->flag [FLAG_SCARED])
    {
      switch (op->attack_movement & LO4)
        {
          case DISTATT:
            dir = dist_att (dir, op, enemy, part, &rv);
            break;

          case RUNATT:
            dir = run_att (dir, op, enemy, part, &rv);
            break;

          case HITRUN:
            dir = hitrun_att (dir, op, enemy);
            break;

          case WAITATT:
            dir = wait_att (dir, op, enemy, part, &rv);
            break;

          case RUSH:         /* default - monster normally moves towards player */
          case ALLRUN:
            break;

          case DISTHIT:
            dir = disthit_att (dir, op, enemy, part, &rv);
            break;

          case WAIT2:
            dir = wait_att2 (dir, op, enemy, part, &rv);
            break;

          default:
            LOG (llevDebug, "Illegal low mon-move: %d\n", op->attack_movement & LO4);
        }
    }

  if (!dir)
    return 0;

  if (!op->flag [FLAG_STAND_STILL])
    {
      if (op->move (dir))        /* Can the monster move directly toward player? */
        {
          /* elmex: Turn our monster after it moved if it has DISTATT attack */
          if ((op->attack_movement & LO4) == DISTATT)
            op->direction = pre_att_dir;

          return 0;
        }

      if (op->flag [FLAG_SCARED] || !can_hit (part, enemy, &rv) || op->flag [FLAG_RUN_AWAY])
        {
          /* Try move around corners if !close */
          int maxdiff = (op->flag [FLAG_ONLY_ATTACK] || rndm (2)) ? 1 : 2;

          for (diff = 1; diff <= maxdiff; diff++)
            {
              /* try different detours */
              int m = 1 - rndm (2) * 2;      /* Try left or right first? */

              if (op->move (absdir (dir + diff * m)) || op->move (absdir (dir - diff * m)))
                return 0;
            }
        }
    }                           /* if monster is not standing still */

  /* elmex: Turn our monster after it moved if it has DISTATT attack */
  if ((op->attack_movement & LO4) == DISTATT)
    op->direction = pre_att_dir;

  /*
   * Eneq(@csd.uu.se): Patch to make RUN_AWAY or SCARED monsters move a random
   * direction if they can't move away.
   */
  if (!op->flag [FLAG_ONLY_ATTACK] && (op->flag [FLAG_RUN_AWAY] || op->flag [FLAG_SCARED]))
    if (move_randomly (op))
      return 0;

  /*
   * Try giving the monster a new enemy - the player that is closest
   * to it.  In this way, it won't just keep trying to get to a target
   * that is inaccessible.
   * This could be more clever - it should go through a list of several
   * enemies, as it is now, you could perhaps get situations where there
   * are two players flanking the monster at close distance, but which
   * the monster can't get to, and a third one at a far distance that
   * the monster could get to - as it is, the monster won't look at that
   * third one.
   */
  if (!op->flag [FLAG_FRIENDLY] && enemy == op->enemy)
    {
      object *nearest_player = get_nearest_player (op);

      if (nearest_player && nearest_player != enemy && !can_hit (part, enemy, &rv))
        {
          op->enemy = 0;
          enemy = nearest_player;
        }
    }

  if (!op->flag [FLAG_SCARED] && can_hit (part, enemy, &rv))
    {
      /* The adjustement to wc that was here before looked totally bogus -
       * since wc can in fact get negative, that would mean by adding
       * the current wc, the creature gets better?  Instead, just
       * add a fixed amount - nasty creatures that are runny away should
       * still be pretty nasty.
       */
      if (op->flag [FLAG_RUN_AWAY])
        {
          part->stats.wc += 10;
          skill_attack (enemy, part, 0, NULL, NULL);
          part->stats.wc -= 10;
        }
      else
        skill_attack (enemy, part, 0, NULL, NULL);
    }                           /* if monster is in attack range */

  if (part->flag [FLAG_FREED])    /* Might be freed by ghost-attack or hit-back */
    return 1;

  if (op->flag [FLAG_ONLY_ATTACK])
    {
      op->drop_and_destroy ();
      return 1;
    }

  return 0;
}

/* determine if we can 'detect' the enemy. Check for walls blocking the
 * los. Also, just because its hidden/invisible, we may be sensitive/smart 
 * enough (based on Wis & Int) to figure out where the enemy is. -b.t. 
 * modified by MSW to use the get_rangevector so that map tiling works
 * properly.  I also so odd code in place that checked for x distance
 * OR y distance being within some range - that seemed wrong - both should
 * be within the valid range. MSW 2001-08-05
 * Returns 0 if enemy can not be detected, 1 if it is detected
 */
int
can_detect_enemy (object *op, object *enemy, rv_vector * rv)
{
  /* null detection for any of these condtions always */
  if (!op || !enemy || !op->map || !enemy->map)
    return 0;

  /* If the monster (op) has no way to get to the enemy, do nothing */
  if (!on_same_map (op, enemy))
    return 0;

  get_rangevector (op, enemy, rv, 0);

  /* Monsters always ignore the DM */
  if (!op->is_player () && enemy->flag [FLAG_WIZ])
    return 0;

  /* simple check.  Should probably put some range checks in here. */
  if (can_see_enemy (op, enemy))
    return 1;

  /* The rest of this is for monsters. Players are on their own for
   * finding enemies!
   */
  if (op->is_player ())
    return 0;

  /* Quality invisible? Bah, we wont see them w/o SEE_INVISIBLE
   * flag (which was already checked) in can_see_enemy (). Lets get out of here 
   */
  if (enemy->invisible && (!enemy->contr || (!enemy->contr->tmp_invis && !enemy->contr->hidden)))
    return 0;

  int radius = MIN_MON_RADIUS;

  /* use this for invis also */
  int hide_discovery = op->stats.Int / 5;

  /* Determine Detection radii */
  if (!enemy->flag [FLAG_HIDDEN])             /* to detect non-hidden (eg dark/invis enemy) */
    radius = max (MIN_MON_RADIUS, op->stats.Wis / 3 + 1);
  else
    {                           /* a level/INT/Dex adjustment for hiding */
      int bonus = op->level / 2 + op->stats.Int / 5;

      if (enemy->is_player ())
        {
          if (object *sk_hide = find_skill_by_number (enemy, SK_HIDING))
            bonus -= sk_hide->level;
          else
            {
              LOG (llevError, "can_detect_enemy() got hidden player w/o hiding skill!\n");
              make_visible (enemy);
              radius = radius < MIN_MON_RADIUS ? MIN_MON_RADIUS : radius;
            }
        }
      else                      /* enemy is not a player */
        bonus -= enemy->level;

      radius += bonus / 5;
      hide_discovery += bonus * 5;
    }                           /* else creature has modifiers for hiding */

  /* Radii stealth adjustment. Only if you are stealthy 
   * will you be able to sneak up closer to creatures */
  if (enemy->flag [FLAG_STEALTH])
    {
      radius /= 2;
      hide_discovery /= 3;
    }

  /* Radii adjustment for enemy standing in the dark */
  if (!stand_in_light (enemy))
    {
      /* on dark maps body heat can help indicate location with infravision
       * undead don't have body heat, so no benefit detecting them.
       */
      if (op->flag [FLAG_SEE_IN_DARK] && !is_true_undead (enemy))
        radius += op->map->darklevel () / 2;
      else
        radius -= op->map->darklevel () / 2;

      /* op next to a monster (and not in complete darkness) 
       * the monster should have a chance to see you. 
       */
      if (radius < MIN_MON_RADIUS && op->map->darklevel () < MAX_DARKNESS && rv->distance <= 1)
        radius = MIN_MON_RADIUS;
    }                           /* if on dark map */

  /* Lets not worry about monsters that have incredible detection
   * radii, we only need to worry here about things the player can
   * (potentially) see.  This is 13, as that is the maximum size the player
   * may have for their map - in that way, creatures at the edge will
   * do something.  Note that the distance field in the
   * vector is real distance, so in theory this should be 18 to
   * find that.
   */
  // note that the above reasoning was utter bullshit even at the time it was written
  // we use 25, lets see if we have the cpu time for it
  radius = min (25, radius);

  /* Enemy in range! Now test for detection */
  if (rv->distance <= radius)
    {
      /* ah, we are within range, detected? take cases */
      if (!enemy->invisible)    /* enemy in dark squares... are seen! */
        return 1;

      /* hidden or low-quality invisible */
      if (enemy->flag [FLAG_HIDDEN] && rv->distance <= 1 && rndm (100) <= hide_discovery)
        {
          make_visible (enemy);

          /* inform players of new status */
          if (enemy->type == PLAYER && player_can_view (enemy, op))
            new_draw_info_format (NDI_UNIQUE, 0, enemy, "You are discovered by %s!", &op->name);

          return 1;             /* detected enemy */
        }
      else if (enemy->invisible)
        {
          /* Change this around - instead of negating the invisible, just
           * return true so that the monster that managed to detect you can
           * do something to you. Decreasing the duration of invisible
           * doesn't make a lot of sense IMO, as a bunch of stupid creatures
           * can then basically negate the spell. The spell isn't negated -
           * they just know where you are!
           */
          if (rndm (50) <= hide_discovery)
            {
              if (enemy->type == PLAYER)
                new_draw_info_format (NDI_UNIQUE, 0, enemy, "You see %s noticing your position.", query_name (op));

              return 1;
            }
        }
    }                           /* within range */

  /* Wasn't detected above, so still hidden */
  return 0;
}

/* determine if op stands in a lighted square. This is not a very
 * intelligent algorithm. For one thing, we ignore los here, SO it 
 * is possible for a bright light to illuminate a player on the 
 * other side of a wall (!). 
 */
int
stand_in_light (object *op)
{
  if (op)
    {
      if (!op->is_on_map ())
        return 0;

      if (op->map->darklevel () <= 0)
        return 1;

      if (op->glow_radius > 0)
        return 1;

      if (op->map)
        unordered_mapwalk (mapwalk_buf, op, -MAX_LIGHT_RADIUS, -MAX_LIGHT_RADIUS, MAX_LIGHT_RADIUS, MAX_LIGHT_RADIUS)
          {
            /* Check the spaces with the max light radius to see if any of them
             * have lights, and if any of them light the player enough, then return 1.
             */
            int light = m->at (nx, ny).light;

            if (expect_false (light > 0) && idistance (dx, dy) <= light)
              return 1;
          }
    }

  return 0;
}

/* assuming no walls/barriers, lets check to see if its *possible* 
 * to see an enemy. Note, "detection" is different from "seeing".
 * See can_detect_enemy() for more details. -b.t.
 * return 0 if can't be seen, 1 if can be
 */
int
can_see_enemy (object *op, object *enemy)
{
  object *looker = op->head ? op->head : op;

  /* safety */
  if (!looker || !enemy || !looker->flag [FLAG_ALIVE])
    return 0;

  /* we dont give a full treatment of xrays here (shorter range than normal,
   * see through walls). Should we change the code elsewhere to make you 
   * blind even if you can xray? 
   */
  if (looker->flag [FLAG_BLIND] && !looker->flag [FLAG_XRAYS])
    return 0;

  /* checking for invisible things */
  if (enemy->invisible)
    {
      /* HIDDEN ENEMY. by definition, you can't see hidden stuff! 
       * However,if you carry any source of light, then the hidden
       * creature is seeable (and stupid) */

      if (enemy->has_carried_lights ())
        {
          if (enemy->flag [FLAG_HIDDEN])
            {
              make_visible (enemy);
              new_draw_info (NDI_UNIQUE, 0, enemy, "Your light reveals your hiding spot!");
            }

          return 1;
        }
      else if (enemy->flag [FLAG_HIDDEN])
        return 0;

      /* Invisible enemy. Break apart the check for invis undead/invis looker
       * into more simple checks - the QUERY_FLAG doesn't return 1/0 values,
       * and making it a conditional makes the code pretty ugly.
       */
      if (!looker->flag [FLAG_SEE_INVISIBLE])
        if (makes_invisible_to (enemy, looker))
          return 0;
    }
  else if (looker->is_player ())      /* for players, a (possible) shortcut */
    if (player_can_view (looker, enemy))
      return 1;

  /* ENEMY IN DARK MAP. Without infravision, the enemy is not seen 
   * unless they carry a light or stand in light. Darkness doesnt
   * inhibit the undead per se (but we should give their archs
   * CAN_SEE_IN_DARK, this is just a safety  
   * we care about the enemy maps status, not the looker.
   * only relevant for tiled maps, but it is possible that the
   * enemy is on a bright map and the looker on a dark - in that
   * case, the looker can still see the enemy
   */
  if (!stand_in_light (enemy)
      && (!looker->flag [FLAG_SEE_IN_DARK] || !is_true_undead (looker) || !looker->flag [FLAG_XRAYS]))
    return 0;

  return 1;
}

//-GPL
Revision:	1.87
Committed:	Thu Apr 29 07:32:34 2010 UTC (14 years, 1 month ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.86:	+2 -2 lines
Log Message:	* empty log message *