server/server/spell_util.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 *
 * Copyright (©) 2017,2018 Marc Alexander Lehmann / the Deliantra team
 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 2001 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>
 */

#include <global.h>
#include <spells.h>
#include <object.h>
#include <errno.h>
#include <sproto.h>
#include <sounds.h>

extern char *spell_mapping[];

/* This returns a random spell from 'ob'.  If skill is set, then
 * the spell must be of this skill, it can be NULL in which case all
 * matching spells are used.
 */
object *
find_random_spell_in_ob (object *ob, shstr_cmp skill)
{
  int k = 0, s;

  for (object *tmp = ob->inv; tmp; tmp = tmp->below)
    if (tmp->type == SPELL && (!skill || tmp->skill == skill))
      k++;

  /* No spells, no need to progess further */
  if (!k)
    return NULL;

  s = rndm (k);

  for (object *tmp = ob->inv; tmp; tmp = tmp->below)
    if (tmp->type == SPELL && (!skill || tmp->skill == skill))
      if (!s)
        return tmp;
      else
        s--;

  /* Should never get here, but just in case */
  return 0;
}

/* Relatively simple function that gets used a lot.
 * Basically, it sets up the skill pointer for the spell being
 * cast.  If op is really casting the spell, then the skill
 * is whatever skill the spell requires.
 * if instead caster (rod, horn, wand, etc) is casting the skill,
 * then they get exp for the skill that you need to use for
 * that object (use magic device).
 */
void
set_spell_skill (object *op, object *caster, object *spob, object *dest)
{
  if (caster == op && spob->skill)
    dest->skill = spob->skill;
  else
    dest->skill = caster->skill;
}

/* pretty basic function - basically just takes
 * an object, sets the x,y, and calls insert_ob_in_map
 */
void
spell_effect (object *spob, int x, int y, maptile *map, object *originator)
{
  if (spob->other_arch)
    map->insert (spob->other_arch->instance (), x, y, originator);
}

static int
attuned_bonus (object *caster, object *spell, int level)
{
  // compute the attuned/repelled bonus
  // attuned only increases up to 2 times the original level (i.e. bonus <= level) */
  // repell has no such quarrels
  return (caster->path_attuned  & spell->path_attuned ? min (level, +ATTUNE_REPELL) : 0)
       + (caster->path_repelled & spell->path_attuned ?             -ATTUNE_REPELL  : 0);
}

/* This function returns the effective level the spell
 * is being cast at.
 */
int
casting_level (object *caster, object *spell)
{
  int level = caster->level;

  /* if a rod is fired by a player, take the use_magic_item skill in consideration. */
  if (caster->type == ROD && caster->env && caster->env->type == PLAYER)
    {
      object *skill = find_skill_by_number (caster->env, SK_USE_MAGIC_ITEM);
      int sk_level = skill ? skill->level : 1;

      level = min (level, sk_level + level / 10 + 1);
    }
  else if (caster->type == PLAYER) /* If this is a player, try to find the matching skill */
    if (object *skill = caster->contr->find_skill (spell->skill))
      level = skill->level;

  int bonus = attuned_bonus (caster, spell, level);

  level += bonus;

  // now scale the effective level from the startinglevel..100 range to 1..100
  if (level < 100)
    level = lerp (level, (int)spell->level, 100, 1, 100);

  /* Always make this at least 1.  If this is zero, we get divide by zero
   * errors in various places.
   */
  return clamp (level, 1, settings.max_level);
}

/* The following function scales the spellpoint cost of
 * a spell by it's increased effectiveness.  Some of the
 * lower level spells become incredibly vicious at high
 * levels.  Very cheap mass destruction.  This function is
 * intended to keep the sp cost related to the effectiveness.
 * op is the player/monster
 * caster is what is casting the spell, can be op.
 * spell is the spell object.
 * Note that it is now possible for a spell to cost both grace and
 * mana.  In that case, we return which ever value is higher.
 */
sint16
SP_level_spellpoint_cost (object *caster, object *spell, int flags)
{
  int sp, grace, level = casting_level (caster, spell);

  if (settings.spellpoint_level_depend == TRUE)
    {
      if (spell->stats.sp && spell->stats.maxsp)
        sp = spell->stats.sp * (1.f + max (0.f, float (level - spell->level) / spell->stats.maxsp));
      else
        sp = spell->stats.sp;

      sp *= (int) PATH_SP_MULT (caster, spell);
      if (!sp && spell->stats.sp)
        sp = 1;

      if (spell->stats.grace && spell->stats.maxgrace)
        grace = spell->stats.grace * (1.f + max (0.f, float (level - spell->level) / spell->stats.maxgrace));
      else
        grace = spell->stats.grace;

      grace *= PATH_SP_MULT (caster, spell);
      if (spell->stats.grace && !grace)
        grace = 1;
    }
  else
    {
      sp = (int) (spell->stats.sp * PATH_SP_MULT (caster, spell));
      if (spell->stats.sp && !sp)
        sp = 1;

      grace = (int) (spell->stats.grace * PATH_SP_MULT (caster, spell));
      if (spell->stats.grace && !grace)
        grace = 1;
    }

  if (flags == SPELL_HIGHEST)
    return max (sp, grace);
  else if (flags == SPELL_GRACE)
    return grace;
  else if (flags == SPELL_MANA)
    return sp;
  else
    {
      LOG (llevError, "SP_level_spellpoint_cost: Unknown flags passed: %d\n", flags);
      return 0;
    }
}

/*
 * Return the effective casting level of the spell.
 * To make spells independent of their starting level, this function
 * scales the range spellstartlevel .. 100 into the range 1..100
 */
static int
SP_casting_level (object *caster, object *spell)
{
  return casting_level (caster, spell);
}

/* SP_level_dam_adjust: Returns adjusted damage based on the caster.
 * spob is the spell we are adjusting.
 */
int
SP_level_dam_adjust (object *caster, object *spob)
{
  if (!spob->dam_modifier)
    return 0;

  return SP_casting_level (caster, spob) / spob->dam_modifier;
}

/* Adjust the strength of the spell based on level.
 * This is basically the same as SP_level_dam_adjust above,
 * but instead looks at the level_modifier value.
 */
int
SP_level_duration_adjust (object *caster, object *spob)
{
  if (!spob->duration_modifier)
    return 0;

  return SP_casting_level (caster, spob) / spob->duration_modifier;
}

/* Adjust the strength of the spell based on level.
 * This is basically the same as SP_level_dam_adjust above,
 * but instead looks at the level_modifier value.
 */
int
SP_level_range_adjust (object *caster, object *spob)
{
  if (!spob->range_modifier)
    return 0;

  return SP_casting_level (caster, spob) / spob->range_modifier;
}

/* Checks to see if player knows the spell.  If the name is the same
 * as an existing spell, we presume they know it.
 * returns 1 if they know the spell, 0 if they don't.
 */
object *
check_spell_known (object *op, shstr_cmp name)
{
  object *spop;

  for (spop = op->inv; spop; spop = spop->below)
    if (spop->type == SPELL && spop->name == name)
      return spop;

  return 0;
}

/*
 * Look at object 'op' and see if they know the spell
 * spname. This is pretty close to check_spell_known
 * above, but it uses a looser matching mechanism.
 * returns the matching spell object, or NULL.
 * If we match multiple spells but don't get an
 * exact match, we also return NULL.
 */
object *
object::find_spell (const_utf8_string prefix) const
{
  if (shstr_cmp name = prefix)
    {
      // case 1, match spell name exactly
      for (object *spob = inv; spob; spob = spob->below)
        if (spob->name == name && spob->type == SPELL)
          return spob;
    }
  else
    {
      // case 2, match prefix
      int len = strlen (prefix);

      for (object *spob = inv; spob; spob = spob->below)
        if (spob->type == SPELL
            && spob->name.length () < len
            && prefix [spob->name.length ()] <= ' '
            && !memcmp (prefix, spob->name, spob->name.length ()))
          return spob;
    }

  return 0;
}

/* reflwall - decides weither the (spell-)object sp_op will
 * be reflected from the given mapsquare. Returns 1 if true.
 * (Note that for living creatures there is a small chance that
 * reflect_spell fails.)
 * Caller should be sure it passes us valid map coordinates
 * eg, updated for tiled maps.
 */
int
reflwall (maptile *m, int x, int y, object *sp_op)
{
  if (OUT_OF_REAL_MAP (m, x, y))
    return 0;

  for (object *op = GET_MAP_OB (m, x, y); op; op = op->above)
    if (op->flag [FLAG_REFL_SPELL]
        && (!op->flag [FLAG_ALIVE]
            || (rndm (0, 99)) < 90 - (sp_op->level / 10)))
      return 1;

  return 0;
}

/* cast_create_object: creates object new_op in direction dir
 * or if that is blocked, beneath the player (op).
 * we pass 'caster', but don't use it for anything.
 * This is really just a simple wrapper function .
 * returns true to indicate whether the operation was successful.
 * destroys the object is unsuccessful.
 */
bool
cast_create_obj (object *op, object *caster, object *new_op, int dir)
{
  mapxy pos (op);
  pos.move (dir);

  if (!pos.normalise ()
      || pos->blocks (op) // perversely enough, we check if the palyer can reach that space
      || !new_op->can_drop_at (pos.m, pos.x, pos.y)
      )
    {
      op->failmsg ("Your spell fizzles! H<Something is in the way.>");
      new_op->destroy ();
      return 0;
    }

  new_op->set_flag (FLAG_IDENTIFIED);

  pos.insert (new_op, op, dir ? 0 : INS_BELOW_ORIGINATOR);

  return 1;
}

static bool
mergable_owner (object *o1, object *o2)
{
  if (o1 == o2)
    return 1;

  if (!o1 || !o2)
    return 0;

  if (o1->flag [FLAG_FRIENDLY] != o1->flag [FLAG_FRIENDLY])
    return 0;

  if (o1->is_player () || o2->is_player ())
    return 0;

  return 1;
}

/* Returns true if it is ok to put spell *op on the space/may provided.
 * immune_stop is basically the attacktype of the spell (why
 * passed as a different value, not sure of).  If immune_stop
 * has the AT_MAGIC bit set, and there is a counterwall
 * on the space, the object doesn't get placed.  if immune stop
 * does not have AT_MAGIC, then counterwalls do not effect the spell.
 */
int
ok_to_put_more (maptile *m, sint16 x, sint16 y, object *op, int immune_stop)
{
  if (!xy_normalise (m, x, y))
    return 0;

  mapspace &ms = m->at (x, y);
  ms.update ();

  if (OB_TYPE_MOVE_BLOCK (op, ms.move_block))
    return 0;

  int max_effects = 5; // max. number of similar spells per mapspace

  for (object *tmp = ms.top; tmp; tmp = tmp->below)
    {
      /* If there is a counterspell on the space, and this
       * object is using magic, don't progress.  I believe we could
       * leave this out and let in progress, and other areas of the code
       * will then remove it, but that would seem to to use more
       * resources, and may not work as well if a player is standing
       * on top of a counterwall spell (may hit the player before being
       * removed.)  On the other hand, it may be more dramatic for the
       * spell to actually hit the counterwall and be sucked up.
       */
      if ((tmp->attacktype & AT_COUNTERSPELL)
          && !tmp->flag [FLAG_MONSTER]
          && (tmp->type != PLAYER)
          && (tmp->type != WEAPON)
          && (tmp->type != BOW)
          && (tmp->type != ARROW)
          && (tmp->type != GOLEM)
          && !tmp->flag [FLAG_IS_FLOOR] // XXX:
                                              // we special case floor here because there
                                              // are sometimes spell effect floors
                                              // which are used to inflict damage
                                              // (and those shouldn't go away from
                                              //  sanctuary) see also: permanent lava
          && (immune_stop & AT_MAGIC))
        return 0;

      if (tmp->type == op->type)
        {
          if (tmp->subtype == op->subtype
              && tmp->arch == op->arch /* no harm if not comparing by name here */)
            {
              /* This is to prevent 'out of control' spells.  Basically, this
               * limits one spell effect per space per spell.  This is definately
               * needed for performance reasons, and just for playability I believe.
               * there are no such things as multispaced spells right now, so
               * we don't need to worry about the head.
               */
              if (tmp->stats.maxhp == op->stats.maxhp)
                return 0;

              /*
               * Combine similar spell effects into one spell effect. Needed for
               * performance reasons with meteor swarm and the like, but also for
               * playability reasons.
               */
              if (((tmp->subtype == SP_EXPLOSION) || (tmp->subtype == SP_CONE && tmp->stats.sp == op->stats.sp)))
                if (mergable_owner (tmp, op))
                  {
                    // if same owner, then combine, but reduce advantage of multiple spells
                    max_it (tmp->stats.dam, op->stats.dam);
                    max_it (tmp->range    , op->range);
                    max_it (tmp->duration , op->duration);
                    return 0;
                  }
            }

          // if there are too many spell effects on this space,
          // then don't allow more of them, for performance reasons.
          if (tmp->type == SPELL_EFFECT
              && !--max_effects)
            return 0;
        }

      /* Perhaps we should also put checks in for no magic and unholy
       * ground to prevent it from moving along?
       */
    }

  /* If it passes the above tests, it must be OK */
  return 1;
}

/* fire_arch_from_position: fires an archetype.
 * op: person firing the object.
 * caster: object casting the spell.
 * x, y: where to fire the spell (note, it then uses op->map for the map
 *   for these coordinates, which is probably a really bad idea.
 * dir: direction to fire in.
 * spell: spell that is being fired.  It uses other_arch for the archetype
 * to fire.
 * returns 0 on failure, 1 on success.
 */
int
fire_arch_from_position (object *op, object *caster, sint16 x, sint16 y, int dir, object *spell)
{
  if (!spell->other_arch)
    return 0;

  object *tmp = spell->other_arch->instance ();

  if (!tmp)
    return 0;

  tmp->stats.dam = spell->stats.dam + SP_level_dam_adjust (caster, spell);
  tmp->duration = spell->duration + SP_level_duration_adjust (caster, spell);
  /* code in time.c uses food for some things, duration for others */
  tmp->stats.food = tmp->duration;
  tmp->range = spell->range + SP_level_range_adjust (caster, spell);
  tmp->attacktype = spell->attacktype;
  tmp->direction = dir;
  tmp->set_owner (op);
  tmp->level = casting_level (caster, spell);
  set_spell_skill (op, caster, spell, tmp);

  /* needed for AT_HOLYWORD,AT_GODPOWER stuff */
  if (tmp->attacktype & AT_HOLYWORD || tmp->attacktype & AT_GODPOWER)
    if (!tailor_god_spell (tmp, op))
      return 0;

  if (tmp->flag [FLAG_IS_TURNABLE])
    SET_ANIMATION (tmp, dir);

  if ((tmp = op->map->insert (tmp, x, y, op)))
    move_spell_effect (tmp);

  return 1;
}

/*****************************************************************************
 *
 * Code related to rods - perhaps better located in another file?
 *
 ****************************************************************************/
void
regenerate_rod (object *rod)
{
  if (rod->stats.hp < rod->stats.maxhp)
    rod->stats.hp = min (rod->stats.maxhp, rod->stats.hp + 1 + rod->stats.maxhp / 20);
}

void
drain_rod_charge (object *rod)
{
  rod->stats.hp -= SP_level_spellpoint_cost (rod, rod->inv, SPELL_HIGHEST);
}

/* this function is commonly used to find a friendly target for
 * spells such as heal or protection or armour
 * op is what is looking for the target (which can be a player),
 * dir is the direction we are looking in.  Return object found, or
 * NULL if no good object.
 */
object *
find_target_for_friendly_spell (object *op, int dir)
{
  object *tmp;

  /* I don't really get this block - if op isn't a player or rune,
   * we then make the owner of this object the target.
   * The owner could very well be no where near op.
   */
  if (op->type != PLAYER && op->type != RUNE)
    {
      tmp = op->owner;
      /* If the owner does not exist, or is not a monster, than apply the spell
       * to the caster.
       */
      if (!tmp || !tmp->flag [FLAG_MONSTER])
        tmp = op;
    }
  else
    {
      maptile *m = op->map;
      sint16 x = op->x + DIRX (dir);
      sint16 y = op->y + DIRY (dir);
      
      tmp = xy_normalise (m, x, y)
            ? m->at (x, y).player ()
            : 0;
    }

  /* didn't find a player there, look in current square for a player */
  if (!tmp)
    tmp = op->ms ().player ();

  return tmp;
}

/* raytrace:
 * spell_find_dir(map, x, y, exclude) will search first the center square
 * then some close squares in the given map at the given coordinates for
 * live objects.
 * It will not consider the object given as exclude (= caster) among possible
 * live objects. If the caster is a player, the spell will go after
 * monsters/generators only. If not, the spell will hunt players only.
 * It returns the direction toward the first/closest live object if it finds
 * any, otherwise -1.
 * note that exclude can be NULL, in which case all bets are off.
 */
int
spell_find_dir (maptile *m, int x, int y, object *exclude)
{
  int i, max = SIZEOFFREE;
  sint16 nx, ny;
  int owner_type = 0, mflags;
  object *tmp;
  maptile *mp;

  if (exclude && exclude->head)
    exclude = exclude->head;
  if (exclude && exclude->type)
    owner_type = exclude->type;

  for (i = rndm (1, 8); i < max; i++)
    {
      nx = x + DIRX (i);
      ny = y + DIRY (i);
      mp = m;
      mflags = get_map_flags (m, &mp, nx, ny, &nx, &ny);
      if (mflags & (P_OUT_OF_MAP | P_BLOCKSVIEW))
        continue;

      tmp = GET_MAP_OB (mp, nx, ny);

      while (tmp != NULL && (((owner_type == PLAYER &&
                               !tmp->flag [FLAG_MONSTER] && !tmp->flag [FLAG_GENERATOR]) ||
                              (owner_type != PLAYER && tmp->type != PLAYER)) || (tmp == exclude || (tmp->head && tmp->head == exclude))))
        tmp = tmp->above;

      if (tmp != NULL && can_see_monsterP (m, x, y, i))
        return freedir[i];
    }
  return -1;                    /* flag for "keep going the way you were" */
}

/* put_a_monster: puts a monster named monstername near by
 * op.  This creates the treasures for the monsters, and
 * also deals with multipart monsters properly.
 */
static void
put_a_monster (object *op, const char *monstername)
{
  object *tmp, *head = NULL, *prev = NULL;
  archetype *at;
  int dir;

  /* Handle cases where we are passed a bogus mosntername */

  if ((at = archetype::find (monstername)) == NULL)
    return;

  /* find a free square nearby
   * first we check the closest square for free squares
   */

  dir = find_first_free_spot (at, op->map, op->x, op->y);
  if (dir != -1)
    {
      /* This is basically grabbed for generate monster.  Fixed 971225 to
       * insert multipart monsters properly
       */
      //TODO: use expand_tail + ...
      while (at != NULL)
        {
          tmp = at->instance ();
          tmp->x = op->x + DIRX (dir) + at->x;
          tmp->y = op->y + DIRY (dir) + at->y;
          tmp->map = op->map;
          if (head)
            {
              tmp->head = head;
              prev->more = tmp;
            }

          if (!head)
            head = tmp;

          prev = tmp;

          at = (archetype *)at->more;
        }

      if (head->randomitems)
        create_treasure (head->randomitems, head, GT_INVISIBLE, op->map->difficulty, 0);

      insert_ob_in_map (head, op->map, op, 0);

      /* thought it'd be cool to insert a burnout, too. */
      op->map->insert (archetype::get (shstr_burnout), op->x + DIRX (dir), op->y + DIRY (dir), op);
    }
}

/* peterm:  function which summons hostile monsters and
 * places them in nearby squares.
 * op is the summoner.
 * n is the number of monsters.
 * monstername is the name of the monster.
 * returns the number of monsters, which is basically n.
 * it should really see how many it successfully replaced and
 * return that instead.
 * Note that this is not used by any spells (summon evil monsters
 * use to call this, but best I can tell, that spell/ability was
 * never used.  This is however used by various failures on the
 * players part (alchemy, reincarnation, etc)
 */
int
summon_hostile_monsters (object *op, int n, const char *monstername)
{
  int i;

  for (i = 0; i < n; i++)
    put_a_monster (op, monstername);

  return n;
}


/*  Some local definitions for shuffle-attack */
struct attacktype_shuffle
{
  int attacktype;
  int face;
} ATTACKS[22] =
{
  { AT_PHYSICAL, 0},
  { AT_PHYSICAL, 0},              /*face = explosion */
  { AT_PHYSICAL, 0},
  { AT_MAGIC, 1},
  { AT_MAGIC, 1},                 /* face = last-burnout */
  { AT_MAGIC, 1},
  { AT_FIRE, 2},
  { AT_FIRE, 2},                  /* face = fire....  */
  { AT_FIRE, 2},
  { AT_ELECTRICITY, 3},
  { AT_ELECTRICITY, 3},           /* ball_lightning */
  { AT_ELECTRICITY, 3},
  { AT_COLD, 4},
  { AT_COLD, 4},                  /* face=icestorm */
  { AT_COLD, 4},
  { AT_CONFUSION, 5},
  { AT_POISON, 7},
  { AT_POISON, 7},                /* face = acid sphere.  generator */
  { AT_POISON, 7},                /* poisoncloud face */
  { AT_SLOW, 8},
  { AT_PARALYZE, 9},
  { AT_FEAR, 10},
};

/* shuffle_attack:  peterm
 * This routine shuffles the attack of op to one of the
 * ones in the list.  It does this at random.  It also
 *  chooses a face appropriate to the attack that is
 *  being committed by that square at the moment.
 *  right now it's being used by color spray and create pool of
 *  chaos.
 * This could really be a better implementation - the
 * faces and attacktypes above are hardcoded, which is never
 * good.  The faces refer to faces in the animation sequence.
 * Not sure how to do better - but not having it hardcoded
 * would be nice.
 * I also fixed a bug here in that attacktype was |= -
 * to me, that would be that it would quickly get all
 * attacktypes, which probably wasn't the intent.  MSW 2003-06-03
 */
void
shuffle_attack (object *op, int change_face)
{
  int i;

  i = rndm (0, 21);

  op->attacktype = ATTACKS[i].attacktype | AT_MAGIC;

  if (change_face)
    {
      SET_ANIMATION (op, ATTACKS[i].face);
    }
}

/* prayer_failure: This is called when a player fails
 * at casting a prayer.
 * op is the player.
 * failure is basically how much grace they had.
 * power is how much grace the spell would normally take to cast.
 */

#define HINT_GRACE " H<Make sure you always have enough grace points for your prayers.>"

static void
prayer_failure (object *op, int failure, int power)
{
  const char *godname;
  object *tmp;

  if (!strcmp ((godname = determine_god (op)), "none"))
    godname = "Your spirit";

  if (failure <= -20 && failure > -40)  /* wonder */
    {
      op->failmsgf ("%s gives a sign to renew your faith." HINT_GRACE, godname);
      tmp = archetype::get (SPELL_WONDER);
      cast_cone (op, op, 0, tmp);
      tmp->destroy ();
    }

  else if (failure <= -40 && failure > -60)     /* confusion */
    {
      op->failmsg ("Your diety touches your mind!" HINT_GRACE);
      confuse_player (op, op, 99);
    }
  else if (failure <= -60 && failure > -150)    /* paralysis */
    {
      op->failmsgf ("%s requires you to pray NOW. "
                    "You comply, ignoring all else." HINT_GRACE,
                    godname);
      paralyze_player (op, op, 99);
    }
  else if (failure <= -150)     /* blast the immediate area */
    {
      tmp = archetype::get (GOD_POWER);
      op->failmsgf ("%s smites you!" HINT_GRACE, godname);
      cast_magic_storm (op, tmp, power);
    }
}

/*
 * spell_failure()  handles the various effects for differing degrees
 * of failure badness.
 * op is the player that failed.
 * failure is a random value of how badly you failed.
 * power is how many spellpoints you'd normally need for the spell.
 * skill is the skill you'd need to cast the spell.
 */
void
spell_failure (object *op, int failure, int power, object *skill)
{
  object *tmp;

  if (settings.spell_failure_effects == FALSE)
    return;

  if (failure <= -20 && failure > -40)  /* wonder */
    {
      op->failmsg ("Your spell causes an unexpected effect.");
      tmp = archetype::get (SPELL_WONDER);
      cast_cone (op, op, 0, tmp);
      tmp->destroy ();
    }

  else if (failure <= -40 && failure > -60)     /* confusion */
    {
      op->failmsg ("Your magic recoils on you, making you confused!");
      confuse_player (op, op, 99);
    }
  else if (failure <= -60 && failure > -80)     /* paralysis */
    {
      op->failmsg ("Your magic stuns you!");
      paralyze_player (op, op, 99);
    }
  else if (failure <= -80)      /* blast the immediate area */
    {
      object *tmp;

      /* Safety check to make sure we don't get any mana storms in scorn */
      if (get_map_flags (op->map, NULL, op->x, op->y, NULL, NULL) & P_NO_MAGIC)
        {
          op->failmsg ("The magic warps and you are turned inside out!");
          hit_player (op, 9998, op, AT_INTERNAL, 1);

        }
      else
        {
          op->failmsg ("You lose control of the mana!  The uncontrolled magic blasts you!");
          tmp = archetype::get (LOOSE_MANA);
          tmp->level = skill->level;

          /* increase the area of destruction a little for more powerful spells */
          tmp->range += isqrt (power);

          if (power > 25)
            tmp->stats.dam = 25 + isqrt (power);
          else
            tmp->stats.dam = power;     /* nasty recoils! */

          tmp->stats.maxhp = tmp->count;

          tmp->insert_at (op);
        }
    }
}

static int
cast_party_spell (object *op, object *caster, int dir, object *spell_ob, char *spellparam)
{
  if (!spell_ob->other_arch)
    {
      LOG (llevError, "cast_party_spell: empty other arch\n");
      return 0;
    }

  object *spell = spell_ob->other_arch->instance ();

  /* Always cast spell on caster */
  int success = cast_spell (op, caster, dir, spell, spellparam);

  if (!op->contr || !op->contr->party)
    {
      spell->remove ();
      return success;
    }

  for_all_players (pl)
    if ((pl->ob->contr->party == op->contr->party)
        && on_same_map (pl->ob, op)
        && pl->ob != op)
      cast_spell (pl->ob, caster, pl->ob->facing, spell, spellparam);

  spell->remove ();
  return success;
}

/* This is where the main dispatch when someone casts a spell.
 *
 * op is the creature that is owner of the object that is casting the spell -
 *    eg, the player or monster.
 * caster is the actual object (wand, potion) casting the spell. can be
 *    same as op.
 * dir is the direction to cast in.  Note in some cases, if the spell
 *    is self only, dir really doesn't make a difference.
 * spell_ob is the spell object that is being cast.  From that,
 *    we can determine what to do.
 * spellparam is any options that are being used.  It can be NULL.  Almost
 *    certainly, only players will set it.  It is basically used as optional
 *    parameters to a spell (eg, item to create, information for marking runes,
 *    etc.
 * returns 1 on successful cast, or 0 on error.  These values should really
 * be swapped, so that 0 is successful, and non zero is failure, with a code
 * of what it failed.
 *
 * Note that this function is really a dispatch routine that calls other
 * functions - it just blindly returns what ever value those functions
 * return.  So if your writing a new function that is called from this,
 * it shoudl also return 1 on success, 0 on failure.
 *
 * if it is a player casting the spell (op->type == PLAYER, op == caster),
 * this function will decrease the mana/grace appropriately.  For other
 * objects, the caller should do what it considers appropriate.
 */
int
cast_spell (object *op, object *caster, int dir, object *spell_ob, char *spellparam)
{
  const char *godname;
  int success = 0;

  // make sure spells always take a while, so a) we don't flood the
  // user with messages and b) too many failures can be harmful (smiting).
  op->speed_left -= 4 * op->speed; // ~0.5s on failure

  if (!spell_ob)
    {
      LOG (llevError, "cast_spell: null spell object passed\n");
      return 0;
    }

  if (!strcmp ((godname = determine_god (op)), "none"))
    godname = "A random spirit";

  /* the caller should set caster to op if appropriate */
  if (!caster)
    {
      LOG (llevError, "cast_spell: null caster object passed\n");
      return 0;
    }

  /* if caster is a spell casting object, this normally shouldn't be
   * an issue, because they don't have any spellpaths set up.
   */
  if (caster->path_denied & spell_ob->path_attuned && !caster->flag [FLAG_WIZCAST])
    {
      op->failmsg ("That spell path is denied to you.");
      return 0;
    }

  object *skill = 0;

  /* if it is a player casting the spell, and they are really casting it
   * (vs it coming from a wand, scroll, or whatever else), do some
   * checks.  We let monsters do special things - eg, they
   * don't need the SKILL, BYpass level checks, etc. The monster function
   * should take care of that.
   * Remove the wiz check here and move it further down - some spells
   * need to have the right skill pointer passed, so we need to
   * at least process that code.
   */
  if (op->type == PLAYER && op == caster)
    {
      if (spell_ob->skill)
        {
          skill = find_skill_by_name (op, spell_ob->skill);

          if (!skill)
            {
              op->failmsgf ("You need the %s skill to cast %s! "
                            "H<You either need to learn the skill via a skill scroll "
                            "or you need to wear a talisman, holy symbol or another skill tool.>",
                            &spell_ob->skill, &spell_ob->name);
              return 0;
            }

          const char *msg = "";

          int caster_level = skill->level;

          if (op->path_attuned & spell_ob->path_attuned)
            {
              caster_level += min (caster_level, ATTUNE_REPELL);
              msg = " (attuned)";
            }

          if (op->path_repelled & spell_ob->path_attuned)
            {
              caster_level -= ATTUNE_REPELL; // negative is ok
              msg = " (repelled)";
            }

          if (spell_ob->level > caster_level)
            {
              op->failmsgf ("You lack enough skill to cast that spell! "
                            "H<Your effective cast level is %d%s, but level %d is required.>",
                            caster_level, msg, spell_ob->level);
              if (!op->is_wiz ())
                return 0;
            }
        }

      /* If the caster is the wiz, they don't ever fail, and don't have
       * to have sufficient grace/mana.
       */
      if (!op->flag [FLAG_WIZCAST])
        {
          if (SP_level_spellpoint_cost (caster, spell_ob, SPELL_MANA) &&
              SP_level_spellpoint_cost (caster, spell_ob, SPELL_MANA) > op->stats.sp)
            {
              op->failmsg ("You don't have enough mana!");
              return 0;
            }

          if (SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE) &&
              SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE) > op->stats.grace)
            {
              if (random_roll (0, op->stats.Wis - 1, op, PREFER_HIGH) + op->stats.grace -
                  10 * SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE) / op->stats.maxgrace > 0)
                op->statusmsg (format ("%s grants your prayer, though you are unworthy.", godname));
              else
                {
                  prayer_failure (op, op->stats.grace, SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE) - op->stats.grace);
                  op->failmsgf ("%s ignores your prayer.", godname);
                  return 0;
                }
            }

          /* player/monster is trying to cast the spell.  might fumble it */
          if (spell_ob->stats.grace && random_roll (0, 99, op, PREFER_HIGH) <
              (spell_ob->level / (float) max (1, op->level) * cleric_chance[op->stats.Wis]))
            {
              op->contr->play_sound (sound_find ("fumble_spell"));
              op->failmsg ("You fumble the prayer.");

              op->stats.grace -= random_roll (1, SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE), op, PREFER_LOW);
              return 0;
            }
          else if (spell_ob->stats.sp)
            {
              int failure = random_roll (0, 199, op, PREFER_HIGH) - op->contr->encumbrance + op->level - spell_ob->level + 35;

              if (failure < 0)
                {
                  op->failmsg ("You bungle the spell because you have too much heavy equipment in use.");
                  if (settings.spell_failure_effects == TRUE)
                    spell_failure (op, failure, SP_level_spellpoint_cost (caster, spell_ob, SPELL_MANA), skill);

                  op->stats.sp -= random_roll (0, SP_level_spellpoint_cost (caster, spell_ob, SPELL_MANA), op, PREFER_LOW);
                  return 0;
                }
            }
        }
    }

  int mflags = op->ms ().flags ();

  /* See if we can cast a spell here.  If the caster and op are
   * not alive, then this would mean that the mapmaker put the
   * objects on the space - presume that they know what they are
   * doing.
   */

  if ((mflags & P_SAFE) && !op->flag [FLAG_WIZCAST])      // There is _ABSOLUTELY_ no magic allowed here (except wizards :-)!
    {
      op->speed_left -= 2 * op->speed; // freeze for two ticks, so we don't flood
      op->failmsg ("This ground is sacred! The gods prevent any magical effects done by you here!");
      return 0;
    }

  if ((spell_ob->type == SPELL)
      && (caster->type != POTION)
      && !op->flag [FLAG_WIZCAST]
      && (caster->flag [FLAG_ALIVE]
          || op->flag [FLAG_ALIVE])
      && (((mflags & P_NO_MAGIC) && spell_ob->stats.sp) || ((mflags & P_NO_CLERIC) && spell_ob->stats.grace)))
    {
      if (op->type != PLAYER)
        return 0;

      if ((mflags & P_NO_CLERIC) && spell_ob->stats.grace)
        op->failmsgf ("This ground is unholy! %s ignores you.", godname);
      else if (object *item = op->contr->ranged_ob)
        {
          if (item->type == SPELL)
            op->failmsg ("Something blocks your spellcasting.");
          else if (item->type == SCROLL)
            op->failmsg ("Something blocks the magic of your scroll.");
          else
            op->failmsg ("Something blocks the magic of your item.");
        }
      else
        op->failmsg ("Something blocks the spell!");

      return 0;
    }

  // undo the flood protection from earlier
  op->speed_left += 4 * op->speed; // ~0.5s on failure

  /* Take into account how long it takes to cast the spell.
   * if the player is casting it, then we use the time in
   * the spell object.  If it is a spell object, have it
   * take two ticks.  Things that cast spells on the players
   * behalf (eg, altars, and whatever else) shouldn't cost
   * the player any time.
   * Ignore casting time for firewalls
   */
  if (caster == op && caster->type != FIREWALL)
    {
      op->speed_left -= spell_ob->casting_time * PATH_TIME_MULT (op, spell_ob) * op->speed;
      /* Other portions of the code may also decrement the speed of the player, so
       * put a lower limit so that the player isn't stuck here too long
       */
      if ((spell_ob->casting_time > 0) && op->speed_left < -spell_ob->casting_time * PATH_TIME_MULT (op, spell_ob) * op->speed)
        op->speed_left = -spell_ob->casting_time * PATH_TIME_MULT (op, spell_ob) * op->speed;
    }
  else if (caster->type == WAND || caster->type == HORN || caster->type == ROD || caster->type == POTION || caster->type == SCROLL)
    op->speed_left -= 2 * op->speed;

  if (op->type == PLAYER && op == caster)
    {
      op->stats.grace -= SP_level_spellpoint_cost (caster, spell_ob, SPELL_GRACE);
      op->stats.sp -= SP_level_spellpoint_cost (caster, spell_ob, SPELL_MANA);
    }

  /* We want to try to find the skill to properly credit exp.
   * for spell casting objects, the exp goes to the skill the casting
   * object requires.
   */
  if (op != caster && !skill && caster->skill)
    {
      skill = find_skill_by_name (op, caster->skill);

      if (!skill)
        {
          op->failmsgf ("You lack the %s skill, which is required to use the %s!", &caster->skill, query_name (caster));
          return 0;
        }
    }

  if (INVOKE_OBJECT (CAST_SPELL, spell_ob, ARG_OBJECT (op), ARG_OBJECT (caster), ARG_INT (dir), ARG_STRING (spellparam)))
    return RESULT_INT (0);

  // temporaroly replace chosen_skill by skill, we assume skill *could* be applied,
  // at least temporarily, which might not be true due to slot restrictions, but hey
  // invoke requires it basically.

  object *chosen_skill = op->chosen_skill;
  op->chosen_skill = skill;

  switch (spell_ob->subtype)
    {
      /* The order of case statements is same as the order they show up
       * in spells.h.
       */
      case SP_RAISE_DEAD:
        success = cast_raise_dead_spell (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_RUNE:
        success = write_rune (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_MAKE_MARK:
        success = write_mark (op, spell_ob, spellparam);
        break;

      case SP_BOLT:
        success = fire_bolt (op, caster, dir, spell_ob, skill);
        break;

      case SP_BULLET:
        success = fire_bullet (op, caster, dir, spell_ob);
        break;

      case SP_CONE:
        success = cast_cone (op, caster, dir, spell_ob);
        break;

      case SP_BOMB:
        success = create_bomb (op, caster, dir, spell_ob);
        break;

      case SP_WONDER:
        success = cast_wonder (op, caster, dir, spell_ob);
        break;

      case SP_SMITE:
        success = cast_smite_spell (op, caster, dir, spell_ob);
        break;

      case SP_MAGIC_MISSILE:
        success = fire_arch_from_position (op, caster, op->x, op->y, dir, spell_ob);
        break;

      case SP_SUMMON_GOLEM:
        success = summon_golem (op, caster, dir, spell_ob);
        break;

      case SP_DIMENSION_DOOR:
        /* dimension door needs the actual caster, because that is what is
         * moved.
         */
        success = dimension_door (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_MAGIC_MAPPING:
        if (op->type == PLAYER)
          {
            spell_effect (spell_ob, op->x, op->y, op->map, op);
            draw_magic_map (op);
            success = 1;
          }
        else
          success = 0;
        break;

      case SP_MAGIC_WALL:
        success = magic_wall (op, caster, dir, spell_ob);
        break;

      case SP_DESTRUCTION:
        success = cast_destruction (op, caster, spell_ob);
        break;

      case SP_PERCEIVE_SELF:
        success = perceive_self (op);
        break;

      case SP_WORD_OF_RECALL:
        success = cast_word_of_recall (op, caster, spell_ob);
        break;

      case SP_INVISIBLE:
        success = cast_invisible (op, caster, spell_ob);
        break;

      case SP_PROBE:
        success = probe (op, caster, spell_ob, dir);
        break;

      case SP_HEALING:
        success = cast_heal (op, caster, spell_ob, dir);
        break;

      case SP_CREATE_FOOD:
        success = cast_create_food (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_EARTH_TO_DUST:
        success = cast_earth_to_dust (op, caster, spell_ob);
        break;

      case SP_CHANGE_ABILITY:
        success = cast_change_ability (op, caster, spell_ob, dir, 0);
        break;

      case SP_BLESS:
        success = cast_bless (op, caster, spell_ob, dir);
        break;

      case SP_CURSE:
        success = cast_curse (op, caster, spell_ob, dir);
        break;

      case SP_SUMMON_MONSTER:
        success = summon_object (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_CHARGING:
        success = recharge (op, caster, spell_ob);
        break;

      case SP_POLYMORPH:
#ifdef NO_POLYMORPH
        /* Not great, but at least provide feedback so if players do have
         * polymorph (ie, find it as a preset item or left over from before
         * it was disabled), they get some feedback.
         */
        op->failmsg ("The spell fizzles!");
        success = 0;
#else
        success = cast_polymorph (op, caster, spell_ob, dir);
#endif
        break;

      case SP_ALCHEMY:
        success = alchemy (op, caster, spell_ob);
        break;

      case SP_REMOVE_CURSE:
        success = remove_curse (op, caster, spell_ob);
        break;

      case SP_IDENTIFY:
        success = cast_identify (op, caster, spell_ob);
        break;

      case SP_DETECTION:
        success = cast_detection (op, caster, spell_ob, skill);
        break;

      case SP_MOOD_CHANGE:
        success = mood_change (op, caster, spell_ob);
        break;

      case SP_MOVING_BALL:
        if (spell_ob->path_repelled && (spell_ob->path_repelled & caster->path_attuned) != spell_ob->path_repelled)
          {
            op->failmsgf ("You lack the proper attunement to cast %s!", &spell_ob->name);
            success = 0;
          }
        else
          success = fire_arch_from_position (op, caster, op->x, op->y, dir, spell_ob);
        break;

      case SP_SWARM:
        success = fire_swarm (op, caster, spell_ob, dir);
        break;

      case SP_CHANGE_MANA:
        success = cast_transfer (op, caster, spell_ob, dir);
        break;

      case SP_DISPEL_RUNE:
        /* in rune.c */
        success = dispel_rune (op, caster, spell_ob, skill, dir);
        break;

      case SP_CREATE_MISSILE:
        success = cast_create_missile (op, caster, spell_ob, dir, spellparam);
        break;

      case SP_CONSECRATE:
        success = cast_consecrate (op, caster, spell_ob);
        break;

      case SP_ANIMATE_WEAPON:
        success = animate_weapon (op, caster, spell_ob, dir);
        break;

      case SP_LIGHT:
        success = cast_light (op, caster, spell_ob, dir);
        break;

      case SP_CHANGE_MAP_LIGHT:
        success = cast_change_map_lightlevel (op, caster, spell_ob);
        break;

      case SP_FAERY_FIRE:
        success = cast_destruction (op, caster, spell_ob);
        break;

      case SP_CAUSE_DISEASE:
        success = cast_cause_disease (op, caster, spell_ob, dir);
        break;

      case SP_AURA:
        success = create_aura (op, caster, spell_ob);
        break;

      case SP_PARTY_SPELL:
        success = cast_party_spell (op, caster, dir, spell_ob, spellparam);
        break;

      default:
        LOG (llevError, "cast_spell: Unhandled spell subtype %d\n", spell_ob->subtype);
    }

  // restore chosen_skill
  op->chosen_skill = chosen_skill;

  op->play_sound (
     success
        ? spell_ob->sound
             ? spell_ob->sound
             : sound_find ("spell_success")
        : sound_find ("fumble_spell")
  );

  return success;
}

/* This is called from time.c/process_object(). That function
 * calls this for any SPELL_EFFECT type objects. This function
 * then dispatches them to the appropriate specific routines.
 */
void
move_spell_effect (object *op)
{
  switch (op->subtype)
    {
      case SP_BOLT:
        move_bolt (op);
        break;

      case SP_BULLET:
        move_bullet (op);
        break;

      case SP_EXPLOSION:
        explosion (op);
        break;

      case SP_CONE:
        move_cone (op);
        break;

      case SP_BOMB:
        animate_bomb (op);
        break;

      case SP_MAGIC_MISSILE:
        move_missile (op);
        break;

      case SP_WORD_OF_RECALL:
        execute_word_of_recall (op);
        break;

      case SP_MOVING_BALL:
        move_ball_spell (op);
        break;

      case SP_SWARM:
        move_swarm_spell (op);
        break;

      case SP_AURA:
        move_aura (op);
        break;
    }
}

/* This is called by move_apply. Basically, if someone
 * moves onto a spell effect and the walk_on or fly_on flags
 * are set, this is called. This should only be called for
 * objects of the appropriate type.
 */
void
apply_spell_effect (object *spell, object *victim)
{
  switch (spell->subtype)
    {
      case SP_CONE:
        if (victim->flag [FLAG_ALIVE] && spell->has_active_speed () && spell->attacktype)
          hit_player (victim, spell->stats.dam, spell, spell->attacktype, 0);
        break;

      case SP_MAGIC_MISSILE:
        if (victim->flag [FLAG_ALIVE])
          {
            hit_player (victim, spell->stats.dam, spell, spell->attacktype, 1);
            spell->destroy ();
          }
        break;

      case SP_MOVING_BALL:
        if (victim->flag [FLAG_ALIVE])
          hit_player (victim, spell->stats.dam, spell, spell->attacktype, 1);
        else if (victim->material != MATERIAL_NULL)
          save_throw_object (victim, spell->attacktype, spell);

        break;
    }
}

/**
 * This function will let a fireball explode at the position of
 * the victim with a specific maximum level.
 */
void
create_exploding_ball_at (object *victim, int level)
{
  object *ball = archetype::get (EXPLODING_FIREBALL);
  ball->dam_modifier = random_roll (1, level, victim, PREFER_LOW) / 5 + 1;
  ball->stats.maxhp  = random_roll (1, level, victim, PREFER_LOW) / 10 + 2;
  ball->insert_at (victim);
}
Revision:	1.131
Committed:	Sat Nov 17 23:40:04 2018 UTC (5 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.130:	+1 -0 lines
Log Message:	copyright update 2018