path: root/engines/glk/adrift/scobjcts.cpp

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */

#include "glk/adrift/scare.h"
#include "glk/adrift/scprotos.h"
#include "glk/adrift/scgamest.h"

namespace Glk {
namespace Adrift {

/* Assorted definitions and constants. */
static const sc_char NUL = '\0';

/* Trace flag, set before running. */
static sc_bool obj_trace = FALSE;


/*
 * obj_is_static()
 * obj_is_surface()
 * obj_is_container()
 *
 * Convenience functions to return TRUE for given object attributes.
 */
sc_bool
obj_is_static (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_bool bstatic;

  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Static";
  bstatic = prop_get_boolean (bundle, "B<-sis", vt_key);
  return bstatic;
}

sc_bool
obj_is_container (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_bool is_container;

  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Container";
  is_container = prop_get_boolean (bundle, "B<-sis", vt_key);
  return is_container;
}

sc_bool
obj_is_surface (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_bool is_surface;

  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Surface";
  is_surface = prop_get_boolean (bundle, "B<-sis", vt_key);
  return is_surface;
}


/*
 * obj_container_object()
 *
 * Return the index of the n'th container object found.
 */
sc_int
obj_container_object (sc_gameref_t game, sc_int n)
{
  sc_int object, count;

  /* Progress through objects until n containers found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      if (obj_is_container (game, object))
        count--;
    }
  return object - 1;
}


/*
 * obj_container_index()
 *
 * Return index such that obj_container_object(index) == objnum.
 */
sc_int
obj_container_index (sc_gameref_t game, sc_int objnum)
{
  sc_int object, count;

  /* Progress through objects up to objnum. */
  count = 0;
  for (object = 0; object < objnum; object++)
    {
      if (obj_is_container (game, object))
        count++;
    }
  return count;
}


/*
 * obj_surface_object()
 *
 * Return the index of the n'th surface object found.
 */
sc_int
obj_surface_object (sc_gameref_t game, sc_int n)
{
  sc_int object, count;

  /* Progress through objects until n surfaces found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      if (obj_is_surface (game, object))
        count--;
    }
  return object - 1;
}


/*
 * obj_surface_index()
 *
 * Return index such that obj_surface_object(index) == objnum.
 */
sc_int
obj_surface_index (sc_gameref_t game, sc_int objnum)
{
  sc_int object, count;

  /* Progress through objects up to objnum. */
  count = 0;
  for (object = 0; object < objnum; object++)
    {
      if (obj_is_surface (game, object))
        count++;
    }
  return count;
}


/*
 * obj_stateful_object()
 *
 * Return the index of the n'th openable or statussed object found.
 */
sc_int
obj_stateful_object (sc_gameref_t game, sc_int n)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_int object, count;

  /* Progress through objects until n matches found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      sc_vartype_t vt_key[3];
      sc_bool is_openable, is_statussed;

      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "Openable";
      is_openable = prop_get_integer (bundle, "I<-sis", vt_key) != 0;
      vt_key[2].string = "CurrentState";
      is_statussed = prop_get_integer (bundle, "I<-sis", vt_key) != 0;
      if (is_openable || is_statussed)
        count--;
    }
  return object - 1;
}


/*
 * obj_stateful_index()
 *
 * Return index such that obj_stateful_object(index) == objnum.
 */
sc_int
obj_stateful_index (sc_gameref_t game, sc_int objnum)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_int object, count;

  /* Progress through objects up to objnum. */
  count = 0;
  for (object = 0; object < objnum; object++)
    {
      sc_vartype_t vt_key[3];
      sc_bool is_openable, is_statussed;

      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "Openable";
      is_openable = prop_get_integer (bundle, "I<-sis", vt_key) != 0;
      vt_key[2].string = "CurrentState";
      is_statussed = prop_get_integer (bundle, "I<-sis", vt_key) != 0;
      if (is_openable || is_statussed)
        count++;
    }
  return count;
}


/*
 * obj_state_name()
 *
 * Return the string name of the state of a given stateful object.  The
 * string is malloc'ed, and needs to be freed by the caller.  Returns NULL
 * if no valid state string found.
 */
sc_char *
obj_state_name (sc_gameref_t game, sc_int objnum)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  const sc_char *states;
  sc_int length, state, count, first, last;
  sc_char *string;

  /* Get the list of state strings for the object. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = objnum;
  vt_key[2].string = "States";
  states = prop_get_string (bundle, "S<-sis", vt_key);

  /* Find the start of the element for the current state. */
  state = gs_object_state (game, objnum);
  length = strlen (states);
  for (first = 0, count = state; first < length && count > 1; first++)
    {
      if (states[first] == '|')
        count--;
    }
  if (count != 1)
    return NULL;

  /* Find the end of the state string. */
  for (last = first; last < length; last++)
    {
      if (states[last] == '|')
        break;
    }

  /* Allocate and take a copy of the state string. */
  string = (sc_char *)sc_malloc (last - first + 1);
  memcpy (string, states + first, last - first);
  string[last - first] = NUL;

  return string;
}


/*
 * obj_dynamic_object()
 *
 * Return the index of the n'th non-static object found.
 */
sc_int
obj_dynamic_object (sc_gameref_t game, sc_int n)
{
  sc_int object, count;

  /* Progress through objects until n matches found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      if (!obj_is_static (game, object))
        count--;
    }
  return object - 1;
}


/*
 * obj_wearable_object()
 *
 * Return the index of the n'th wearable object found.
 */
sc_int
obj_wearable_object (sc_gameref_t game, sc_int n)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_int object, count;

  /* Progress through objects until n matches found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      if (!obj_is_static (game, object))
        {
          sc_vartype_t vt_key[3];

          vt_key[0].string = "Objects";
          vt_key[1].integer = object;
          vt_key[2].string = "Wearable";
          if (prop_get_boolean (bundle, "B<-sis", vt_key))
            count--;
        }
    }
  return object - 1;
}


/*
 * Size is held in the ten's digit of SizeWeight, and weight in the units.
 * Size and weight are multipliers -- the relative size and weight of objects
 * rises by a factor of three for each incremental multiplier.  These factors
 * are also used for the maximum size of object that can fit in a container,
 * and the number of these that fit.
 */
enum
{ OBJ_DIMENSION_DIVISOR = 10,
  OBJ_DIMENSION_MULTIPLE = 3
};

/*
 * obj_get_size()
 * obj_get_weight()
 *
 * Return the relative size and weight of an object.  For containers, the
 * weight includes the weight of each contained object.
 *
 * TODO It's possible to have static objects in the player inventory, moved
 * by events -- how should these be handled, as they have no SizeWeight?
 */
sc_int
obj_get_size (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_int size, count;

  /* TODO For now, give static objects no size. */
  if (obj_is_static (game, object))
    return 0;

  /* Size is the 'tens' component of SizeWeight. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "SizeWeight";
  count = prop_get_integer (bundle, "I<-sis", vt_key) / OBJ_DIMENSION_DIVISOR;

  /*
   * Calculate base object size.  Unlike weights below, we take this as simply
   * being the maximum size; that is, when a container carries other objects
   * its weight increases by the sum of objects carried, but its size remains
   * constant.
   */
  size = 1;
  for (; count > 0; count--)
    size *= OBJ_DIMENSION_MULTIPLE;

  if (obj_trace)
    sc_trace ("Object: object %ld is size %ld\n", object, size);

  /* Return total size. */
  return size;
}

sc_int
obj_get_weight (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_int weight, count;

  /* TODO For now, give static objects no weight. */
  if (obj_is_static (game, object))
    return 0;

  /* Weight is the 'units' component of SizeWeight. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "SizeWeight";
  count = prop_get_integer (bundle, "I<-sis", vt_key) % OBJ_DIMENSION_DIVISOR;

  /* Calculate base object weight. */
  weight = 1;
  for (; count > 0; count--)
    weight *= OBJ_DIMENSION_MULTIPLE;

  /* If this is a container or a surface, add weights of parented objects. */
  if (obj_is_container (game, object) || obj_is_surface (game, object))
    {
      sc_int other;

      /* Find and add contained or surface objects. */
      for (other = 0; other < gs_object_count (game); other++)
        {
          if ((gs_object_position (game, other) == OBJ_IN_OBJECT
               || gs_object_position (game, other) == OBJ_ON_OBJECT)
              && gs_object_parent (game, other) == object)
            {
              weight += obj_get_weight (game, other);
            }
        }
    }

  if (obj_trace)
    sc_trace ("Object: object %ld is weight %ld\n", object, weight);

  /* Return total weight. */
  return weight;
}


/*
 * obj_convert_player_limit()
 * obj_get_player_size_limit()
 * obj_get_player_weight_limit()
 *
 * Return the limits set on the sizes and weights a player can handle.  Not
 * really object-related except that they deal with sizing multiples.
 */
static sc_int
obj_convert_player_limit (sc_int value)
{
  sc_int retval, index_;

  /* 'Tens' of value multiplied by 3 to the power 'units' of value. */
  retval = value / OBJ_DIMENSION_DIVISOR;
  for (index_ = 0; index_ < value % OBJ_DIMENSION_DIVISOR; index_++)
    retval *= OBJ_DIMENSION_MULTIPLE;

  return retval;
}

sc_int
obj_get_player_size_limit (sc_gameref_t game)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[2];
  sc_int max_size;

  vt_key[0].string = "Globals";
  vt_key[1].string = "MaxSize";
  max_size = prop_get_integer (bundle, "I<-ss", vt_key);

  return obj_convert_player_limit (max_size);
}

sc_int
obj_get_player_weight_limit (sc_gameref_t game)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[2];
  sc_int max_weight;

  vt_key[0].string = "Globals";
  vt_key[1].string = "MaxWt";
  max_weight = prop_get_integer (bundle, "I<-ss", vt_key);

  return obj_convert_player_limit (max_weight);
}


/*
 * obj_get_container_maxsize()
 * obj_get_container_capacity()
 *
 * Return the maximum size of an object that can be placed in a container,
 * and the number that will fit.
 */
sc_int
obj_get_container_maxsize (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_int maxsize, count;

  /* Maxsize is found from the 'units' component of Capacity. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Capacity";
  count = prop_get_integer (bundle, "I<-sis", vt_key) % OBJ_DIMENSION_DIVISOR;

  /* Calculate and return maximum size. */
  maxsize = 1;
  for (; count > 0; count--)
    maxsize *= OBJ_DIMENSION_MULTIPLE;

  if (obj_trace)
    sc_trace ("Object: object %ld has max size %ld\n", object, maxsize);

  return maxsize;
}

sc_int
obj_get_container_capacity (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_int capacity;

  /* The count of objects is in the 'tens' component of Capacity. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Capacity";
  capacity = prop_get_integer (bundle, "I<-sis", vt_key)
             / OBJ_DIMENSION_DIVISOR;

  if (obj_trace)
    sc_trace ("Object: object %ld has capacity %ld\n", object, capacity);

  return capacity;
}


/* Sit/lie bit mask enumerations. */
enum
{ OBJ_STANDABLE_MASK = 1 << 0,
  OBJ_LIEABLE_MASK = 1 << 1
};

/*
 * obj_standable_object()
 *
 * Return the index of the n'th standable object found.
 */
sc_int
obj_standable_object (sc_gameref_t game, sc_int n)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_int object, count;

  /* Progress through objects until n standable found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      sc_vartype_t vt_key[3];
      sc_int sit_lie_flags;

      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "SitLie";
      sit_lie_flags = prop_get_integer (bundle, "I<-sis", vt_key);
      if (sit_lie_flags & OBJ_STANDABLE_MASK)
        count--;
    }
  return object - 1;
}


/*
 * obj_lieable_object()
 *
 * Return the index of the n'th lieable object found.
 */
sc_int
obj_lieable_object (sc_gameref_t game, sc_int n)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_int object, count;

  /* Progress through objects until n lieable found. */
  count = n;
  for (object = 0; object < gs_object_count (game) && count >= 0; object++)
    {
      sc_vartype_t vt_key[3];
      sc_int sit_lie_flags;

      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "SitLie";
      sit_lie_flags = prop_get_integer (bundle, "I<-sis", vt_key);
      if (sit_lie_flags & OBJ_LIEABLE_MASK)
        count--;
    }
  return object - 1;
}


/*
 * obj_appears_plural()
 *
 * Return TRUE if the object appears to be plural.  Adrift makes a guess at
 * this to produce "... is on.." or "... are on...".  It's not clear how it
 * does it, but it looks something like: singular if prefix is "a" or "an"
 * or ""; plural if prefix is "the" or "some" and short name ends with 's'
 * that is not preceded by 'u'.
 */
sc_bool
obj_appears_plural (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  const sc_char *prefix, *name;

  /* Check prefix for "a", "an", or empty. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "Prefix";
  prefix = prop_get_string (bundle, "S<-sis", vt_key);

  if (!(sc_strempty (prefix)
        || sc_compare_word (prefix, "a", 1)
        || sc_compare_word (prefix, "an", 2)))
    {
      sc_int length;

      /* Check name for ending in 's', but not 'us'. */
      vt_key[2].string = "Short";
      name = prop_get_string (bundle, "S<-sis", vt_key);
      length = strlen (name);

      if (!sc_strempty (name)
          && sc_tolower (name[length - 1]) == 's'
          && (length < 2 || sc_tolower (name[length - 2]) != 'u'))
        return TRUE;
    }

  /* Doesn't look plural. */
  return FALSE;
}


/*
 * obj_directly_in_room_internal()
 * obj_directly_in_room()
 *
 * Return TRUE if a given object is currently on the floor of a given room.
 */
static sc_bool
obj_directly_in_room_internal (sc_gameref_t game, sc_int object, sc_int room)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);

  /* See if the object is static or dynamic. */
  if (obj_is_static (game, object))
    {
      sc_vartype_t vt_key[5];
      sc_int type;

      /* Static object moved to player or room by event? */
      if (!gs_object_static_unmoved (game, object))
        {
          if (gs_object_position (game, object) == OBJ_HELD_PLAYER)
            return FALSE;
          else
            return gs_object_position (game, object) - 1 == room;
        }

      /* Check and return the room list for the object. */
      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "Where";
      vt_key[3].string = "Type";
      type = prop_get_integer (bundle, "I<-siss", vt_key);
      switch (type)
        {
        case ROOMLIST_ALL_ROOMS:
          return TRUE;
        case ROOMLIST_NO_ROOMS:
        case ROOMLIST_NPC_PART:
          return FALSE;

        case ROOMLIST_ONE_ROOM:
          vt_key[3].string = "Room";
          return prop_get_integer (bundle, "I<-siss", vt_key) == room + 1;

        case ROOMLIST_SOME_ROOMS:
          vt_key[3].string = "Rooms";
          vt_key[4].integer = room + 1;
          return prop_get_boolean (bundle, "B<-sissi", vt_key);

        default:
          sc_fatal ("obj_directly_in_room_internal:"
                    " invalid type, %ld\n", type);
          return FALSE;
        }
    }
  else
    return gs_object_position (game, object) == room + 1;
}

sc_bool
obj_directly_in_room (sc_gameref_t game, sc_int object, sc_int room)
{
  sc_bool result;

  /* Check, trace result, and return. */
  result = obj_directly_in_room_internal (game, object, room);

  if (obj_trace)
    {
      sc_trace ("Object: checking for object %ld directly in room %ld, %s\n",
                object, room, result ? "true" : "false");
    }

  return result;
}


/*
 * obj_indirectly_in_room_internal()
 * obj_indirectly_in_room()
 *
 * Return TRUE if a given object is currently in a given room, either
 * directly, on an object indirectly, in an open object indirectly, or
 * carried by an NPC in the room.
 */
static sc_bool
obj_indirectly_in_room_internal (sc_gameref_t game, sc_int object, sc_int room)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);

  /* See if the object is static or dynamic. */
  if (obj_is_static (game, object))
    {
      sc_vartype_t vt_key[5];
      sc_int type;

      /* Static object moved to player or room by event? */
      if (!gs_object_static_unmoved (game, object))
        {
          if (gs_object_position (game, object) == OBJ_HELD_PLAYER)
            return gs_player_in_room (game, room);
          else
            return gs_object_position (game, object) - 1 == room;
        }

      /* Check and return the room list for the object. */
      vt_key[0].string = "Objects";
      vt_key[1].integer = object;
      vt_key[2].string = "Where";
      vt_key[3].string = "Type";
      type = prop_get_integer (bundle, "I<-siss", vt_key);
      switch (type)
        {
        case ROOMLIST_ALL_ROOMS:
          return TRUE;
        case ROOMLIST_NO_ROOMS:
          return FALSE;

        case ROOMLIST_ONE_ROOM:
          vt_key[3].string = "Room";
          return prop_get_integer (bundle, "I<-siss", vt_key) == room + 1;

        case ROOMLIST_SOME_ROOMS:
          vt_key[3].string = "Rooms";
          vt_key[4].integer = room + 1;
          return prop_get_boolean (bundle, "B<-sissi", vt_key);

        case ROOMLIST_NPC_PART:
          {
            sc_int npc;

            vt_key[2].string = "Parent";
            npc = prop_get_integer (bundle, "I<-sis", vt_key);
            if (npc == 0)
              return gs_player_in_room (game, room);
            else
              return npc_in_room (game, npc - 1, room);
          }

        default:
          sc_fatal ("obj_indirectly_in_room_internal:"
                    " invalid type, %ld\n", type);
          return FALSE;
        }
    }
  else
    {
      sc_int parent, position;

      /* Get dynamic object's parent and position. */
      parent = gs_object_parent (game, object);
      position = gs_object_position (game, object);

      /* Decide depending on positioning. */
      switch (position)
        {
        case OBJ_HIDDEN:       /* Hidden. */
          return FALSE;

        case OBJ_HELD_PLAYER:  /* Held by player. */
        case OBJ_WORN_PLAYER:  /* Worn by player. */
          return gs_player_in_room (game, room);

        case OBJ_HELD_NPC:     /* Held by NPC. */
        case OBJ_WORN_NPC:     /* Worn by NPC. */
          return npc_in_room (game, parent, room);

        case OBJ_IN_OBJECT:    /* In another object. */
          {
            sc_int openness;

            openness = gs_object_openness (game, parent);
            switch (openness)
              {
              case OBJ_WONTCLOSE:
              case OBJ_OPEN:
                return obj_indirectly_in_room (game, parent, room);
              default:
                return FALSE;
              }
          }

        case OBJ_ON_OBJECT:    /* On another object. */
          return obj_indirectly_in_room (game, parent, room);

        default:               /* Within a room. */
          if (position > gs_room_count (game) + 1)
            {
              sc_error ("sc_object_indirectly_in_room:"
                        " position out of bounds, %ld\n", position);
            }
          return position - 1 == room;
        }
    }
}

sc_bool
obj_indirectly_in_room (sc_gameref_t game,
                        sc_int object, sc_int room)
{
  sc_bool result;

  /* Check, trace result, and return. */
  result = obj_indirectly_in_room_internal (game, object, room);

  if (obj_trace)
    {
      sc_trace ("Object: checking for object %ld indirectly in room %ld, %s\n",
                object, room, result ? "true" : "false");
    }

  return result;
}


/*
 * obj_indirectly_held_by_player_internal()
 * obj_indirectly_held_by_player()
 *
 * Return TRUE if a given object is currently held by the player, either
 * directly, on an object indirectly, or in an open object indirectly.
 */
static sc_bool
obj_indirectly_held_by_player_internal (sc_gameref_t game,
                                        sc_int object)
{
  /* See if the object is static or dynamic. */
  if (obj_is_static (game, object))
    {
      /* Static object moved to player or room by event? */
      if (!gs_object_static_unmoved (game, object))
        {
          if (gs_object_position (game, object) == OBJ_HELD_PLAYER)
            return TRUE;
          else
            return FALSE;
        }

      /* An unmoved static object is not held by the player. */
      return FALSE;
    }
  else
    {
      sc_int parent, position;

      /* Get dynamic object's parent and position. */
      parent = gs_object_parent (game, object);
      position = gs_object_position (game, object);

      /* Decide depending on positioning. */
      switch (position)
        {
        case OBJ_HIDDEN:       /* Hidden. */
          return FALSE;

        case OBJ_HELD_PLAYER:  /* Held by player. */
        case OBJ_WORN_PLAYER:  /* Worn by player. */
          return TRUE;

        case OBJ_HELD_NPC:     /* Held by NPC. */
        case OBJ_WORN_NPC:     /* Worn by NPC. */
          return FALSE;

        case OBJ_IN_OBJECT:    /* In another object. */
          {
            sc_int openness;

            openness = gs_object_openness (game, parent);
            switch (openness)
              {
              case OBJ_WONTCLOSE:
              case OBJ_OPEN:
                return obj_indirectly_held_by_player (game, parent);
              default:
                return FALSE;
              }
          }

        case OBJ_ON_OBJECT:    /* On another object. */
          return obj_indirectly_held_by_player (game, parent);

        default:               /* Within a room. */
          return FALSE;
        }
    }
}

sc_bool
obj_indirectly_held_by_player (sc_gameref_t game, sc_int object)
{
  sc_bool result;

  /* Check, trace result, and return. */
  result = obj_indirectly_held_by_player_internal (game, object);

  if (obj_trace)
    {
      sc_trace ("Object: checking for object %ld indirectly"
                " held by player, %s\n", object, result ? "true" : "false");
    }

  return result;
}


/*
 * sc_obj_shows_initial_description()
 *
 * Return TRUE if this object should be listed as room content.
 */
sc_bool
obj_shows_initial_description (sc_gameref_t game, sc_int object)
{
  const sc_prop_setref_t bundle = gs_get_bundle (game);
  sc_vartype_t vt_key[3];
  sc_int onlywhennotmoved;

  /* Get only when moved property. */
  vt_key[0].string = "Objects";
  vt_key[1].integer = object;
  vt_key[2].string = "OnlyWhenNotMoved";
  onlywhennotmoved = prop_get_integer (bundle, "I<-sis", vt_key);

  /* Combine this with game in mysterious ways. */
  switch (onlywhennotmoved)
    {
    case 0:
      return TRUE;

    case 1:
      return gs_object_unmoved (game, object);

    case 2:
      {
        sc_int initialposition;

        if (gs_object_unmoved (game, object))
          return TRUE;

        vt_key[2].string = "InitialPosition";
        initialposition = prop_get_integer (bundle, "I<-sis", vt_key) - 3;
        return gs_object_position (game, object) == initialposition;
      }
    }

  /* What you talkin' 'bout, Willis? */
  return FALSE;
}


/*
 * obj_turn_update()
 * obj_setup_initial()
 *
 * Set initial values for object states, and update after a turn.
 */
void
obj_turn_update (sc_gameref_t game)
{
  sc_int index_;

  /* Update object seen flag to current state. */
  for (index_ = 0; index_ < gs_object_count (game); index_++)
    {
      if (!gs_object_seen (game, index_)
          && obj_indirectly_in_room (game, index_, gs_playerroom (game)))
        gs_set_object_seen (game, index_, TRUE);
    }
}

void
obj_setup_initial (sc_gameref_t game)
{
  /* Set initial seen states for objects. */
  obj_turn_update (game);
}


/*
 * obj_debug_trace()
 *
 * Set object tracing on/off.
 */
void
obj_debug_trace (sc_bool flag)
{
  obj_trace = flag;
}

} // End of namespace Adrift
} // End of namespace Glk