server/common/los.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 2002,2007 Mark Wedel & Crossfire Development Team
 * Copyright (©) 1992,2007 Frank Tore Johansen
 * 
 * Deliantra 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 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 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 <cmath>

#define SEE_IN_DARK_RADIUS 3

// los flags
enum {
  FLG_XI      = 0x01, // we have an x-parent
  FLG_YI      = 0x02, // we have an y-parent
  FLG_BLOCKED = 0x04, // this space blocks the view
  FLG_QUEUED  = 0x80  // already queued in queue, or border
};

struct los_info
{
  uint8 flags;   // FLG_xxx
  uint8 culled;  // culled from "tree"
  uint8 visible;
  uint8 pad0;

  sint8 xo, yo;  // obscure angle
  sint8 xe, ye;  // angle deviation
};

// temporary storage for the los algorithm,
// one los_info for each lightable map space
static los_info los[MAP_CLIENT_X][MAP_CLIENT_Y];

struct point
{
  sint8 x, y;
};

// minimum size, but must be a power of two
#define QUEUE_LENGTH ((MAP_CLIENT_X + MAP_CLIENT_Y) * 2)

// a queue of spaces to calculate
static point queue [QUEUE_LENGTH];
static int q1, q2; // queue start, end

/*
 * Clears/initialises the los-array associated to the player
 * controlling the object.
 */
void
player::clear_los (sint8 value)
{
  memset (los, value, sizeof (los));
}

// enqueue a single mapspace, but only if it hasn't
// been enqueued yet.
static void
enqueue (sint8 dx, sint8 dy, uint8 flags = 0)
{
  sint8 x = LOS_X0 + dx;
  sint8 y = LOS_Y0 + dy;

  los_info &l = los[x][y];

  l.flags |= flags;

  if (l.flags & FLG_QUEUED)
    return;

  l.flags |= FLG_QUEUED;

  queue[q1].x = dx;
  queue[q1].y = dy;

  q1 = (q1 + 1) & (QUEUE_LENGTH - 1);
}

// run the los algorithm
// this is a variant of a spiral los algorithm taken from
// http://www.geocities.com/temerra/los_rays.html
// which has been simplified and changed considerably, but
// still is basically the same algorithm.
static void
calculate_los (player *pl)
{
  {
    // we keep one line for ourselves, for the border flag
    // so the client area is actually MAP_CLIENT_(X|Y) - 2
    int half_x = min (LOS_X0 - 1, pl->ns->mapx / 2);
    int half_y = min (LOS_Y0 - 1, pl->ns->mapy / 2);

    // create borders, the corners are not touched
    for (int dx = -half_x; dx <= half_x; ++dx)
      los [dx + LOS_X0][LOS_Y0 - (half_y + 1)].flags =
      los [dx + LOS_X0][LOS_Y0 + (half_y + 1)].flags = FLG_QUEUED;

    for (int dy = -half_y; dy <= half_y; ++dy)
      los [LOS_X0 - (half_x + 1)][dy + LOS_Y0].flags =
      los [LOS_X0 + (half_x + 1)][dy + LOS_Y0].flags = FLG_QUEUED;

    // now reset the los area and also add blocked flags
    // which supposedly is faster than doing it inside the
    // spiral path algorithm below, except when very little
    // area is visible, in which case it is slower, evening
    // out los calculation times between large and small los maps.
    // apply_lights also iterates over this area, maybe these
    // two passes could be combined somehow.
    rectangular_mapspace_iterate_begin (pl->observe, -half_x, half_x, -half_y, half_y)
      los_info &l = los [LOS_X0 + dx][LOS_Y0 + dy];
      l.flags = m && m->at (nx, ny).flags () & P_BLOCKSVIEW ? FLG_BLOCKED : 0;
    rectangular_mapspace_iterate_end
  }

  q1 = 0; q2 = 0; // initialise queue, not strictly required
  enqueue (0, 0); // enqueue center

  // treat the origin specially
  los[LOS_X0][LOS_Y0].visible = 1;
  pl->los[LOS_X0][LOS_Y0] = 0;

  // loop over all enqueued points until the queue is empty
  // the order in which this is done ensures that we
  // never touch a mapspace whose input spaces we haven't checked
  // yet.
  while (q1 != q2)
    {
      sint8 dx = queue[q2].x;
      sint8 dy = queue[q2].y;

      q2 = (q2 + 1) & (QUEUE_LENGTH - 1);

      sint8 x = LOS_X0 + dx;
      sint8 y = LOS_Y0 + dy;

      los_info &l = los[x][y];

      if (expect_true (l.flags & (FLG_XI | FLG_YI)))
        {
          l.culled = 1;
          l.xo = l.yo = l.xe = l.ye = 0;

          // check contributing spaces, first horizontal
          if (expect_true (l.flags & FLG_XI))
            {
              los_info *xi = &los[x - sign (dx)][y];

              // don't cull unless obscured
              l.culled &= !xi->visible;

              /* merge input space */
              if (expect_false (xi->xo || xi->yo))
                {
                  // The X input can provide two main pieces of information: 
                  // 1. Progressive X obscurity.
                  // 2. Recessive Y obscurity.
                          
                  // Progressive X obscurity, favouring recessive input angle
                  if (xi->xe > 0 && l.xo == 0)
                    {
                      l.xe = xi->xe - xi->yo;
                      l.ye = xi->ye + xi->yo;
                      l.xo = xi->xo;
                      l.yo = xi->yo;
                    }

                  // Recessive Y obscurity
                  if (xi->ye <= 0 && xi->yo > 0 && xi->xe > 0)
                    {
                      l.ye = xi->yo + xi->ye;
                      l.xe = xi->xe - xi->yo;
                      l.xo = xi->xo;
                      l.yo = xi->yo;
                    }
                }
            }
                
          // check contributing spaces, last vertical, identical structure
          if (expect_true (l.flags & FLG_YI))
            {
              los_info *yi = &los[x][y - sign (dy)];

              // don't cull unless obscured
              l.culled &= !yi->visible;

              /* merge input space */
              if (expect_false (yi->yo || yi->xo))
                {
                  // The Y input can provide two main pieces of information: 
                  // 1. Progressive Y obscurity.
                  // 2. Recessive X obscurity.
                          
                  // Progressive Y obscurity, favouring recessive input angle
                  if (yi->ye > 0 && l.yo == 0)
                    {
                      l.ye = yi->ye - yi->xo;
                      l.xe = yi->xe + yi->xo;
                      l.yo = yi->yo;
                      l.xo = yi->xo;
                    }

                  // Recessive X obscurity
                  if (yi->xe <= 0 && yi->xo > 0 && yi->ye > 0)
                    {
                      l.xe = yi->xo + yi->xe;
                      l.ye = yi->ye - yi->xo;
                      l.yo = yi->yo;
                      l.xo = yi->xo;
                    }
                }
            }

          if (l.flags & FLG_BLOCKED)
            {
              l.xo = l.xe = abs (dx);
              l.yo = l.ye = abs (dy);

              // we obscure dependents, but might be visible
              // copy the los from the square towards the player,
              // so outward diagonal corners are lit.
              pl->los[x][y] = los[x - sign0 (dx)][y - sign0 (dy)].visible ? 0 : LOS_BLOCKED;

              l.visible = false;
            }
          else
            {
              // we are not blocked, so calculate visibility, by checking
              // whether we are inside or outside the shadow
              l.visible = (l.xe <= 0 || l.xe > l.xo)
                       && (l.ye <= 0 || l.ye > l.yo);

              pl->los[x][y] = l.culled  ? LOS_BLOCKED
                            : l.visible ? 0
                                        : 3;
            }

        }

      // Expands by the unit length in each component's current direction.
      // If a component has no direction, then it is expanded in both of its 
      // positive and negative directions.
      if (!l.culled)
        {
          if (dx >= 0) enqueue (dx + 1, dy, FLG_XI);
          if (dx <= 0) enqueue (dx - 1, dy, FLG_XI);
          if (dy >= 0) enqueue (dx, dy + 1, FLG_YI);
          if (dy <= 0) enqueue (dx, dy - 1, FLG_YI);
        }
    }
}

/* returns true if op carries one or more lights
 * This is a trivial function now days, but it used to
 * be a bit longer.  Probably better for callers to just
 * check the op->glow_radius instead of calling this.
 */
int
has_carried_lights (const object *op)
{
  /* op may glow! */
  if (op->glow_radius > 0)
    return 1;

  return 0;
}

/* radius, distance => lightness adjust */
static sint8 light_atten[MAX_LIGHT_RADIUS * 2 + 1][MAX_LIGHT_RADIUS * 3 / 2 + 1];
static sint8 vision_atten[MAX_DARKNESS + SEE_IN_DARK_RADIUS + 1][(MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2 + 1];

static struct los_init
{
  los_init ()
  {
    assert (("QUEUE_LENGTH, MAP_CLIENT_X and MAP_CLIENT_Y *must* be powers of two",
             !(QUEUE_LENGTH & (QUEUE_LENGTH - 1))));

    /* for lights */
    for (int radius = -MAX_LIGHT_RADIUS; radius <= MAX_LIGHT_RADIUS; ++radius)
      for (int distance = 0; distance <= MAX_LIGHT_RADIUS * 3 / 2; ++distance)
        {
          // max intensity
          int intensity = min (LOS_MAX, abs (radius) + 1);

          // actual intensity
          intensity = max (0, lerp_rd (distance, 0, abs (radius) + 1, intensity, 0));

          light_atten [radius + MAX_LIGHT_RADIUS][distance] = radius < 0
            ? min (3, intensity)
            : LOS_MAX - intensity;
        }

    /* for general vision */
    for (int radius = 0; radius <= MAX_DARKNESS + SEE_IN_DARK_RADIUS; ++radius)
      for (int distance = 0; distance <= (MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2; ++distance)
        vision_atten [radius][distance] = distance <= radius ? 3 : 4;
  }
} los_init;

sint8
los_brighten (sint8 b, sint8 l)
{
  return b == LOS_BLOCKED ? b : min (b, l);
}

sint8
los_darken (sint8 b, sint8 l)
{
  return max (b, l);
}

template<sint8 change_it (sint8, sint8)>
static void
apply_light (player *pl, int dx, int dy, int light, const sint8 *atten_table)
{
  // min or max the circular area around basex, basey
  dx += LOS_X0;
  dy += LOS_Y0;

  int hx = pl->ns->mapx / 2;
  int hy = pl->ns->mapy / 2;

  int ax0 = max (LOS_X0 - hx, dx - light);
  int ay0 = max (LOS_Y0 - hy, dy - light);
  int ax1 = min (dx + light, LOS_X0 + hx);
  int ay1 = min (dy + light, LOS_Y0 + hy);

  for (int ax = ax0; ax <= ax1; ax++)
    for (int ay = ay0; ay <= ay1; ay++)
      pl->los[ax][ay] =
        change_it (pl->los[ax][ay], atten_table [idistance (ax - dx, ay - dy)]);
}

/* add light, by finding all (non-null) nearby light sources, then 
 * mark those squares specially.
 */
static void
apply_lights (player *pl)
{
  object *op = pl->observe;
  int darklevel = op->map->darklevel ();

  int half_x = pl->ns->mapx / 2;
  int half_y = pl->ns->mapy / 2;

  int pass2 = 0; // negative lights have an extra pass

  if (!darklevel)
    pass2 = 1;
  else
    {
      /* first, make everything totally dark */
      for (int dx = -half_x; dx <= half_x; dx++)
        for (int dy = -half_x; dy <= half_y; dy++)
          max_it (pl->los[dx + LOS_X0][dy + LOS_Y0], LOS_MAX);

      /*
       * Only process the area of interest.
       * the basex, basey values represent the position in the op->contr->los
       * array. Its easier to just increment them here (and start with the right
       * value) than to recalculate them down below.
       */
      rectangular_mapspace_iterate_begin (pl->observe, -half_x - MAX_LIGHT_RADIUS, half_x + MAX_LIGHT_RADIUS, -half_y - MAX_LIGHT_RADIUS, half_y + MAX_LIGHT_RADIUS)
        if (m)
          {
            mapspace &ms = m->at (nx, ny);
            ms.update ();
            sint8 light = ms.light;

            if (expect_false (light))
              if (light < 0)
                pass2 = 1;
              else
                apply_light<los_brighten> (pl, dx, dy, light, light_atten [light + MAX_LIGHT_RADIUS]);
          }
      rectangular_mapspace_iterate_end

      /* grant some vision to the player, based on the darklevel */
      {
        int light = clamp (MAX_DARKNESS - darklevel, 0, MAX_DARKNESS);

        /* If the player can see in the dark, lower the darklevel for him */
        if (op->flag [FLAG_SEE_IN_DARK])
          light += SEE_IN_DARK_RADIUS;

        apply_light<los_brighten> (pl, 0, 0, light, vision_atten [light]);
      }
    }

  // possibly do 2nd pass for rare negative glow radii
  // for effect, those are always considered to be stronger than anything else
  // but they can't darken a place completely
  if (pass2)
    rectangular_mapspace_iterate_begin (pl->observe, -half_x - MAX_LIGHT_RADIUS, half_x + MAX_LIGHT_RADIUS, -half_y - MAX_LIGHT_RADIUS, half_y + MAX_LIGHT_RADIUS)
     if (m)
       {
         mapspace &ms = m->at (nx, ny);
         ms.update ();
         sint8 light = ms.light;

         if (expect_false (light < 0))
           apply_light<los_darken> (pl, dx, dy, -light, light_atten [light + MAX_LIGHT_RADIUS]);
       }
    rectangular_mapspace_iterate_end
}

/* blinded_sight() - sets all viewable squares to blocked except 
 * for the one the central one that the player occupies.  A little
 * odd that you can see yourself (and what your standing on), but
 * really need for any reasonable game play.
 */
static void
blinded_sight (player *pl)
{
  pl->los[LOS_X0][LOS_Y0] = 1;
}

/*
 * update_los() recalculates the array which specifies what is
 * visible for the given player-object.
 */
void
player::update_los ()
{
  if (ob->flag [FLAG_REMOVED])//D really needed?
    return;

  if (ob->flag [FLAG_WIZLOOK])
    clear_los (0);
  else if (observe->flag [FLAG_BLIND])      /* player is blind */
    {
      clear_los ();
      blinded_sight (this);
    }
  else
    {
      clear_los ();
      calculate_los (this);
      apply_lights (this);
    }

  if (observe->flag [FLAG_XRAYS])
    for (int dx = -2; dx <= 2; dx++)
      for (int dy = -2; dy <= 2; dy++)
        min_it (los[dx + LOS_X0][dy + LOS_Y0], 1);
}

/* update all_map_los is like update_all_los below,
 * but updates everyone on the map, no matter where they
 * are. This generally should not be used, as a per
 * specific map change doesn't make much sense when tiling
 * is considered (lowering darkness would certainly be a
 * strange effect if done on a tile map, as it makes
 * the distinction between maps much more obvious to the
 * players, which is should not be.
 * Currently, this function is called from the
 * change_map_light function
 */
void
update_all_map_los (maptile *map)
{
  for_all_players_on_map (pl, map)
    pl->do_los = 1;
}

/*
 * This function makes sure that update_los() will be called for all
 * players on the given map within the next frame.
 * It is triggered by removal or inserting of objects which blocks
 * the sight in the map.
 * Modified by MSW 2001-07-12 to take a coordinate of the changed
 * position, and to also take map tiling into account.  This change
 * means that just being on the same map is not sufficient - the
 * space that changes must be withing your viewable area.
 *
 * map is the map that changed, x and y are the coordinates.
 */
void
update_all_los (const maptile *map, int x, int y)
{
  map->at (x, y).invalidate ();

  for_all_players (pl)
    {
      /* Player should not have a null map, but do this
       * check as a safety
       */
      if (!pl->ob || !pl->ob->map || !pl->ns)
        continue;

      /* Same map is simple case - see if pl is close enough.
       * Note in all cases, we did the check for same map first,
       * and then see if the player is close enough and update
       * los if that is the case.  If the player is on the
       * corresponding map, but not close enough, then the
       * player can't be on another map that may be closer,
       * so by setting it up this way, we trim processing
       * some.
       */
      if (pl->ob->map == map)
        {
          if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
            pl->do_los = 1;
        }

      /* Now we check to see if player is on adjacent
       * maps to the one that changed and also within
       * view.  The tile_maps[] could be null, but in that
       * case it should never match the pl->ob->map, so
       * we want ever try to dereference any of the data in it.
       *
       * The logic for 0 and 3 is to see how far the player is
       * from the edge of the map (height/width) - pl->ob->(x,y)
       * and to add current position on this map - that gives a
       * distance.
       * For 1 and 2, we check to see how far the given
       * coordinate (x,y) is from the corresponding edge,
       * and then add the players location, which gives
       * a distance.
       */
      else if (pl->ob->map == map->tile_map[0])
        {
          if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (y + map->tile_map[0]->height - pl->ob->y) <= pl->ns->mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[2])
        {
          if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y + map->height - y) <= pl->ns->mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[1])
        {
          if ((abs (pl->ob->x + map->width - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[3])
        {
          if ((abs (x + map->tile_map[3]->width - pl->ob->x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
            pl->do_los = 1;
        }
    }
}

static const int season_darkness[5][HOURS_PER_DAY] = {
  /*0  1  2  3  4  5  6  7  8  9 10 11 12 13 14  1  2  3  4  5  6  7  8  9 10 11 12 13 */
  { 5, 5, 4, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 1, 2, 2, 2, 3, 3, 4, 4, 5 },
  { 5, 5, 4, 4, 4, 4, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4 },
  { 5, 4, 4, 4, 4, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 4, 4 },
  { 4, 4, 4, 4, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 4 },
  { 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4 }
};

/*
 * Tell players the time and compute the darkness level for all maps in the game.
 * MUST be called exactly once per hour.
 */
void
maptile::adjust_daylight ()
{
  timeofday_t tod;

  get_tod (&tod);

  // log the time to log-1 every hour, and to chat every day
  {
    char todbuf[512];

    format_tod (todbuf, sizeof (todbuf), &tod);

    for_all_players (pl)
      pl->ns->send_msg (NDI_GREY, tod.hour == 15 ? CHAT_CHANNEL : LOG_CHANNEL, todbuf);
  }

  /* If the light level isn't changing, no reason to do all
   * the work below.
   */
  sint8 new_darkness = season_darkness[tod.season][tod.hour];

  if (new_darkness == maptile::outdoor_darkness)
    return;

  new_draw_info (NDI_GREY | NDI_UNIQUE | NDI_ALL, 1, 0,
                 new_darkness > maptile::outdoor_darkness
                 ? "It becomes darker."
                 : "It becomes brighter.");

  maptile::outdoor_darkness = new_darkness;

  // we simply update the los for all players, which is unnecessarily
  // costly, but should do for the moment.
  for_all_players (pl)
    pl->do_los = 1;
}

/*
 * make_sure_seen: The object is supposed to be visible through walls, thus
 * check if any players are nearby, and edit their LOS array.
 */
void
make_sure_seen (const object *op)
{
  for_all_players (pl)
    if (pl->ob->map == op->map &&
        pl->ob->y - pl->ns->mapy / 2 <= op->y &&
        pl->ob->y + pl->ns->mapy / 2 >= op->y && pl->ob->x - pl->ns->mapx / 2 <= op->x && pl->ob->x + pl->ns->mapx / 2 >= op->x)
      pl->los[op->x - pl->ob->x + LOS_X0][op->y - pl->ob->y + LOS_Y0] = 0;
}

/*
 * make_sure_not_seen: The object which is supposed to be visible through
 * walls has just been removed from the map, so update the los of any
 * players within its range
 */
void
make_sure_not_seen (const object *op)
{
  for_all_players (pl)
    if (pl->ob->map == op->map &&
        pl->ob->y - pl->ns->mapy / 2 <= op->y &&
        pl->ob->y + pl->ns->mapy / 2 >= op->y && pl->ob->x - pl->ns->mapx / 2 <= op->x && pl->ob->x + pl->ns->mapx / 2 >= op->x)
      pl->do_los = 1;
}
Revision:	1.51
Committed:	Wed Dec 24 01:37:23 2008 UTC (15 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.50:	+10 -10 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2005,2006,2007,2008 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	* Copyright (©) 2002,2007 Mark Wedel & Crossfire Development Team
6	* Copyright (©) 1992,2007 Frank Tore Johansen
7	*
8	* Deliantra is free software: you can redistribute it and/or modify
9	* it under the terms of the GNU General Public License as published by
10	* the Free Software Foundation, either version 3 of the License, or
11	* (at your option) any later version.
12	*
13	* This program is distributed in the hope that it will be useful,
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16	* GNU General Public License for more details.
17	*
18	* You should have received a copy of the GNU General Public License
19	* along with this program. If not, see <http://www.gnu.org/licenses/>.
20	*
21	* The authors can be reached via e-mail to <support@deliantra.net>
22	*/
23
24	#include <global.h>
25	#include <cmath>
26
27	#define SEE_IN_DARK_RADIUS 3
28
29	// los flags
30	enum {
31	FLG_XI = 0x01, // we have an x-parent
32	FLG_YI = 0x02, // we have an y-parent
33	FLG_BLOCKED = 0x04, // this space blocks the view
34	FLG_QUEUED = 0x80 // already queued in queue, or border
35	};
36
37	struct los_info
38	{
39	uint8 flags; // FLG_xxx
40	uint8 culled; // culled from "tree"
41	uint8 visible;
42	uint8 pad0;
43
44	sint8 xo, yo; // obscure angle
45	sint8 xe, ye; // angle deviation
46	};
47
48	// temporary storage for the los algorithm,
49	// one los_info for each lightable map space
50	static los_info los[MAP_CLIENT_X][MAP_CLIENT_Y];
51
52	struct point
53	{
54	sint8 x, y;
55	};
56
57	// minimum size, but must be a power of two
58	#define QUEUE_LENGTH ((MAP_CLIENT_X + MAP_CLIENT_Y) * 2)
59
60	// a queue of spaces to calculate
61	static point queue [QUEUE_LENGTH];
62	static int q1, q2; // queue start, end
63
64	/*
65	* Clears/initialises the los-array associated to the player
66	* controlling the object.
67	*/
68	void
69	player::clear_los (sint8 value)
70	{
71	memset (los, value, sizeof (los));
72	}
73
74	// enqueue a single mapspace, but only if it hasn't
75	// been enqueued yet.
76	static void
77	enqueue (sint8 dx, sint8 dy, uint8 flags = 0)
78	{
79	sint8 x = LOS_X0 + dx;
80	sint8 y = LOS_Y0 + dy;
81
82	los_info &l = los[x][y];
83
84	l.flags \|= flags;
85
86	if (l.flags & FLG_QUEUED)
87	return;
88
89	l.flags \|= FLG_QUEUED;
90
91	queue[q1].x = dx;
92	queue[q1].y = dy;
93
94	q1 = (q1 + 1) & (QUEUE_LENGTH - 1);
95	}
96
97	// run the los algorithm
98	// this is a variant of a spiral los algorithm taken from
99	// http://www.geocities.com/temerra/los_rays.html
100	// which has been simplified and changed considerably, but
101	// still is basically the same algorithm.
102	static void
103	calculate_los (player *pl)
104	{
105	{
106	// we keep one line for ourselves, for the border flag
107	// so the client area is actually MAP_CLIENT_(X\|Y) - 2
108	int half_x = min (LOS_X0 - 1, pl->ns->mapx / 2);
109	int half_y = min (LOS_Y0 - 1, pl->ns->mapy / 2);
110
111	// create borders, the corners are not touched
112	for (int dx = -half_x; dx <= half_x; ++dx)
113	los [dx + LOS_X0][LOS_Y0 - (half_y + 1)].flags =
114	los [dx + LOS_X0][LOS_Y0 + (half_y + 1)].flags = FLG_QUEUED;
115
116	for (int dy = -half_y; dy <= half_y; ++dy)
117	los [LOS_X0 - (half_x + 1)][dy + LOS_Y0].flags =
118	los [LOS_X0 + (half_x + 1)][dy + LOS_Y0].flags = FLG_QUEUED;
119
120	// now reset the los area and also add blocked flags
121	// which supposedly is faster than doing it inside the
122	// spiral path algorithm below, except when very little
123	// area is visible, in which case it is slower, evening
124	// out los calculation times between large and small los maps.
125	// apply_lights also iterates over this area, maybe these
126	// two passes could be combined somehow.
127	rectangular_mapspace_iterate_begin (pl->observe, -half_x, half_x, -half_y, half_y)
128	los_info &l = los [LOS_X0 + dx][LOS_Y0 + dy];
129	l.flags = m && m->at (nx, ny).flags () & P_BLOCKSVIEW ? FLG_BLOCKED : 0;
130	rectangular_mapspace_iterate_end
131	}
132
133	q1 = 0; q2 = 0; // initialise queue, not strictly required
134	enqueue (0, 0); // enqueue center
135
136	// treat the origin specially
137	los[LOS_X0][LOS_Y0].visible = 1;
138	pl->los[LOS_X0][LOS_Y0] = 0;
139
140	// loop over all enqueued points until the queue is empty
141	// the order in which this is done ensures that we
142	// never touch a mapspace whose input spaces we haven't checked
143	// yet.
144	while (q1 != q2)
145	{
146	sint8 dx = queue[q2].x;
147	sint8 dy = queue[q2].y;
148
149	q2 = (q2 + 1) & (QUEUE_LENGTH - 1);
150
151	sint8 x = LOS_X0 + dx;
152	sint8 y = LOS_Y0 + dy;
153
154	los_info &l = los[x][y];
155
156	if (expect_true (l.flags & (FLG_XI \| FLG_YI)))
157	{
158	l.culled = 1;
159	l.xo = l.yo = l.xe = l.ye = 0;
160
161	// check contributing spaces, first horizontal
162	if (expect_true (l.flags & FLG_XI))
163	{
164	los_info *xi = &los[x - sign (dx)][y];
165
166	// don't cull unless obscured
167	l.culled &= !xi->visible;
168
169	/* merge input space */
170	if (expect_false (xi->xo \|\| xi->yo))
171	{
172	// The X input can provide two main pieces of information:
173	// 1. Progressive X obscurity.
174	// 2. Recessive Y obscurity.
175
176	// Progressive X obscurity, favouring recessive input angle
177	if (xi->xe > 0 && l.xo == 0)
178	{
179	l.xe = xi->xe - xi->yo;
180	l.ye = xi->ye + xi->yo;
181	l.xo = xi->xo;
182	l.yo = xi->yo;
183	}
184
185	// Recessive Y obscurity
186	if (xi->ye <= 0 && xi->yo > 0 && xi->xe > 0)
187	{
188	l.ye = xi->yo + xi->ye;
189	l.xe = xi->xe - xi->yo;
190	l.xo = xi->xo;
191	l.yo = xi->yo;
192	}
193	}
194	}
195
196	// check contributing spaces, last vertical, identical structure
197	if (expect_true (l.flags & FLG_YI))
198	{
199	los_info *yi = &los[x][y - sign (dy)];
200
201	// don't cull unless obscured
202	l.culled &= !yi->visible;
203
204	/* merge input space */
205	if (expect_false (yi->yo \|\| yi->xo))
206	{
207	// The Y input can provide two main pieces of information:
208	// 1. Progressive Y obscurity.
209	// 2. Recessive X obscurity.
210
211	// Progressive Y obscurity, favouring recessive input angle
212	if (yi->ye > 0 && l.yo == 0)
213	{
214	l.ye = yi->ye - yi->xo;
215	l.xe = yi->xe + yi->xo;
216	l.yo = yi->yo;
217	l.xo = yi->xo;
218	}
219
220	// Recessive X obscurity
221	if (yi->xe <= 0 && yi->xo > 0 && yi->ye > 0)
222	{
223	l.xe = yi->xo + yi->xe;
224	l.ye = yi->ye - yi->xo;
225	l.yo = yi->yo;
226	l.xo = yi->xo;
227	}
228	}
229	}
230
231	if (l.flags & FLG_BLOCKED)
232	{
233	l.xo = l.xe = abs (dx);
234	l.yo = l.ye = abs (dy);
235
236	// we obscure dependents, but might be visible
237	// copy the los from the square towards the player,
238	// so outward diagonal corners are lit.
239	pl->los[x][y] = los[x - sign0 (dx)][y - sign0 (dy)].visible ? 0 : LOS_BLOCKED;
240
241	l.visible = false;
242	}
243	else
244	{
245	// we are not blocked, so calculate visibility, by checking
246	// whether we are inside or outside the shadow
247	l.visible = (l.xe <= 0 \|\| l.xe > l.xo)
248	&& (l.ye <= 0 \|\| l.ye > l.yo);
249
250	pl->los[x][y] = l.culled ? LOS_BLOCKED
251	: l.visible ? 0
252	: 3;
253	}
254
255	}
256
257	// Expands by the unit length in each component's current direction.
258	// If a component has no direction, then it is expanded in both of its
259	// positive and negative directions.
260	if (!l.culled)
261	{
262	if (dx >= 0) enqueue (dx + 1, dy, FLG_XI);
263	if (dx <= 0) enqueue (dx - 1, dy, FLG_XI);
264	if (dy >= 0) enqueue (dx, dy + 1, FLG_YI);
265	if (dy <= 0) enqueue (dx, dy - 1, FLG_YI);
266	}
267	}
268	}
269
270	/* returns true if op carries one or more lights
271	* This is a trivial function now days, but it used to
272	* be a bit longer. Probably better for callers to just
273	* check the op->glow_radius instead of calling this.
274	*/
275	int
276	has_carried_lights (const object *op)
277	{
278	/* op may glow! */
279	if (op->glow_radius > 0)
280	return 1;
281
282	return 0;
283	}
284
285	/* radius, distance => lightness adjust */
286	static sint8 light_atten[MAX_LIGHT_RADIUS * 2 + 1][MAX_LIGHT_RADIUS * 3 / 2 + 1];
287	static sint8 vision_atten[MAX_DARKNESS + SEE_IN_DARK_RADIUS + 1][(MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2 + 1];
288
289	static struct los_init
290	{
291	los_init ()
292	{
293	assert (("QUEUE_LENGTH, MAP_CLIENT_X and MAP_CLIENT_Y must be powers of two",
294	!(QUEUE_LENGTH & (QUEUE_LENGTH - 1))));
295
296	/* for lights */
297	for (int radius = -MAX_LIGHT_RADIUS; radius <= MAX_LIGHT_RADIUS; ++radius)
298	for (int distance = 0; distance <= MAX_LIGHT_RADIUS * 3 / 2; ++distance)
299	{
300	// max intensity
301	int intensity = min (LOS_MAX, abs (radius) + 1);
302
303	// actual intensity
304	intensity = max (0, lerp_rd (distance, 0, abs (radius) + 1, intensity, 0));
305
306	light_atten [radius + MAX_LIGHT_RADIUS][distance] = radius < 0
307	? min (3, intensity)
308	: LOS_MAX - intensity;
309	}
310
311	/* for general vision */
312	for (int radius = 0; radius <= MAX_DARKNESS + SEE_IN_DARK_RADIUS; ++radius)
313	for (int distance = 0; distance <= (MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2; ++distance)
314	vision_atten [radius][distance] = distance <= radius ? 3 : 4;
315	}
316	} los_init;
317
318	sint8
319	los_brighten (sint8 b, sint8 l)
320	{
321	return b == LOS_BLOCKED ? b : min (b, l);
322	}
323
324	sint8
325	los_darken (sint8 b, sint8 l)
326	{
327	return max (b, l);
328	}
329
330	template<sint8 change_it (sint8, sint8)>
331	static void
332	apply_light (player pl, int dx, int dy, int light, const sint8 atten_table)
333	{
334	// min or max the circular area around basex, basey
335	dx += LOS_X0;
336	dy += LOS_Y0;
337
338	int hx = pl->ns->mapx / 2;
339	int hy = pl->ns->mapy / 2;
340
341	int ax0 = max (LOS_X0 - hx, dx - light);
342	int ay0 = max (LOS_Y0 - hy, dy - light);
343	int ax1 = min (dx + light, LOS_X0 + hx);
344	int ay1 = min (dy + light, LOS_Y0 + hy);
345
346	for (int ax = ax0; ax <= ax1; ax++)
347	for (int ay = ay0; ay <= ay1; ay++)
348	pl->los[ax][ay] =
349	change_it (pl->los[ax][ay], atten_table [idistance (ax - dx, ay - dy)]);
350	}
351
352	/* add light, by finding all (non-null) nearby light sources, then
353	* mark those squares specially.
354	*/
355	static void
356	apply_lights (player *pl)
357	{
358	object *op = pl->observe;
359	int darklevel = op->map->darklevel ();
360
361	int half_x = pl->ns->mapx / 2;
362	int half_y = pl->ns->mapy / 2;
363
364	int pass2 = 0; // negative lights have an extra pass
365
366	if (!darklevel)
367	pass2 = 1;
368	else
369	{
370	/* first, make everything totally dark */
371	for (int dx = -half_x; dx <= half_x; dx++)
372	for (int dy = -half_x; dy <= half_y; dy++)
373	max_it (pl->los[dx + LOS_X0][dy + LOS_Y0], LOS_MAX);
374
375	/*
376	* Only process the area of interest.
377	* the basex, basey values represent the position in the op->contr->los
378	* array. Its easier to just increment them here (and start with the right
379	* value) than to recalculate them down below.
380	*/
381	rectangular_mapspace_iterate_begin (pl->observe, -half_x - MAX_LIGHT_RADIUS, half_x + MAX_LIGHT_RADIUS, -half_y - MAX_LIGHT_RADIUS, half_y + MAX_LIGHT_RADIUS)
382	if (m)
383	{
384	mapspace &ms = m->at (nx, ny);
385	ms.update ();
386	sint8 light = ms.light;
387
388	if (expect_false (light))
389	if (light < 0)
390	pass2 = 1;
391	else
392	apply_light<los_brighten> (pl, dx, dy, light, light_atten [light + MAX_LIGHT_RADIUS]);
393	}
394	rectangular_mapspace_iterate_end
395
396	/* grant some vision to the player, based on the darklevel */
397	{
398	int light = clamp (MAX_DARKNESS - darklevel, 0, MAX_DARKNESS);
399
400	/* If the player can see in the dark, lower the darklevel for him */
401	if (op->flag [FLAG_SEE_IN_DARK])
402	light += SEE_IN_DARK_RADIUS;
403
404	apply_light<los_brighten> (pl, 0, 0, light, vision_atten [light]);
405	}
406	}
407
408	// possibly do 2nd pass for rare negative glow radii
409	// for effect, those are always considered to be stronger than anything else
410	// but they can't darken a place completely
411	if (pass2)
412	rectangular_mapspace_iterate_begin (pl->observe, -half_x - MAX_LIGHT_RADIUS, half_x + MAX_LIGHT_RADIUS, -half_y - MAX_LIGHT_RADIUS, half_y + MAX_LIGHT_RADIUS)
413	if (m)
414	{
415	mapspace &ms = m->at (nx, ny);
416	ms.update ();
417	sint8 light = ms.light;
418
419	if (expect_false (light < 0))
420	apply_light<los_darken> (pl, dx, dy, -light, light_atten [light + MAX_LIGHT_RADIUS]);
421	}
422	rectangular_mapspace_iterate_end
423	}
424
425	/* blinded_sight() - sets all viewable squares to blocked except
426	* for the one the central one that the player occupies. A little
427	* odd that you can see yourself (and what your standing on), but
428	* really need for any reasonable game play.
429	*/
430	static void
431	blinded_sight (player *pl)
432	{
433	pl->los[LOS_X0][LOS_Y0] = 1;
434	}
435
436	/*
437	* update_los() recalculates the array which specifies what is
438	* visible for the given player-object.
439	*/
440	void
441	player::update_los ()
442	{
443	if (ob->flag [FLAG_REMOVED])//D really needed?
444	return;
445
446	if (ob->flag [FLAG_WIZLOOK])
447	clear_los (0);
448	else if (observe->flag [FLAG_BLIND]) /* player is blind */
449	{
450	clear_los ();
451	blinded_sight (this);
452	}
453	else
454	{
455	clear_los ();
456	calculate_los (this);
457	apply_lights (this);
458	}
459
460	if (observe->flag [FLAG_XRAYS])
461	for (int dx = -2; dx <= 2; dx++)
462	for (int dy = -2; dy <= 2; dy++)
463	min_it (los[dx + LOS_X0][dy + LOS_Y0], 1);
464	}
465
466	/* update all_map_los is like update_all_los below,
467	* but updates everyone on the map, no matter where they
468	* are. This generally should not be used, as a per
469	* specific map change doesn't make much sense when tiling
470	* is considered (lowering darkness would certainly be a
471	* strange effect if done on a tile map, as it makes
472	* the distinction between maps much more obvious to the
473	* players, which is should not be.
474	* Currently, this function is called from the
475	* change_map_light function
476	*/
477	void
478	update_all_map_los (maptile *map)
479	{
480	for_all_players_on_map (pl, map)
481	pl->do_los = 1;
482	}
483
484	/*
485	* This function makes sure that update_los() will be called for all
486	* players on the given map within the next frame.
487	* It is triggered by removal or inserting of objects which blocks
488	* the sight in the map.
489	* Modified by MSW 2001-07-12 to take a coordinate of the changed
490	* position, and to also take map tiling into account. This change
491	* means that just being on the same map is not sufficient - the
492	* space that changes must be withing your viewable area.
493	*
494	* map is the map that changed, x and y are the coordinates.
495	*/
496	void
497	update_all_los (const maptile *map, int x, int y)
498	{
499	map->at (x, y).invalidate ();
500
501	for_all_players (pl)
502	{
503	/* Player should not have a null map, but do this
504	* check as a safety
505	*/
506	if (!pl->ob \|\| !pl->ob->map \|\| !pl->ns)
507	continue;
508
509	/* Same map is simple case - see if pl is close enough.
510	* Note in all cases, we did the check for same map first,
511	* and then see if the player is close enough and update
512	* los if that is the case. If the player is on the
513	* corresponding map, but not close enough, then the
514	* player can't be on another map that may be closer,
515	* so by setting it up this way, we trim processing
516	* some.
517	*/
518	if (pl->ob->map == map)
519	{
520	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
521	pl->do_los = 1;
522	}
523
524	/* Now we check to see if player is on adjacent
525	* maps to the one that changed and also within
526	* view. The tile_maps[] could be null, but in that
527	* case it should never match the pl->ob->map, so
528	* we want ever try to dereference any of the data in it.
529	*
530	* The logic for 0 and 3 is to see how far the player is
531	* from the edge of the map (height/width) - pl->ob->(x,y)
532	* and to add current position on this map - that gives a
533	* distance.
534	* For 1 and 2, we check to see how far the given
535	* coordinate (x,y) is from the corresponding edge,
536	* and then add the players location, which gives
537	* a distance.
538	*/
539	else if (pl->ob->map == map->tile_map[0])
540	{
541	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (y + map->tile_map[0]->height - pl->ob->y) <= pl->ns->mapy / 2))
542	pl->do_los = 1;
543	}
544	else if (pl->ob->map == map->tile_map[2])
545	{
546	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y + map->height - y) <= pl->ns->mapy / 2))
547	pl->do_los = 1;
548	}
549	else if (pl->ob->map == map->tile_map[1])
550	{
551	if ((abs (pl->ob->x + map->width - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
552	pl->do_los = 1;
553	}
554	else if (pl->ob->map == map->tile_map[3])
555	{
556	if ((abs (x + map->tile_map[3]->width - pl->ob->x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
557	pl->do_los = 1;
558	}
559	}
560	}
561
562	static const int season_darkness[5][HOURS_PER_DAY] = {
563	/0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 11 12 13 /
564	{ 5, 5, 4, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 1, 2, 2, 2, 3, 3, 4, 4, 5 },
565	{ 5, 5, 4, 4, 4, 4, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4 },
566	{ 5, 4, 4, 4, 4, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 4, 4 },
567	{ 4, 4, 4, 4, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 4 },
568	{ 5, 5, 4, 4, 4, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4 }
569	};
570
571	/*
572	* Tell players the time and compute the darkness level for all maps in the game.
573	* MUST be called exactly once per hour.
574	*/
575	void
576	maptile::adjust_daylight ()
577	{
578	timeofday_t tod;
579
580	get_tod (&tod);
581
582	// log the time to log-1 every hour, and to chat every day
583	{
584	char todbuf[512];
585
586	format_tod (todbuf, sizeof (todbuf), &tod);
587
588	for_all_players (pl)
589	pl->ns->send_msg (NDI_GREY, tod.hour == 15 ? CHAT_CHANNEL : LOG_CHANNEL, todbuf);
590	}
591
592	/* If the light level isn't changing, no reason to do all
593	* the work below.
594	*/
595	sint8 new_darkness = season_darkness[tod.season][tod.hour];
596
597	if (new_darkness == maptile::outdoor_darkness)
598	return;
599
600	new_draw_info (NDI_GREY \| NDI_UNIQUE \| NDI_ALL, 1, 0,
601	new_darkness > maptile::outdoor_darkness
602	? "It becomes darker."
603	: "It becomes brighter.");
604
605	maptile::outdoor_darkness = new_darkness;
606
607	// we simply update the los for all players, which is unnecessarily
608	// costly, but should do for the moment.
609	for_all_players (pl)
610	pl->do_los = 1;
611	}
612
613	/*
614	* make_sure_seen: The object is supposed to be visible through walls, thus
615	* check if any players are nearby, and edit their LOS array.
616	*/
617	void
618	make_sure_seen (const object *op)
619	{
620	for_all_players (pl)
621	if (pl->ob->map == op->map &&
622	pl->ob->y - pl->ns->mapy / 2 <= op->y &&
623	pl->ob->y + pl->ns->mapy / 2 >= op->y && pl->ob->x - pl->ns->mapx / 2 <= op->x && pl->ob->x + pl->ns->mapx / 2 >= op->x)
624	pl->los[op->x - pl->ob->x + LOS_X0][op->y - pl->ob->y + LOS_Y0] = 0;
625	}
626
627	/*
628	* make_sure_not_seen: The object which is supposed to be visible through
629	* walls has just been removed from the map, so update the los of any
630	* players within its range
631	*/
632	void
633	make_sure_not_seen (const object *op)
634	{
635	for_all_players (pl)
636	if (pl->ob->map == op->map &&
637	pl->ob->y - pl->ns->mapy / 2 <= op->y &&
638	pl->ob->y + pl->ns->mapy / 2 >= op->y && pl->ob->x - pl->ns->mapx / 2 <= op->x && pl->ob->x + pl->ns->mapx / 2 >= op->x)
639	pl->do_los = 1;
640	}