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)
{
  {
    memset (los, 0, sizeof (los));

    // 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. which evens
    // 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.
    unordered_mapwalk (pl->observe, -half_x, -half_y, half_x, half_y)
      {
        los_info &l = los [LOS_X0 + dx][LOS_Y0 + dy];
        l.flags = m->at (nx, ny).flags () & P_BLOCKSVIEW ? FLG_BLOCKED : 0;
      }
  }

  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);
        }
    }
}

/* 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

  maprect *rects = pl->observe->map->split_to_tiles (
    pl->observe->x - half_x - MAX_LIGHT_RADIUS,
    pl->observe->y - half_y - MAX_LIGHT_RADIUS,
    pl->observe->x + half_x + MAX_LIGHT_RADIUS + 1,
    pl->observe->y + half_y + MAX_LIGHT_RADIUS + 1
  );

  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.
       */
      for (maprect *r = rects; r->m; ++r)
        rect_mapwalk (r, 0, 0)
          {
            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 - pl->observe->x, dy - pl->observe->y, light, light_atten [light + MAX_LIGHT_RADIUS]);
          }

      /* 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)
    for (maprect *r = rects; r->m; ++r)
      rect_mapwalk (r, 0, 0)
        {
          mapspace &ms = m->at (nx, ny);
          ms.update ();
          sint8 light = ms.light;

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

/* 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)
{
  // no need to do anything if we don't have darkness
  if (map->darklevel () <= 0)
    return;

  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:	1.55
Committed:	Tue Jan 6 19:17:06 2009 UTC (15 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.54:	+0 -15 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	memset (los, 0, sizeof (los));
107
108	// we keep one line for ourselves, for the border flag
109	// so the client area is actually MAP_CLIENT_(X\|Y) - 2
110	int half_x = min (LOS_X0 - 1, pl->ns->mapx / 2);
111	int half_y = min (LOS_Y0 - 1, pl->ns->mapy / 2);
112
113	// create borders, the corners are not touched
114	for (int dx = -half_x; dx <= half_x; ++dx)
115	los [dx + LOS_X0][LOS_Y0 - (half_y + 1)].flags =
116	los [dx + LOS_X0][LOS_Y0 + (half_y + 1)].flags = FLG_QUEUED;
117
118	for (int dy = -half_y; dy <= half_y; ++dy)
119	los [LOS_X0 - (half_x + 1)][dy + LOS_Y0].flags =
120	los [LOS_X0 + (half_x + 1)][dy + LOS_Y0].flags = FLG_QUEUED;
121
122	// now reset the los area and also add blocked flags
123	// which supposedly is faster than doing it inside the
124	// spiral path algorithm below, except when very little
125	// area is visible, in which case it is slower. which evens
126	// out los calculation times between large and small los maps.
127	// apply_lights also iterates over this area, maybe these
128	// two passes could be combined somehow.
129	unordered_mapwalk (pl->observe, -half_x, -half_y, half_x, half_y)
130	{
131	los_info &l = los [LOS_X0 + dx][LOS_Y0 + dy];
132	l.flags = m->at (nx, ny).flags () & P_BLOCKSVIEW ? FLG_BLOCKED : 0;
133	}
134	}
135
136	q1 = 0; q2 = 0; // initialise queue, not strictly required
137	enqueue (0, 0); // enqueue center
138
139	// treat the origin specially
140	los[LOS_X0][LOS_Y0].visible = 1;
141	pl->los[LOS_X0][LOS_Y0] = 0;
142
143	// loop over all enqueued points until the queue is empty
144	// the order in which this is done ensures that we
145	// never touch a mapspace whose input spaces we haven't checked
146	// yet.
147	while (q1 != q2)
148	{
149	sint8 dx = queue[q2].x;
150	sint8 dy = queue[q2].y;
151
152	q2 = (q2 + 1) & (QUEUE_LENGTH - 1);
153
154	sint8 x = LOS_X0 + dx;
155	sint8 y = LOS_Y0 + dy;
156
157	los_info &l = los[x][y];
158
159	if (expect_true (l.flags & (FLG_XI \| FLG_YI)))
160	{
161	l.culled = 1;
162	l.xo = l.yo = l.xe = l.ye = 0;
163
164	// check contributing spaces, first horizontal
165	if (expect_true (l.flags & FLG_XI))
166	{
167	los_info *xi = &los[x - sign (dx)][y];
168
169	// don't cull unless obscured
170	l.culled &= !xi->visible;
171
172	/* merge input space */
173	if (expect_false (xi->xo \|\| xi->yo))
174	{
175	// The X input can provide two main pieces of information:
176	// 1. Progressive X obscurity.
177	// 2. Recessive Y obscurity.
178
179	// Progressive X obscurity, favouring recessive input angle
180	if (xi->xe > 0 && l.xo == 0)
181	{
182	l.xe = xi->xe - xi->yo;
183	l.ye = xi->ye + xi->yo;
184	l.xo = xi->xo;
185	l.yo = xi->yo;
186	}
187
188	// Recessive Y obscurity
189	if (xi->ye <= 0 && xi->yo > 0 && xi->xe > 0)
190	{
191	l.ye = xi->yo + xi->ye;
192	l.xe = xi->xe - xi->yo;
193	l.xo = xi->xo;
194	l.yo = xi->yo;
195	}
196	}
197	}
198
199	// check contributing spaces, last vertical, identical structure
200	if (expect_true (l.flags & FLG_YI))
201	{
202	los_info *yi = &los[x][y - sign (dy)];
203
204	// don't cull unless obscured
205	l.culled &= !yi->visible;
206
207	/* merge input space */
208	if (expect_false (yi->yo \|\| yi->xo))
209	{
210	// The Y input can provide two main pieces of information:
211	// 1. Progressive Y obscurity.
212	// 2. Recessive X obscurity.
213
214	// Progressive Y obscurity, favouring recessive input angle
215	if (yi->ye > 0 && l.yo == 0)
216	{
217	l.ye = yi->ye - yi->xo;
218	l.xe = yi->xe + yi->xo;
219	l.yo = yi->yo;
220	l.xo = yi->xo;
221	}
222
223	// Recessive X obscurity
224	if (yi->xe <= 0 && yi->xo > 0 && yi->ye > 0)
225	{
226	l.xe = yi->xo + yi->xe;
227	l.ye = yi->ye - yi->xo;
228	l.yo = yi->yo;
229	l.xo = yi->xo;
230	}
231	}
232	}
233
234	if (l.flags & FLG_BLOCKED)
235	{
236	l.xo = l.xe = abs (dx);
237	l.yo = l.ye = abs (dy);
238
239	// we obscure dependents, but might be visible
240	// copy the los from the square towards the player,
241	// so outward diagonal corners are lit.
242	pl->los[x][y] = los[x - sign0 (dx)][y - sign0 (dy)].visible ? 0 : LOS_BLOCKED;
243
244	l.visible = false;
245	}
246	else
247	{
248	// we are not blocked, so calculate visibility, by checking
249	// whether we are inside or outside the shadow
250	l.visible = (l.xe <= 0 \|\| l.xe > l.xo)
251	&& (l.ye <= 0 \|\| l.ye > l.yo);
252
253	pl->los[x][y] = l.culled ? LOS_BLOCKED
254	: l.visible ? 0
255	: 3;
256	}
257
258	}
259
260	// Expands by the unit length in each component's current direction.
261	// If a component has no direction, then it is expanded in both of its
262	// positive and negative directions.
263	if (!l.culled)
264	{
265	if (dx >= 0) enqueue (dx + 1, dy, FLG_XI);
266	if (dx <= 0) enqueue (dx - 1, dy, FLG_XI);
267	if (dy >= 0) enqueue (dx, dy + 1, FLG_YI);
268	if (dy <= 0) enqueue (dx, dy - 1, FLG_YI);
269	}
270	}
271	}
272
273	/* radius, distance => lightness adjust */
274	static sint8 light_atten[MAX_LIGHT_RADIUS * 2 + 1][MAX_LIGHT_RADIUS * 3 / 2 + 1];
275	static sint8 vision_atten[MAX_DARKNESS + SEE_IN_DARK_RADIUS + 1][(MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2 + 1];
276
277	static struct los_init
278	{
279	los_init ()
280	{
281	assert (("QUEUE_LENGTH, MAP_CLIENT_X and MAP_CLIENT_Y must be powers of two",
282	!(QUEUE_LENGTH & (QUEUE_LENGTH - 1))));
283
284	/* for lights */
285	for (int radius = -MAX_LIGHT_RADIUS; radius <= MAX_LIGHT_RADIUS; ++radius)
286	for (int distance = 0; distance <= MAX_LIGHT_RADIUS * 3 / 2; ++distance)
287	{
288	// max intensity
289	int intensity = min (LOS_MAX, abs (radius) + 1);
290
291	// actual intensity
292	intensity = max (0, lerp_rd (distance, 0, abs (radius) + 1, intensity, 0));
293
294	light_atten [radius + MAX_LIGHT_RADIUS][distance] = radius < 0
295	? min (3, intensity)
296	: LOS_MAX - intensity;
297	}
298
299	/* for general vision */
300	for (int radius = 0; radius <= MAX_DARKNESS + SEE_IN_DARK_RADIUS; ++radius)
301	for (int distance = 0; distance <= (MAX_DARKNESS + SEE_IN_DARK_RADIUS) * 3 / 2; ++distance)
302	vision_atten [radius][distance] = distance <= radius ? 3 : 4;
303	}
304	} los_init;
305
306	sint8
307	los_brighten (sint8 b, sint8 l)
308	{
309	return b == LOS_BLOCKED ? b : min (b, l);
310	}
311
312	sint8
313	los_darken (sint8 b, sint8 l)
314	{
315	return max (b, l);
316	}
317
318	template<sint8 change_it (sint8, sint8)>
319	static void
320	apply_light (player pl, int dx, int dy, int light, const sint8 atten_table)
321	{
322	// min or max the circular area around basex, basey
323	dx += LOS_X0;
324	dy += LOS_Y0;
325
326	int hx = pl->ns->mapx / 2;
327	int hy = pl->ns->mapy / 2;
328
329	int ax0 = max (LOS_X0 - hx, dx - light);
330	int ay0 = max (LOS_Y0 - hy, dy - light);
331	int ax1 = min (dx + light, LOS_X0 + hx);
332	int ay1 = min (dy + light, LOS_Y0 + hy);
333
334	for (int ax = ax0; ax <= ax1; ax++)
335	for (int ay = ay0; ay <= ay1; ay++)
336	pl->los[ax][ay] =
337	change_it (pl->los[ax][ay], atten_table [idistance (ax - dx, ay - dy)]);
338	}
339
340	/* add light, by finding all (non-null) nearby light sources, then
341	* mark those squares specially.
342	*/
343	static void
344	apply_lights (player *pl)
345	{
346	object *op = pl->observe;
347	int darklevel = op->map->darklevel ();
348
349	int half_x = pl->ns->mapx / 2;
350	int half_y = pl->ns->mapy / 2;
351
352	int pass2 = 0; // negative lights have an extra pass
353
354	maprect *rects = pl->observe->map->split_to_tiles (
355	pl->observe->x - half_x - MAX_LIGHT_RADIUS,
356	pl->observe->y - half_y - MAX_LIGHT_RADIUS,
357	pl->observe->x + half_x + MAX_LIGHT_RADIUS + 1,
358	pl->observe->y + half_y + MAX_LIGHT_RADIUS + 1
359	);
360
361	if (!darklevel)
362	pass2 = 1;
363	else
364	{
365	/* first, make everything totally dark */
366	for (int dx = -half_x; dx <= half_x; dx++)
367	for (int dy = -half_x; dy <= half_y; dy++)
368	max_it (pl->los[dx + LOS_X0][dy + LOS_Y0], LOS_MAX);
369
370	/*
371	* Only process the area of interest.
372	* the basex, basey values represent the position in the op->contr->los
373	* array. Its easier to just increment them here (and start with the right
374	* value) than to recalculate them down below.
375	*/
376	for (maprect *r = rects; r->m; ++r)
377	rect_mapwalk (r, 0, 0)
378	{
379	mapspace &ms = m->at (nx, ny);
380	ms.update ();
381	sint8 light = ms.light;
382
383	if (expect_false (light))
384	if (light < 0)
385	pass2 = 1;
386	else
387	apply_light<los_brighten> (pl, dx - pl->observe->x, dy - pl->observe->y, light, light_atten [light + MAX_LIGHT_RADIUS]);
388	}
389
390	/* grant some vision to the player, based on the darklevel */
391	{
392	int light = clamp (MAX_DARKNESS - darklevel, 0, MAX_DARKNESS);
393
394	/* If the player can see in the dark, lower the darklevel for him */
395	if (op->flag [FLAG_SEE_IN_DARK])
396	light += SEE_IN_DARK_RADIUS;
397
398	apply_light<los_brighten> (pl, 0, 0, light, vision_atten [light]);
399	}
400	}
401
402	// possibly do 2nd pass for rare negative glow radii
403	// for effect, those are always considered to be stronger than anything else
404	// but they can't darken a place completely
405	if (pass2)
406	for (maprect *r = rects; r->m; ++r)
407	rect_mapwalk (r, 0, 0)
408	{
409	mapspace &ms = m->at (nx, ny);
410	ms.update ();
411	sint8 light = ms.light;
412
413	if (expect_false (light < 0))
414	apply_light<los_darken> (pl, dx - pl->observe->x, dy - pl->observe->y, -light, light_atten [light + MAX_LIGHT_RADIUS]);
415	}
416	}
417
418	/* blinded_sight() - sets all viewable squares to blocked except
419	* for the one the central one that the player occupies. A little
420	* odd that you can see yourself (and what your standing on), but
421	* really need for any reasonable game play.
422	*/
423	static void
424	blinded_sight (player *pl)
425	{
426	pl->los[LOS_X0][LOS_Y0] = 1;
427	}
428
429	/*
430	* update_los() recalculates the array which specifies what is
431	* visible for the given player-object.
432	*/
433	void
434	player::update_los ()
435	{
436	if (ob->flag [FLAG_REMOVED])//D really needed?
437	return;
438
439	if (ob->flag [FLAG_WIZLOOK])
440	clear_los (0);
441	else if (observe->flag [FLAG_BLIND]) /* player is blind */
442	{
443	clear_los ();
444	blinded_sight (this);
445	}
446	else
447	{
448	clear_los ();
449	calculate_los (this);
450	apply_lights (this);
451	}
452
453	if (observe->flag [FLAG_XRAYS])
454	for (int dx = -2; dx <= 2; dx++)
455	for (int dy = -2; dy <= 2; dy++)
456	min_it (los[dx + LOS_X0][dy + LOS_Y0], 1);
457	}
458
459	/* update all_map_los is like update_all_los below,
460	* but updates everyone on the map, no matter where they
461	* are. This generally should not be used, as a per
462	* specific map change doesn't make much sense when tiling
463	* is considered (lowering darkness would certainly be a
464	* strange effect if done on a tile map, as it makes
465	* the distinction between maps much more obvious to the
466	* players, which is should not be.
467	* Currently, this function is called from the
468	* change_map_light function
469	*/
470	void
471	update_all_map_los (maptile *map)
472	{
473	for_all_players_on_map (pl, map)
474	pl->do_los = 1;
475	}
476
477	/*
478	* This function makes sure that update_los() will be called for all
479	* players on the given map within the next frame.
480	* It is triggered by removal or inserting of objects which blocks
481	* the sight in the map.
482	* Modified by MSW 2001-07-12 to take a coordinate of the changed
483	* position, and to also take map tiling into account. This change
484	* means that just being on the same map is not sufficient - the
485	* space that changes must be withing your viewable area.
486	*
487	* map is the map that changed, x and y are the coordinates.
488	*/
489	void
490	update_all_los (const maptile *map, int x, int y)
491	{
492	// no need to do anything if we don't have darkness
493	if (map->darklevel () <= 0)
494	return;
495
496	map->at (x, y).invalidate ();
497
498	for_all_players (pl)
499	{
500	/* Player should not have a null map, but do this
501	* check as a safety
502	*/
503	if (!pl->ob \|\| !pl->ob->map \|\| !pl->ns)
504	continue;
505
506	/* Same map is simple case - see if pl is close enough.
507	* Note in all cases, we did the check for same map first,
508	* and then see if the player is close enough and update
509	* los if that is the case. If the player is on the
510	* corresponding map, but not close enough, then the
511	* player can't be on another map that may be closer,
512	* so by setting it up this way, we trim processing
513	* some.
514	*/
515	if (pl->ob->map == map)
516	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
517	pl->do_los = 1;
518
519	/* Now we check to see if player is on adjacent
520	* maps to the one that changed and also within
521	* view. The tile_maps[] could be null, but in that
522	* case it should never match the pl->ob->map, so
523	* we want ever try to dereference any of the data in it.
524	*
525	* The logic for 0 and 3 is to see how far the player is
526	* from the edge of the map (height/width) - pl->ob->(x,y)
527	* and to add current position on this map - that gives a
528	* distance.
529	* For 1 and 2, we check to see how far the given
530	* coordinate (x,y) is from the corresponding edge,
531	* and then add the players location, which gives
532	* a distance.
533	*/
534	else if (pl->ob->map == map->tile_map[0])
535	{
536	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (y + map->tile_map[0]->height - pl->ob->y) <= pl->ns->mapy / 2))
537	pl->do_los = 1;
538	}
539	else if (pl->ob->map == map->tile_map[2])
540	{
541	if ((abs (pl->ob->x - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y + map->height - y) <= pl->ns->mapy / 2))
542	pl->do_los = 1;
543	}
544	else if (pl->ob->map == map->tile_map[1])
545	{
546	if ((abs (pl->ob->x + map->width - x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
547	pl->do_los = 1;
548	}
549	else if (pl->ob->map == map->tile_map[3])
550	{
551	if ((abs (x + map->tile_map[3]->width - pl->ob->x) <= pl->ns->mapx / 2) && (abs (pl->ob->y - y) <= pl->ns->mapy / 2))
552	pl->do_los = 1;
553	}
554	}
555	}
556
557	static const int season_darkness[5][HOURS_PER_DAY] = {
558	/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 /
559	{ 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 },
560	{ 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 },
561	{ 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 },
562	{ 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 },
563	{ 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 }
564	};
565
566	/*
567	* Tell players the time and compute the darkness level for all maps in the game.
568	* MUST be called exactly once per hour.
569	*/
570	void
571	maptile::adjust_daylight ()
572	{
573	timeofday_t tod;
574
575	get_tod (&tod);
576
577	// log the time to log-1 every hour, and to chat every day
578	{
579	char todbuf[512];
580
581	format_tod (todbuf, sizeof (todbuf), &tod);
582
583	for_all_players (pl)
584	pl->ns->send_msg (NDI_GREY, tod.hour == 15 ? CHAT_CHANNEL : LOG_CHANNEL, todbuf);
585	}
586
587	/* If the light level isn't changing, no reason to do all
588	* the work below.
589	*/
590	sint8 new_darkness = season_darkness[tod.season][tod.hour];
591
592	if (new_darkness == maptile::outdoor_darkness)
593	return;
594
595	new_draw_info (NDI_GREY \| NDI_UNIQUE \| NDI_ALL, 1, 0,
596	new_darkness > maptile::outdoor_darkness
597	? "It becomes darker."
598	: "It becomes brighter.");
599
600	maptile::outdoor_darkness = new_darkness;
601
602	// we simply update the los for all players, which is unnecessarily
603	// costly, but should do for the moment.
604	for_all_players (pl)
605	pl->do_los = 1;
606	}
607
608	/*
609	* make_sure_seen: The object is supposed to be visible through walls, thus
610	* check if any players are nearby, and edit their LOS array.
611	*/
612	void
613	make_sure_seen (const object *op)
614	{
615	for_all_players (pl)
616	if (pl->ob->map == op->map &&
617	pl->ob->y - pl->ns->mapy / 2 <= op->y &&
618	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)
619	pl->los[op->x - pl->ob->x + LOS_X0][op->y - pl->ob->y + LOS_Y0] = 0;
620	}
621
622	/*
623	* make_sure_not_seen: The object which is supposed to be visible through
624	* walls has just been removed from the map, so update the los of any
625	* players within its range
626	*/
627	void
628	make_sure_not_seen (const object *op)
629	{
630	for_all_players (pl)
631	if (pl->ob->map == op->map &&
632	pl->ob->y - pl->ns->mapy / 2 <= op->y &&
633	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)
634	pl->do_los = 1;
635	}
636