server/common/los.C


/*
 * static char *rcsid_los_c =
 *   "$Id: los.C,v 1.3 2006-09-03 00:18:40 root Exp $";
 */

/*
    CrossFire, A Multiplayer game for X-windows

    Copyright (C) 2002 Mark Wedel & Crossfire Development Team
    Copyright (C) 1992 Frank Tore Johansen

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

    The authors can be reached via e-mail at crossfire-devel@real-time.com
*/

/* Nov 95 - inserted USE_LIGHTING code stuff in here - b.t. */

#include <global.h>
#include <funcpoint.h>
#include <math.h>


/* Distance must be less than this for the object to be blocked.
 * An object is 1.0 wide, so if set to 0.5, it means the object
 * that blocks half the view (0.0 is complete block) will
 * block view in our tables.
 * .4 or less lets you see through walls.  .5 is about right.
 */

#define SPACE_BLOCK     0.5

typedef struct blstr
{
  int x[4], y[4];
  int index;
} blocks;

blocks block[MAP_CLIENT_X][MAP_CLIENT_Y];

static void expand_lighted_sight (object *op);

/*
 * Used to initialise the array used by the LOS routines.
 * What this sets if that x,y blocks the view of bx,by
 * This then sets up a relation - for example, something
 * at 5,4 blocks view at 5,3 which blocks view at 5,2
 * etc.  So when we check 5,4 and find it block, we have
 * the data to know that 5,3 and 5,2 and 5,1 should also
 * be blocked.
 */

static void
set_block (int x, int y, int bx, int by)
{
  int index = block[x][y].index, i;

  /* Due to flipping, we may get duplicates - better safe than sorry.
   */
  for (i = 0; i < index; i++)
    {
      if (block[x][y].x[i] == bx && block[x][y].y[i] == by)
        return;
    }

  block[x][y].x[index] = bx;
  block[x][y].y[index] = by;
  block[x][y].index++;
#ifdef LOS_DEBUG
  LOG (llevDebug, "setblock: added %d %d -> %d %d (%d)\n", x, y, bx, by, block[x][y].index);
#endif
}

/*
 * initialises the array used by the LOS routines.
 */

/* since we are only doing the upper left quadrant, only
 * these spaces could possibly get blocked, since these
 * are the only ones further out that are still possibly in the
 * sightline.
 */

void
init_block (void)
{
  int x, y, dx, dy, i;
  static int block_x[3] = { -1, -1, 0 }, block_y[3] =
  {
  -1, 0, -1};

  for (x = 0; x < MAP_CLIENT_X; x++)
    for (y = 0; y < MAP_CLIENT_Y; y++)
      {
        block[x][y].index = 0;
      }


  /* The table should be symmetric, so only do the upper left
   * quadrant - makes the processing easier.
   */
  for (x = 1; x <= MAP_CLIENT_X / 2; x++)
    {
      for (y = 1; y <= MAP_CLIENT_Y / 2; y++)
        {
          for (i = 0; i < 3; i++)
            {
              dx = x + block_x[i];
              dy = y + block_y[i];

              /* center space never blocks */
              if (x == MAP_CLIENT_X / 2 && y == MAP_CLIENT_Y / 2)
                continue;

              /* If its a straight line, its blocked */
              if ((dx == x && x == MAP_CLIENT_X / 2) || (dy == y && y == MAP_CLIENT_Y / 2))
                {
                  /* For simplicity, we mirror the coordinates to block the other
                   * quadrants.
                   */
                  set_block (x, y, dx, dy);
                  if (x == MAP_CLIENT_X / 2)
                    {
                      set_block (x, MAP_CLIENT_Y - y - 1, dx, MAP_CLIENT_Y - dy - 1);
                    }
                  else if (y == MAP_CLIENT_Y / 2)
                    {
                      set_block (MAP_CLIENT_X - x - 1, y, MAP_CLIENT_X - dx - 1, dy);
                    }
                }
              else
                {
                  float d1, r, s, l;

                  /* We use the algorihm that found out how close the point
                   * (x,y) is to the line from dx,dy to the center of the viewable
                   * area.  l is the distance from x,y to the line.
                   * r is more a curiosity - it lets us know what direction (left/right)
                   * the line is off
                   */

                  d1 = (float) (pow (MAP_CLIENT_X / 2 - dx, 2) + pow (MAP_CLIENT_Y / 2 - dy, 2));
                  r = (float) ((dy - y) * (dy - MAP_CLIENT_Y / 2) - (dx - x) * (MAP_CLIENT_X / 2 - dx)) / d1;
                  s = (float) ((dy - y) * (MAP_CLIENT_X / 2 - dx) - (dx - x) * (MAP_CLIENT_Y / 2 - dy)) / d1;
                  l = FABS (sqrt (d1) * s);

                  if (l <= SPACE_BLOCK)
                    {
                      /* For simplicity, we mirror the coordinates to block the other
                       * quadrants.
                       */
                      set_block (x, y, dx, dy);
                      set_block (MAP_CLIENT_X - x - 1, y, MAP_CLIENT_X - dx - 1, dy);
                      set_block (x, MAP_CLIENT_Y - y - 1, dx, MAP_CLIENT_Y - dy - 1);
                      set_block (MAP_CLIENT_X - x - 1, MAP_CLIENT_Y - y - 1, MAP_CLIENT_X - dx - 1, MAP_CLIENT_Y - dy - 1);
                    }
                }
            }
        }
    }
}

/*
 * Used to initialise the array used by the LOS routines.
 * x,y are indexes into the blocked[][] array.
 * This recursively sets the blocked line of sight view.
 * From the blocked[][] array, we know for example
 * that if some particular space is blocked, it blocks
 * the view of the spaces 'behind' it, and those blocked
 * spaces behind it may block other spaces, etc.  
 * In this way, the chain of visibility is set.
 */

static void
set_wall (object *op, int x, int y)
{
  int i;

  for (i = 0; i < block[x][y].index; i++)
    {
      int dx = block[x][y].x[i], dy = block[x][y].y[i], ax, ay;

      /* ax, ay are the values as adjusted to be in the
       * socket look structure.
       */
      ax = dx - (MAP_CLIENT_X - op->contr->socket.mapx) / 2;
      ay = dy - (MAP_CLIENT_Y - op->contr->socket.mapy) / 2;

      if (ax < 0 || ax >= op->contr->socket.mapx || ay < 0 || ay >= op->contr->socket.mapy)
        continue;
#if 0
      LOG (llevDebug, "blocked %d %d -> %d %d\n", dx, dy, ax, ay);
#endif
      /* we need to adjust to the fact that the socket
       * code wants the los to start from the 0,0
       * and not be relative to middle of los array.
       */
      op->contr->blocked_los[ax][ay] = 100;
      set_wall (op, dx, dy);
    }
}

/*
 * Used to initialise the array used by the LOS routines.
 * op is the object, x and y values based on MAP_CLIENT_X and Y.
 * this is because they index the blocked[][] arrays.
 */

static void
check_wall (object *op, int x, int y)
{
  int ax, ay;

  if (!block[x][y].index)
    return;

  /* ax, ay are coordinates as indexed into the look window */
  ax = x - (MAP_CLIENT_X - op->contr->socket.mapx) / 2;
  ay = y - (MAP_CLIENT_Y - op->contr->socket.mapy) / 2;

  /* If the converted coordinates are outside the viewable
   * area for the client, return now.
   */
  if (ax < 0 || ay < 0 || ax >= op->contr->socket.mapx || ay >= op->contr->socket.mapy)
    return;

#if 0
  LOG (llevDebug, "check_wall, ax,ay=%d, %d  x,y = %d, %d  blocksview = %d, %d\n",
       ax, ay, x, y, op->x + x - MAP_CLIENT_X / 2, op->y + y - MAP_CLIENT_Y / 2);
#endif

  /* If this space is already blocked, prune the processing - presumably
   * whatever has set this space to be blocked has done the work and already
   * done the dependency chain.
   */
  if (op->contr->blocked_los[ax][ay] == 100)
    return;


  if (get_map_flags (op->map, NULL, op->x + x - MAP_CLIENT_X / 2, op->y + y - MAP_CLIENT_Y / 2, NULL, NULL) & (P_BLOCKSVIEW | P_OUT_OF_MAP))
    set_wall (op, x, y);
}

/*
 * Clears/initialises the los-array associated to the player
 * controlling the object.
 */

void
clear_los (object *op)
{
  /* This is safer than using the socket->mapx, mapy because
   * we index the blocked_los as a 2 way array, so clearing
   * the first z spaces may not not cover the spaces we are
   * actually going to use
   */
  (void) memset ((void *) op->contr->blocked_los, 0, MAP_CLIENT_X * MAP_CLIENT_Y);
}

/*
 * expand_sight goes through the array of what the given player is
 * able to see, and expands the visible area a bit, so the player will,
 * to a certain degree, be able to see into corners.
 * This is somewhat suboptimal, would be better to improve the formula.
 */

static void
expand_sight (object *op)
{
  int i, x, y, dx, dy;

  for (x = 1; x < op->contr->socket.mapx - 1; x++)      /* loop over inner squares */
    for (y = 1; y < op->contr->socket.mapy - 1; y++)
      {
        if (!op->contr->blocked_los[x][y] &&
            !(get_map_flags (op->map, NULL,
                             op->x - op->contr->socket.mapx / 2 + x,
                             op->y - op->contr->socket.mapy / 2 + y, NULL, NULL) & (P_BLOCKSVIEW | P_OUT_OF_MAP)))
          {

            for (i = 1; i <= 8; i += 1)
              {                 /* mark all directions */
                dx = x + freearr_x[i];
                dy = y + freearr_y[i];
                if (op->contr->blocked_los[dx][dy] > 0) /* for any square blocked */
                  op->contr->blocked_los[dx][dy] = -1;
              }
          }
      }

  if (MAP_DARKNESS (op->map) > 0)       /* player is on a dark map */
    expand_lighted_sight (op);


  /* clear mark squares */
  for (x = 0; x < op->contr->socket.mapx; x++)
    for (y = 0; y < op->contr->socket.mapy; y++)
      if (op->contr->blocked_los[x][y] < 0)
        op->contr->blocked_los[x][y] = 0;
}


/* 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;
}

static void
expand_lighted_sight (object *op)
{
  int x, y, darklevel, ax, ay, basex, basey, mflags, light, x1, y1;
  mapstruct *m = op->map;
  sint16 nx, ny;

  darklevel = MAP_DARKNESS (m);

  /* If the player can see in the dark, lower the darklevel for him */
  if (QUERY_FLAG (op, FLAG_SEE_IN_DARK))
    darklevel -= 2;

  /* add light, by finding all (non-null) nearby light sources, then 
   * mark those squares specially. If the darklevel<1, there is no
   * reason to do this, so we skip this function 
   */

  if (darklevel < 1)
    return;

  /* Do a sanity check.  If not valid, some code below may do odd
   * things.
   */
  if (darklevel > MAX_DARKNESS)
    {
      LOG (llevError, "Map darkness for %s on %s is too high (%d)\n", &op->name, op->map->path, darklevel);
      darklevel = MAX_DARKNESS;
    }

  /* First, limit player furthest (unlighted) vision */
  for (x = 0; x < op->contr->socket.mapx; x++)
    for (y = 0; y < op->contr->socket.mapy; y++)
      if (op->contr->blocked_los[x][y] != 100)
        op->contr->blocked_los[x][y] = MAX_LIGHT_RADII;

  /* the spaces[] darkness value contains the information we need.
   * Only process the area of interest.
   * the basex, basey values represent the position in the op->contr->blocked_los
   * array.  Its easier to just increment them here (and start with the right
   * value) than to recalculate them down below.
   */
  for (x = (op->x - op->contr->socket.mapx / 2 - MAX_LIGHT_RADII), basex = -MAX_LIGHT_RADII;
       x <= (op->x + op->contr->socket.mapx / 2 + MAX_LIGHT_RADII); x++, basex++)
    {

      for (y = (op->y - op->contr->socket.mapy / 2 - MAX_LIGHT_RADII), basey = -MAX_LIGHT_RADII;
           y <= (op->y + op->contr->socket.mapy / 2 + MAX_LIGHT_RADII); y++, basey++)
        {
          m = op->map;
          nx = x;
          ny = y;

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

          if (mflags & P_OUT_OF_MAP)
            continue;

          /* This space is providing light, so we need to brighten up the
           * spaces around here.
           */
          light = GET_MAP_LIGHT (m, nx, ny);
          if (light != 0)
            {
#if 0
              LOG (llevDebug, "expand_lighted_sight: Found light at x=%d, y=%d, basex=%d, basey=%d\n", x, y, basex, basey);
#endif
              for (ax = basex - light; ax <= basex + light; ax++)
                {
                  if (ax < 0 || ax >= op->contr->socket.mapx)
                    continue;
                  for (ay = basey - light; ay <= basey + light; ay++)
                    {
                      if (ay < 0 || ay >= op->contr->socket.mapy)
                        continue;

                      /* If the space is fully blocked, do nothing.  Otherwise, we
                       * brighten the space.  The further the light is away from the
                       * source (basex-x), the less effect it has.  Though light used
                       * to dim in a square manner, it now dims in a circular manner
                       * using the the pythagorean theorem. glow_radius still 
                       * represents the radius 
                       */
                      if (op->contr->blocked_los[ax][ay] != 100)
                        {
                          x1 = abs (basex - ax) * abs (basex - ax);
                          y1 = abs (basey - ay) * abs (basey - ay);
                          if (light > 0)
                            op->contr->blocked_los[ax][ay] -= MAX ((light - isqrt (x1 + y1)), 0);
                          if (light < 0)
                            op->contr->blocked_los[ax][ay] -= MIN ((light + isqrt (x1 + y1)), 0);
                        }
                    }           /* for ay */
                }               /* for ax */
            }                   /* if this space is providing light */
        }                       /* for y */
    }                           /* for x */

  /* Outdoor should never really be completely pitch black dark like
   * a dungeon, so let the player at least see a little around themselves
   */
  if (op->map->outdoor && darklevel > (MAX_DARKNESS - 3))
    {
      if (op->contr->blocked_los[op->contr->socket.mapx / 2][op->contr->socket.mapy / 2] > (MAX_DARKNESS - 3))
        op->contr->blocked_los[op->contr->socket.mapx / 2][op->contr->socket.mapy / 2] = MAX_DARKNESS - 3;

      for (x = -1; x <= 1; x++)
        for (y = -1; y <= 1; y++)
          {
            if (op->contr->blocked_los[x + op->contr->socket.mapx / 2][y + op->contr->socket.mapy / 2] > (MAX_DARKNESS - 2))
              op->contr->blocked_los[x + op->contr->socket.mapx / 2][y + op->contr->socket.mapy / 2] = MAX_DARKNESS - 2;
          }
    }
  /*  grant some vision to the player, based on the darklevel */
  for (x = darklevel - MAX_DARKNESS; x < MAX_DARKNESS + 1 - darklevel; x++)
    for (y = darklevel - MAX_DARKNESS; y < MAX_DARKNESS + 1 - darklevel; y++)
      if (!(op->contr->blocked_los[x + op->contr->socket.mapx / 2][y + op->contr->socket.mapy / 2] == 100))
        op->contr->blocked_los[x + op->contr->socket.mapx / 2][y + op->contr->socket.mapy / 2] -=
          MAX (0, 6 - darklevel - MAX (abs (x), abs (y)));
}

/* blinded_sight() - sets all veiwable 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 (object *op)
{
  int x, y;

  for (x = 0; x < op->contr->socket.mapx; x++)
    for (y = 0; y < op->contr->socket.mapy; y++)
      op->contr->blocked_los[x][y] = 100;

  op->contr->blocked_los[op->contr->socket.mapx / 2][op->contr->socket.mapy / 2] = 0;
}

/*
 * update_los() recalculates the array which specifies what is
 * visible for the given player-object.
 */

void
update_los (object *op)
{
  int dx = op->contr->socket.mapx / 2, dy = op->contr->socket.mapy / 2, x, y;

  if (QUERY_FLAG (op, FLAG_REMOVED))
    return;

  clear_los (op);
  if (QUERY_FLAG (op, FLAG_WIZ) /* ||XRAYS(op) */ )
    return;

  /* For larger maps, this is more efficient than the old way which
   * used the chaining of the block array.  Since many space views could
   * be blocked by different spaces in front, this mean that a lot of spaces
   * could be examined multile times, as each path would be looked at.
   */
  for (x = (MAP_CLIENT_X - op->contr->socket.mapx) / 2 - 1; x < (MAP_CLIENT_X + op->contr->socket.mapx) / 2 + 1; x++)
    for (y = (MAP_CLIENT_Y - op->contr->socket.mapy) / 2 - 1; y < (MAP_CLIENT_Y + op->contr->socket.mapy) / 2 + 1; y++)
      check_wall (op, x, y);


  /* do the los of the player. 3 (potential) cases */
  if (QUERY_FLAG (op, FLAG_BLIND))      /* player is blind */
    blinded_sight (op);
  else
    expand_sight (op);

  if (QUERY_FLAG (op, FLAG_XRAYS))
    {
      int x, y;

      for (x = -2; x <= 2; x++)
        for (y = -2; y <= 2; y++)
          op->contr->blocked_los[dx + x][dy + y] = 0;
    }
}

/* 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 (mapstruct *map)
{
  player *pl;

  for (pl = first_player; pl != NULL; pl = pl->next)
    {
      if (pl->ob->map == 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 mapstruct *map, int x, int y)
{
  player *pl;

  for (pl = first_player; pl != NULL; pl = pl->next)
    {
      /* Player should not have a null map, but do this
       * check as a safety
       */
      if (!pl->ob->map)
        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->socket.mapx / 2) && (abs (pl->ob->y - y) <= pl->socket.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->socket.mapx / 2) && (abs (y + MAP_HEIGHT (map->tile_map[0]) - pl->ob->y) <= pl->socket.mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[2])
        {
          if ((abs (pl->ob->x - x) <= pl->socket.mapx / 2) && (abs (pl->ob->y + MAP_HEIGHT (map) - y) <= pl->socket.mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[1])
        {
          if ((abs (pl->ob->x + MAP_WIDTH (map) - x) <= pl->socket.mapx / 2) && (abs (pl->ob->y - y) <= pl->socket.mapy / 2))
            pl->do_los = 1;
        }
      else if (pl->ob->map == map->tile_map[3])
        {
          if ((abs (x + MAP_WIDTH (map->tile_map[3]) - pl->ob->x) <= pl->socket.mapx / 2) && (abs (pl->ob->y - y) <= pl->socket.mapy / 2))
            pl->do_los = 1;
        }
    }
}

/*
 * Debug-routine which dumps the array which specifies the visible
 * area of a player.  Triggered by the z key in DM mode.
 */

void
print_los (object *op)
{
  int x, y;
  char buf[50], buf2[10];

  strcpy (buf, "   ");
  for (x = 0; x < op->contr->socket.mapx; x++)
    {
      sprintf (buf2, "%2d", x);
      strcat (buf, buf2);
    }
  new_draw_info (NDI_UNIQUE, 0, op, buf);
  for (y = 0; y < op->contr->socket.mapy; y++)
    {
      sprintf (buf, "%2d:", y);
      for (x = 0; x < op->contr->socket.mapx; x++)
        {
          sprintf (buf2, " %1d", op->contr->blocked_los[x][y]);
          strcat (buf, buf2);
        }
      new_draw_info (NDI_UNIQUE, 0, op, buf);
    }
}

/*
 * 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)
{
  player *pl;

  for (pl = first_player; pl; pl = pl->next)
    if (pl->ob->map == op->map &&
        pl->ob->y - pl->socket.mapy / 2 <= op->y &&
        pl->ob->y + pl->socket.mapy / 2 >= op->y && pl->ob->x - pl->socket.mapx / 2 <= op->x && pl->ob->x + pl->socket.mapx / 2 >= op->x)
      pl->blocked_los[pl->socket.mapx / 2 + op->x - pl->ob->x][pl->socket.mapy / 2 + op->y - pl->ob->y] = 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)
{
  player *pl;

  for (pl = first_player; pl; pl = pl->next)
    if (pl->ob->map == op->map &&
        pl->ob->y - pl->socket.mapy / 2 <= op->y &&
        pl->ob->y + pl->socket.mapy / 2 >= op->y && pl->ob->x - pl->socket.mapx / 2 <= op->x && pl->ob->x + pl->socket.mapx / 2 >= op->x)
      pl->do_los = 1;
}
Revision:	1.4
Committed:	Sun Sep 10 16:00:23 2006 UTC (17 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.3:	+448 -385 lines
Log Message:	indent