server/server/weather.C

/*
    CrossFire, A Multiplayer game for X-windows

    Copyright (C) 2002 Tim Rightnour
    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 to <crossfire@schmorp.de>
*/

/* This weather system was written for crossfire by Tim Rightnour */

#include <global.h>
#include <tod.h>
#include <map.h>
#ifndef __CEXTRACT__
# include <sproto.h>
#endif

extern unsigned long todtick;
extern weathermap_t **weathermap;

static void dawn_to_dusk (const timeofday_t * tod);
static void write_skymap (void);
static void write_pressuremap (void);
static void read_pressuremap (void);
static void init_pressure (void);
static void write_winddirmap (void);
static void read_winddirmap (void);
static void write_windspeedmap (void);
static void read_windspeedmap (void);
static void init_wind (void);
static void write_gulfstreammap (void);
static void read_gulfstreammap (void);
static void init_gulfstreammap (void);
static void write_humidmap (void);
static void read_humidmap (void);
static void write_elevmap (void);
static void read_elevmap (void);
static void write_watermap (void);
static void read_watermap (void);
static void init_humid_elev (void);
static void write_temperaturemap (void);
static void read_temperaturemap (void);
static void init_temperature (void);
static void write_rainfallmap (void);
static void read_rainfallmap (void);
static void init_rainfall (void);
static void init_weatheravoid (weather_avoids_t wa[]);
static void perform_weather (void);
static object *avoid_weather (int *av, maptile *m, int x, int y, int *gs, int grow);
static void calculate_temperature (maptile *m, int wx, int wy);
static void let_it_snow (maptile *m, int wx, int wy);
static void singing_in_the_rain (maptile *m, int wx, int wy);
static void plant_a_garden (maptile *m, int wx, int wy);
static void change_the_world (maptile *m, int wx, int wy);

//static void feather_map(maptile *m, int wx, int wy);
static const char *weathermap_to_worldmap_corner (int wx, int wy, int *x, int *y, int dir);
static int polar_distance (int x, int y, int equator);
static void update_humid (void);
static int humid_tile (int x, int y);
static void temperature_calc (int x, int y, const timeofday_t * tod);
static int real_temperature (int x, int y);
static void smooth_pressure (void);
static void perform_pressure (void);
static void smooth_wind (void);
static void plot_gulfstream (void);
static void compute_sky (void);
static void process_rain (void);
static void spin_globe (void);
static void write_weather_images (void);

static int gulf_stream_speed[GULF_STREAM_WIDTH][WEATHERMAPTILESY];
static int gulf_stream_dir[GULF_STREAM_WIDTH][WEATHERMAPTILESY];
static int gulf_stream_start;
static int gulf_stream_direction;

static const int season_timechange[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 */
  {0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1,
   1, 1, 1, 1, 1, 1},
  {0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 1, 1,
   1, 1, 1, 1, 1, 0},
  {0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
   1, 1, 1, 1, 1, 0},
  {0, 0, 0, 0, 0, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
   1, 1, 1, 1, 1, 0},
  {0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1,
   1, 1, 1, 1, 1, 0}
};

static const int season_tempchange[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 */
  0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 1, 1,
  1, 1, 1, 1, 1, 1
};

/*
 * The table below is used to set which tiles the weather will avoid
 * processing.  This keeps it from putting snow on snow, and putting snow
 * on the ocean, and other things like that.
 */

static weather_avoids_t weather_avoids[] = {
  {"snow", 1, NULL},
  {"snow2", 1, NULL},
  {"snow3", 1, NULL},
  {"snow4", 1, NULL},
  {"snow5", 1, NULL},
  {"mountain1_snow", 1, NULL},
  {"mountain2_snow", 1, NULL},
  {"rain1", 1, NULL},
  {"rain2", 1, NULL},
  {"rain3", 1, NULL},
  {"rain4", 1, NULL},
  {"rain5", 1, NULL},
  {"mountain1_rivlets", 1, NULL},
  {"mountain2_rivlets", 1, NULL},
  {"drifts", 0, NULL},
  {"glacier", 0, NULL},
  {"cforest1", 0, NULL},
  {"sea", 0, NULL},
  {"sea1", 0, NULL},
  {"deep_sea", 0, NULL},
  {"shallow_sea", 0, NULL},
  {"lava", 0, NULL},
  {"permanent_lava", 0, NULL},
  {NULL, 0, NULL}
};

/*
 * this table is identical to the one above, except these are tiles to avoid
 * when processing growth.  IE, don't grow herbs in the ocean.  The second
 * field is unused.
 */

static weather_avoids_t growth_avoids[] = {
  {"cobblestones", 0, NULL},
  {"cobblestones2", 0, NULL},
  {"flagstone", 0, NULL},
  {"stonefloor2", 0, NULL},
  {"lava", 0, NULL},
  {"permanent_lava", 0, NULL},
  {"sea", 0, NULL},
  {"sea1", 0, NULL},
  {"deep_sea", 0, NULL},
  {"shallow_sea", 0, NULL},
  {"farmland", 0, NULL},
  {"dungeon_magic", 0, NULL},
  {"dungeon_floor", 0, NULL},
  {"lake", 0, NULL},
  {"grasspond", 0, NULL},
  {NULL, 0, NULL}
};

/*
 * The table below is used in let_it_snow() and singing_in_the_rain() to
 * decide what type of snow/rain/etc arch to put down.  The first field is the
 * name of the arch we want to match.  The second field is the special snow
 * type we use to cover that arch.  The third field is the doublestack arch,
 * NULL if none, used to stack over the snow after covering the tile.
 * The fourth field is 1 if you want to match arch->name, 0 to match ob->name.
 */

static weather_replace_t weather_replace[] = {
  {"impossible_match", "snow5", NULL, 0},
  {"impossible_match2", "snow4", NULL, 0},      /* placeholders */
  {"impossible_match3", "snow3", NULL, 0},
  {"hills", "drifts", NULL, 0},
  {"treed_hills", "drifts", "woods5", 1},
  {"grass", "snow", NULL, 0},
  {"sand", "snow", NULL, 0},
  {"stones", "snow2", NULL, 0},
  {"steppe", "snow2", NULL, 0},
  {"brush", "snow2", NULL, 0},
  {"farmland", "snow3", NULL, 0},
  {"wasteland", "glacier", NULL, 0},
  {"mountain", "mountain1_snow", NULL, 1},
  {"mountain2", "mountain2_snow", NULL, 1},
  {"mountain4", "mountain2_snow", NULL, 1},
  {"evergreens", "snow", "evergreens2", 1},
  {"evergreen", "snow", "tree5", 1},
  {"tree", "snow", "tree3", 0},
  {"woods", "snow3", "woods4", 1},
  {"woods_3", "snow", "woods5", 1},
  {NULL, NULL, NULL, 0},
};

/*
 * The table below is used to grow things on the map. See include/tod.h for
 * the meanings of all of the fields.
 */

static const weather_grow_t weather_grow[] = {
  /* herb, tile, random, rfmin, rfmax, humin, humax, tempmin, tempmax, elevmin, elevmax, season */
  {"mint", "grass", 10, 1.0, 2.0, 30, 100, 10, 25, -100, 9999, 2},
  {"rose_red", "grass", 15, 1.0, 2.0, 30, 100, 10, 25, -100, 9999, 2},
  {"rose_red", "hills", 15, 1.0, 2.0, 30, 100, 10, 25, -100, 9999, 2},
  {"mint", "brush", 8, 1.0, 2.0, 30, 100, 10, 25, -100, 9999, 2},
  {"blackroot", "swamp", 15, 1.6, 2.0, 60, 100, 20, 30, -100, 1500, 0},
  {"mushroom_1", "grass", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"mushroom_2", "grass", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"mushroom_1", "swamp", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"mushroom_2", "swamp", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"mushroom_1", "hills", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"mushroom_2", "hills", 15, 1.6, 2.0, 60, 100, 3, 30, -100, 1500, 0},
  {"pipeweed", "farmland", 20, 1.0, 2.0, 30, 100, 10, 25, 100, 5000, 0},
  {"cabbage", "farmland", 10, 1.0, 2.0, 30, 100, 10, 25, -100, 9999, 0},
  {"onion", "farmland", 10, 1.0, 2.0, 30, 100, 10, 25, 100, 9999, 0},
  {"carrot", "farmland", 10, 1.0, 2.0, 30, 100, 10, 25, 100, 9999, 0},
  {"thorns", "brush", 15, 0.5, 1.3, 30, 100, 10, 25, -100, 9999, 0},
  {"mountain_foilage", "mountain", 6, 1.0, 2.0, 25, 100, 5, 30, 0, 15999, 2},
  {NULL, NULL, 1, 0.0, 0.0, 0, 0, 0, 0, 0, 0, 0}
};

/*
 * The table below uses the same format as the one above.  However this
 * table is used to change the layout of the worldmap itself.  The tile
 * parameter is a base tile to lay down underneath the herb tile.
 */

static const weather_grow_t weather_tile[] = {
  /* herb, tile, random, rfmin, rfmax, humin, humax, tempmin, tempmax, elevmin, elevmax */
  {"dunes", NULL, 2, 0.0, 0.03, 0, 20, 10, 99, 0, 4000, 0},
  {"desert", NULL, 1, 0.0, 0.05, 0, 20, 10, 99, 0, 4000, 0},
  {"pstone_2", NULL, 1, 0.0, 0.05, 0, 20, -30, 10, 0, 4000, 0},
  {"pstone_3", NULL, 1, 0.0, 0.05, 0, 20, -30, 10, 0, 4000, 0},
  {"grassbrown", NULL, 1, 0.05, 1.0, 20, 80, -20, -3, 0, 5000, 0},
  {"grass_br_gr", NULL, 1, 0.05, 1.0, 20, 80, -3, 5, 0, 5000, 0},
  {"grass", NULL, 1, 0.05, 1.0, 20, 80, 5, 15, 0, 5000, 0},
  {"grassmedium", NULL, 1, 0.05, 1.0, 20, 80, 15, 25, 0, 5000, 0},
  {"grassdark", NULL, 1, 0.05, 1.0, 20, 80, 25, 35, 0, 5000, 0},
  {"brush", NULL, 1, 0.2, 1.0, 25, 70, 0, 30, 500, 6000, 0},
  /* small */
  {"evergreens2", "brush", 1, 0.5, 1.8, 30, 90, -30, 24, 3000, 8000, 0},
  {"fernsdense", "brush", 1, 0.9, 2.5, 50, 100, 10, 35, 1000, 6000, 0},
  {"fernssparse", "brush", 1, 0.7, 2.0, 30, 90, -15, 35, 0, 4000, 0},
  {"woods4", "brush", 1, 0.1, 0.8, 30, 60, -5, 25, 1000, 4500, 0},
  {"woods5", "brush", 1, 0.6, 1.5, 20, 70, -15, 20, 2000, 5500, 0},
  {"forestsparse", "brush", 1, 0.3, 1.5, 15, 60, -20, 25, 0, 4500, 0},
  /* big */
  /*
     {"ytree_2", "brush", 2, 0.1, 0.6, 30, 60, 10, 25, 1000, 3500, 0},
     {"tree3", "grass", 2, 0.9, 2.5, 50, 100, 10, 35, 1000, 4000, 0},
     {"tree5", "grass", 2, 0.5, 1.5, 40, 90, -10, 24, 3000, 8000, 0},
     {"tree3", "grassmeduim", 2, 0.9, 2.5, 50, 100, 10, 35, 1000, 4000, 0},
     {"tree5", "grassmedium", 2, 0.5, 1.5, 40, 90, -10, 24, 3000, 8000, 0},
     {"tree3", "grassdark", 2, 0.9, 2.5, 50, 100, 10, 35, 1000, 4000, 0},
     {"tree5", "grassdark", 2, 0.5, 1.5, 40, 90, -10, 24, 3000, 8000, 0}, */
  /* mountians */
  {"steppe", NULL, 1, 0.5, 1.3, 0, 30, -20, 35, 1000, 6000, 0},
  {"steppelight", NULL, 1, 0.0, 0.6, 0, 20, -50, 35, 0, 5000, 0},
  {"hills", NULL, 1, 0.1, 0.9, 20, 80, -10, 30, 5000, 8500, 0},
  {"hills_rocky", NULL, 1, 0.0, 0.9, 0, 100, -50, 50, 5000, 8500, 0},
  {"swamp", NULL, 1, 1.0, 9.9, 55, 80, 10, 50, 0, 1000, 0},
  {"deep_swamp", NULL, 1, 1.0, 9.9, 80, 100, 10, 50, 0, 1000, 0},
  {"mountain", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 8000, 10000, 0},
  {"mountain2", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 9500, 11000, 0},
  {"mountain4", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 10500, 12000, 0},
  {"mountain5", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 11500, 13500, 0},
  {"wasteland", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 13000, 99999, 0},
  /* catchalls */
  {"palms", "pstone_1", 1, 0.01, 0.1, 0, 30, 5, 99, 0, 4000, 0},
  {"large_stones", NULL, 1, 0.0, 9.9, 0, 100, -50, 50, 6000, 8000, 0},
  {"earth", NULL, 1, 0.0, 1.0, 0, 70, -30, 15, 0, 6000, 0},
  {"medium_stones", NULL, 1, 1.0, 3.0, 70, 100, -30, 10, 0, 4000, 0},   /*unsure */
  {"earth", NULL, 1, 0.1, 0.9, 20, 80, -30, 30, 0, 4999, 0},    /* tundra */
  {"swamp", NULL, 1, 1.0, 9.9, 50, 100, -30, 10, 0, 4000, 0},   /* cold marsh */
  {"earth", NULL, 1, 0.0, 99.9, 0, 100, -99, 99, 0, 99999, 0},  /* debug */
  {NULL, NULL, 1, 0.0, 0.0, 0, 0, 0, 0, 0, 0, 0}
};

/* This stuff is for creating the images. */

/* Colour offsets into pixel array. */
#define RED   0
#define GREEN 1
#define BLUE  2

/* Colours used for wind directions.
 * winddir is the directoin wind is coming from.
 *   812  456
 *   7 3  3 7
 *   654  218
 */
static const uint32 directions[] = {
  0x0000FFFF,                   /* south */
  0x000000FF,                   /* south west */
  0x00FF00FF,                   /* west */
  0x00FFFFFF,                   /* north west */
  0x00000000,                   /* north */
  0x00FF0000,                   /* north east */
  0x00FFFF00,                   /* east */
  0x0000FF00                    /* south east */
};

/* Colours used for weather types. */
static const uint32 skies[] = {
  0x000000FF,                   /* SKY_CLEAR         0 */
  0x000000BD,                   /* SKY_LIGHTCLOUD    1 */
  0x0000007E,                   /* SKY_OVERCAST      2 */
  0x0000FF00,                   /* SKY_LIGHT_RAIN    3 */
  0x0000BD00,                   /* SKY_RAIN          4 */
  0x00007E00,                   /* SKY_HEAVY_RAIN    5 */
  0x00FFFF00,                   /* SKY_HURRICANE     6 */

/* wierd weather 7-12 */
  0x00FF0000,                   /* SKY_FOG           7 */
  0x00FF00FF,                   /* SKY_HAIL          8 */
  0x00000000,
  0x00000000,
  0x00000000,
  0x00000000,

/* snow */
  0x003F3F3F,                   /* SKY_LIGHT_SNOW    13 */
  0x007E7E7E,                   /* SKY_SNOW          14 */
  0x00BDBDBD,                   /* SKY_HEAVY_SNOW    15 */
  0x00FFFFFF                    /* SKY_BLIZZARD      16 */
};


/*
 * Set the darkness level for a map.  Requires the map pointer.
 */

void
set_darkness_map (maptile *m)
{
  int i;
  timeofday_t tod;

  if (!m->outdoor)
    return;

  get_tod (&tod);
  m->darkness = 0;
  for (i = HOURS_PER_DAY / 2; i < HOURS_PER_DAY; i++)
    change_map_light (m, season_timechange[tod.season][i]);
  for (i = 0; i <= tod.hour; i++)
    change_map_light (m, season_timechange[tod.season][i]);
}

/*
 * Compute the darkness level for all maps in the game.  Requires the
 * time of day as an argument.
 */

static void
dawn_to_dusk (const timeofday_t * tod)
{
  maptile *m;

  /* If the light level isn't changing, no reason to do all
   * the work below.
   */
  if (season_timechange[tod->season][tod->hour] == 0)
    return;

  for (m = first_map; m != NULL; m = m->next)
    {
      if (!m->outdoor)
        continue;
      change_map_light (m, season_timechange[tod->season][tod->hour]);
    }
}

/*
 * This performs the basic function of advancing the clock one tick
 * forward.  Every 20 ticks, the clock is saved to disk.  It is also
 * saved on shutdown.  Any time dependant functions should be called
 * from this function, and probably be passed tod as an argument.
 * Please don't modify tod in the dependant function.
 */

void
tick_the_clock (void)
{
  timeofday_t tod;

  todtick++;
  if (todtick % 20 == 0)
    write_todclock ();
  if (settings.dynamiclevel > 0)
    {
      if (todtick % 21 == 0)
        write_pressuremap ();
      if (todtick % 22 == 0)
        write_winddirmap ();
      if (todtick % 23 == 0)
        write_windspeedmap ();
      if (todtick % 24 == 0)
        write_humidmap ();

/*      if (todtick%25 == 0)
            write_elevmap(); */
      if (todtick % 26 == 0)
        write_temperaturemap ();
      if (todtick % 27 == 0)
        write_gulfstreammap ();
      if (todtick % 28 == 0)
        write_skymap ();
      if (todtick % 29 == 0)
        write_rainfallmap ();
    }
  get_tod (&tod);
  dawn_to_dusk (&tod);
  /* call the weather calculators, here, in order */
  if (settings.dynamiclevel > 0)
    {
      perform_pressure ();      /* pressure is the random factor */
      smooth_wind ();           /* calculate the wind. depends on pressure */
      plot_gulfstream ();
      update_humid ();
      init_temperature ();
      compute_sky ();
      if (tod.hour == 0)
        process_rain ();
    }
  /* perform_weather must follow calculators */
  perform_weather ();
  if (settings.dynamiclevel > 0)
    {
      write_weather_images ();
      spin_globe ();
    }
}

/*
 * This batch of routines reads and writes the various
 * weathermap structures.  Each type of data is stored
 * in a separate file to allow the size of these structures to be
 * changed more or less on the fly.  If weather goes haywire, the admin
 * can simply delete and boot the server, and it will regen.
 *
 * The write functions should be called occasionally to keep the data
 * in the maps current.  Whereas the read functions should only be called
 * at boot.  If the read function cannot find the appropriate map, it
 * calls the init function, to initialize that map.
 */

/* sky. We never read this map, only write it for debugging purposes */

static void
write_skymap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/skymap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].sky);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

/* pressure */

static void
write_pressuremap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/pressuremap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].pressure);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_pressuremap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/pressuremap", settings.localdir);
  LOG (llevDebug, "Reading pressure data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      LOG (llevDebug, "Initializing pressure maps...");
      init_pressure ();
      write_pressuremap ();
      LOG (llevDebug, "Done\n");
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%hd ", &weathermap[x][y].pressure);
          if (weathermap[x][y].pressure < 960 || weathermap[x][y].pressure > 1040)
            weathermap[x][y].pressure = rndm (960, 1040);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

static void
init_pressure (void)
{
  int x, y;
  int l, n, k, r;

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      weathermap[x][y].pressure = 1000;

  for (l = 0; l < PRESSURE_ITERATIONS; l++)
    {
      x = rndm (0, WEATHERMAPTILESX - 1);
      y = rndm (0, WEATHERMAPTILESY - 1);
      n = rndm (PRESSURE_MIN, PRESSURE_MAX);
      for (k = 1; k < PRESSURE_AREA; k++)
        {
          r = rndm (0, 3);
          switch (r)
            {
                case 0:
                  if (x < WEATHERMAPTILESX - 1)
                    x++;
                  break;
                case 1:
                  if (y < WEATHERMAPTILESY - 1)
                    y++;
                  break;
                case 2:
                  if (x)
                    x--;
                  break;
                case 3:
                  if (y)
                    y--;
                  break;
            }
          weathermap[x][y].pressure = (weathermap[x][y].pressure + n) / 2;
        }
    }
  /* create random spikes in the pressure */
  for (l = 0; l < PRESSURE_SPIKES; l++)
    {
      x = rndm (0, WEATHERMAPTILESX - 1);
      y = rndm (0, WEATHERMAPTILESY - 1);
      n = rndm (500, 2000);
      weathermap[x][y].pressure = n;
    }
  smooth_pressure ();
}

/* winddir */

static void
write_winddirmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/winddirmap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].winddir);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_winddirmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y, d;

  sprintf (filename, "%s/winddirmap", settings.localdir);
  LOG (llevDebug, "Reading wind direction data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      LOG (llevDebug, "Initializing wind maps...");
      init_wind ();
      write_winddirmap ();
      LOG (llevDebug, "Done\n");
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &d);
          weathermap[x][y].winddir = d;
          if (weathermap[x][y].winddir < 1 || weathermap[x][y].winddir > 8)
            weathermap[x][y].winddir = rndm (1, 8);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

/* windspeed */

static void
write_windspeedmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/windspeedmap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].windspeed);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_windspeedmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y, d;

  sprintf (filename, "%s/windspeedmap", settings.localdir);
  LOG (llevDebug, "Reading wind speed data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      LOG (llevDebug, "Initializing wind maps...");
      init_wind ();
      write_windspeedmap ();
      LOG (llevDebug, "Done\n");
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &d);
          weathermap[x][y].windspeed = d;
          if (weathermap[x][y].windspeed < 0 || weathermap[x][y].windspeed > 120)
            weathermap[x][y].windspeed = rndm (1, 30);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

/* initialize the wind randomly. Does both direction and speed in one pass */

static void
init_wind (void)
{
  int x, y;

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      {
        weathermap[x][y].winddir = rndm (1, 8);
        weathermap[x][y].windspeed = rndm (1, 10);
      }
}

/* gulf stream */

static void
write_gulfstreammap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/gulfstreammap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < GULF_STREAM_WIDTH; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", gulf_stream_speed[x][y]);
      fprintf (fp, "\n");
    }
  for (x = 0; x < GULF_STREAM_WIDTH; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", gulf_stream_dir[x][y]);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_gulfstreammap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/gulfstreammap", settings.localdir);
  LOG (llevDebug, "Reading gulf stream data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      LOG (llevDebug, "Initializing gulf stream maps...");
      init_gulfstreammap ();
      write_gulfstreammap ();
      LOG (llevDebug, "Done\n");
      return;
    }
  for (x = 0; x < GULF_STREAM_WIDTH; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &gulf_stream_speed[x][y]);
          if (gulf_stream_speed[x][y] < 0 || gulf_stream_speed[x][y] > 120)
            gulf_stream_speed[x][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
        }
      fscanf (fp, "\n");
    }
  for (x = 0; x < GULF_STREAM_WIDTH; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &gulf_stream_dir[x][y]);
          if (gulf_stream_dir[x][y] < 0 || gulf_stream_dir[x][y] > 120)
            gulf_stream_dir[x][y] = rndm (1, 8);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

static void
init_gulfstreammap (void)
{
  int x, y, tx;

  /* build a gulf stream */
  x = rndm (GULF_STREAM_WIDTH, WEATHERMAPTILESX - GULF_STREAM_WIDTH);
  /* doth the great bob inhale or exhale? */
  gulf_stream_direction = rndm (0, 1);
  gulf_stream_start = x;

  if (gulf_stream_direction)
    {
      for (y = WEATHERMAPTILESY - 1; y >= 0; y--)
        {
          switch (rndm (0, 6))
            {
                case 0:
                case 1:
                case 2:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      if (x == 0)
                        gulf_stream_dir[tx][y] = 7;
                      else
                        {
                          gulf_stream_dir[tx][y] = 8;
                          if (tx == 0)
                            x--;
                        }
                    }
                  break;
                case 3:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      gulf_stream_dir[tx][y] = 7;
                    }
                  break;
                case 4:
                case 5:
                case 6:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      if (x == WEATHERMAPTILESX - 1)
                        gulf_stream_dir[tx][y] = 7;
                      else
                        {
                          gulf_stream_dir[tx][y] = 6;
                          if (tx == 0)
                            x++;
                        }
                    }
                  break;
            }
        }
    }
  else
    {                           /* go right to left */
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          switch (rndm (0, 6))
            {
                case 0:
                case 1:
                case 2:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      if (x == 0)
                        gulf_stream_dir[tx][y] = 3;
                      else
                        {
                          gulf_stream_dir[tx][y] = 2;
                          if (tx == 0)
                            x--;
                        }
                    }
                  break;
                case 3:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      gulf_stream_dir[tx][y] = 3;
                    }
                  break;
                case 4:
                case 5:
                case 6:
                  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
                    {
                      gulf_stream_speed[tx][y] = rndm (GULF_STREAM_BASE_SPEED, GULF_STREAM_BASE_SPEED + 10);
                      if (x == WEATHERMAPTILESX - 1)
                        gulf_stream_dir[tx][y] = 3;
                      else
                        {
                          gulf_stream_dir[tx][y] = 4;
                          if (tx == 0)
                            x++;
                        }
                    }
                  break;
            }
        }
    }                           /* done */
}

/* humidity */

static void
write_humidmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/humidmap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].humid);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_humidmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y, d;

  sprintf (filename, "%s/humidmap", settings.localdir);
  LOG (llevDebug, "Reading humidity data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      LOG (llevDebug, "Initializing humidity and elevation maps...");
      init_humid_elev ();
      write_elevmap ();
      write_humidmap ();
      write_watermap ();
      LOG (llevDebug, "Done\n");
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &d);
          weathermap[x][y].humid = d;
          if (weathermap[x][y].humid < 0 || weathermap[x][y].humid > 100)
            weathermap[x][y].humid = rndm (0, 100);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

/* average elevation */

static void
write_elevmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/elevmap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].avgelev);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_elevmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/elevmap", settings.localdir);
  LOG (llevDebug, "Reading elevation data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      /* initializing these is expensive, and should have been done
         by the humidity.  It's not worth the wait to do it twice. */
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &weathermap[x][y].avgelev);
          if (weathermap[x][y].avgelev < -10000 || weathermap[x][y].avgelev > 15000)
            weathermap[x][y].avgelev = rndm (-1000, 10000);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

/* water % */

static void
write_watermap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/watermap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].water);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_watermap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y, d;

  sprintf (filename, "%s/watermap", settings.localdir);
  LOG (llevDebug, "Reading water data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      /* initializing these is expensive, and should have been done
         by the humidity.  It's not worth the wait to do it twice. */
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%d ", &d);
          weathermap[x][y].water = d;
          if (weathermap[x][y].water > 100)
            weathermap[x][y].water = rndm (0, 100);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

/*
 * initialize both humidity and elevation
 */

static void
init_humid_elev (void)
{
  int x, y, tx, ty, nx, ny, ax, ay, j;
  int spwtx, spwty;
  const char *mapname;
  long int elev;
  int water, space;
  maptile *m;

  /* handling of this is kinda nasty.  For that reason,
   * we do the elevation here too.  Not because it makes the
   * code cleaner, or makes handling easier, but because I do *not*
   * want to maintain two of these nightmares.
   */

  spwtx = (settings.worldmaptilesx * settings.worldmaptilesizex) / WEATHERMAPTILESX;
  spwty = (settings.worldmaptilesy * settings.worldmaptilesizey) / WEATHERMAPTILESY;
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          water = 0;
          elev = 0;
          nx = 0;
          ny = 0;
          space = 0;

          /* top left */
          mapname = weathermap_to_worldmap_corner (x, y, &tx, &ty, 8);
          m = load_original_map (mapname, 0);
          if (m == NULL)
            continue;
          m = load_overlay_map (mapname, m);
          if (m == NULL)
            continue;
          for (nx = 0, ax = tx; (nx < spwtx && (uint32) ax < settings.worldmaptilesizex && space < spwtx * spwty); ax++, nx++)
            {
              for (ny = 0, ay = ty; (ny < spwty && (uint32) ay < settings.worldmaptilesizey && space < spwtx * spwty); ay++, ny++, space++)
                if (GET_MAP_OB (m, ax, ay))
                  {
                    if (QUERY_FLAG (GET_MAP_OB (m, ax, ay), FLAG_IS_WATER))
                      water++;
                    elev += GET_MAP_OB (m, ax, ay)->elevation;
                  }
            }
          delete_map (m);

          /* bottom left */
          mapname = weathermap_to_worldmap_corner (x, y, &tx, &ty, 6);
          m = load_original_map (mapname, 0);
          if (m == NULL)
            continue;
          m = load_overlay_map (mapname, m);
          if (m == NULL)
            continue;
          j = ny;
          for (nx = 0, ax = tx; (nx < spwtx && (uint32) ax < settings.worldmaptilesizex && space < spwtx * spwty); ax++, nx++)
            {
              for (ny = j, ay = MAX (0, ty - (spwty - 1)); (ny < spwty && ay <= ty && space < spwtx * spwty); space++, ay++, ny++)
                if (GET_MAP_OB (m, ax, ay))
                  {
                    if (QUERY_FLAG (GET_MAP_OB (m, ax, ay), FLAG_IS_WATER))
                      water++;
                    elev += GET_MAP_OB (m, ax, ay)->elevation;
                  }
            }
          delete_map (m);

          /* top right */
          mapname = weathermap_to_worldmap_corner (x, y, &tx, &ty, 2);
          m = load_original_map (mapname, 0);
          if (m == NULL)
            continue;
          m = load_overlay_map (mapname, m);
          if (m == NULL)
            continue;
          for (ax = MAX (0, tx - (spwtx - 1)); (nx < spwtx && ax < tx && space < spwtx * spwty); ax++, nx++)
            {
              for (ny = 0, ay = ty; (ny < spwty && (uint32) ay < settings.worldmaptilesizey && space < spwtx * spwty); ay++, ny++, space++)
                if (GET_MAP_OB (m, ax, ay))
                  {
                    if (QUERY_FLAG (GET_MAP_OB (m, ax, ay), FLAG_IS_WATER))
                      water++;
                    elev += GET_MAP_OB (m, ax, ay)->elevation;
                  }
            }
          delete_map (m);

          /* bottom left */
          mapname = weathermap_to_worldmap_corner (x, y, &tx, &ty, 4);
          m = load_original_map (mapname, 0);
          if (m == NULL)
            continue;
          m = load_overlay_map (mapname, m);
          if (m == NULL)
            continue;
          for (nx = 0, ax = MAX (0, tx - (spwtx - 1)); (nx < spwtx && ax < tx && space < spwtx * spwty); ax++, nx++)
            {
              for (ny = 0, ay = MAX (0, ty - (spwty - 1)); (ny < spwty && ay <= ty && space < spwtx * spwty); space++, ay++, ny++)
                if (GET_MAP_OB (m, ax, ay))
                  {
                    if (QUERY_FLAG (GET_MAP_OB (m, ax, ay), FLAG_IS_WATER))
                      water++;
                    elev += GET_MAP_OB (m, ax, ay)->elevation;
                  }
            }
          delete_map (m);
          /* jesus thats confusing as all hell */
          weathermap[x][y].humid = water * 100 / (spwtx * spwty);
          weathermap[x][y].avgelev = elev / (spwtx * spwty);
          weathermap[x][y].water = weathermap[x][y].humid;
        }
    }

  /* and this does all the real work */
  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      weathermap[x][y].humid = humid_tile (x, y);
}

/* temperature */

static void
write_temperaturemap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/temperaturemap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%d ", weathermap[x][y].temp);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_temperaturemap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/temperaturemap", settings.localdir);
  LOG (llevDebug, "Reading temperature data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      init_temperature ();
      write_temperaturemap ();
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%hd ", &weathermap[x][y].temp);
          if (weathermap[x][y].temp < -30 || weathermap[x][y].temp > 60)
            weathermap[x][y].temp = rndm (-10, 40);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

static void
init_temperature (void)
{
  int x, y;
  timeofday_t tod;

  get_tod (&tod);
  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      temperature_calc (x, y, &tod);
}

/* rainfall */

static void
write_rainfallmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/rainfallmap", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        fprintf (fp, "%u ", weathermap[x][y].rainfall);
      fprintf (fp, "\n");
    }
  fclose (fp);
}

static void
read_rainfallmap (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;

  sprintf (filename, "%s/rainfallmap", settings.localdir);
  LOG (llevDebug, "Reading rainfall data from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Cannot open %s for reading\n", filename);
      init_rainfall ();
      write_rainfallmap ();
      return;
    }
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          fscanf (fp, "%u ", &weathermap[x][y].rainfall);
        }
      fscanf (fp, "\n");
    }
  LOG (llevDebug, "Done.\n");
  fclose (fp);
}

static void
init_rainfall (void)
{
  int x, y;
  int days;

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      {
        days = todtick / HOURS_PER_DAY;
        if (weathermap[x][y].humid < 10)
          weathermap[x][y].rainfall = days / 20;
        else if (weathermap[x][y].humid < 20)
          weathermap[x][y].rainfall = days / 15;
        else if (weathermap[x][y].humid < 30)
          weathermap[x][y].rainfall = days / 10;
        else if (weathermap[x][y].humid < 40)
          weathermap[x][y].rainfall = days / 5;
        else if (weathermap[x][y].humid < 50)
          weathermap[x][y].rainfall = days / 2;
        else if (weathermap[x][y].humid < 60)
          weathermap[x][y].rainfall = days;
        else if (weathermap[x][y].humid < 80)
          weathermap[x][y].rainfall = days * 2;
        else
          weathermap[x][y].rainfall = days * 3;
      }
}

/* END of read/write/init */


static void
init_weatheravoid (weather_avoids_t wa[])
{
  int i;

  for (i = 0; wa[i].name != NULL; i++)
    {
      wa[i].what = archetype::find (wa[i].name);
    }
}

static int wmperformstartx;
static int wmperformstarty;

/*
 * This function initializes the weather system.  It should be called once,
 * at game startup only.
 */


void
init_weather (void)
{
  int y, tx, ty;
  char filename[MAX_BUF];
  FILE *fp;

  /* all this stuff needs to be set, otherwise this function will cause
   * chaos and destruction.
   */
  if (settings.dynamiclevel < 1)
    return;
  if (settings.worldmapstartx < 1 || settings.worldmapstarty < 1 ||
      settings.worldmaptilesx < 1 || settings.worldmaptilesy < 1 || settings.worldmaptilesizex < 1 || settings.worldmaptilesizex < 1)
    return;
  /*prepare structures used for avoidance */
  init_weatheravoid (weather_avoids);
  init_weatheravoid (growth_avoids);


  LOG (llevDebug, "Initializing the weathermap...\n");

  weathermap = (weathermap_t **) malloc (sizeof (weathermap_t *) * WEATHERMAPTILESX);
  if (weathermap == NULL)
    fatal (OUT_OF_MEMORY);
  for (y = 0; y < WEATHERMAPTILESY; y++)
    {
      weathermap[y] = (weathermap_t *) malloc (sizeof (weathermap_t) * WEATHERMAPTILESY);
      if (weathermap[y] == NULL)
        fatal (OUT_OF_MEMORY);
    }
  /* now we load the values in the big worldmap weather array */
  /* do not re-order these */
  read_pressuremap ();
  read_winddirmap ();
  read_windspeedmap ();
  read_gulfstreammap ();
  read_watermap ();
  read_humidmap ();
  read_elevmap ();              /* elevation must allways follow humidity */
  read_temperaturemap ();
  gulf_stream_direction = rndm (0, 1);
  for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
    for (ty = 0; ty < WEATHERMAPTILESY - 1; ty++)
      if (gulf_stream_direction)
        switch (gulf_stream_dir[tx][ty])
          {
              case 2:
                gulf_stream_dir[tx][ty] = 6;
                break;
              case 3:
                gulf_stream_dir[tx][ty] = 7;
                break;
              case 4:
                gulf_stream_dir[tx][ty] = 8;
                break;
          }
      else
        switch (gulf_stream_dir[tx][ty])
          {
              case 6:
                gulf_stream_dir[tx][ty] = 2;
                break;
              case 7:
                gulf_stream_dir[tx][ty] = 3;
                break;
              case 8:
                gulf_stream_dir[tx][ty] = 4;
                break;
          }
  gulf_stream_start = rndm (GULF_STREAM_WIDTH, WEATHERMAPTILESY - GULF_STREAM_WIDTH);
  read_rainfallmap ();

  LOG (llevDebug, "Done reading weathermaps\n");
  sprintf (filename, "%s/wmapcurpos", settings.localdir);
  LOG (llevDebug, "Reading current weather position from %s...", filename);
  if ((fp = fopen (filename, "r")) == NULL)
    {
      LOG (llevError, "Can't open %s.\n", filename);
      wmperformstartx = -1;
      return;
    }
  fscanf (fp, "%d %d", &wmperformstartx, &wmperformstarty);
  LOG (llevDebug, "curposx=%d curposy=%d\n", wmperformstartx, wmperformstarty);
  fclose (fp);
  if ((uint32) wmperformstartx > settings.worldmaptilesx)
    wmperformstartx = -1;
  if ((uint32) wmperformstarty > settings.worldmaptilesy)
    wmperformstarty = 0;
}

/*
 * This routine slowly loads the world, patches it up due to the weather,
 * and saves it back to disk.  In this way, the world constantly feels the
 * effects of weather uniformly, without relying on players wandering.
 *
 * The main point of this is stuff like growing herbs, soil, decaying crap,
 * etc etc etc.  Not actual *weather*, but weather *effects*.
 */

static void
perform_weather (void)
{
  maptile *m;
  char filename[MAX_BUF];
  FILE *fp;

  if (!settings.dynamiclevel)
    return;

  /* move right to left, top to bottom */
  if ((uint32) wmperformstartx + 1 == settings.worldmaptilesx)
    {
      wmperformstartx = 0;
      wmperformstarty++;
    }
  else
    wmperformstartx++;
  if ((uint32) wmperformstarty == settings.worldmaptilesy)
    wmperformstartx = wmperformstarty = 0;

  sprintf (filename, "world/world_%d_%d", wmperformstartx + settings.worldmapstartx, wmperformstarty + settings.worldmapstarty);

  m = ready_map_name (filename, 0);
  if (m == NULL)
    return;                     /* hrmm */

  /* for now, all we do is decay stuff.  more to come */
  decay_objects (m);
  weather_effect (filename);

  /* done */
  new_save_map (m, 2);          /* write the overlay */
  m->in_memory = MAP_IN_MEMORY; /*reset this */
  sprintf (filename, "%s/wmapcurpos", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }

  if (players_on_map (m, TRUE) == 0)
    delete_map (m);

  fprintf (fp, "%d %d", wmperformstartx, wmperformstarty);
  fclose (fp);
}

/*
 * perform actual effect of weather.  Should be called from perform_weather,
 * or when a map is loaded. (player enter map).  Filename is the name of
 * the map.  The map *must allready be loaded*.
 *
 * This is where things like snow, herbs, earthly rototilling, etc should
 * occur.
 */

void
weather_effect (const char *filename)
{
  maptile *m;
  int wx, wy, x, y;

  /* if the dm shut off weather, go home */
  if (settings.dynamiclevel < 1)
    return;

  m = ready_map_name (filename, 0);
  if (!m->outdoor)
    return;

  x = 0;
  y = 0;
  /* for now, just bail if it's not the worldmap */
  if (worldmap_to_weathermap (x, y, &wx, &wy, m) != 0)
    return;
  /*First, calculate temperature */
  calculate_temperature (m, wx, wy);
  /* we change the world first, if needed */
  if (settings.dynamiclevel >= 5)
    {
      change_the_world (m, wx, wy);
    }
  if (settings.dynamiclevel >= 2)
    {
      let_it_snow (m, wx, wy);
      singing_in_the_rain (m, wx, wy);
    }
  /*    if (settings.dynamiclevel >= 4) {
     feather_map(m, wx, wy, filename);
     } */
  if (settings.dynamiclevel >= 3)
    {
      plant_a_garden (m, wx, wy);
    }
}

/*
 * Check the current square to see if we should avoid this one for
 * weather processing.  Must pass av and gs, which will be filled in
 * with 1 or 0.  gs will be 1 if we found snow/rain here.  av will be
 * 1 if we should avoid processing this tile. (don't rain on lakes)
 * x and y are the coordinates inside the current map m. If grow is
 * 1, we use the growth table, rather than the avoidance table.
 *
 * Returns the object pointer for any snow item it found, so you can 
 * destroy/melt it.
 */

static object *
avoid_weather (int *av, maptile *m, int x, int y, int *gs, int grow)
{
  int avoid, gotsnow, i, n;

  object *tmp;

  avoid = 0;
  gotsnow = 0;
  if (grow)
    {
      for (tmp = GET_MAP_OB (m, x, y), n = 0; tmp; tmp = tmp->above, n++)
        {
          /* look for things like walls, holes, etc */
          if (n)
            if (!QUERY_FLAG (tmp, FLAG_IS_FLOOR) && !(tmp->material & M_ICE || tmp->material & M_LIQUID))
              gotsnow++;
          for (i = 0; growth_avoids[i].name != NULL; i++)
            {
              /*if (!strcmp(tmp->arch->name, growth_avoids[i].name)) { */
              if (tmp->arch == growth_avoids[i].what)
                {
                  avoid++;
                  break;
                }
            }
          if (!strncmp (tmp->arch->name, "biglake_", 8))
            {
              avoid++;
              break;
            }
          if (avoid)
            break;
        }
    }
  else
    {
      for (tmp = GET_MAP_OB (m, x, y); tmp; tmp = tmp->above)
        {
          for (i = 0; weather_avoids[i].name != NULL; i++)
            {
              /*if (!strcmp(tmp->arch->name, weather_avoids[i].name)) { */
              if (tmp->arch == weather_avoids[i].what)
                {
                  if (weather_avoids[i].snow == 1)
                    gotsnow++;
                  else
                    avoid++;
                  break;
                }
            }
          if (avoid || gotsnow)
            break;
        }
    }
  *gs = gotsnow;
  *av = avoid;
  return tmp;
}

/* Temperature is used in a lot of weather function.
 * This need to be precalculated before used.
 */
static void
calculate_temperature (maptile *m, int wx, int wy)
{
  uint32 x, y;

  for (x = 0; x < settings.worldmaptilesizex; x++)
    {
      for (y = 0; y < settings.worldmaptilesizey; y++)
        {
          weathermap[wx][wy].realtemp = real_world_temperature (x, y, m);
        }
    }
}

/*
 * Process snow.  m is the map we are currently processing.  wx and wy are
 * the weathermap coordinates for the weathermap square we want to work on.
 * filename is the pathname for the current map.  This should be called from
 * weather_effect()
 */

static void
let_it_snow (maptile *m, int wx, int wy)
{
  int x, y, i;
  uint32 nx, ny, j, d;
  int avoid, two, temp, sky, gotsnow, found, nodstk;
  const char *doublestack, *doublestack2;
  object *ob, *tmp, *oldsnow, *topfloor;
  archetype *at;

  for (nx = 0; nx < settings.worldmaptilesizex; nx++)
    {
      for (ny = 0; ny < settings.worldmaptilesizey; ny++)
        {
          /* jitter factor */
          if (rndm (0, 2) > 0)
            {
              x = y = d = -1;
              while (OUT_OF_REAL_MAP (m, x, y))
                {
                  d++;
                  j = rndm (1, 8);
                  x = nx + freearr_x[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  y = ny + freearr_y[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  if (d > 15)
                    {
                      x = nx;
                      y = ny;
                    }
                }
            }
          else
            {
              x = nx;
              y = ny;
            }
          /* we use the unjittered coordinates */
          (void) worldmap_to_weathermap (nx, ny, &wx, &wy, m);
          ob = NULL;
          at = NULL;
          /* this will definately need tuning */
          avoid = 0;
          two = 0;
          gotsnow = 0;
          nodstk = 0;
          /*temp = real_world_temperature(x, y, m); */
          temp = weathermap[wx][wy].realtemp;
          sky = weathermap[wx][wy].sky;
          if (temp <= 0 && sky > SKY_OVERCAST && sky < SKY_FOG)
            sky += 10;          /*let it snow */
          oldsnow = avoid_weather (&avoid, m, x, y, &gotsnow, 0);
          if (!avoid)
            {
              if (sky >= SKY_LIGHT_SNOW && sky < SKY_HEAVY_SNOW)
                at = archetype::find (weather_replace[0].special_snow);
              if (sky >= SKY_HEAVY_SNOW)
                at = archetype::find (weather_replace[1].special_snow);
              if (sky >= SKY_LIGHT_SNOW)
                {
                  /* the bottom floor of scorn is not IS_FLOOR */
                  topfloor = NULL;
                  for (tmp = GET_MAP_OB (m, x, y); tmp; topfloor = tmp, tmp = tmp->above)
                    {
                      if (strcmp (tmp->arch->name, "dungeon_magic") != 0)
                        if (!QUERY_FLAG (tmp, FLAG_IS_FLOOR))
                          break;
                    }
                  /* topfloor should now be the topmost IS_FLOOR=1 */
                  if (topfloor == NULL)
                    continue;
                  if (tmp != NULL)
                    nodstk++;
                  /* something is wrong with that sector. just skip it */
                  found = 0;
                  for (i = 0; weather_replace[i].tile != NULL; i++)
                    {
                      if (weather_replace[i].arch_or_name == 1)
                        {
                          if (!strcmp (topfloor->arch->name, weather_replace[i].tile))
                            found++;
                        }
                      else
                        {
                          if (!strcmp (topfloor->name, weather_replace[i].tile))
                            found++;
                        }
                      if (found)
                        {
                          if (weather_replace[i].special_snow != NULL)
                            at = archetype::find (weather_replace[i].special_snow);
                          if (weather_replace[i].doublestack_arch != NULL && !nodstk)
                            {
                              two++;
                              doublestack = weather_replace[i].doublestack_arch;
                            }
                          break;
                        }
                    }
                }
              if (gotsnow && at)
                {
                  if (!strcmp (oldsnow->arch->name, at->name))
                    at = NULL;
                  else
                    {
                      oldsnow->destroy ();

                      tmp = GET_MAP_OB (m, x, y);
                      /* clean up the trees we put over the snow */
                      found = 0;
                      doublestack2 = NULL;
                      if (tmp)
                        for (i = 0; weather_replace[i].tile != NULL; i++)
                          {
                            if (weather_replace[i].doublestack_arch == NULL)
                              continue;

                            if (weather_replace[i].arch_or_name == 1)
                              {
                                if (!strcmp (tmp->arch->name, weather_replace[i].tile))
                                  found++;
                              }
                            else if (!strcmp (tmp->name, weather_replace[i].tile))
                              found++;

                            if (found)
                              {
                                tmp = tmp->above;
                                doublestack2 = weather_replace[i].doublestack_arch;
                                break;
                              }
                          }

                      if (tmp != NULL && doublestack2 != NULL)
                        if (strcmp (tmp->arch->name, doublestack2) == 0)
                          tmp->destroy ();
                    }
                }
              if (at != NULL)
                {
                  ob = arch_to_object (at);
                  ob->x = x;
                  ob->y = y;
                  ob->material = M_ICE;
                  SET_FLAG (ob, FLAG_OVERLAY_FLOOR);
                  CLEAR_FLAG (ob, FLAG_IS_FLOOR);
                  insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                  if (two)
                    {
                      at = NULL;
                      at = archetype::find (doublestack);
                      if (at != NULL)
                        {
                          ob = arch_to_object (at);
                          ob->x = x;
                          ob->y = y;
                          insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ON_TOP);
                        }
                    }
                }
            }
          if (temp > 8 && GET_MAP_OB (m, x, y) != NULL)
            {
              /* melt some snow */
              for (tmp = GET_MAP_OB (m, x, y)->above; tmp; tmp = tmp->above)
                {
                  avoid = 0;
                  for (i = 0; weather_replace[i].tile != NULL; i++)
                    {
                      if (weather_replace[i].special_snow == NULL)
                        continue;
                      if (!strcmp (tmp->arch->name, weather_replace[i].special_snow))
                        avoid++;
                      if (avoid)
                        break;
                    }
                  if (avoid)
                    {
                      /* replace snow with a big puddle */
                      tmp->destroy ();
                      tmp = GET_MAP_OB (m, x, y);

                      if (tmp && (!strcmp (tmp->arch->name, "mountain")))
                        at = archetype::find ("mountain1_rivlets");
                      else if (tmp && (!strcmp (tmp->arch->name, "mountain2")))
                        at = archetype::find ("mountain2_rivlets");
                      else if (tmp && (!strcmp (tmp->arch->name, "mountain4")))
                        at = archetype::find ("mountain2_rivlets");
                      else
                        at = archetype::find ("rain5");

                      if (at != NULL)
                        {
                          ob = arch_to_object (at);
                          ob->x = x;
                          ob->y = y;
                          SET_FLAG (ob, FLAG_OVERLAY_FLOOR);
                          ob->material = M_LIQUID;
                          insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                        }
                    }
                }
            }
          /* woo it's cold out */
          if (temp < -8)
            {
              avoid = 0;
              for (tmp = GET_MAP_OB (m, x, y); tmp; tmp = tmp->above)
                {
                  if (!strcasecmp (tmp->name, "ice"))
                    avoid--;
                }
              tmp = GET_MAP_OB (m, x, y);
              if (tmp && (!strcasecmp (tmp->name, "sea")))
                avoid++;
              else if (tmp && (!strcasecmp (tmp->name, "sea1")))
                avoid++;
              else if (tmp && (!strcasecmp (tmp->name, "deep_sea")))
                avoid++;
              else if (tmp && (!strcasecmp (tmp->name, "shallow_sea")))
                avoid++;
              if (avoid > 0)
                {
                  at = archetype::find ("ice");
                  ob = arch_to_object (at);
                  ob->x = x;
                  ob->y = y;
                  insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                }
            }
        }
    }
}

/*
 * Process rain.  m is the map we are currently processing.  wx and wy are
 * the weathermap coordinates for the weathermap square we want to work on.
 * filename is the pathname for the current map.  This should be called from
 * weather_effect()
 */

static void
singing_in_the_rain (maptile *m, int wx, int wy)
{
  int x, y, i;
  uint32 nx, ny, d, j;
  int avoid, two, temp, sky, gotsnow, found, nodstk;
  object *ob, *tmp, *oldsnow, *topfloor;
  const char *doublestack, *doublestack2;
  archetype *at;

  for (nx = 0; nx < settings.worldmaptilesizex; nx++)
    {
      for (ny = 0; ny < settings.worldmaptilesizey; ny++)
        {
          /* jitter factor */
          if (rndm (0, 2) > 0)
            {
              x = y = d = -1;
              while (OUT_OF_REAL_MAP (m, x, y))
                {
                  d++;
                  j = rndm (1, 8);
                  x = nx + freearr_x[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  y = ny + freearr_y[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  if (d > 15)
                    {
                      x = nx;
                      y = ny;
                    }
                }
            }
          else
            {
              x = nx;
              y = ny;
            }
          /* we use the unjittered coordinates */
          (void) worldmap_to_weathermap (nx, ny, &wx, &wy, m);
          ob = NULL;
          at = NULL;
          avoid = 0;
          two = 0;
          gotsnow = 0;
          nodstk = 0;
          /*temp = real_world_temperature(x, y, m); */
          temp = weathermap[wx][wy].realtemp;
          sky = weathermap[wx][wy].sky;
          /* it's probably allready snowing */
          if (temp < 0)
            continue;
          oldsnow = avoid_weather (&avoid, m, x, y, &gotsnow, 0);
          if (!avoid)
            {
              tmp = GET_MAP_OB (m, x, y);
              if (tmp && (!strcmp (tmp->arch->name, "mountain")))
                {
                  at = archetype::find ("mountain1_rivlets");
                  break;
                }
              else if (tmp && (!strcmp (tmp->arch->name, "mountain2")))
                {
                  at = archetype::find ("mountain2_rivlets");
                  break;
                }
              else if (tmp && (!strcmp (tmp->arch->name, "mountain4")))
                {
                  at = archetype::find ("mountain2_rivlets");
                  break;
                }
              if (sky == SKY_LIGHT_RAIN || sky == SKY_RAIN)
                {
                  switch (rndm (0, SKY_HAIL - sky))
                    {
                        case 0:
                          at = archetype::find ("rain1");
                          break;
                        case 1:
                          at = archetype::find ("rain2");
                          break;
                        default:
                          at = NULL;
                    }
                }
              if (sky >= SKY_HEAVY_RAIN && sky <= SKY_HURRICANE)
                {
                  switch (rndm (0, SKY_HAIL - sky))
                    {
                        case 0:
                          at = archetype::find ("rain3");
                          break;
                        case 1:
                          at = archetype::find ("rain4");
                          break;
                        case 2:
                          at = archetype::find ("rain5");
                          break;
                        default:
                          at = NULL;
                    }
                }
              /* the bottom floor of scorn is not IS_FLOOR */
              topfloor = NULL;
              for (tmp = GET_MAP_OB (m, x, y); tmp; topfloor = tmp, tmp = tmp->above)
                {
                  if (strcmp (tmp->arch->name, "dungeon_magic") != 0)
                    if (!QUERY_FLAG (tmp, FLAG_IS_FLOOR))
                      break;
                }
              /* topfloor should now be the topmost IS_FLOOR=1 */
              if (topfloor == NULL)
                continue;
              if (tmp != NULL)
                nodstk++;
              /* something is wrong with that sector. just skip it */
              found = 0;
              for (i = 0; weather_replace[i].tile != NULL; i++)
                {
                  if (weather_replace[i].arch_or_name == 1)
                    {
                      if (!strcmp (topfloor->arch->name, weather_replace[i].tile))
                        found++;
                    }
                  else
                    {
                      if (!strcmp (topfloor->name, weather_replace[i].tile))
                        found++;
                    }
                  if (found)
                    {
                      if (weather_replace[i].doublestack_arch != NULL && !nodstk)
                        {
                          two++;
                          doublestack = weather_replace[i].doublestack_arch;
                        }
                      break;
                    }
                }
              if (gotsnow && at)
                {
                  if (!strcmp (oldsnow->arch->name, at->name))
                    at = NULL;
                  else
                    {
                      tmp = GET_MAP_OB (m, x, y);
                      oldsnow->remove ();
                      /* clean up the trees we put over the snow */
                      found = 0;
                      doublestack2 = NULL;
                      for (i = 0; weather_replace[i].tile != NULL; i++)
                        {
                          if (weather_replace[i].doublestack_arch == NULL)
                            continue;
                          if (weather_replace[i].arch_or_name == 1)
                            {
                              if (!strcmp (tmp->arch->name, weather_replace[i].tile))
                                found++;
                            }
                          else
                            {
                              if (!strcmp (tmp->name, weather_replace[i].tile))
                                found++;
                            }
                          if (found)
                            {
                              tmp = tmp->above;
                              doublestack2 = weather_replace[i].doublestack_arch;
                              break;
                            }
                        }

                      oldsnow->destroy ();

                      if (tmp != NULL && doublestack2 != NULL)
                        if (strcmp (tmp->arch->name, doublestack2) == 0)
                          tmp->destroy ();
                    }
                }

              if (at != NULL)
                {
                  ob = arch_to_object (at);
                  ob->x = x;
                  ob->y = y;
                  SET_FLAG (ob, FLAG_OVERLAY_FLOOR);
                  ob->material = M_LIQUID;
                  insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                  if (two)
                    {
                      at = archetype::find (doublestack);
                      if (at != NULL)
                        {
                          ob = arch_to_object (at);
                          ob->x = x;
                          ob->y = y;
                          insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ON_TOP);
                        }
                    }
                }
            }
          /* Things evaporate fast in the heat */
          if (GET_MAP_OB (m, x, y) && temp > 8 && sky < SKY_OVERCAST && rndm (temp, 60) > 50)
            {
              /* evaporate */
              for (tmp = GET_MAP_OB (m, x, y)->above; tmp; tmp = tmp->above)
                {
                  avoid = 0;
                  if (!strcmp (tmp->arch->name, "rain1"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "rain2"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "rain3"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "rain4"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "rain5"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "mountain1_rivlets"))
                    avoid++;
                  else if (!strcmp (tmp->arch->name, "mountain2_rivlets"))
                    avoid++;
                  if (avoid)
                    {
                      tmp->destroy ();

                      if (weathermap[wx][wy].humid < 100 && rndm (0, 50) == 0)
                        weathermap[wx][wy].humid++;

                      tmp = GET_MAP_OB (m, x, y);
                      /* clean up the trees we put over the rain */
                      found = 0;
                      doublestack2 = NULL;
                      for (i = 0; weather_replace[i].tile != NULL; i++)
                        {
                          if (weather_replace[i].doublestack_arch == NULL)
                            continue;
                          if (weather_replace[i].arch_or_name == 1)
                            {
                              if (!strcmp (tmp->arch->name, weather_replace[i].tile))
                                found++;
                            }
                          else if (!strcmp (tmp->name, weather_replace[i].tile))
                            found++;

                          if (found)
                            {
                              tmp = tmp->above;
                              doublestack2 = weather_replace[i].doublestack_arch;
                              break;
                            }
                        }

                      if (tmp != NULL && doublestack2 != NULL)
                        if (strcmp (tmp->arch->name, doublestack2) == 0)
                          tmp->destroy ();

                      break;
                    }
                }
            }
        }
    }
}

/*
 * Process growth.  m is the map we are currently processing.  wx and wy are
 * the weathermap coordinates for the weathermap square we want to work on.
 * filename is the pathname for the current map.  This should be called from
 * weather_effect()
 */

static void
plant_a_garden (maptile *m, int wx, int wy)
{
  uint32 x, y, i;
  int avoid, two, temp, sky, gotsnow, found, days;
  object *ob, *tmp;
  archetype *at;

  days = todtick / HOURS_PER_DAY;
  for (x = 0; x < settings.worldmaptilesizex; x++)
    {
      for (y = 0; y < settings.worldmaptilesizey; y++)
        {
          (void) worldmap_to_weathermap (x, y, &wx, &wy, m);
          ob = NULL;
          at = NULL;
          avoid = 0;
          two = 0;
          gotsnow = 0;
          /*temp = real_world_temperature(x, y, m); */
          temp = weathermap[wx][wy].realtemp;
          sky = weathermap[wx][wy].sky;
          (void) avoid_weather (&avoid, m, x, y, &gotsnow, 1);
          if (!avoid)
            {
              found = 0;
              for (i = 0; weather_grow[i].herb != NULL; i++)
                {
                  for (tmp = GET_MAP_OB (m, x, y); tmp; tmp = tmp->above)
                    {
                      if (strcmp (tmp->arch->name, weather_grow[i].herb) != 0)
                        continue;
                      /* we found there is a herb here allready */
                      found++;
                      if ((float) weathermap[wx][wy].rainfall / days < weather_grow[i].rfmin ||
                          (float) weathermap[wx][wy].rainfall / days > weather_grow[i].rfmax ||
                          weathermap[wx][wy].humid < weather_grow[i].humin ||
                          weathermap[wx][wy].humid > weather_grow[i].humax ||
                          temp < weather_grow[i].tempmin ||
                          temp > weather_grow[i].tempmax || rndm (0, MIN (weather_grow[i].random / 2, 1)) == 0)
                        {
                          /* the herb does not belong, randomly delete
                             herbs to prevent overgrowth. */
                          tmp->destroy ();
                          break;
                        }
                    }
                  /* don't doublestack herbs */
                  if (found)
                    continue;
                  /* add a random factor */
                  if (rndm (1, weather_grow[i].random) != 1)
                    continue;
                  /* we look up through two tiles for a matching tile */
                  if (weather_grow[i].tile != NULL && GET_MAP_OB (m, x, y) != NULL)
                    {
                      if (strcmp (GET_MAP_OB (m, x, y)->arch->name, weather_grow[i].tile) != 0)
                        {
                          if (GET_MAP_OB (m, x, y)->above != NULL)
                            {
                              if (strcmp (GET_MAP_OB (m, x, y)->above->arch->name, weather_grow[i].tile) != 0)
                                continue;
                            }
                          else
                            continue;
                        }
                    }
                  if ((float) weathermap[wx][wy].rainfall / days < weather_grow[i].rfmin ||
                      (float) weathermap[wx][wy].rainfall / days > weather_grow[i].rfmax)
                    continue;
                  if (weathermap[wx][wy].humid < weather_grow[i].humin || weathermap[wx][wy].humid > weather_grow[i].humax)
                    continue;
                  if (temp < weather_grow[i].tempmin || temp > weather_grow[i].tempmax)
                    continue;
                  if ((!GET_MAP_OB (m, x, y)) ||
                      GET_MAP_OB (m, x, y)->elevation < weather_grow[i].elevmin ||
                      GET_MAP_OB (m, x, y)->elevation > weather_grow[i].elevmax)
                    continue;
                  /* we got this far.. must be a match */
                  at = archetype::find (weather_grow[i].herb);
                  break;
                }
              if (at != NULL)
                {
                  ob = arch_to_object (at);
                  ob->x = x;
                  ob->y = y;
                  /* XXX is this right?  maybe.. */
                  SET_FLAG (ob, FLAG_OVERLAY_FLOOR);
                  insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                }
            }
        }
    }
}

/*
 * Process worldmap regrowth.  m is the map we are currently processing.
 * wx and wy are
 * the weathermap coordinates for the weathermap square we want to work on.
 * This should be called from weather_effect()
 */

static void
change_the_world (maptile *m, int wx, int wy)
{
  int x, y, i;
  uint32 nx, ny, j, d;
  int avoid, two, temp, sky, gotsnow, found, days;
  object *ob, *tmp, *doublestack;
  archetype *at, *dat;

  days = todtick / HOURS_PER_DAY;
  for (nx = 0; nx < settings.worldmaptilesizex; nx++)
    {
      for (ny = 0; ny < settings.worldmaptilesizey; ny++)
        {
          /* jitter factor */
          if (rndm (0, 2) > 0)
            {
              x = y = d = -1;
              while (OUT_OF_REAL_MAP (m, x, y))
                {
                  d++;
                  j = rndm (1, 8);
                  x = nx + freearr_x[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  y = ny + freearr_y[j] * (rndm (0, 1) + rndm (0, 1) + rndm (0, 1) + 1);
                  if (d > 15)
                    {
                      x = nx;
                      y = ny;
                    }
                }
            }
          else
            {
              x = nx;
              y = ny;
            }
          /* we use the unjittered coordinates */
          (void) worldmap_to_weathermap (nx, ny, &wx, &wy, m);
          ob = NULL;
          at = NULL;
          dat = NULL;
          avoid = 0;
          two = 0;
          gotsnow = 0;
          /*temp = real_world_temperature(x, y, m); */
          temp = weathermap[wx][wy].realtemp;
          sky = weathermap[wx][wy].sky;
          (void) avoid_weather (&avoid, m, x, y, &gotsnow, 1);
          if (!avoid)
            {
              for (i = 0; weather_tile[i].herb != NULL; i++)
                {
                  found = 0;
                  doublestack = NULL;
                  if (GET_MAP_OB (m, x, y))
                    for (tmp = GET_MAP_OB (m, x, y)->above; tmp; tmp = tmp->above)
                      {
                        if (weather_tile[i].tile != NULL)
                          if (strcmp (tmp->arch->name, weather_tile[i].tile) == 0)
                            {
                              doublestack = tmp;
                              continue;
                            }
                        if (strcmp (tmp->arch->name, weather_tile[i].herb) != 0)
                          continue;
                        if ((float) weathermap[wx][wy].rainfall / days < weather_tile[i].rfmin ||
                            (float) weathermap[wx][wy].rainfall / days > weather_tile[i].rfmax ||
                            weathermap[wx][wy].humid < weather_tile[i].humin ||
                            weathermap[wx][wy].humid > weather_tile[i].humax ||
                            temp < weather_tile[i].tempmin || temp > weather_tile[i].tempmax)
                          {
                            tmp->destroy ();

                            if (doublestack)
                              doublestack->destroy ();

                            break;
                          }
                        else
                          {
                            found++;    /* there is one here allready. leave it */
                            break;
                          }
                      }
                  if (found)
                    break;
                  /* add a random factor */
                  if (rndm (1, weather_tile[i].random) != 1)
                    continue;
                  if ((float) weathermap[wx][wy].rainfall / days < weather_tile[i].rfmin ||
                      (float) weathermap[wx][wy].rainfall / days > weather_tile[i].rfmax)
                    continue;
                  if (weathermap[wx][wy].humid < weather_tile[i].humin || weathermap[wx][wy].humid > weather_tile[i].humax)
                    continue;
                  if (temp < weather_tile[i].tempmin || temp > weather_tile[i].tempmax)
                    continue;
                  if ((!GET_MAP_OB (m, x, y)) ||
                      GET_MAP_OB (m, x, y)->elevation < weather_tile[i].elevmin ||
                      GET_MAP_OB (m, x, y)->elevation > weather_tile[i].elevmax)
                    continue;
                  /* we got this far.. must be a match */
                  if (GET_MAP_OB (m, x, y) && strcmp (GET_MAP_OB (m, x, y)->arch->name, weather_tile[i].herb) == 0)
                    break;      /* no sense in doubling up */
                  at = archetype::find (weather_tile[i].herb);
                  break;
                }
              if (at != NULL)
                {
                  if (weather_tile[i].tile != NULL && GET_MAP_OB (m, x, y) &&
                      strcmp (weather_tile[i].tile, GET_MAP_OB (m, x, y)->arch->name) != 0)
                    dat = archetype::find (weather_tile[i].tile);
                  if (dat != NULL)
                    {
                      ob = arch_to_object (dat);
                      ob->x = x;
                      ob->y = y;
                      insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                    }
                  if (gotsnow == 0)
                    {
                      ob = arch_to_object (at);
                      ob->x = x;
                      ob->y = y;
                      if (dat != NULL)
                        insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ON_TOP);
                      else
                        insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
                    }
                }
            }
        }
    }
}


/*
 * Reduce the blockiness of the maps. m is the map we are currently processing.
 * wx and wy are
 * the weathermap coordinates for the weathermap square we want to work on.
 * This should be called from weather_effect()
 */
#if 0
static void
feather_map (maptile *m, int wx, int wy)
{
  uint32 x, y, i, nx, ny, j;
  int avoid, two, gotsnow, nodstk;
  object *ob, *tmp, *oldsnow, *topfloor, *ntmp, *ntopfloor;
  archetype *at;

  for (x = 0; x < settings.worldmaptilesizex; x++)
    {
      for (y = 0; y < settings.worldmaptilesizey; y++)
        {
          (void) worldmap_to_weathermap (x, y, &wx, &wy, m);
          ob = NULL;
          at = NULL;
          avoid = 0;
          two = 0;
          j = 0;
          gotsnow = 0;
          nodstk = 0;
          oldsnow = avoid_weather (&avoid, m, x, y, &gotsnow, 1);
          if (avoid)
            continue;
          if (rndm (0, 20) == 0)
            continue;
          // the bottom floor of scorn is not IS_FLOOR
          topfloor = NULL;
          for (tmp = GET_MAP_OB (m, x, y); tmp; topfloor = tmp, tmp = tmp->above)
            {
              if (strcmp (tmp->arch->name, "dungeon_magic") != 0)
                if (!QUERY_FLAG (tmp, FLAG_IS_FLOOR) && !QUERY_FLAG (tmp, FLAG_OVERLAY_FLOOR))
                  break;
            }
          // topfloor should now be the topmost IS_FLOOR=1
          if (topfloor == NULL)
            continue;
          if (tmp != NULL)
            nodstk++;
          // something is wrong with that sector. just skip it

          j = rndm (1, 8);
          nx = freearr_x[j] + x;
          ny = freearr_y[j] + y;
          if (OUT_OF_REAL_MAP (m, nx, ny))
            continue;
          oldsnow = avoid_weather (&avoid, m, nx, ny, &gotsnow, 1);
          if (avoid)
            continue;
          ntopfloor = NULL;
          for (ntmp = GET_MAP_OB (m, nx, ny); ntmp; ntopfloor = ntmp, ntmp = ntmp->above)
            {
              if (strcmp (ntmp->arch->name, "dungeon_magic") != 0)
                if (!QUERY_FLAG (ntmp, FLAG_IS_FLOOR) && !QUERY_FLAG (ntmp, FLAG_OVERLAY_FLOOR))
                  break;
            }
          if (ntopfloor != NULL && QUERY_FLAG (ntopfloor, FLAG_IS_FLOOR))
            {
              topfloor->destroy ();
              if (tmp != NULL)
                {
                  for (i = 0; weather_tile[i].herb != NULL; i++)
                    {
                      if (strcmp (tmp->arch->name, weather_tile[i].herb) == 0)
                        {
                          tmp->destroy ();
                          break;
                        }
                    }
                }
            }
          else
            {
              continue;
            }
          ob = arch_to_object (ntopfloor->arch);
          ob->x = x;
          ob->y = y;
          insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ABOVE_FLOOR_ONLY);
          if (ntmp != NULL && nodstk == 0)
            {
              for (i = 0; weather_tile[i].herb != NULL; i++)
                {
                  if (strcmp (ntmp->arch->name, weather_tile[i].herb) == 0)
                    {
                      ob = arch_to_object (ntmp->arch);
                      ob->x = x;
                      ob->y = y;
                      insert_ob_in_map (ob, m, ob, INS_NO_MERGE | INS_NO_WALK_ON | INS_ON_TOP);
                      break;
                    }
                }
            }
        }
    }
}
#endif

/* provide wx and wy. Will fill in with weathermap coordinates.  Requires
   the current mapname (must be a worldmap), and your coordinates on the
   map.  returns -1 if you give it something it can't figure out. 0 normally.
*/

int
worldmap_to_weathermap (int x, int y, int *wx, int *wy, maptile *m)
{
  int spwtx, spwty;
  uint32 fx, fy;
  uint32 nx, ny;
  char *filename = m->path;

  spwtx = (settings.worldmaptilesx * settings.worldmaptilesizex) / WEATHERMAPTILESX;
  spwty = (settings.worldmaptilesy * settings.worldmaptilesizey) / WEATHERMAPTILESY;

  while (*filename == '/')
    *filename++;

  fx = m->worldpartx;
  fy = m->worldparty;
  if (fx > settings.worldmapstartx + settings.worldmaptilesx ||
      fx < settings.worldmapstartx || fy > settings.worldmapstarty + settings.worldmaptilesy || fy < settings.worldmapstarty)
    {
      LOG (llevDebug, "worldmap_to_weathermap(%s)\n", filename);
      sscanf (filename, "world/world_%d_%d", &fx, &fy);
      m->worldpartx = fx;
      m->worldparty = fy;
    }
  if (fx > settings.worldmapstartx + settings.worldmaptilesx || fx < settings.worldmapstartx)
    return -1;
  if (fy > settings.worldmapstarty + settings.worldmaptilesy || fy < settings.worldmapstarty)
    return -1;
  fx -= settings.worldmapstartx;
  fy -= settings.worldmapstarty;

  nx = fx * settings.worldmaptilesizex + x;
  ny = fy * settings.worldmaptilesizey + y;

  *wx = nx / spwtx;
  *wy = ny / spwty;

  return 0;
}

/* provide x and y.  Will fill in with the requested corner of the real
 * world map, given the current weathermap section.  dir selects which
 * corner to return.  Valid values are 2 4 6 8 for the corners.  return
 * value is the name of the map that corner resides in.
 */

static const char *
weathermap_to_worldmap_corner (int wx, int wy, int *x, int *y, int dir)
{
  int spwtx, spwty;
  int tx, ty, nx, ny;
  static char mapname[MAX_BUF];

  spwtx = (settings.worldmaptilesx * settings.worldmaptilesizex) / WEATHERMAPTILESX;
  spwty = (settings.worldmaptilesy * settings.worldmaptilesizey) / WEATHERMAPTILESY;
  switch (dir)
    {
        case 2:
          wx++;
          break;
        case 4:
          wx++;
          wy++;
          break;
        case 6:
          wy++;
          break;
        case 8:
          break;
    }
  if (wx > 0)
    tx = (wx * spwtx) - 1;
  else
    tx = wx;
  if (wy > 0)
    ty = (wy * spwty) - 1;
  else
    ty = wy;

  nx = (tx / settings.worldmaptilesizex) + settings.worldmapstartx;
  ny = (ty / settings.worldmaptilesizey) + settings.worldmapstarty;
  snprintf (mapname, MAX_BUF, "world/world_%d_%d", nx, ny);

  *x = tx % settings.worldmaptilesizex;
  *y = ty % settings.worldmaptilesizey;
  return mapname;
}

/*
 * Calculates the distance to the nearest pole. x,y are the weathermap
 * coordinates, equator is the current location of the equator.  returns
 * distance as an int.
 */


static int
polar_distance (int x, int y, int equator)
{
  if ((x + y) > equator)
    {                           /* south pole */
      x = WEATHERMAPTILESX - x;
      y = WEATHERMAPTILESY - y;
      return ((x + y) / 2);
    }
  else if ((x + y) < equator)
    {                           /* north pole */
      return ((x + y) / 2);
    }
  else
    {
      return equator / 2;
    }
}

/*
 * update the humidity for all weathermap tiles.
 */

static void
update_humid (void)
{
  int x, y;

  for (y = 0; y < WEATHERMAPTILESY; y++)
    for (x = 0; x < WEATHERMAPTILESX; x++)
      weathermap[x][y].humid = humid_tile (x, y);
}

/*
 * calculate the humidity of this tile.  x and y are the weathermap coordinates
 * we wish to calculate humidity for. Returns the humidity of the weathermap
 * square.
 */

static int
humid_tile (int x, int y)
{
  int ox, oy, humid;

  ox = x;
  oy = y;

  /* find the square the wind is coming from, without going out of bounds */

  if (weathermap[x][y].winddir == 8 || weathermap[x][y].winddir <= 2)
    {
      if (y != 0)
        oy = y - 1;
    }
  if (weathermap[x][y].winddir >= 6)
    {
      if (x != 0)
        ox = x - 1;
    }
  if (weathermap[x][y].winddir >= 4 && weathermap[x][y].winddir <= 6)
    {
      if (y < WEATHERMAPTILESY - 1)
        oy = y + 1;
    }
  if (weathermap[x][y].winddir >= 2 && weathermap[x][y].winddir <= 4)
    {
      if (x < WEATHERMAPTILESX - 1)
        ox = x + 1;
    }
  humid = (weathermap[x][y].humid * 2 +
           weathermap[ox][oy].humid * weathermap[ox][oy].windspeed +
           weathermap[x][y].water + rndm (0, 10)) / (weathermap[ox][oy].windspeed + 3) + rndm (0, 5);
  if (humid < 0)
    humid = 1;
  if (humid > 100)
    humid = 100;
  return humid;
}

/*
 * calculate temperature of the weathermap square x,y.  Requires the current
 * time of day in *tod.
 */

static void
temperature_calc (int x, int y, const timeofday_t * tod)
{
  int dist, equator, elev, n;
  float diff, tdiff;

  equator = (WEATHERMAPTILESX + WEATHERMAPTILESY) / 4;
  diff = (float) (EQUATOR_BASE_TEMP - POLAR_BASE_TEMP) / (float) equator;
  tdiff = (float) SEASONAL_ADJUST / ((float) MONTHS_PER_YEAR / 2.0);
  equator *= 2;
  n = 0;
  /* we essentially move the equator during the season */
  if (tod->month > (MONTHS_PER_YEAR / 2))
    {                           /* EOY */
      n -= (int) (tod->month * tdiff);
    }
  else
    {
      n = (int) ((MONTHS_PER_YEAR - tod->month) * tdiff);
    }
  dist = polar_distance (x - n / 2, y - n / 2, equator);

  /* now we have the base temp, unadjusted for time.  Time adjustment
     is not recorded on the map, rather, it's done JIT. */
  weathermap[x][y].temp = (int) (dist * diff);
  /* just scrap these for now, its mostly ocean */
  if (weathermap[x][y].avgelev < 0)
    elev = 0;
  else
    elev = MAX (10000, weathermap[x][y].avgelev) / 1000;
  weathermap[x][y].temp -= elev;
}

/* Compute the real (adjusted) temperature of a given weathermap tile.
 * This takes into account the wind, base temp, sunlight, and other fun
 * things.  Seasons are automatically handled by moving the equator.
 * Elevation is partially considered in the base temp. x and y are the
 * weathermap coordinates.
*/

static int
real_temperature (int x, int y)
{
  int i, temp;
  timeofday_t tod;

  /* adjust for time of day */
  temp = weathermap[x][y].temp;
  get_tod (&tod);
  for (i = HOURS_PER_DAY / 2; i < HOURS_PER_DAY; i++)
    {
      temp += season_tempchange[i];
      /* high amounts of water has a buffering effect on the temp */
      if (weathermap[x][y].water > 33)
        i++;
    }
  for (i = 0; i <= tod.hour; i++)
    {
      temp += season_tempchange[i];
      if (weathermap[x][y].water > 33)
        i++;
    }

  /* windchill */
  for (i = 1; i < weathermap[x][y].windspeed; i += i)
    temp--;

  return temp;
}

/* Given a worldmap name, and x and y on that map, compute the temperature
   for a specific square.  Used to normalize elevation.
*/

int
real_world_temperature (int x, int y, maptile *m)
{
  int wx, wy, temp, eleva, elevb;
  object *op;

  /*LOG(llevDebug, "real_world_temperature: worldmaptoweathermap : %s\n",m->path); */
  worldmap_to_weathermap (x, y, &wx, &wy, /*m->path */ m);
  temp = real_temperature (wx, wy);
  if (weathermap[wx][wy].avgelev < 0)
    eleva = 0;
  else
    eleva = weathermap[x][y].avgelev;

  op = GET_MAP_OB (m, x, y);
  if (!op)
    return eleva;

  elevb = op->elevation;
  if (elevb < 0)
    elevb = 0;
  if (elevb > eleva)
    {
      elevb -= eleva;
      temp -= elevb / 1000;
    }
  else
    {
      elevb = eleva - elevb;
      temp += elevb / 1000;
    }
  return temp;
}

/* this code simply smooths the pressure map */

static void
smooth_pressure (void)
{
  int x, y;
  int k;

  for (k = 0; k < PRESSURE_ROUNDING_ITER; k++)
    {
      for (x = 2; x < WEATHERMAPTILESX - 2; x++)
        {
          for (y = 2; y < WEATHERMAPTILESY - 2; y++)
            {
              weathermap[x][y].pressure = (weathermap[x][y].pressure *
                                           PRESSURE_ROUNDING_FACTOR + weathermap[x - 1][y].pressure +
                                           weathermap[x][y - 1].pressure + weathermap[x - 1][y - 1].pressure +
                                           weathermap[x + 1][y].pressure + weathermap[x][y + 1].pressure +
                                           weathermap[x + 1][y + 1].pressure + weathermap[x + 1][y - 1].pressure +
                                           weathermap[x - 1][y + 1].pressure) / (PRESSURE_ROUNDING_FACTOR + 8);
            }
        }
      for (x = WEATHERMAPTILESX - 2; x > 2; x--)
        {
          for (y = WEATHERMAPTILESY - 2; y > 2; y--)
            {
              weathermap[x][y].pressure = (weathermap[x][y].pressure *
                                           PRESSURE_ROUNDING_FACTOR + weathermap[x - 1][y].pressure +
                                           weathermap[x][y - 1].pressure + weathermap[x - 1][y - 1].pressure +
                                           weathermap[x + 1][y].pressure + weathermap[x][y + 1].pressure +
                                           weathermap[x + 1][y + 1].pressure + weathermap[x + 1][y - 1].pressure +
                                           weathermap[x - 1][y + 1].pressure) / (PRESSURE_ROUNDING_FACTOR + 8);
            }
        }
    }

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      {
        weathermap[x][y].pressure = MIN (weathermap[x][y].pressure, PRESSURE_MAX);
        weathermap[x][y].pressure = MAX (weathermap[x][y].pressure, PRESSURE_MIN);
      }

}

/*
 * perform small randomizations in the pressure map.  Then, apply the
 * smoothing algorithim.. This causes the pressure to change very slowly
 */

static void
perform_pressure (void)
{
  int x, y, l, n, j, k;

  /* create random spikes in the pressure */
  for (l = 0; l < PRESSURE_SPIKES; l++)
    {
      x = rndm (0, WEATHERMAPTILESX - 1);
      y = rndm (0, WEATHERMAPTILESY - 1);
      n = rndm (600, 1300);
      weathermap[x][y].pressure = n;
      if (x > 5 && y > 5 && x < WEATHERMAPTILESX - 5 && y < WEATHERMAPTILESY - 5)
        {
          for (j = x - 2; j < x + 2; j++)
            for (k = y - 2; k < y + 2; k++)
              {
                weathermap[j][k].pressure = n;
                /* occasionally add a storm */
                if (rndm (1, 20) == 1)
                  weathermap[j][k].humid = rndm (50, 80);
              }
        }
    }

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      weathermap[x][y].pressure += rndm (-1, 4);

  smooth_pressure ();
}


/*
 * is direction a similar to direction b? Find out in this exciting function
 * below. Returns 1 if true, 0 for false.
 */

int
similar_direction (int a, int b)
{
  /* shortcut the obvious */
  if (a == b)
    return 1;

  switch (a)
    {
        case 1:
          if (b <= 2 || b == 8)
            return 1;
          break;
        case 2:
          if (b > 0 && b < 4)
            return 1;
          break;
        case 3:
          if (b > 1 && b < 5)
            return 1;
          break;
        case 4:
          if (b > 2 && b < 6)
            return 1;
          break;
        case 5:
          if (b > 3 && b < 7)
            return 1;
          break;
        case 6:
          if (b > 4 && b < 8)
            return 1;
          break;
        case 7:
          if (b > 5)
            return 1;
          break;
        case 8:
          if (b > 6 || b == 1)
            return 1;
          break;
    }
  return 0;
}

/*
 * It doesn't really smooth it as such.  The main function of this is to
 * apply the pressuremap to the wind direction and speed.  Then, we run
 * a quick pass to update the windspeed.
 */

static void
smooth_wind (void)
{
  int x, y;
  int tx, ty, dx, dy;
  int minp;

  /* skip the outer squares.. it makes handling alot easier */
  dx = 0;
  dy = 0;
  for (x = 1; x < WEATHERMAPTILESX - 1; x++)
    for (y = 1; y < WEATHERMAPTILESY - 1; y++)
      {
        minp = PRESSURE_MAX + 1;
        for (tx = -1; tx < 2; tx++)
          for (ty = -1; ty < 2; ty++)
            if (!(tx == 0 && ty == 0))
              if (weathermap[x + tx][y + ty].pressure < minp)
                {
                  minp = weathermap[x + tx][y + ty].pressure;
                  dx = tx;
                  dy = ty;
                }

        /* if the wind is strong, the pressure won't decay it completely */
        if (weathermap[x][y].windspeed > 5 && !similar_direction (weathermap[x][y].winddir, find_dir_2 (dx, dy)))
          {
            weathermap[x][y].windspeed -= 2 * 2;
          }
        else
          {
            weathermap[x][y].winddir = find_dir_2 (dx, dy);
            weathermap[x][y].windspeed = (sint8) ((weathermap[x][y].pressure - weathermap[x + dx][y + dy].pressure) * WIND_FACTOR);
          }
        /* Add in sea breezes. */
        weathermap[x][y].windspeed += weathermap[x][y].water / 4;
        if (weathermap[x][y].windspeed < 0)
          weathermap[x][y].windspeed = 0;
      }

  /*  now, lets crank on the speed.  When surrounding tiles all have
     the same speed, inc ours.  If it's chaos. drop it.
   */
  for (x = 1; x < WEATHERMAPTILESX - 1; x++)
    for (y = 1; y < WEATHERMAPTILESY - 1; y++)
      {
        minp = 0;
        for (tx = -1; tx < 2; tx++)
          for (ty = -1; ty < 2; ty++)
            if (ty != 0 && ty != 0)
              if (similar_direction (weathermap[x][y].winddir, weathermap[x + tx][y + ty].winddir))
                minp++;
        if (minp > 4)
          weathermap[x][y].windspeed++;
        if (minp > 6)
          weathermap[x][y].windspeed += 2;
        if (minp < 2)
          weathermap[x][y].windspeed--;
        if (weathermap[x][y].windspeed < 0)
          weathermap[x][y].windspeed = 0;
      }
}

/*
 * Plot the gulfstream map over the wind map.  This is done after the wind,
 * to avoid the windsmoothing scrambling the jet stream.
 */

static void
plot_gulfstream (void)
{
  int x, y, tx;

  x = gulf_stream_start;

  if (gulf_stream_direction)
    {
      for (y = WEATHERMAPTILESY - 1; y > 0; y--)
        {
          for (tx = 0; tx < GULF_STREAM_WIDTH && x + tx < WEATHERMAPTILESX; tx++)
            {
              if (similar_direction (weathermap[x + tx][y].winddir,
                                     gulf_stream_dir[tx][y]) && weathermap[x + tx][y].windspeed < GULF_STREAM_BASE_SPEED - 5)
                weathermap[x + tx][y].windspeed += gulf_stream_speed[tx][y];
              else
                weathermap[x + tx][y].windspeed = gulf_stream_speed[tx][y];
              weathermap[x + tx][y].winddir = gulf_stream_dir[tx][y];
              if (tx == GULF_STREAM_WIDTH - 1)
                {
                  switch (gulf_stream_dir[tx][y])
                    {
                        case 6:
                          x--;
                          break;
                        case 7:
                          break;
                        case 8:
                          x++;;
                          break;
                    }
                }
              if (x < 0)
                x++;
              if (x >= WEATHERMAPTILESX - GULF_STREAM_WIDTH)
                x--;
            }
        }
    }
  else
    {
      for (y = 0; y < WEATHERMAPTILESY - 1; y++)
        {
          for (tx = 0; tx < GULF_STREAM_WIDTH && x + tx < WEATHERMAPTILESX; tx++)
            {
              if (similar_direction (weathermap[x + tx][y].winddir,
                                     gulf_stream_dir[tx][y]) && weathermap[x + tx][y].windspeed < GULF_STREAM_BASE_SPEED - 5)
                weathermap[x + tx][y].windspeed += gulf_stream_speed[tx][y];
              else
                weathermap[x + tx][y].windspeed = gulf_stream_speed[tx][y];
              weathermap[x + tx][y].winddir = gulf_stream_dir[tx][y];
              if (tx == GULF_STREAM_WIDTH - 1)
                {
                  switch (gulf_stream_dir[tx][y])
                    {
                        case 2:
                          x++;
                          break;
                        case 3:
                          break;
                        case 4:
                          x--;
                          break;
                    }
                }
              if (x < 0)
                x++;
              if (x >= WEATHERMAPTILESX - GULF_STREAM_WIDTH)
                x--;
            }
        }
    }
  /* occasionally move the stream */
  if (rndm (1, 500) == 1)
    {
      gulf_stream_direction = rndm (0, 1);
      for (tx = 0; tx < GULF_STREAM_WIDTH; tx++)
        for (y = 0; y < WEATHERMAPTILESY - 1; y++)
          if (gulf_stream_direction)
            switch (gulf_stream_dir[tx][y])
              {
                  case 2:
                    gulf_stream_dir[tx][y] = 6;
                    break;
                  case 3:
                    gulf_stream_dir[tx][y] = 7;
                    break;
                  case 4:
                    gulf_stream_dir[tx][y] = 8;
                    break;
              }
          else
            switch (gulf_stream_dir[tx][y])
              {
                  case 6:
                    gulf_stream_dir[tx][y] = 2;
                    break;
                  case 7:
                    gulf_stream_dir[tx][y] = 3;
                    break;
                  case 8:
                    gulf_stream_dir[tx][y] = 4;
                    break;
              }
    }
  if (rndm (1, 25) == 1)
    gulf_stream_start += rndm (-1, 1);
  if (gulf_stream_start >= WEATHERMAPTILESX - GULF_STREAM_WIDTH)
    gulf_stream_start--;
  if (gulf_stream_start < 1)
    gulf_stream_start++;

}

/*
 * let the madness, begin.
 *
 * This function is the one that ties everything together.  Here we loop
 * over all the weathermaps, and compare the various conditions we have
 * calculated up to now, to figure out what the sky conditions are for this
 * square.
 */

static void
compute_sky (void)
{
  int x, y;
  int temp;

  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {
          temp = real_temperature (x, y);
          if (weathermap[x][y].pressure < 980)
            {
              if (weathermap[x][y].humid < 20)
                weathermap[x][y].sky = SKY_LIGHTCLOUD;
              else if (weathermap[x][y].humid < 30)
                weathermap[x][y].sky = SKY_OVERCAST;
              else if (weathermap[x][y].humid < 40)
                weathermap[x][y].sky = SKY_LIGHT_RAIN;
              else if (weathermap[x][y].humid < 55)
                weathermap[x][y].sky = SKY_RAIN;
              else if (weathermap[x][y].humid < 70)
                weathermap[x][y].sky = SKY_HEAVY_RAIN;
              else
                weathermap[x][y].sky = SKY_HURRICANE;
              if (weathermap[x][y].sky < SKY_HURRICANE && weathermap[x][y].windspeed > 30)
                weathermap[x][y].sky++;
              if (temp <= 0 && weathermap[x][y].sky > SKY_OVERCAST)
                weathermap[x][y].sky += 10;     /*let it snow */
            }
          else if (weathermap[x][y].pressure < 1000)
            {
              if (weathermap[x][y].humid < 10)
                weathermap[x][y].sky = SKY_CLEAR;
              else if (weathermap[x][y].humid < 25)
                weathermap[x][y].sky = SKY_LIGHTCLOUD;
              else if (weathermap[x][y].humid < 45)
                weathermap[x][y].sky = SKY_OVERCAST;
              else if (weathermap[x][y].humid < 60)
                weathermap[x][y].sky = SKY_LIGHT_RAIN;
              else if (weathermap[x][y].humid < 75)
                weathermap[x][y].sky = SKY_RAIN;
              else
                weathermap[x][y].sky = SKY_HEAVY_RAIN;
              if (weathermap[x][y].sky < SKY_HURRICANE && weathermap[x][y].windspeed > 30)
                weathermap[x][y].sky++;
              if (temp <= 0 && weathermap[x][y].sky > SKY_OVERCAST)
                weathermap[x][y].sky += 10;     /*let it snow */
              if (temp > 0 && temp < 5 && weathermap[x][y].humid > 95 && weathermap[x][y].windspeed < 3)
                weathermap[x][y].sky = SKY_FOG; /* rare */
              if (temp > 0 && temp < 5 && weathermap[x][y].humid > 70 && weathermap[x][y].windspeed > 35)
                weathermap[x][y].sky = SKY_HAIL;        /* rare */
            }
          else if (weathermap[x][y].pressure < 1020)
            {
              if (weathermap[x][y].humid < 20)
                weathermap[x][y].sky = SKY_CLEAR;
              else if (weathermap[x][y].humid < 30)
                weathermap[x][y].sky = SKY_LIGHTCLOUD;
              else if (weathermap[x][y].humid < 40)
                weathermap[x][y].sky = SKY_OVERCAST;
              else if (weathermap[x][y].humid < 55)
                weathermap[x][y].sky = SKY_LIGHT_RAIN;
              else if (weathermap[x][y].humid < 70)
                weathermap[x][y].sky = SKY_RAIN;
              else
                weathermap[x][y].sky = SKY_HEAVY_RAIN;
              if (weathermap[x][y].sky < SKY_HURRICANE && weathermap[x][y].windspeed > 30)
                weathermap[x][y].sky++;
              if (temp <= 0 && weathermap[x][y].sky > SKY_OVERCAST)
                weathermap[x][y].sky += 10;     /*let it snow */
            }
          else
            {
              if (weathermap[x][y].humid < 35)
                weathermap[x][y].sky = SKY_CLEAR;
              else if (weathermap[x][y].humid < 55)
                weathermap[x][y].sky = SKY_LIGHTCLOUD;
              else if (weathermap[x][y].humid < 70)
                weathermap[x][y].sky = SKY_OVERCAST;
              else if (weathermap[x][y].humid < 85)
                weathermap[x][y].sky = SKY_LIGHT_RAIN;
              else if (weathermap[x][y].humid < 95)
                weathermap[x][y].sky = SKY_RAIN;
              else
                weathermap[x][y].sky = SKY_HEAVY_RAIN;
              if (weathermap[x][y].sky < SKY_HURRICANE && weathermap[x][y].windspeed > 30)
                weathermap[x][y].sky++;
              if (temp <= 0 && weathermap[x][y].sky > SKY_OVERCAST)
                weathermap[x][y].sky += 10;     /*let it snow */
            }
        }
    }
}

/*
 * Keep track of how much rain has fallen in a given weathermap square.
 */

static void
process_rain (void)
{
  int x, y, rain;

  for (x = 0; x < WEATHERMAPTILESX; x++)
    for (y = 0; y < WEATHERMAPTILESY; y++)
      {
        rain = weathermap[x][y].sky;
        if (rain >= SKY_LIGHT_SNOW)
          rain -= 10;
        if (rain > SKY_OVERCAST && rain < SKY_FOG)
          {
            rain -= SKY_OVERCAST;
            weathermap[x][y].rainfall += rain;
          }
      }
}

/*
 * The world spinning drags the weather with it.
 * The equator is diagonal, and the poles are 45 degrees from north /south.
 * What the hell, lets spin the planet backwards.
 */

static void
spin_globe (void)
{
  int x, y;
  int buffer_humid;
  int buffer_sky;

  for (y = 0; y < WEATHERMAPTILESY; y++)
    {
      buffer_humid = weathermap[0][y].humid;
      buffer_sky = weathermap[0][y].sky;
      for (x = 0; x < (WEATHERMAPTILESX - 1); x++)
        {
          weathermap[x][y].humid = weathermap[x + 1][y].humid;
          weathermap[x][y].sky = weathermap[x + 1][y].sky;
        }
      weathermap[WEATHERMAPTILESX - 1][y].humid = buffer_humid;
      weathermap[WEATHERMAPTILESX - 1][y].sky = buffer_sky;
    }
}

/*
 * Dump all the weather data as an image.
 * Writes two other files that are useful for creating animations and web pages.
 */

static void
write_weather_images (void)
{
  char filename[MAX_BUF];
  FILE *fp;
  int x, y;
  sint32 min[10], max[10], realmaxwind;
  uint32 avgrain, avgwind;
  double scale[10], realscalewind;
  uint8 pixels[3 * 3 * WEATHERMAPTILESX];
  sint64 total_rainfall = 0;
  sint64 total_wind = 0;

  min[0] = 0;
  max[0] = 100;
  min[1] = 0;
  max[1] = 0;
  min[2] = 0;
  max[2] = 0;
  min[3] = PRESSURE_MIN;
  max[3] = PRESSURE_MAX;
  min[4] = 0;
  max[4] = 0;
  min[5] = 1;
  max[5] = 8;
  min[6] = 0;
  max[6] = 100;
  min[7] = -45;
  max[7] = 45;
  min[8] = 0;
  max[8] = 16;
  min[9] = 0;
  max[9] = 0;
  for (x = 0; x < WEATHERMAPTILESX; x++)
    {
      for (y = 0; y < WEATHERMAPTILESY; y++)
        {

/*          min[0] = MIN(min[0], weathermap[x][y].water); */
          min[1] = MIN (min[1], weathermap[x][y].avgelev);
          min[2] = MIN ((uint32) min[2], weathermap[x][y].rainfall);

/*          min[3] = MIN(min[3], weathermap[x][y].pressure); */
          min[4] = MIN (min[4], weathermap[x][y].windspeed);

/*          min[5] = MIN(min[5], weathermap[x][y].winddir); */

/*          min[6] = MIN(min[6], weathermap[x][y].humid); */

/*          min[7] = MIN(min[7], real_temp[x][y]); */

/*          min[8] = MIN(min[8], weathermap[x][y].sky); */

/*          min[9] = MIN(min[9], weathermap[x][y].darkness); */

/*          max[0] = MAX(max[0], weathermap[x][y].water); */
          max[1] = MAX (max[1], weathermap[x][y].avgelev);
          max[2] = MAX ((uint32) max[2], weathermap[x][y].rainfall);

/*          max[3] = MAX(max[3], weathermap[x][y].pressure); */
          max[4] = MAX (max[4], weathermap[x][y].windspeed);

/*          max[5] = MAX(max[5], weathermap[x][y].winddir); */

/*          max[6] = MAX(max[6], weathermap[x][y].humid); */

/*          max[7] = MAX(max[7], real_temp[x][y]); */

/*          max[8] = MAX(max[8], weathermap[x][y].sky); */

/*          max[9] = MAX(max[9], weathermap[x][y].darkness); */
          total_rainfall += weathermap[x][y].rainfall;
          total_wind += weathermap[x][y].windspeed;
        }
    }
  avgrain = total_rainfall / (WEATHERMAPTILESX * WEATHERMAPTILESY);
  avgwind = (total_wind / ((WEATHERMAPTILESX * WEATHERMAPTILESY) * 3 / 2));
  max[2] = avgrain - 1;
  realscalewind = 255.0l / (max[4] - min[4]);
  realmaxwind = max[4];
  max[4] = avgwind - 1;
  for (x = 0; x < 10; x++)
    scale[x] = 255.0l / (max[x] - min[x]);

  sprintf (filename, "%s/weather.ppm", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  fprintf (fp, "P6\n%d %d\n", 3 * WEATHERMAPTILESX, 3 * WEATHERMAPTILESY);
  fprintf (fp, "255\n");
  for (y = 0; y < WEATHERMAPTILESY; y++)
    {
      for (x = 0; x < (3 * 3 * WEATHERMAPTILESX); x++)
        pixels[x] = 0;
      for (x = 0; x < WEATHERMAPTILESX; x++)
        {
          pixels[3 * x + (0 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((weathermap[x][y].water - min[0]) * scale[0]);
          if (weathermap[x][y].avgelev >= 0)
            pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + GREEN)] = (uint8) ((weathermap[x][y].avgelev - min[1]) * scale[1]);
          else
            pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((weathermap[x][y].avgelev - min[1]) * scale[1]);
          if (weathermap[x][y].rainfall >= avgrain)     /* rainfall is rather spikey, this gives us more detail. */
            pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + RED)] = 255;
          else
            pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((weathermap[x][y].rainfall - min[2]) * scale[2]);
        }
      fwrite (pixels, sizeof (uint8), (3 * 3 * WEATHERMAPTILESX), fp);
    }
  for (y = 0; y < WEATHERMAPTILESY; y++)
    {
      for (x = 0; x < WEATHERMAPTILESX; x++)
        {
          uint32 dir = directions[weathermap[x][y].winddir - 1];
          uint32 speed = weathermap[x][y].windspeed;
          uint8 pressure = (uint8) ((weathermap[x][y].pressure - min[3]) * scale[3]);

          pixels[3 * x + (0 * WEATHERMAPTILESX * 3 + RED)] = pressure;
          pixels[3 * x + (0 * WEATHERMAPTILESX * 3 + GREEN)] = pressure;
          pixels[3 * x + (0 * WEATHERMAPTILESX * 3 + BLUE)] = pressure;
          if (speed < avgwind)
            {
              speed = (uint32) ((speed - min[4]) * scale[4]);
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + RED)] = speed;
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + GREEN)] = speed;
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + BLUE)] = speed;
            }
          else
            {
              speed = (uint32) ((speed - realmaxwind) * realscalewind);

/*              if (speed < 100)*/

/*                  speed = 100;*/
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + RED)] = speed;
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + GREEN)] = 0;
              pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + BLUE)] = 0;
            }
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + RED)] = (uint8) ((dir & 0x00FF0000) >> 16);
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + GREEN)] = (uint8) ((dir & 0x0000FF00) >> 8);
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((dir & 0x000000FF));
        }
      fwrite (pixels, sizeof (uint8), (3 * 3 * WEATHERMAPTILESX), fp);
    }
  for (y = 0; y < WEATHERMAPTILESY; y++)
    {
      for (x = 0; x < (3 * 3 * WEATHERMAPTILESX); x++)
        pixels[x] = 0;
      for (x = 0; x < WEATHERMAPTILESX; x++)
        {
          uint32 dir = skies[weathermap[x][y].sky];

          pixels[3 * x + (0 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((weathermap[x][y].humid - min[6]) * scale[6]);
          /*pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + RED)]   = (uint8) ((real_temp[x][y]  - min[7]) * scale[7]); */
          pixels[3 * x + (1 * WEATHERMAPTILESX * 3 + RED)] = 1;
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + RED)] = (uint8) ((dir & 0x00FF0000) >> 16);
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + GREEN)] = (uint8) ((dir & 0x0000FF00) >> 8);
          pixels[3 * x + (2 * WEATHERMAPTILESX * 3 + BLUE)] = (uint8) ((dir & 0x000000FF));

        }
      fwrite (pixels, sizeof (uint8), (3 * 3 * WEATHERMAPTILESX), fp);
    }
  fclose (fp);

  sprintf (filename, "%s/todtick", settings.localdir);
  if ((fp = fopen (filename, "w")) == NULL)
    {
      LOG (llevError, "Cannot open %s for writing\n", filename);
      return;
    }
  fprintf (fp, "%lu", todtick);
  fclose (fp);
}
Revision:	1.11
Committed:	Mon Dec 25 14:54:44 2006 UTC (17 years, 4 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.10:	+4 -4 lines
Log Message:	the big rename