[Freeciv-Dev] (PR#9627) PATCH: correct some parameters in map generator and clean-up

["Marcelo Burda" <mburda@xxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9627 >

LAST CHANGES
adjust_map has be rewrie to do a linear distribution of values from 0 to
maxval. this allow to handle map very easy

sample:
(hmap < 0.33 * maxval) handel the 33% lowerest part of the map

this is used in make_land and make_relief to avoid some loops


Marcelo


diff -ruN -Xfreeciv/diff_ignore freeciv/common/map.h freeciv_/common/map.h
--- freeciv/common/map.h        2004-08-13 17:59:12.000000000 +0200
+++ freeciv_/common/map.h       2004-08-22 15:10:44.757331104 +0200
@@ -621,7 +621,7 @@
 #define MAP_MIN_SEED             0
 #define MAP_MAX_SEED             (MAX_UINT32 >> 1)
 
-#define MAP_DEFAULT_LANDMASS     30
+#define MAP_DEFAULT_LANDMASS     35
 #define MAP_MIN_LANDMASS         15
 #define MAP_MAX_LANDMASS         85
 
@@ -629,11 +629,11 @@
 #define MAP_MIN_RICHES           0
 #define MAP_MAX_RICHES           1000
 
-#define MAP_DEFAULT_MOUNTAINS    30
-#define MAP_MIN_MOUNTAINS        10
+#define MAP_DEFAULT_MOUNTAINS    10
+#define MAP_MIN_MOUNTAINS        5
 #define MAP_MAX_MOUNTAINS        100
 
-#define MAP_DEFAULT_GRASS       35
+#define MAP_DEFAULT_GRASS       55
 #define MAP_MIN_GRASS           20
 #define MAP_MAX_GRASS           100
 
@@ -649,7 +649,7 @@
 #define MAP_MIN_RIVERS           0
 #define MAP_MAX_RIVERS           100
 
-#define MAP_DEFAULT_FORESTS      20
+#define MAP_DEFAULT_FORESTS      12
 #define MAP_MIN_FORESTS          0
 #define MAP_MAX_FORESTS          100
 
diff -ruN -Xfreeciv/diff_ignore freeciv/server/mapgen.c freeciv_/server/mapgen.c
--- freeciv/server/mapgen.c     2004-08-19 09:34:25.000000000 +0200
+++ freeciv_/server/mapgen.c    2004-08-22 19:17:29.377686712 +0200
@@ -25,6 +25,7 @@
 #include "game.h"
 #include "log.h"
 #include "map.h"
+#include "maphand.h" /* assign_continent_numberd(),MASS_SIZE(), MAP_NCONT */
 #include "mem.h"
 #include "rand.h"
 #include "shared.h"
@@ -75,8 +76,13 @@
 static int *river_map;
 
 static int *height_map;
-static int maxval=0;
-static int forests=0;
+static const int maxval=1000;
+static int reliefval=0, seaval=0;
+static int forests_to_be_placed =0;
+static int deserts_to_be_placed=0;
+static int grass_to_be_placed=0;
+static int plains_to_be_placed=0;
+static int swamps_to_be_placed=0;
 
 struct isledata {
   int goodies;
@@ -84,23 +90,43 @@
 };
 static struct isledata *islands;
 
-/* this is used for generator>1 */
-#define MAP_NCONT 255
-
 /* this is the maximal temperature at equators returned by map_temperature */
 #define MAX_TEMP 1000
 
 /* An estimate of the linear (1-dimensional) size of the map. */
 #define SQSIZE MAX(1, sqrt(map.xsize * map.ysize / 1000))
 
+/* define the 4 region of a Earth like map
+  =========================================================
+   0-COLD_LV                cold region: most ice/tundra/mountains
+   COLD_LV-TREOPICAL_LV     temperate region: all terrains types
+   TROPICAL_LV-WET_LV  tropical dry region: most dessert/mountains
+   WET_LV-MAX_TEMP     tropical wet region: most jungle/mountains
+*/
+#define COLD_LEVEL (10 * MAX_TEMP / 100)
+#define TROPICAL_LEVEL (65 * MAX_TEMP / 100)
+#define WET_LEVEL (80 * MAX_TEMP / 100)
+
 /* used to create the poles and for separating them.  In a
  * mercator projection map we don't want the poles to be too big. */
 #define ICE_BASE_LEVEL                                         \
   ((!topo_has_flag(TF_WRAPX) || !topo_has_flag(TF_WRAPY))      \
    /* 5% for little maps; 2% for big ones */                   \
    ? MAX_TEMP * (3 + 2 * SQSIZE) / (100 * SQSIZE)              \
-   : 5 * MAX_TEMP / 100  /* 5% for all maps */)
+   : COLD_LEVEL / 2  /* for all maps */)
 
+#define T_NOTPLACED T_UNKNOWN
+
+/********************************************************************
+ * used to initialize a array with some value
+ ********************************************************************/
+#define INITIALIZE_ARRAY(A, MAX, VAL)                            \
+  { \
+    int INI_INEX; \
+    for(INI_INEX = 0; INI_INEX < (MAX);INI_INEX++) { \
+      (A)[INI_INEX] = (VAL); \
+     } \
+  } 
 /****************************************************************************
   Returns the temperature of this map position.  This is a value in the
   range of 0 to MAX_TEMP (inclusive).
@@ -283,41 +309,65 @@
 }
 
 /**************************************************************************
-  make_mountains() will convert all squares that are higher than thill to
-  mountains and hills. Notice that thill will be adjusted according to
-  the map.mountains value, so increase map.mountains and you'll get more 
-  hills and mountains (and vice versa).
+  Checks if land has not yet been placed on tile at (x, y) 
 **************************************************************************/
-static void make_mountains(int thill)
+static bool not_placed(x, y)
 {
-  int mount;
-  int j;
+  return map_get_terrain(x, y) == T_NOTPLACED;
+}
 
-  for (j = 0; j < 10; j++) {
-    mount = 0;
-    whole_map_iterate(x, y) {
-      if (hmap(x, y) > thill) {
-       mount++;
-      }
-    } whole_map_iterate_end;
-    if (mount < (map_num_tiles() * map.mountains) / 1000) {
-      thill *= 95;
-    } else {
-      thill *= 105;
+/**************************************************************************
+  we don't want huge areas of grass/plains, 
+  so we put in a hill here and there, where it gets too 'clean' 
+
+  Return TRUE if the terrain at the given map position is "clean".  This
+  means that all the terrain for 2 squares around it is not mountain or hill.
+****************************************************************************/
+static bool terrain_is_clean(int map_x, int map_y,int thill, int my_high)
+{
+  int biger_me = 0;
+  square_iterate(map_x, map_y, 2, x1, y1) {
+    if (hmap(x1, y1) > thill) {
+      return FALSE;
+    }
+    if (hmap(x1, y1) > my_high){
+      if(map_distance(map_x, map_y, x1, y1) == 1) {
+       return FALSE;
+      }
+      if(++biger_me > 2) {
+       return FALSE;
+      };
     }
-    thill /= 100;
+  } square_iterate_end;
+
+  if ((thill - seaval) * (biger_me)  > (my_high - seaval) * 4 ) {
+      return FALSE;
   }
-  
+  return TRUE;
+}
+
+/**************************************************************************
+  make_relief() will convert all squares that are higher than thill to
+  mountains and hills. Notice that thill will be adjusted according to
+  the map.mountains value, so increase map.mountains and you'll get more 
+  hills and mountains (and vice versa).
+  TODO: extend to place ocean/deepocean/abys relief in oceans
+**************************************************************************/
+static void make_relief()
+{
+  reliefval = ((maxval - seaval)* (100 - map.mountains)) / 100 + seaval;
   whole_map_iterate(x, y) {
-    if (hmap(x, y) > thill && !is_ocean(map_get_terrain(x,y))) { 
+    if (not_placed(x,y) 
+       && (hmap(x, y) > reliefval 
+           || terrain_is_clean(x, y, reliefval, hmap(x, y)))) { 
       /* Randomly place hills and mountains on "high" tiles.  But don't
        * put hills near the poles (they're too green). */
-      if (myrand(100) > 75 
-         || map_temperature(x, y) <= MAX_TEMP / 10) {
+      if (myrand(100) > 70 
+         || map_temperature(x, y) <= COLD_LEVEL) {
        map_set_terrain(x, y, T_MOUNTAINS);
-      } else if (myrand(100) > 25) {
+      } else {
        map_set_terrain(x, y, T_HILLS);
-      }
+      }  
     }
   } whole_map_iterate_end;
 }
@@ -355,6 +405,24 @@
     }
   } whole_map_iterate_end;
 }
+/*************************************************************************
+ if separatepoles is set, return false if this tile has to kip ocean
+************************************************************************/
+static bool ok_for_separate_poles(int x, int y) 
+{
+  if (!map.separatepoles) {
+    return TRUE;
+  }
+  adjc_iterate(x, y, x1, y1) {
+    if(!is_ocean(map_get_terrain(x1, y1))
+       && map_get_continent(x1, y1 ) != 0) {
+      return FALSE;
+    }
+  } adjc_iterate_end;
+  return TRUE;
+}
+
+
 
 /****************************************************************************
   Place untextured land at the poles.  This is used by generators 1 and 5.
@@ -365,30 +433,17 @@
   struct tile *ptile;
   int T;
 
+  assign_continent_numbers();
   whole_map_iterate(map_x, map_y) {
     T = map_temperature(map_x, map_y); /* temperature parameter */
     ptile = map_get_tile(map_x, map_y);
-    if (T < 1.5 * ICE_BASE_LEVEL) {
-      ptile->terrain = T_GRASSLAND;
-    } else if ((T <= 2 * ICE_BASE_LEVEL) && myrand(10) > 4 ) { 
-      ptile->terrain = T_GRASSLAND;
-    }
-  } whole_map_iterate_end;
-}
-
-/****************************************************************************
-  Create tundra in cold zones.  Used by generators 1 and 5.  This must be
-  called after make_arctic since it will fill all remaining untextured
-  areas (we don't want any grassland left on the poles).
-****************************************************************************/
-static void make_tundra(void)
-{
-  whole_map_iterate(x, y) {
-    int T = map_temperature(x, y);
-
-    if (map_get_terrain(x, y) == T_GRASSLAND 
-       && (2 * ICE_BASE_LEVEL > T || myrand(MAX_TEMP/5) > T)) {
-      map_set_terrain(x, y, T_TUNDRA);
+    if (T < 1.5 * ICE_BASE_LEVEL && ok_for_separate_poles(map_x, map_y)) {
+      ptile->terrain = T_NOTPLACED;
+      map_set_continent(map_x, map_y, 0);
+    } else if ((T <= 2 * ICE_BASE_LEVEL) 
+              && myrand(10) > 4 && ok_for_separate_poles(map_x, map_y)) { 
+      ptile->terrain = T_NOTPLACED;
+      map_set_continent(map_x, map_y, 0);
     }
   } whole_map_iterate_end;
 }
@@ -401,8 +456,8 @@
   whole_map_iterate(x, y) {
     int T = map_temperature(x, y);
 
-    if (map_get_terrain(x, y) == T_GRASSLAND 
-       && myrand(15 * MAX_TEMP / 100) > T -  ICE_BASE_LEVEL 
+    if (not_placed(x, y)
+       && myrand(1.5 * COLD_LEVEL) > T -  ICE_BASE_LEVEL 
        && T <= 3 * ICE_BASE_LEVEL) {
       map_set_terrain(x, y, T_ARCTIC);
     }
@@ -423,14 +478,16 @@
 {
   const int DeltaT = MAX_TEMP / (3 * SQSIZE);
 
+  if(deserts_to_be_placed <= 0) { return; }
+
   if (abs(hmap(x, y) - height) < diff 
-      && map_get_terrain(x, y) == T_GRASSLAND) {
+      && not_placed(x, y) && count_ocean_near_tile(x,y) <= 2) {
     map_set_terrain(x, y, T_DESERT);
+    deserts_to_be_placed--;
     cardinal_adjc_iterate(x, y, x1, y1) {
       make_desert(x1, y1, height,
                  diff - 1 - abs(map_temperature(x1, y1) - base_T) / DeltaT,
                  base_T);
-     
     } cardinal_adjc_iterate_end;
   }
 }
@@ -443,125 +500,171 @@
 **************************************************************************/
 static void make_forest(int map_x, int map_y, int height, int diff)
 {
-  int nat_x, nat_y, T;
+  int T;
 
-  map_to_native_pos(&nat_x, &nat_y, map_x, map_y);
-  T = map_temperature(map_x, map_y);
-  if (map_get_terrain(map_x, map_y) == T_GRASSLAND) {
-    if (T > 8 * MAX_TEMP / 10 
-       && myrand(1000) > 500 - 300 * (T * 1000 / MAX_TEMP - 800)) {
+  if(forests_to_be_placed <= 0) { return; }
+  if (not_placed(map_x, map_y)) {
+    if ((T = map_temperature(map_x, map_y))> WET_LEVEL         && myrand(100) 
>  50) {
       map_set_terrain(map_x, map_y, T_JUNGLE);
     } else {
       map_set_terrain(map_x, map_y, T_FOREST);
     }
+    forests_to_be_placed--;
     if (abs(hmap(map_x, map_y) - height) < diff) {
       cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(10) > 5) {
+       if (myrand(10) > 5 || (T > WET_LEVEL && myrand(10) >  5)) {
          make_forest(x1, y1, height, diff - 5);
        }
       } cardinal_adjc_iterate_end;
     }
-    forests++;
   }
 }
 
 /**************************************************************************
-  makeforest calls make_forest with random grassland locations until there
-  has been made enough forests. (the map.forestsize value controls this) 
+  a recursive function that adds swamps to the current location and try
+  to spread out to the neighbours.
 **************************************************************************/
-static void make_forests(void)
+static void make_swamp(int map_x, int map_y, int height, int diff)
 {
-  int x, y;
-  int forestsize = (map_num_tiles() * map.forestsize) / 1000;
-
-  forests = 0;
-
-  do {
-    /* Place one forest clump anywhere. */
-    if (rand_map_pos_temperature(&x, &y,
-                                MAX_TEMP / 10, MAX_TEMP,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
-    } else { 
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
-    }
-
-    /* Now add another tropical forest clump (70-100% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                7 *MAX_TEMP / 10, MAX_TEMP,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
-    }
-
-    /* And add a cold forest clump (10%-30% temperature). */
-    if (rand_map_pos_temperature(&x, &y,
-                                1 * MAX_TEMP / 10, 3 * MAX_TEMP / 10,
-                                T_GRASSLAND)) {
-      make_forest(x, y, hmap(x, y), 25);
+  if(swamps_to_be_placed <= 0) { return; }
+  if (not_placed(map_x, map_y) 
+      && ( 2 * (hmap(map_x, map_y) - seaval) < myrand(reliefval - seaval)
+       || (map_temperature(map_x, map_y) > WET_LEVEL && myrand(40) >  30))) {
+      map_set_terrain(map_x, map_y, T_SWAMP);
+      swamps_to_be_placed--;
+      if (abs(hmap(map_x, map_y) - height) < diff) {
+         cardinal_adjc_iterate(map_x, map_y, x1, y1) {
+         make_forest(x1, y1, height, diff - 5);
+      } cardinal_adjc_iterate_end;
     }
-  } while (forests < forestsize);
+  }
 }
-
 /**************************************************************************
-  swamps, is placed on low lying locations, that will typically be close to
-  the shoreline. They're put at random (where there is grassland)
-  and with 50% chance each of it's neighbour squares will be converted to
-  swamp aswell
+  a simple function that adds plains or tundra to the current location.
 **************************************************************************/
-static void make_swamps(void)
+static void make_plain(int x, int y)
 {
-  int x, y, swamps;
-  int forever = 0;
+  int T = map_temperature(x, y);
 
-  for (swamps = 0; swamps < map.swampsize; ) {
-    forever++;
-    if (forever > 1000) {
-      return;
-    }
-    rand_map_pos(&x, &y);
-    if (map_get_terrain(x, y) == T_GRASSLAND
-       && hmap(x, y) < (maxval * 60) / 100) {
-      map_set_terrain(x, y, T_SWAMP);
-      cardinal_adjc_iterate(x, y, x1, y1) {
-       if (myrand(10) > 5 && !is_ocean(map_get_terrain(x1, y1)) 
-           && map_get_terrain(x1, y1) != T_SWAMP ) { 
-         map_set_terrain(x1, y1, T_SWAMP);
-         swamps++;
-       }
-      } cardinal_adjc_iterate_end;
-      swamps++;
-    }
+  if(2 * ICE_BASE_LEVEL > T || myrand(2 * COLD_LEVEL) > T) {
+    map_set_terrain(x, y, T_TUNDRA); /* in cold place we get tundra instead */
+  } else {
+    map_set_terrain(x, y, T_PLAINS);
   }
+  plains_to_be_placed--;
 }
 
-/*************************************************************************
-  Make deserts until we have enough of them.
+/**************************************************************************
+  make_terrains calls make_forest, make_dessert  with random free locations 
+  until there  has been made enough.
+ Comment: funtions as make_swamp, etc. has to have a non 0 probability
+ to place one terrains in called position. Else make_terrains can get
+ in a infinite loop!
 **************************************************************************/
-static void make_deserts(void)
+static void make_terrains(void)
 {
-  int x, y, i = map.deserts, j = 0;
+  int x, y;
+  int total = 0;
+  whole_map_iterate(x, y) {
+    if(not_placed(x,y)) {
+      total++;
+    }
+  } whole_map_iterate_end;
 
-  /* "i" is the number of desert clumps made; "j" is the number of tries. */
-  /* TODO: j is no longer needed */
-  while (i > 0 && j < 100 * map.deserts) {
-    j++;
+  forests_to_be_placed = total * map.forestsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize );
+  deserts_to_be_placed = total * map.deserts
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  swamps_to_be_placed = total * map.swampsize
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
 
-    /* Choose a random coordinate between 20 and 30 degrees north/south
-     * (deserts tend to be between 15 and 35; make_desert will expand
-     * them). */
-    if (rand_map_pos_temperature(&x, &y,
-                                65 * MAX_TEMP / 100, 80 * MAX_TEMP / 100,
-                                T_GRASSLAND)){
-      make_desert(x, y, hmap(x, y), 50, map_temperature(x, y));
-      i--;
-    } else {
-      /* If rand_map_pos_temperature returns FALSE we may as well stop
-       * looking. */
-      break;
+  /* tundra and plains is counted in map.grasssize */
+  grass_to_be_placed = total * map.grasssize / 2
+       / ( map.forestsize + map.deserts + map.grasssize +  map.swampsize);
+  plains_to_be_placed = total /* and tundra */
+      - forests_to_be_placed - deserts_to_be_placed - grass_to_be_placed;
+
+  /* the plasing loop */
+  do {
+    if(forests_to_be_placed > 0) {
+      /* Place one forest clump between Very Cold level and MAX_TEMP. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  (COLD_LEVEL + ICE_BASE_LEVEL) / 2, MAX_TEMP,
+                                  T_NOTPLACED)) {
+       make_forest(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for forest. */
+       plains_to_be_placed += forests_to_be_placed;
+       forests_to_be_placed = 0;
+      }
     }
-  }
+
+    if(swamps_to_be_placed > 0) {
+      /* Place one swamp clump between COLD_LEVEL and MAX_TEMP.. */
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOTPLACED)) {
+       make_swamp(x, y, hmap(x, y), 25);
+      } else { 
+        /* If rand_map_pos_temperature returns FALSE we may as well stop
+         * looking for swamp. */
+       plains_to_be_placed += swamps_to_be_placed; /* reactivate plains */
+       swamps_to_be_placed = 0;
+      }
+    }
+
+    if(deserts_to_be_placed > 0) {
+      /* Choose a random coordinate between TROPICAL_LEVEL and WET_LEVEL;
+        make_desert will expand them). */
+      if (rand_map_pos_temperature(&x, &y,
+                                  TROPICAL_LEVEL, WET_LEVEL,
+                                  T_NOTPLACED)){
+         make_desert(x, y, hmap(x, y), 40, map_temperature(x, y));
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for dessert. (convert to plains) */
+       plains_to_be_placed += deserts_to_be_placed;
+       deserts_to_be_placed = 0;
+      }
+    }
+
+    /* Make the grass */
+    if(grass_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  COLD_LEVEL, MAX_TEMP,
+                                  T_NOTPLACED)){
+       map_set_terrain(x, y, T_GRASSLAND);
+       grass_to_be_placed--;
+      } else {
+         plains_to_be_placed += grass_to_be_placed;
+         grass_to_be_placed = 0;
+      }
+    }
+
+    /* there is very important: this place all terrains when there
+       is not posibe for other types kip the 0, MAX_TEMP range. */
+    /* make the plains and tundras */
+    if(plains_to_be_placed > 0) {
+      if (rand_map_pos_temperature(&x, &y,
+                                  0, MAX_TEMP,
+                                  T_NOTPLACED)){
+       make_plain(x,y);
+      } else {
+       /* If rand_map_pos_temperature returns FALSE we may as well stop
+        * looking for plains. */
+       plains_to_be_placed = 0;
+      }
+    }
+
+  } while (forests_to_be_placed > 0 || deserts_to_be_placed > 0 
+          || grass_to_be_placed > 0 || plains_to_be_placed > 0 
+          || swamps_to_be_placed > 0 );
+
+  /* final test */
+  whole_map_iterate(x, y) {
+    assert(!not_placed(x,y));
+  } whole_map_iterate_end;
 }
 
 /*********************************************************************
@@ -814,7 +917,7 @@
     if (adjacent_river_tiles4(x, y) != 0
        || adjacent_ocean_tiles4(x, y) != 0
         || (map_get_terrain(x, y) == T_ARCTIC 
-           && map_temperature(x, y) < 8 * MAX_TEMP / 100)) { 
+           && map_temperature(x, y) < 0.8 * COLD_LEVEL)) { 
 
       freelog(LOG_DEBUG,
              "The river ended at (%d, %d).\n", x, y);
@@ -1027,56 +1130,6 @@
   river_map = NULL;
 }
 
-/**************************************************************************
-  make_plains converts 50% of the remaining grassland to plains, this should
-  maybe be lowered to 30% or done in batches, like the swamps?
-**************************************************************************/
-static void make_plains(void)
-{
-  whole_map_iterate(x, y) {
-    if (map_get_terrain(x, y) == T_GRASSLAND && myrand(100) > 50)
-      map_set_terrain(x, y, T_PLAINS);
-  } whole_map_iterate_end;
-}
-/****************************************************************************
-  Return TRUE if the terrain at the given map position is "clean".  This
-  means that all the terrain for 2 squares around it is either grassland or
-  plains.
-****************************************************************************/
-static bool terrain_is_clean(int map_x, int map_y)
-{
-  square_iterate(map_x, map_y, 2, x1, y1) {
-    if (map_get_terrain(x1, y1) != T_GRASSLAND
-       && map_get_terrain(x1, y1) != T_PLAINS) {
-      return FALSE;
-    }
-  } square_iterate_end;
-
-  return TRUE;
-}
-
-/**************************************************************************
-  we don't want huge areas of grass/plains, 
- so we put in a hill here and there, where it gets too 'clean' 
-**************************************************************************/
-static void make_fair(void)
-{
-  whole_map_iterate(map_x, map_y) {
-    if (terrain_is_clean(map_x, map_y)) {
-      if (!map_has_special(map_x, map_y, S_RIVER)) {
-       map_set_terrain(map_x, map_y, T_HILLS);
-      }
-      cardinal_adjc_iterate(map_x, map_y, x1, y1) {
-       if (myrand(100) > 66
-           && !is_ocean(map_get_terrain(x1, y1))
-           && !map_has_special(x1, y1, S_RIVER)) {
-         map_set_terrain(x1, y1, T_HILLS);
-       }
-      } cardinal_adjc_iterate_end;
-    }
-  } whole_map_iterate_end;
-}
-
 /****************************************************************************
   Lower the land near the polar region to avoid too much land there.
 
@@ -1117,6 +1170,21 @@
     }
   } whole_map_iterate_end;
 }
+/**************************************************************************
+ if there are room the isle is grownd by one else isle is deleted
+**************************************************************************/
+static void grown_tiny_isle(int x,int y, int nr) {
+  adjc_iterate(x, y, x1, y1) {
+    if(count_ocean_near_tile(x1,y1) == 7) {
+      map_set_terrain(x1, y1, T_NOTPLACED);
+      map_set_continent(x1, y1, nr);
+      MASS_SIZE(nr)++;
+      return;
+    }
+  } adjc_iterate_end;
+  map_set_terrain(x, y, T_OCEAN);
+  return;
+}
 
 /**************************************************************************
   make land simply does it all based on a generated heightmap
@@ -1125,44 +1193,34 @@
 **************************************************************************/
 static void make_land(void)
 {
-  int tres;
-  int count=0;
-  int total = (map_num_tiles() * map.landpercent) / 100;
-  int forever=0;
-
   adjust_map();
   normalize_hmap_poles();
-  tres = (maxval * map.landpercent) / 100;
-
-  do {
-    forever++;
-    if (forever>50) break; /* loop elimination */
-    count=0;
-    whole_map_iterate(x, y) {
-      if (hmap(x, y) < tres)
-       map_set_terrain(x, y, T_OCEAN);
-      else {
-       map_set_terrain(x, y, T_GRASSLAND);
-       count++;
-      }
-    } whole_map_iterate_end;
-    if (count>total)
-      tres*=11;
-    else
-      tres*=9;
-    tres/=10;
-  } while (abs(total-count)> maxval/40);
-
+  seaval = maxval - (maxval * map.landpercent) / 100;
+  whole_map_iterate(x, y) {
+    if (hmap(x, y) < seaval)
+      map_set_terrain(x, y, T_OCEAN);
+    else {
+      map_set_terrain(x, y, T_NOTPLACED);
+    }
+  } whole_map_iterate_end;
   renormalize_hmap_poles();
   make_polar_land(); /* make extra land at poles*/
-  make_mountains(maxval*8/10);
-  make_arctic();
-  make_tundra();
-  make_forests();
-  make_swamps();
-  make_deserts();
-  make_plains();
-  make_fair();
+  assign_continent_numbers(); /* count sizes */
+  whole_map_iterate(x, y) {
+      int nr = map_get_continent(x,y);
+      /* avoid too small oceans */
+      if (is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) < 8) {
+       map_set_terrain(x, y, T_NOTPLACED);  
+      } 
+      /* avoid tiny isles */
+      else if (!is_ocean(map_get_terrain(x, y)) && MASS_SIZE(nr) == 1) {
+       grown_tiny_isle(x, y, nr);
+      }
+  } whole_map_iterate_end;
+
+  make_relief(); /* base relief on map */
+  make_arctic(); 
+  make_terrains();/* place forest/dessert/swamp/grass/tundra and plains */
   make_rivers();
 
   assign_continent_numbers();
@@ -1204,63 +1262,6 @@
   } whole_map_iterate_end;
 }
 
-/**************************************************************************
-  Number this tile and recursive adjacent tiles with specified
-  continent number, by flood-fill algorithm.
-  is_land tells us whether we are assigning continent numbers or ocean 
-  numbers.
-**************************************************************************/
-static void assign_continent_flood(int x, int y, bool is_land, int nr)
-{
-  if (map_get_continent(x, y) != 0) {
-    return;
-  }
-
-  if ((is_land && is_ocean(map_get_terrain(x, y)))
-      || (!is_land && !is_ocean(map_get_terrain(x, y)))) {
-    return;
-  }
-
-  map_set_continent(x, y, nr);
-
-  adjc_iterate(x, y, x1, y1) {
-    assign_continent_flood(x1, y1, is_land, nr);
-  } adjc_iterate_end;
-}
-
-/**************************************************************************
-  Assign continent and ocean numbers to all tiles, set map.num_continents 
-  and map.num_oceans.
-  Continents have numbers 1 to map.num_continents _inclusive_.
-  Oceans have (negative) numbers -1 to -map.num_oceans _inclusive_.
-**************************************************************************/
-void assign_continent_numbers(void)
-{
-  /* Initialize */
-  map.num_continents = 0;
-  map.num_oceans = 0;
-  whole_map_iterate(x, y) {
-    map_set_continent(x, y, 0);
-  } whole_map_iterate_end;
-
-  /* Assign new numbers */
-  whole_map_iterate(x, y) {
-    if (map_get_continent(x, y) != 0) {
-      /* Already assigned */
-      continue;
-    }
-    if (!is_ocean(map_get_terrain(x, y))) {
-      map.num_continents++;
-      assign_continent_flood(x, y, TRUE, map.num_continents);
-    } else {
-      map.num_oceans++;
-      assign_continent_flood(x, y, FALSE, -map.num_oceans);
-    }      
-  } whole_map_iterate_end;
-
-  freelog(LOG_VERBOSE, "Map has %d continents and %d oceans", 
-         map.num_continents, map.num_oceans);
-}
 
 /****************************************************************************
   Return an approximation of the goodness of a tile to a civilization.
@@ -1674,9 +1675,9 @@
 static void adjust_terrain_param(void)
 {
   int total;
-  int polar = 5; /* FIXME: convert to a server option */
+  int polar = ICE_BASE_LEVEL * 100 / MAX_TEMP;
 
-  total = map.mountains + map.deserts + map.forestsize + map.swampsize 
+  total = map.mountains + map.deserts + map.forestsize + map.swampsize
     + map.grasssize;
 
   if (total != 100 - polar) {
@@ -1690,25 +1691,43 @@
 }
 
 /**************************************************************************
-  Adjust the map so that its minimum height is 0.  This raises or lowers
-  every position by a fixed amount and sets the "maxval" global variable
-  to hold the maximum height.
+  Adjust the hmap to be a linearize distribution of heights
+  form 0 to maxval (maxval is a global const )
+  sample
+  ( hmap[x,y] < 0.13 * maxval) handle the 13% lowerest part of the map
 **************************************************************************/
 static void adjust_map(void)
 {
-  int minval = maxval = hnat(0, 0);
+  int i, min = hnat(0, 0), max = hnat(0, 0);
+  int count=0, f[maxval];
+  
+  INITIALIZE_ARRAY(f,maxval,0);
 
   /* Determine minimum and maximum heights. */
   whole_map_iterate(x, y) {
-    maxval = MAX(maxval, hmap(x, y));
-    minval = MIN(minval, hmap(x, y));
+    max = MAX(max, hmap(x, y));
+    min = MIN(min, hmap(x, y));
   } whole_map_iterate_end;
 
-  /* Translate heights so the minimum height is 0. */
-  maxval -= minval;
+  /* Translate heights so the minimum height is 0 and  maximum is maxval.
+     and count pos in granularity */
+  max -= min;
   whole_map_iterate(x, y) {
-    hmap(x, y) -= minval;
+    hmap(x, y) = (hmap(x, y) - min) * maxval;
+    hmap(x, y) /= max;
+    f[hmap(x, y)]++;
   } whole_map_iterate_end;
+
+  /* create the linearize function */
+  for(i =  -1; i++ < maxval;) {
+      count += f[i];
+      f[i] = (count * maxval) / (map.xsize * map.ysize) ;
+     }
+
+  /* apply the linearize function */
+  whole_map_iterate(x, y) {
+    hmap(x, y) = f[hmap(x, y)];
+  } whole_map_iterate_end; 
 }
 
 /**************************************************************************
@@ -2364,6 +2383,17 @@
 #define DMSIS 10
 
 /**************************************************************************
+  make_plains converts 50% of the remaining grassland to plains, this should
+  maybe be lowered to 30% or done in batches, like the swamps?
+**************************************************************************/
+static void make_plains(void)
+{
+  whole_map_iterate(x, y) {
+    if (map_get_terrain(x, y) == T_GRASSLAND && myrand(100) > 50)
+      map_set_terrain(x, y, T_PLAINS);
+  } whole_map_iterate_end;
+}
+/**************************************************************************
   island base map generators
 **************************************************************************/
 static void mapgenerator2(void)
diff -ruN -Xfreeciv/diff_ignore freeciv/server/mapgen.h freeciv_/server/mapgen.h
--- freeciv/server/mapgen.h     2003-08-28 17:54:11.000000000 +0200
+++ freeciv_/server/mapgen.h    2004-08-22 15:10:44.771328976 +0200
@@ -13,7 +13,6 @@
 #ifndef FC__MAPGEN_H
 #define FC__MAPGEN_H
 
-void assign_continent_numbers(void);
 void map_fractal_generate(void);
 void create_start_positions(void);
 
diff -ruN -Xfreeciv/diff_ignore freeciv/server/maphand.c 
freeciv_/server/maphand.c
--- freeciv/server/maphand.c    2004-08-20 22:53:03.000000000 +0200
+++ freeciv_/server/maphand.c   2004-08-22 15:10:44.773328672 +0200
@@ -32,7 +32,6 @@
 #include "citytools.h"
 #include "cityturn.h"
 #include "gamelog.h"
-#include "mapgen.h"            /* assign_continent_numbers */
 #include "plrhand.h"           /* notify_player */
 #include "sernet.h"
 #include "srv_main.h"
@@ -41,6 +40,74 @@
 
 #include "maphand.h"
 
+
+int mass_size[2 * MAP_NCONT];
+/**************************************************************************
+  Number this tile and recursive adjacent tiles with specified
+  continent number, by flood-fill algorithm.
+  is_land tells us whether we are assigning continent numbers or ocean 
+  numbers.
+**************************************************************************/
+static void assign_continent_flood(int x, int y, bool is_land, int nr)
+{
+  if (map_get_continent(x, y) != 0) {
+    return;
+  }
+
+  if (!XOR(is_land , is_ocean(map_get_terrain(x, y)))) {
+    return;
+  }
+
+  map_set_continent(x, y, nr);
+  MASS_SIZE(nr)++;
+
+  adjc_iterate(x, y, x1, y1) {
+    assign_continent_flood(x1, y1, is_land, nr);
+  } adjc_iterate_end;
+}
+
+/**************************************************************************
+  Assign continent and ocean numbers to all tiles, set map.num_continents 
+  and map.num_oceans.
+  Continents have numbers 1 to map.num_continents _inclusive_.
+  Oceans have (negative) numbers -1 to -map.num_oceans _inclusive_.
+**************************************************************************/
+void assign_continent_numbers(void)
+{
+  int i;
+
+  /* Initialize */
+  for(i = 0; i < 2 * MAP_NCONT; i++) {
+    MASS_SIZE(i) = 0;
+  }
+  map.num_continents = 0;
+  map.num_oceans = 0;
+    
+  whole_map_iterate(x, y) {
+    map_set_continent(x, y, 0);
+  } whole_map_iterate_end;
+
+  /* Assign new numbers */
+  whole_map_iterate(x, y) {
+    if (map_get_continent(x, y) != 0) {
+      /* Already assigned */
+      continue;
+    }
+    if (!is_ocean(map_get_terrain(x, y))) {
+      map.num_continents++;
+      assert ( map.num_continents < MAP_NCONT);
+      assign_continent_flood(x, y, TRUE, map.num_continents);
+    } else {
+      map.num_oceans++;
+      assert ( map.num_oceans < MAP_NCONT);
+      assign_continent_flood(x, y, FALSE, -map.num_oceans);
+    }      
+  } whole_map_iterate_end;
+
+  freelog(LOG_VERBOSE, "Map has %d continents and %d oceans", 
+         map.num_continents, map.num_oceans);
+}
+
 static void player_tile_init(int x, int y, struct player *pplayer);
 static void give_tile_info_from_player_to_player(struct player *pfrom,
                                                 struct player *pdest,
diff -ruN -Xfreeciv/diff_ignore freeciv/server/maphand.h 
freeciv_/server/maphand.h
--- freeciv/server/maphand.h    2004-08-09 07:24:35.000000000 +0200
+++ freeciv_/server/maphand.h   2004-08-22 15:10:44.775328368 +0200
@@ -49,6 +49,15 @@
   short last_updated;
 };
 
+/* this is used for generator 2-4 and in assign_continent number */
+#define MAP_NCONT 300
+
+/* signus safe way for nr continent <0 or >0 */
+extern int mass_size[2 * MAP_NCONT];
+#define MASS_SIZE(nr) (mass_size[FC_WRAP((nr), 2 * MAP_NCONT)]) 
+void assign_continent_numbers(void);
+
+
 void global_warming(int effect);
 void nuclear_winter(int effect);
 void give_map_from_player_to_player(struct player *pfrom, struct player 
*pdest);
diff -ruN -Xfreeciv/diff_ignore freeciv/server/stdinhand.c 
freeciv_/server/stdinhand.c
--- freeciv/server/stdinhand.c  2004-08-09 17:45:49.000000000 +0200
+++ freeciv_/server/stdinhand.c 2004-08-22 15:10:44.781327456 +0200
@@ -369,7 +369,7 @@
 
   GEN_INT("grass", map.grasssize,
          SSET_MAP_GEN, SSET_ECOLOGY, SSET_SITUATIONAL, SSET_TO_CLIENT,
-         N_("Amount of grass squares"), "", NULL,
+         N_("Amount of grass and plains squares"), "", NULL,
          MAP_MIN_GRASS, MAP_MAX_GRASS, MAP_DEFAULT_GRASS)
 
   GEN_INT("forests", map.forestsize,
diff -ruN -Xfreeciv/diff_ignore freeciv/utility/shared.h 
freeciv_/utility/shared.h
--- freeciv/utility/shared.h    2004-07-24 14:26:07.000000000 +0200
+++ freeciv_/utility/shared.h   2004-08-22 15:10:44.783327152 +0200
@@ -101,8 +101,8 @@
      ? ((value) % (range) != 0 ? (value) % (range) + (range) : 0)           \
      : ((value) >= (range) ? (value) % (range) : (value)))
 
-#define BOOL_VAL(x) ((x)!=0)
-
+#define BOOL_VAL(x) ((x) != 0)
+#define XOR(p,q)   (!(p) != !(q))
 /*
  * DIVIDE() divides and rounds down, rather than just divides and
  * rounds toward 0.  It is assumed that the divisor is positive.