[Freeciv-Dev] (PR#9593) another autosettlers patch

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9593 >

This patch improves ai_calc_irrigate, ai_calc_mine, and 
ai_calc_transform a bit more.

- It checks TER_NO_CITIES rather than is_ocean when changing the terrain 
type.

- The special-case for not auto-irrigation of city centers is removed. 
This makes removing auto-irrigation easier (which may be desirable at 
some point) and has practically no disadvantages.

- ai_calc_mine now handles changing the terrain.  This will calculate 
the advantage of mining grassland into forest, for instance.

- ai_calc_transform and ai_calc_mine don't hard-code the source terrain 
types.  Doing so is totally unnecessary since all the information is 
encoded in the ruleset.

- Changes the structure of the functions slightly to be more similar.  I 
added an "r" variable to ai_calc_irrigate and ai_calc_mine.

- Fixes some random style, adds some comments.

jason

? diff
Index: server/settlers.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/settlers.c,v
retrieving revision 1.186
diff -u -r1.186 settlers.c
--- server/settlers.c   3 Aug 2004 03:08:54 -0000       1.186
+++ server/settlers.c   3 Aug 2004 03:55:48 -0000
@@ -571,23 +571,22 @@
   enum tile_terrain_type t = ptile->terrain;
   struct tile_type *type = get_tile_type(t);
   enum tile_special_type s = ptile->special;
+  enum tile_terrain_type r = type->irrigation_result;
 
-  if (ptile->terrain != type->irrigation_result
-      && type->irrigation_result != T_LAST) {
+  if (t != r && r != T_LAST) {
     /* Irrigation would change the terrain type, clearing the mine
      * in the process.  Calculate the benefit of doing so. */
-    if (ptile->city && is_ocean(type->irrigation_result)) {
+    if (ptile->city && terrain_has_flag(r, TER_NO_CITIES)) {
       return -1;
     }
-    ptile->terrain = type->irrigation_result;
+    ptile->terrain = r;
     map_clear_special(mx, my, S_MINE);
     m = city_tile_value(pcity, cx, cy, 0, 0);
     ptile->terrain = t;
     ptile->special = s;
     return m;
-  } else if (ptile->terrain == type->irrigation_result
+  } else if (t == r
             && !tile_has_special(ptile, S_IRRIGATION)
-            && !ptile->city
             && is_wet_or_is_wet_cardinal_around(pplayer, mx, my)) {
     /* The tile is currently unirrigated; irrigating it would put an
      * S_IRRIGATE on it replacing any S_MINE already there.  Calculate
@@ -598,11 +597,10 @@
     ptile->special = s;
     assert(ptile->terrain == t);
     return m;
-  } else if (ptile->terrain == type->irrigation_result
+  } else if (t == r
             && tile_has_special(ptile, S_IRRIGATION)
             && !tile_has_special(ptile, S_FARMLAND)
             && player_knows_techs_with_flag(pplayer, TF_FARMLAND)
-            && !ptile->city
             && is_wet_or_is_wet_cardinal_around(pplayer, mx, my)) {
     /* The tile is currently irrigated; irrigating it more puts an
      * S_FARMLAND on it.  Calculate the benefit of doing so. */
@@ -633,22 +631,34 @@
 {
   int m;
   struct tile *ptile = map_get_tile(mx, my);
+  enum tile_terrain_type t = ptile->terrain;
+  struct tile_type *type = get_tile_type(t);
   enum tile_special_type s = ptile->special;
+  enum tile_terrain_type r = type->mining_result;
 
-  /* FIXME: currently this only handles building a mine on a hill or
-   * mountain terrain.  It should instead work the same way as
-   * ai_calc_irrigate does, by looking at mining_result. */
-
-  if ((ptile->terrain == T_HILLS || ptile->terrain == T_MOUNTAINS)
-      && !tile_has_special(ptile, S_MINE)) {
-    /* The tile is currently unmined; mining it would put an S_MINE
-     * on it replacing any S_IRRIGATION/S_FARMLAND already there.  Calculate
+  if (t != r && r != T_LAST) {
+    /* Mining would change the terrain type, clearing the irrigation
+     * in the process.  Calculate the benefit of doing so. */
+    if (ptile->city && terrain_has_flag(r, TER_NO_CITIES)) {
+      return -1;
+    }
+    ptile->terrain = r;
+    map_clear_special(mx, my, S_IRRIGATION);
+    map_clear_special(mx, my, S_FARMLAND);
+    m = city_tile_value(pcity, cx, cy, 0, 0);
+    ptile->terrain = t;
+    ptile->special = s;
+    return m;
+  } else if (t == r && !tile_has_special(ptile, S_MINE)) {
+    /* The tile is currently unmined; mining it would put an S_MINE on it
+     * replacing any S_IRRIGATION/S_FARMLAND already there.  Calculate
      * the benefit of doing so. */
     map_clear_special(mx, my, S_IRRIGATION);
     map_clear_special(mx, my, S_FARMLAND);
     map_set_special(mx, my, S_MINE);
     m = city_tile_value(pcity, cx, cy, 0, 0);
     ptile->special = s;
+    assert(ptile->terrain == t);
     return m;
   } else {
     return -1;
@@ -656,7 +666,16 @@
 }
 
 /**************************************************************************
-  Calculates the value of doing a terrain transformation.
+  Calculate the benefit of transforming the given tile.
+
+    (mx, my) is the map position of the tile.
+    (cx, cy) is the city position of the tile with respect to pcity.
+    pplayer is the player under consideration.
+
+  The return value is the goodness of the tile after the transform.  This
+  should be compared to the goodness of the tile currently (see
+  city_tile_value(); note that this depends on the AI's weighting
+  values).
 **************************************************************************/
 static int ai_calc_transform(struct city *pcity, int cx, int cy, int mx,
                             int my)
@@ -675,17 +694,16 @@
     return -1;
   }
 
-  if ((t == T_ARCTIC || t == T_DESERT || t == T_JUNGLE || t == T_SWAMP  || 
-       t == T_TUNDRA || t == T_MOUNTAINS) && r != T_LAST) {
-    if (is_ocean(r) && ptile->city) {
+  if (t != r && r != T_LAST) {
+    if (ptile->city && terrain_has_flag(r, TER_NO_CITIES)) {
       return -1;
     }
 
     ptile->terrain = r;
 
-    if (get_tile_type(r)->mining_result != r) 
+    if (get_tile_type(r)->mining_result != r) {
       map_clear_special(mx, my, S_MINE);
-
+    }
     if (get_tile_type(r)->irrigation_result != r) {
       map_clear_special(mx, my, S_FARMLAND);
       map_clear_special(mx, my, S_IRRIGATION);
@@ -694,8 +712,10 @@
     m = city_tile_value(pcity, cx, cy, 0, 0);
     ptile->terrain = t;
     ptile->special = s;
-    return(m);
-  } else return(-1);
+    return m;
+  } else {
+    return -1;
+  }
 }
 
 /**************************************************************************