[Freeciv-Dev] (PR#6652) don't make poles for a N-S-wrapping map

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

When the map wraps N-S, the map generator shouldn't generally make 
poles.  For instance with current CVS, if you "/set topology 3" you'll 
get some rather arbitrary polar areas.

Originally I just wanted to disable poles when topo_has_flag(TF_WRAPY). 
  But Ross wants this to be a server variable.  So in this patch I add a 
"haspoles" server variable with three values.  The default value should 
give the desired behavior in (almost?) all cases.

For instance with this patch and
   set topology 3
   set xsize 60
   set ysize 60
you can get a nicely formed torus map (using whatever generator you prefer).

jason

Index: common/map.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.h,v
retrieving revision 1.161
diff -u -r1.161 map.h
--- common/map.h        2003/10/27 14:25:24     1.161
+++ common/map.h        2003/10/27 19:44:34
@@ -169,6 +169,7 @@
   int riverlength;
   int forestsize;
   int generator;
+  int has_poles;
   bool tinyisles;
   bool separatepoles;
   int num_start_positions;
@@ -664,6 +665,10 @@
 #define MAP_DEFAULT_TOPO         TF_WRAPX
 #define MAP_MIN_TOPO             0
 #define MAP_MAX_TOPO             3
+
+#define MAP_DEFAULT_HASPOLES     0
+#define MAP_MIN_HASPOLES         0
+#define MAP_MAX_HASPOLES         2
 
 #define MAP_DEFAULT_SEED         0
 #define MAP_MIN_SEED             0
Index: server/mapgen.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/mapgen.c,v
retrieving revision 1.119
diff -u -r1.119 mapgen.c
--- server/mapgen.c     2003/10/21 22:04:53     1.119
+++ server/mapgen.c     2003/10/27 19:44:34
@@ -59,6 +59,7 @@
 static int *height_map;
 static int maxval=0;
 static int forests=0;
+static bool has_poles;
 
 struct isledata {
   int goodies;
@@ -854,7 +855,7 @@
       tres*=9;
     tres/=10;
   } while (abs(total-count)> maxval/40);
-  if (map.separatepoles) {
+  if (map.separatepoles && has_poles) {
     make_passable();
   }
   make_mountains(maxval*8/10);
@@ -862,7 +863,9 @@
   make_swamps();
   make_deserts();
   make_plains();
-  make_polar();
+  if (has_poles) {
+    make_polar();
+  }
   make_fair();
   make_rivers();
 }
@@ -970,7 +973,7 @@
   islands = fc_calloc((map.num_continents + 1), sizeof(struct isledata));
   
   /* the arctic and the antarctic are continents 1 and 2 for generator > 0 */
-  if ((map.generator > 0) && map.separatepoles) {
+  if ((map.generator > 0) && map.separatepoles && has_poles) {
     firstcont = 3;
   } else {
     firstcont = 1;
@@ -1154,6 +1157,8 @@
     map.seed = (myrand(MAX_UINT32) ^ time(NULL)) & (MAX_UINT32 >> 1);
 
   mysrand(map.seed);
+  has_poles = ((map.has_poles == 0 && !topo_has_flag(TF_WRAPY))
+              || map.has_poles == 2);
   
   /* don't generate tiles with mapgen==0 as we've loaded them from file */
   /* also, don't delete (the handcrafted!) tiny islands in a scenario */
@@ -2140,7 +2145,7 @@
     for (y = 0; y < ydiv2; y++) {
       hmap(0, y * ymax / ydiv) -= avoidedge;
       hmap(xmax, y * ymax / ydiv) -= avoidedge;
-      if (map.separatepoles) {
+      if (map.separatepoles && has_poles) {
        hmap(2, y * ymax / ydiv) = hmap(0, y * ymax / ydiv) 
                                                        - myrand(3*avoidedge);
        hmap(xmax - 2, y * ymax / ydiv) 
@@ -2153,7 +2158,7 @@
     for (x = 0; x < xdiv2; x++) {
       hmap(x * xmax / xdiv, 0) -= avoidedge;
       hmap(x * xmax / xdiv, ymax) -= avoidedge;
-      if (map.separatepoles){
+      if (map.separatepoles && has_poles) {
        hmap(x * xmax / xdiv, 2) = hmap(x * xmax / xdiv, 0) 
                                                        - myrand(3*avoidedge);
        hmap(x * xmax / xdiv, ymax - 2) 
Index: server/stdinhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/stdinhand.c,v
retrieving revision 1.300
diff -u -r1.300 stdinhand.c
--- server/stdinhand.c  2003/10/27 14:25:25     1.300
+++ server/stdinhand.c  2003/10/27 19:44:35
@@ -267,6 +267,13 @@
        "(Zero indicates a scenario map.)"), NULL,
          MAP_MIN_GENERATOR, MAP_MAX_GENERATOR, MAP_DEFAULT_GENERATOR)
 
+  GEN_INT("haspoles", map.has_poles, SSET_MAP_GEN, SSET_TO_CLIENT,
+         N_("Whether the map has polar regions"),
+         N_("  0 = only if the map doesn't wrap north-south;\n"
+            "  1 = never;\n"
+            "  2 = always"), NULL,
+         MAP_MIN_HASPOLES, MAP_MAX_HASPOLES, MAP_DEFAULT_HASPOLES)
+
   GEN_BOOL("tinyisles", map.tinyisles, SSET_MAP_GEN, SSET_TO_CLIENT,
           N_("Presence or absence of 1x1 islands"),
           N_("0 = no 1x1 islands; 1 = some 1x1 islands"), NULL,