[Freeciv-Dev] Re: bug in mapgen (PR#1043)

[jdorje@xxxxxxxxxxxxxxxxxxxxx]

Ross W. Wetmore wrote:

> I would delete the lines. I don't think they are actually used after
> this point, but I didn't do an exhaustive check. Create_island() resets
> them each time, and when you leave at this point you aren't looping
> back to place_island().

I do not think the lines can be deleted.  The crash happens because of 
the oddball random number generation in fill_island and 
fill_island_rivers; these appear to use n/s/e/w as set up by 
create_island and place_island.  All of this takes place within make_island.
IMO the random map position should be done safely.  The attached patch 
does this in a simple (though not perfect) way.

> Since they are (badly named) globals anybody could access them, but it
> isn't really likely.

I strongly agree that the globals should be removed, and the data be 
passed around in a struct as Raimar's patch accomplishes.  Really, 
though, that might as well be a different patch.  Raimar: I think you 
should apply it.  If you want I'll clean it up (by removing the 
bug-related code).
jason

? freeciv.kdevses
? old
? topology
Index: server/mapgen.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/mapgen.c,v
retrieving revision 1.77
diff -u -r1.77 mapgen.c
--- server/mapgen.c     2001/11/11 17:46:21     1.77
+++ server/mapgen.c     2001/11/26 13:56:10
@@ -1457,8 +1457,10 @@
     i= 0;
 
   while (i && failsafe--) {
+    do {
     y = myrand(s - n) + n;
     x = myrand(e - w) + w;
+    } while (!normalize_map_pos(&x, &y));
     if (map_get_continent(x,y) == isleindex &&
                map_get_terrain(x,y) == T_GRASSLAND) {
 
@@ -1510,8 +1512,10 @@
   if(failsafe<0){ failsafe= -failsafe; }
 
   while (i && failsafe--) {
+    do {
     y = myrand(s - n) + n;
     x = myrand(e - w) + w;
+    } while (!normalize_map_pos(&x, &y));
     if (map_get_continent(x,y) == isleindex &&
                map_get_terrain(x,y) == T_GRASSLAND) {