fairland: Simplify search for next wilderness to elevate

To find the wilderness sector to elevate next, elevate_land() searches
the non-mountain, non-capital sectors of the island for one that
maximizes a function of its distance to mountains and to sea.

The search ignores already elevated sectors in a less than obvious
way: 1. it never picks a sector where the function yields -INFINITY or
less, and 2. when elevating a wilderness, its (cached) distances get
reset to values that make the function return a more negative value.

Use a more direct check of "not yet elevated": elevation is still the
initial -INFINITY.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>

diff --git a/src/util/fairland.c b/src/util/fairland.c
index 7f58e0254217dc76a47b897c7c7ef1e92b9bfcf4..263b6e68adacc430127fd14d352c0f3f6f541744 100644 (file)
--- a/src/util/fairland.c
+++ b/src/util/fairland.c
@@ -1002,15 +1002,16 @@ elevate_land(void)
          (100 * (HIGHMIN - LANDMIN)) / (ns - nm - ((c < nc) ? 3 : 1)) :
          100 * INFINITY;
        for (k = 100 * (HIGHMIN - 1);; k -= dk) {
          (100 * (HIGHMIN - LANDMIN)) / (ns - nm - ((c < nc) ? 3 : 1)) :
          100 * INFINITY;
        for (k = 100 * (HIGHMIN - 1);; k -= dk) {

-           highest = -INFINITY;
+           highest = 0;

            where = -1;
            for (i = 0; i < ns; ++i) {
            where = -1;
            for (i = 0; i < ns; ++i) {

-               if (ELEV != INFINITY &&
+               if (ELEV == -INFINITY &&

                    (c >= nc || ((!(capx[c] == sectx[c][i] &&
                                    capy[c] == secty[c][i])) &&
                                 (!(new_x(capx[c] + 2) == sectx[c][i] &&
                                    capy[c] == secty[c][i]))))) {
                    h = 3 * (5 - dmoun[i]) + dsea[i];
                    (c >= nc || ((!(capx[c] == sectx[c][i] &&
                                    capy[c] == secty[c][i])) &&
                                 (!(new_x(capx[c] + 2) == sectx[c][i] &&
                                    capy[c] == secty[c][i]))))) {
                    h = 3 * (5 - dmoun[i]) + dsea[i];

+                   assert(h > 0);

                    if (h > highest) {
                        highest = h;
                        where = i;
                    if (h > highest) {
                        highest = h;
                        where = i;


@@ -1025,8 +1026,6 @@ elevate_land(void)
            if (newk < LANDMIN)
                newk = LANDMIN;
            elev[sectx[c][where]][secty[c][where]] = newk;
            if (newk < LANDMIN)
                newk = LANDMIN;
            elev[sectx[c][where]][secty[c][where]] = newk;

-           dsea[where] = -INFINITY;
-           dmoun[where] = INFINITY;

        }
 
 /* Elevate the mountains and capitals */
        }
 
 /* Elevate the mountains and capitals */