Change fairland island size probability distribution

Island size is randomly chosen from the interval [1..2*is+1], with
expected value is.  Use two dice to roll the size instead of one.
This makes extreme sizes much less likely.

diff --git a/src/util/fairland.c b/src/util/fairland.c
index a8867f1fbc0f65f68e2d8fb844a4425a80c7c9ad..88fe72efca02cc87a175a50dbb490d2fa616187b 100644 (file)
--- a/src/util/fairland.c
+++ b/src/util/fairland.c
@@ -821,7 +821,7 @@ grow_islands(void)
        secs = 0;
        if (!place_island(c, &x, &y))
            return;
        secs = 0;
        if (!place_island(c, &x, &y))
            return;

-       isiz = 1 + rnd(2 * is - 1);
+       isiz = 1 + rnd(is) + rnd(is);

        do {
            ++secs;
            find_coast(c);
        do {
            ++secs;
            find_coast(c);