fairland: Track adjacent land sectors

[empserver] / src / util / fairland.c

diff --git a/src/util/fairland.c b/src/util/fairland.c
index ca125371027416b4e2ea2a5c7eae9f117ec2cd1a..563c2330a91fc6e24c0ffc33dbcf0f6a28d24e88 100644 (file)
--- a/src/util/fairland.c
+++ b/src/util/fairland.c
@@ -188,6 +188,13 @@ static int diry[] = { 0, -1, -1, 0, 1, 1 };
 
 static int **own;              /* owner of the sector.  -1 means water */
 
+/*
+ * Adjacent land sectors
+ * adj_land[XYOFFSET(x, y)] bit d is set exactly when the sector next
+ * to x, y in direction d is land.
+ */
+static unsigned char *adj_land;
+
 /*
  * Exclusive zones
  * Each island is surrounded by an exclusive zone where only it may
@@ -494,6 +501,7 @@ allocate_memory(void)
     capx = calloc(nc, sizeof(int));
     capy = calloc(nc, sizeof(int));
     own = calloc(WORLD_X, sizeof(int *));
+    adj_land = malloc(WORLD_SZ() * sizeof(*adj_land));
     xzone = malloc(WORLD_SZ() * sizeof(*xzone));
     elev = calloc(WORLD_X, sizeof(int *));
     for (i = 0; i < WORLD_X; ++i) {
@@ -530,6 +538,7 @@ init(void)
            own[i][j] = -1;
        }
     }
+    memset(adj_land, 0, WORLD_SZ() * sizeof(*adj_land));
 }
 
 /****************************************************************************
@@ -766,6 +775,21 @@ can_grow_at(int c, int x, int y)
     return own[x][y] == -1 && xzone_ok(c, x, y);
 }
 
+static void
+adj_land_update(int x, int y)
+{
+    int dir, nx, ny, noff;
+
+    assert(own[x][y] != -1);
+
+    for (dir = DIR_FIRST; dir <= DIR_LAST; dir++) {
+       nx = new_x(x + diroff[dir][0]);
+       ny = new_y(y + diroff[dir][1]);
+       noff = XYOFFSET(nx, ny);
+       adj_land[noff] |= 1u << DIR_BACK(dir);
+    }
+}
+
 static void
 add_sector(int c, int x, int y)
 {
@@ -775,6 +799,7 @@ add_sector(int c, int x, int y)
     secty[c][isecs[c]] = y;
     isecs[c]++;
     own[x][y] = c;
+    adj_land_update(x, y);
 }
 
 static int