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-rw-r--r--src/town_cmd.cpp48
1 files changed, 47 insertions, 1 deletions
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index 6674c905b..810499d04 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -1297,6 +1297,44 @@ static void GrowTownInTile(TileIndex *tile_ptr, RoadBits cur_rb, DiagDirection t
}
/**
+ * Checks whether a road can be followed or is a dead end, that can not be extended to the next tile.
+ * This only checks trivial but often cases.
+ * @param tile Start tile for road.
+ * @param dir Direction for road to follow or build.
+ * @return true If road is or can be connected in the specified direction.
+ */
+static bool CanFollowRoad(TileIndex tile, DiagDirection dir)
+{
+ TileIndex target_tile = tile + TileOffsByDiagDir(dir);
+ if (!IsValidTile(target_tile)) return false;
+ if (HasTileWaterGround(target_tile)) return false;
+
+ RoadBits target_rb = GetTownRoadBits(target_tile);
+ if (_settings_game.economy.allow_town_roads) {
+ /* Check whether a road connection exists or can be build. */
+ switch (GetTileType(target_tile)) {
+ case MP_ROAD:
+ return target_rb != ROAD_NONE;
+
+ case MP_HOUSE:
+ case MP_STATION:
+ case MP_INDUSTRY:
+ case MP_OBJECT:
+ return false;
+
+ default:
+ /* Checked for void and water earlier */
+ return true;
+ }
+ } else {
+ /* Check whether a road connection already exists,
+ * and it leads somewhere else. */
+ RoadBits back_rb = DiagDirToRoadBits(ReverseDiagDir(dir));
+ return (target_rb & back_rb) != 0 && (target_rb & back_rb) != back_rb;
+ }
+}
+
+/**
* Returns "growth" if a house was built, or no if the build failed.
* @param t town to inquiry
* @param tile to inquiry
@@ -1348,7 +1386,15 @@ static int GrowTownAtRoad(Town *t, TileIndex tile)
} else {
/* Select a random bit from the blockmask, walk a step
* and continue the search from there. */
- do target_dir = RandomDiagDir(); while (!(cur_rb & DiagDirToRoadBits(target_dir)));
+ do {
+ if (cur_rb == ROAD_NONE) return GROWTH_SEARCH_STOPPED;
+ RoadBits target_bits;
+ do {
+ target_dir = RandomDiagDir();
+ target_bits = DiagDirToRoadBits(target_dir);
+ } while (!(cur_rb & target_bits));
+ cur_rb &= ~target_bits;
+ } while (!CanFollowRoad(tile, target_dir));
}
tile = TileAddByDiagDir(tile, target_dir);