Add setting for whether water floods from map edges

src/lang/extra/english.txt

@@ -579,6 +579,9 @@ STR_CONFIG_SETTING_MIN_CITY_LAND_AREA_HELPTEXT                  :Cities can only
 STR_CONFIG_SETTING_MIN_LAND_AREA_VALUE                          :{NUM}
 STR_CONFIG_SETTING_MIN_LAND_AREA_ZERO                           :Off
 
+STR_CONFIG_SETTING_FLOOD_FROM_EDGES                             :Water floods from map edges: {STRING2}
+STR_CONFIG_SETTING_FLOOD_FROM_EDGES_HELPTEXT                    :Whether water floods into edge tiles at sea level from the map edge.
+
 STR_CONFIG_SETTING_TREES_AROUND_SNOWLINE                        :Adjusted arctic tree placement: {STRING2}
 STR_CONFIG_SETTING_TREES_AROUND_SNOWLINE_HELPTEXT               :Adjust placement of trees around snow line in artic climate. Trees thin out above snowline. Trees are a mix of arctic and temperate just below snowline. Below that trees are temperate.
 STR_CONFIG_SETTING_TREES_AROUND_SNOWLINE_RANGE                  :Arctic tree range: {STRING2}

src/settings_gui.cpp

@@ -2455,6 +2455,7 @@ static SettingsContainer &GetSettingsTree()
 				treedist->Add(new SettingEntry("construction.tree_growth_rate"));
 			}
 
+			environment->Add(new SettingEntry("construction.flood_from_edges"));
 			environment->Add(new SettingEntry("economy.day_length_factor"));
 			environment->Add(new SettingEntry("station.modified_catchment"));
 			environment->Add(new SettingEntry("station.catchment_increase"));

src/settings_type.h

@@ -477,6 +477,7 @@ struct ConstructionSettings {
 	uint8  raw_industry_construction;        ///< type of (raw) industry construction (none, "normal", prospecting)
 	uint8  industry_platform;                ///< the amount of flat land around an industry
 	bool   freeform_edges;                   ///< allow terraforming the tiles at the map edges
+	bool   flood_from_edges;                 ///< whether water floods from map edges
 	uint8  extra_tree_placement;             ///< (dis)allow building extra trees in-game
 	uint8  trees_around_snow_line_range;     ///< range around snowline for mixed and arctic forest.
 	bool   trees_around_snow_line_enabled;   ///< enable mixed and arctic forest around snowline, and no trees above snowline

src/table/settings/settings.ini

@@ -3951,6 +3951,14 @@ pre_cb   = CheckFreeformEdges
 post_cb  = UpdateFreeformEdges
 cat      = SC_EXPERT
 
+[SDT_BOOL]
+var      = construction.flood_from_edges
+def      = true
+str      = STR_CONFIG_SETTING_FLOOD_FROM_EDGES
+strhelp  = STR_CONFIG_SETTING_FLOOD_FROM_EDGES_HELPTEXT
+cat      = SC_ADVANCED
+patxname = ""construction.flood_from_edges""
+
 [SDT_VAR]
 var      = game_creation.water_borders
 type     = SLE_UINT8

src/water_cmd.cpp

@@ -1165,7 +1165,7 @@ FloodingBehaviour GetFloodingBehaviour(TileIndex tile)
 			return (GetObjectGroundType(tile) == OBJECT_GROUND_SHORE ? FLOOD_DRYUP : ((GetWaterClass(tile) == WATER_CLASS_SEA) ? FLOOD_ACTIVE : FLOOD_NONE));
 
 		case MP_VOID:
-			return FLOOD_ACTIVE;
+			return _settings_game.construction.flood_from_edges ? FLOOD_ACTIVE : FLOOD_NONE;
 
 		default:
 			return FLOOD_NONE;