Add setting for map edge behaviour, and how to display area outside map

src/heightmap.cpp

@@ -473,6 +473,11 @@ void FixSlopes()
 			}
 		}
 	}
+
+	extern bool CheckMapEdgesAreWater();
+	if (_settings_game.construction.map_edge_mode != 0 && !CheckMapEdgesAreWater()) {
+		_settings_game.construction.map_edge_mode = 0;
+	}
 }
 
 /**

src/lang/extra/english.txt

@@ -566,6 +566,12 @@ 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_MAP_EDGE_MODE                                :Map edge behaviour: {STRING2}
+STR_CONFIG_SETTING_MAP_EDGE_MODE_HELPTEXT                       :Whether raising the map edges above sea-level is allowed, and how the void area outside the map is displayed
+STR_CONFIG_SETTING_MAP_EDGE_MODE_DEFAULT                        :Default
+STR_CONFIG_SETTING_MAP_EDGE_MODE_SEA_LEVEL                      :Map edges restricted to sea level
+STR_CONFIG_SETTING_MAP_EDGE_MODE_SEA_LEVEL_OUTSIDE_WATER        :Map edges restricted to sea level, outside map shown as water
+
 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.cpp

@@ -1462,6 +1462,15 @@ static void ViewportMapLandscapeModeChanged(int32 new_value)
 	MarkAllViewportMapLandscapesDirty();
 }
 
+static void MarkAllViewportsDirty(int32 new_value)
+{
+	extern void MarkAllViewportMapLandscapesDirty();
+	MarkAllViewportMapLandscapesDirty();
+
+	extern void MarkWholeNonMapViewportsDirty();
+	MarkWholeNonMapViewportsDirty();
+}
+
 static void UpdateLinkgraphColours(int32 new_value)
 {
 	BuildLinkStatsLegend();
@@ -1655,6 +1664,35 @@ static void UpdateFreeformEdges(int32 new_value)
 	MarkWholeScreenDirty();
 }
 
+bool CheckMapEdgesAreWater()
+{
+	auto check_tile = [&](uint x, uint y) -> bool {
+		int h = 0;
+		Slope slope = GetTilePixelSlopeOutsideMap(x, y, &h);
+		return slope == SLOPE_FLAT && h == 0;
+	};
+	for (uint x = 0; x <= MapMaxX(); x++) {
+		if (!check_tile(x, 0) || !check_tile(x, MapMaxY())) return false;
+	}
+	for (uint y = 1; y < MapMaxY(); y++) {
+		if (!check_tile(0, y) || !check_tile(MapMaxX(), y)) return false;
+	}
+
+	return true;
+}
+
+static bool CheckMapEdgeMode(int32 &new_value)
+{
+	if (_game_mode == GM_MENU || !_settings_game.construction.freeform_edges || new_value == 0) return true;
+
+	if (!CheckMapEdgesAreWater()) {
+		ShowErrorMessage(STR_CONFIG_SETTING_EDGES_NOT_WATER, INVALID_STRING_ID, WL_ERROR);
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * Changing the setting "allow multiple NewGRF sets" is not allowed
  * if there are vehicles.

src/settings_gui.cpp

@@ -2414,6 +2414,7 @@ static SettingsContainer &GetSettingsTree()
 			}
 
 			environment->Add(new SettingEntry("construction.flood_from_edges"));
+			environment->Add(new SettingEntry("construction.map_edge_mode"));
 			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

@@ -508,6 +508,7 @@ struct ConstructionSettings {
 	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  map_edge_mode;                    ///< map edge mode
 	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/sl/saveload.cpp

@@ -3544,6 +3544,9 @@ static SaveOrLoadResult DoLoad(LoadFilter *reader, bool load_check)
 		 * No pools are loaded. References are not possible, and thus do not need resolving. */
 		SlLoadCheckChunks();
 	} else {
+		/* Unconditionally default this to 0 when loading a savegame */
+		_settings_game.construction.map_edge_mode = 0;
+
 		/* Load chunks and resolve references */
 		SlLoadChunks();
 		SlFixPointers();
@@ -3676,6 +3679,9 @@ SaveOrLoadResult SaveOrLoad(const std::string &filename, SaveLoadOperation fop,
 
 			InitializeGame(256, 256, true, true); // set a mapsize of 256x256 for TTDPatch games or it might get confused
 
+			/* Unconditionally default this to 0 when loading a savegame */
+			_settings_game.construction.map_edge_mode = 0;
+
 			/* TTD/TTO savegames have no NewGRFs, TTDP savegame have them
 			 * and if so a new NewGRF list will be made in LoadOldSaveGame.
 			 * Note: this is done here because AfterLoadGame is also called

src/table/settings/world_settings.ini

@@ -13,8 +13,10 @@
 static bool CheckMaxHeightLevel(int32_t &new_value);
 static bool CheckFreeformEdges(int32_t &new_value);
 static void UpdateFreeformEdges(int32_t new_value);
+static bool CheckMapEdgeMode(int32_t &new_value);
 static void ClimateThresholdModeChanged(int32 new_value);
 static void PublicRoadsSettingChange(int32 new_value);
+static void MarkAllViewportsDirty(int32 new_value);
 
 static bool AllowRoadStopsUnderBridgesSettingGUI(SettingOnGuiCtrlData &data);
 static bool TreePlacerSettingGUI(SettingOnGuiCtrlData &data);
@@ -929,6 +931,20 @@ strhelp  = STR_CONFIG_SETTING_FLOOD_FROM_EDGES_HELPTEXT
 cat      = SC_ADVANCED
 patxname = ""construction.flood_from_edges""
 
+[SDT_VAR]
+var      = construction.map_edge_mode
+type     = SLE_UINT8
+flags    = SF_GUI_DROPDOWN | SF_PATCH
+def      = 0
+min      = 0
+max      = 2
+str      = STR_CONFIG_SETTING_MAP_EDGE_MODE
+strhelp  = STR_CONFIG_SETTING_MAP_EDGE_MODE_HELPTEXT
+strval   = STR_CONFIG_SETTING_MAP_EDGE_MODE_DEFAULT
+pre_cb   = CheckMapEdgeMode
+post_cb  = MarkAllViewportsDirty
+cat      = SC_ADVANCED
+
 [SDT_VAR]
 var      = construction.extra_tree_placement
 type     = SLE_UINT8

src/terraform_cmd.cpp

@@ -227,7 +227,15 @@ CommandCost CmdTerraformLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 			assert(t < MapSize());
 			/* MP_VOID tiles can be terraformed but as tunnels and bridges
 			 * cannot go under / over these tiles they don't need checking. */
-			if (IsTileType(t, MP_VOID)) continue;
+			if (IsTileType(t, MP_VOID)) {
+				if (_settings_game.construction.map_edge_mode != 0) {
+					CommandCost err(STR_ERROR_TOO_CLOSE_TO_EDGE_OF_MAP);
+					err.SetTile(t);
+					return err;
+				} else {
+					continue;
+				}
+			}
 
 			/* Find new heights of tile corners */
 			int z_N = TerraformGetHeightOfTile(&ts, t + TileDiffXY(0, 0));

src/viewport.cpp

@@ -1752,6 +1752,12 @@ static void ViewportAddLandscape()
 				/* Outside of map. If we are on the north border of the map, there may still be a bridge visible,
 				 * so we need to loop over more rows to possibly find one. */
 				if ((tilecoord.x <= 0 || tilecoord.y <= 0) && min_visible_height < potential_bridge_height + MAX_TILE_EXTENT_TOP) last_row = false;
+
+				if (_settings_game.construction.map_edge_mode == 2 && _cur_ti.tileh == SLOPE_FLAT && _cur_ti.z == 0 && min_visible_height <= 0) {
+					last_row = false;
+					AddTileSpriteToDraw(SPR_FLAT_WATER_TILE, PAL_NONE, _cur_ti.x, _cur_ti.y, _cur_ti.z);
+					continue;
+				}
 			}
 
 			if (tile_visible) {
@@ -3255,34 +3261,39 @@ static inline TileIndex ViewportMapGetMostSignificantTileType(const Viewport * c
 	return result;
 }
 
+static uint32 ViewportMapVoidColour()
+{
+	return (_settings_game.construction.map_edge_mode == 2) ? _vp_map_water_colour[SLOPE_FLAT] : 0;
+}
+
 /** Get the colour of a tile, can be 32bpp RGB or 8bpp palette index. */
 template <bool is_32bpp, bool show_slope>
 uint32 ViewportMapGetColour(const Viewport * const vp, int x, int y, const uint colour_index)
 {
-	if (x >= static_cast<int>(MapMaxX() * TILE_SIZE) || y >= static_cast<int>(MapMaxY() * TILE_SIZE)) return 0;
+	if (x >= static_cast<int>(MapMaxX() * TILE_SIZE) || y >= static_cast<int>(MapMaxY() * TILE_SIZE)) return ViewportMapVoidColour();
 
 	/* Very approximative but fast way to get the tile when taking Z into account. */
 	const TileIndex tile_tmp = TileVirtXY(std::max(0, x), std::max(0, y));
 	const int z = TileHeight(tile_tmp) * 4;
 	if (x + z < 0 || y + z < 0 || static_cast<uint>(x + z) >= MapSizeX() << 4) {
 		/* Wrapping of tile X coordinate causes a graphic glitch below south west border. */
-		return 0;
+		return ViewportMapVoidColour();
 	}
 	TileIndex tile = TileVirtXY(x + z, y + z);
-	if (tile >= MapSize()) return 0;
+	if (tile >= MapSize()) return ViewportMapVoidColour();
 	const int z2 = TileHeight(tile) * 4;
 	if (unlikely(z2 != z)) {
 		const int approx_z = (z + z2) / 2;
 		if (x + approx_z < 0 || y + approx_z < 0 || static_cast<uint>(x + approx_z) >= MapSizeX() << 4) {
 			/* Wrapping of tile X coordinate causes a graphic glitch below south west border. */
-			return 0;
+			return ViewportMapVoidColour();
 		}
 		tile = TileVirtXY(x + approx_z, y + approx_z);
-		if (tile >= MapSize()) return 0;
+		if (tile >= MapSize()) return ViewportMapVoidColour();
 	}
 	TileType tile_type = MP_VOID;
 	tile = ViewportMapGetMostSignificantTileType(vp, tile, &tile_type);
-	if (tile_type == MP_VOID) return 0;
+	if (tile_type == MP_VOID) return ViewportMapVoidColour();
 
 	/* Return the colours. */
 	switch (vp->map_type) {