Improve lake generation

Prior to this change, lakes could be very small and could also not be deactivated.

This change allows the deactivation of lake creation and the lake size is now the set size +- 25% instead of anything between 0 and lake_size.

src/landscape.cpp

@@ -1333,7 +1333,7 @@ static bool FlowRiver(TileIndex spring, TileIndex begin, uint min_river_length)
 	if (found) {
 		/* Flow further down hill. */
 		found = FlowRiver(spring, end, min_river_length);
-	} else if (count > 32) {
+	} else if (count > 32 && _settings_game.game_creation.lake_size != 0) {
 		/* Maybe we can make a lake. Find the Nth of the considered tiles. */
 		TileIndex lakeCenter = 0;
 		int i = RandomRange(count - 1) + 1;
@@ -1358,7 +1358,10 @@ static bool FlowRiver(TileIndex spring, TileIndex begin, uint min_river_length)
 			/* Remove desert directly around the river tile. */
 			CircularTileSearch(&lakeCenter, _settings_game.game_creation.river_tropics_width, RiverModifyDesertZone, nullptr);
 			lakeCenter = end;
-			uint range = RandomRange(_settings_game.game_creation.lake_size) + 3;
+
+			// Setting lake size +- 25%
+			const auto random_percentage = 75 + RandomRange(50);
+			const uint range = ((_settings_game.game_creation.lake_size * random_percentage) / 100) + 3;
 
 			MakeLakeData data;
 			data.centre = lakeCenter;
@@ -1401,7 +1404,7 @@ static void CreateRivers()
 
 	for (; wells > num_short_rivers; wells--) {
 		IncreaseGeneratingWorldProgress(GWP_RIVER);
-		for (int tries = 0; tries < 512; tries++) {
+		for (int tries = 0; tries < 128; tries++) {
 			TileIndex t = RandomTile();
 			if (!CircularTileSearch(&t, 8, FindSpring, nullptr)) continue;
 			_current_spring = t;

src/lang/english.txt

@@ -1502,6 +1502,8 @@ STR_CONFIG_SETTING_RIVER_TROPICS_WIDTH                          :Tropics width a
 STR_CONFIG_SETTING_RIVER_TROPICS_WIDTH_HELPTEXT                 :Controls the width of the tropic zone that surrounds rivers in sub-tropic landscape.
 STR_CONFIG_SETTING_LAKE_SIZE                                    :Size of lakes: {STRING}
 STR_CONFIG_SETTING_LAKE_SIZE_HELPTEXT                           :Controls the size of lakes that are generated along rivers.
+STR_CONFIG_SETTING_LAKE_SIZE_VALUE                              :{NUM}
+STR_CONFIG_SETTING_LAKE_SIZE_ZERO                               :No lakes
 STR_CONFIG_SETTING_LAKES_ALLOWED_IN_DESERTS                     :Lakes can be generated in sub-tropic climate deserts: {STRING}
 STR_CONFIG_SETTING_LAKES_ALLOWED_IN_DESERTS_HELPTEXT            :Choose whether the lakes that spawn along rivers are allowed in deserts.
 STR_CONFIG_SETTING_RIVER_AMOUNT                                 :River amount: {STRING2}

src/table/settings.ini

@@ -4000,14 +4000,14 @@ patxname = ""rivers.game_creation.river_tropics_width""
 base     = GameSettings
 var      = game_creation.lake_size
 type     = SLE_UINT8
-guiflags = SGF_NEWGAME_ONLY | SGF_SCENEDIT_TOO
+guiflags = SGF_NEWGAME_ONLY | SGF_SCENEDIT_TOO | SGF_0ISDISABLED
 def      = 8
-min      = 1
-max      = 100
+min      = 0
+max      = 255
 cat      = SC_EXPERT
 str      = STR_CONFIG_SETTING_LAKE_SIZE
 strhelp  = STR_CONFIG_SETTING_LAKE_SIZE_HELPTEXT
-strval   = STR_JUST_COMMA
+strval   = STR_CONFIG_SETTING_LAKE_SIZE_VALUE
 patxname = ""rivers.game_creation.lake_size""
 
 [SDT_BOOL]