(svn r15755) -Fix: Number of houses in house variables 0x44, 0x60 and 0x61 were incorrect after 0xFF had been reached and could desync clients joining afterwards.

src/newgrf_house.cpp

@@ -22,7 +22,7 @@
 #include "animated_tile_func.h"
 #include "company_base.h"
 
-static BuildingCounts    _building_counts;
+static BuildingCounts<uint32> _building_counts;
 static HouseClassMapping _class_mapping[HOUSE_CLASS_MAX];
 
 HouseOverrideManager _house_mngr(NEW_HOUSE_OFFSET, HOUSE_MAX, INVALID_HOUSE_ID);
@@ -61,20 +61,13 @@ void IncreaseBuildingCount(Town *t, HouseID house_id)
 
 	if (!_loaded_newgrf_features.has_newhouses) return;
 
-	/* If there are 255 buildings of this type in this town, there are also
-	 * at least that many houses of the same class in the town, and
-	 * therefore on the map as well. */
-	if (t->building_counts.id_count[house_id] == 255) return;
-
 	t->building_counts.id_count[house_id]++;
-	if (_building_counts.id_count[house_id] < 255) _building_counts.id_count[house_id]++;
+	_building_counts.id_count[house_id]++;
 
-	/* Similarly, if there are 255 houses of this class in this town, there
-	 * must be at least that number on the map too. */
-	if (class_id == HOUSE_NO_CLASS || t->building_counts.class_count[class_id] == 255) return;
+	if (class_id == HOUSE_NO_CLASS) return;
 
 	t->building_counts.class_count[class_id]++;
-	if (_building_counts.class_count[class_id] < 255) _building_counts.class_count[class_id]++;
+	_building_counts.class_count[class_id]++;
 }
 
 /**
@@ -121,10 +114,10 @@ static uint32 GetNumHouses(HouseID house_id, const Town *town)
 	uint8 map_id_count, town_id_count, map_class_count, town_class_count;
 	HouseClassID class_id = GetHouseSpecs(house_id)->class_id;
 
-	map_id_count     = _building_counts.id_count[house_id];
-	map_class_count  = _building_counts.class_count[class_id];
-	town_id_count    = town->building_counts.id_count[house_id];
-	town_class_count = town->building_counts.class_count[class_id];
+	map_id_count     = ClampU(_building_counts.id_count[house_id], 0, 255);
+	map_class_count  = ClampU(_building_counts.class_count[class_id], 0, 255);
+	town_id_count    = ClampU(town->building_counts.id_count[house_id], 0, 255);
+	town_class_count = ClampU(town->building_counts.class_count[class_id], 0, 255);
 
 	return map_class_count << 24 | town_class_count << 16 | map_id_count << 8 | town_id_count;
 }

src/town.h

@@ -90,9 +90,10 @@ enum HouseExtraFlags {
 
 DECLARE_ENUM_AS_BIT_SET(HouseExtraFlags)
 
+template <typename T>
 struct BuildingCounts {
-	uint8 id_count[HOUSE_MAX];
-	uint8 class_count[HOUSE_CLASS_MAX];
+	T id_count[HOUSE_MAX];
+	T class_count[HOUSE_CLASS_MAX];
 };
 
 static const uint CUSTOM_TOWN_NUMBER_DIFFICULTY  = 4; ///< value for custom town number in difficulty settings
@@ -176,7 +177,7 @@ struct Town : PoolItem<Town, TownID, &_Town_pool> {
 	uint32 squared_town_zone_radius[HZB_END];
 
 	/* NOSAVE: The number of each type of building in the town. */
-	BuildingCounts building_counts;
+	BuildingCounts<uint16> building_counts;
 
 	/**
 	 * Creates a new town