(svn r22702) [1.1] -Backport from trunk:

- Fix: Cost of adding an extra road type to a bridge or tunnel was undercalculated [FS#4680, FS#4681] (r22700, r22699)
- Fix: Only insert cleared object tiles into _cleared_object_areas if clearing actually succeeds, else subsequential tests of the same tile will be skipped and considered successful [FS#4694] (r22698)
- Fix: When building a house it could be built at the wrong place if multitile houses failed some tests (r22697)

src/bridge_gui.cpp

@@ -420,7 +420,11 @@ void ShowBuildBridgeWindow(TileIndex start, TileIndex end, TransportType transpo
 
 		Money infra_cost = 0;
 		switch (transport_type) {
-			case TRANSPORT_ROAD: infra_cost = (bridge_len + 2) * _price[PR_BUILD_ROAD] * 2; break;
+			case TRANSPORT_ROAD:
+				infra_cost = (bridge_len + 2) * _price[PR_BUILD_ROAD] * 2;
+				/* In case we add a new road type as well, we must be aware of those costs. */
+				if (IsBridgeTile(start)) infra_cost *= CountBits(GetRoadTypes(start) | (RoadTypes)road_rail_type);
+				break;
 			case TRANSPORT_RAIL: infra_cost = (bridge_len + 2) * RailBuildCost((RailType)road_rail_type); break;
 			default: break;
 		}

src/object_cmd.cpp

@@ -425,10 +425,6 @@ static CommandCost ClearTile_Object(TileIndex tile, DoCommandFlag flags)
 	Object *o = Object::GetByTile(tile);
 	TileArea ta = o->location;
 
-	ClearedObjectArea *cleared_area = _cleared_object_areas.Append();
-	cleared_area->first_tile = tile;
-	cleared_area->area = ta;
-
 	CommandCost cost(EXPENSES_CONSTRUCTION, spec->GetClearCost() * ta.w * ta.h / 5);
 	if (spec->flags & OBJECT_FLAG_CLEAR_INCOME) cost.MultiplyCost(-1); // They get an income!
 
@@ -486,6 +482,10 @@ static CommandCost ClearTile_Object(TileIndex tile, DoCommandFlag flags)
 			break;
 	}
 
+	ClearedObjectArea *cleared_area = _cleared_object_areas.Append();
+	cleared_area->first_tile = tile;
+	cleared_area->area = ta;
+
 	if (flags & DC_EXEC) ReallyClearObjectTile(o);
 
 	return cost;

src/road_cmd.cpp

@@ -662,12 +662,14 @@ do_clear:;
 		if (ret.Failed()) return ret;
 
 	}
-	cost.AddCost(CountBits(pieces) * _price[PR_BUILD_ROAD]);
 
-	if (!need_to_clear && IsTileType(tile, MP_TUNNELBRIDGE)) {
-		/* Pay for *every* tile of the bridge or tunnel */
-		cost.MultiplyCost(GetTunnelBridgeLength(GetOtherTunnelBridgeEnd(tile), tile) + 2);
-	}
+	uint num_pieces = (!need_to_clear && IsTileType(tile, MP_TUNNELBRIDGE)) ?
+			/* There are 2 pieces on *every* tile of the bridge or tunnel */
+			2 * (GetTunnelBridgeLength(GetOtherTunnelBridgeEnd(tile), tile) + 2) :
+			/* Count pieces */
+			CountBits(pieces);
+
+	cost.AddCost(num_pieces * _price[PR_BUILD_ROAD]);
 
 	if (flags & DC_EXEC) {
 		switch (GetTileType(tile)) {

src/town_cmd.cpp

@@ -2125,8 +2125,16 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
 	}
 
 	uint maxz = GetTileMaxZ(tile);
+	TileIndex baseTile = tile;
 
 	while (probability_max > 0) {
+		/* Building a multitile building can change the location of tile.
+		 * The building would still be built partially on that tile, but
+		 * its nothern tile would be elsewere. However, if the callback
+		 * fails we would be basing further work from the changed tile.
+		 * So a next 1x1 tile building could be built on the wrong tile. */
+		tile = baseTile;
+
 		uint r = RandomRange(probability_max);
 		uint i;
 		for (i = 0; i < num; i++) {

src/tunnelbridge_cmd.cpp

@@ -468,7 +468,7 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
 		bridge_len += 2; // begin and end tiles/ramps
 
 		switch (transport_type) {
-			case TRANSPORT_ROAD: cost.AddCost(bridge_len * _price[PR_BUILD_ROAD] * 2); break;
+			case TRANSPORT_ROAD: cost.AddCost(bridge_len * _price[PR_BUILD_ROAD] * 2 * CountBits(roadtypes)); break;
 			case TRANSPORT_RAIL: cost.AddCost(bridge_len * RailBuildCost(railtype)); break;
 			default: break;
 		}