(svn r23106) -Codechange: pass int* to GetTileSlope and friends

26 files changed, 86 insertions, 86 deletions

diff --git a/src/ai/api/ai_tile.cpp b/src/ai/api/ai_tile.cpp
index 677c845a3..b07c7cbf5 100644
--- a/src/ai/api/ai_tile.cpp
+++ b/src/ai/api/ai_tile.cpp
@@ -170,7 +170,7 @@
 {
 	if (!::IsValidTile(tile) || !::IsValidCorner((::Corner)corner)) return -1;
 
-	uint z;
+	int z;
 	::Slope slope = ::GetTileSlope(tile, &z);
 	return (z + ::GetSlopeZInCorner(slope, (::Corner)corner));
 }
diff --git a/src/ai/api/ai_tunnel.cpp b/src/ai/api/ai_tunnel.cpp
index 99aec30c4..310a751af 100644
--- a/src/ai/api/ai_tunnel.cpp
+++ b/src/ai/api/ai_tunnel.cpp
@@ -29,13 +29,13 @@
 	/* If it's a tunnel already, take the easy way out! */
 	if (IsTunnelTile(tile)) return ::GetOtherTunnelEnd(tile);
 
-	uint start_z;
+	int start_z;
 	Slope start_tileh = ::GetTileSlope(tile, &start_z);
 	DiagDirection direction = ::GetInclinedSlopeDirection(start_tileh);
 	if (direction == INVALID_DIAGDIR) return INVALID_TILE;
 
 	TileIndexDiff delta = ::TileOffsByDiagDir(direction);
-	uint end_z;
+	int end_z;
 	do {
 		tile += delta;
 		if (!::IsValidTile(tile)) return INVALID_TILE;
diff --git a/src/autoslope.h b/src/autoslope.h
index e9bfa140f..4ff48e796 100644
--- a/src/autoslope.h
+++ b/src/autoslope.h
@@ -31,7 +31,7 @@
  * @param entrance Entrance edge.
  * @return true iff terraforming is allowed.
  */
-static inline bool AutoslopeCheckForEntranceEdge(TileIndex tile, uint z_new, Slope tileh_new, DiagDirection entrance)
+static inline bool AutoslopeCheckForEntranceEdge(TileIndex tile, int z_new, Slope tileh_new, DiagDirection entrance)
 {
 	if (GetTileMaxZ(tile) != z_new + GetSlopeMaxZ(tileh_new)) return false;
 	return ((tileh_new == SLOPE_FLAT) || CanBuildDepotByTileh(entrance, tileh_new));
diff --git a/src/bridge_map.cpp b/src/bridge_map.cpp
index 5bfd7e97f..6ebf80424 100644
--- a/src/bridge_map.cpp
+++ b/src/bridge_map.cpp
@@ -67,9 +67,9 @@ TileIndex GetOtherBridgeEnd(TileIndex tile)
  * @param tile the bridge ramp tile to get the bridge height from
  * @return the height of the bridge.
  */
-uint GetBridgeHeight(TileIndex t)
+int GetBridgeHeight(TileIndex t)
 {
-	uint h;
+	int h;
 	Slope tileh = GetTileSlope(t, &h);
 	Foundation f = GetBridgeFoundation(tileh, DiagDirToAxis(GetTunnelBridgeDirection(t)));
 
diff --git a/src/bridge_map.h b/src/bridge_map.h
index 8dd4bb634..8c6bf839a 100644
--- a/src/bridge_map.h
+++ b/src/bridge_map.h
@@ -89,13 +89,13 @@ TileIndex GetNorthernBridgeEnd(TileIndex t);
 TileIndex GetSouthernBridgeEnd(TileIndex t);
 TileIndex GetOtherBridgeEnd(TileIndex t);
 
-uint GetBridgeHeight(TileIndex tile);
+int GetBridgeHeight(TileIndex tile);
 /**
  * Get the height ('z') of a bridge in pixels.
  * @param tile the bridge ramp tile to get the bridge height from
  * @return the height of the bridge in pixels
  */
-static inline uint GetBridgePixelHeight(TileIndex tile)
+static inline int GetBridgePixelHeight(TileIndex tile)
 {
 	return GetBridgeHeight(tile) * TILE_HEIGHT;
 }
diff --git a/src/clear_cmd.cpp b/src/clear_cmd.cpp
index c173d196e..b5c110808 100644
--- a/src/clear_cmd.cpp
+++ b/src/clear_cmd.cpp
@@ -109,7 +109,7 @@ static void DrawTile_Clear(TileInfo *ti)
 
 static uint GetSlopePixelZ_Clear(TileIndex tile, uint x, uint y)
 {
-	uint z;
+	int z;
 	Slope tileh = GetTilePixelSlope(tile, &z);
 
 	return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
@@ -230,7 +230,7 @@ static void TileLoop_Clear(TileIndex tile)
 {
 	/* If the tile is at any edge flood it to prevent maps without water. */
 	if (_settings_game.construction.freeform_edges && DistanceFromEdge(tile) == 1) {
-		uint z;
+		int z;
 		Slope slope = GetTileSlope(tile, &z);
 		if (z == 0 && slope == SLOPE_FLAT) {
 			DoFloodTile(tile);
diff --git a/src/dock_gui.cpp b/src/dock_gui.cpp
index d1a76ed12..96c840561 100644
--- a/src/dock_gui.cpp
+++ b/src/dock_gui.cpp
@@ -59,7 +59,7 @@ void CcBuildCanal(const CommandCost &result, TileIndex tile, uint32 p1, uint32 p
  */
 static TileIndex GetOtherAqueductEnd(TileIndex tile_from, TileIndex *tile_to = NULL)
 {
-	uint z;
+	int z;
 	DiagDirection dir = GetInclinedSlopeDirection(GetTileSlope(tile_from, &z));
 
 	/* If the direction isn't right, just return the next tile so the command
diff --git a/src/elrail.cpp b/src/elrail.cpp
index 86170149f..4232b190a 100644
--- a/src/elrail.cpp
+++ b/src/elrail.cpp
@@ -401,7 +401,7 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 
 		if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile)) {
 			Track bridgetrack = GetBridgeAxis(ti->tile) == AXIS_X ? TRACK_X : TRACK_Y;
-			uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
+			int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
 
 			if ((height <= GetTileMaxZ(ti->tile) + 1) &&
 					(i == PCPpositions[bridgetrack][0] || i == PCPpositions[bridgetrack][1])) {
@@ -438,7 +438,7 @@ static void DrawCatenaryRailway(const TileInfo *ti)
 
 	/* Don't draw a wire under a low bridge */
 	if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile) && !IsTransparencySet(TO_CATENARY)) {
-		uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
+		int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
 
 		if (height <= GetTileMaxZ(ti->tile) + 1) return;
 	}
diff --git a/src/industry_cmd.cpp b/src/industry_cmd.cpp
index 3f1aa0613..e42e87e51 100644
--- a/src/industry_cmd.cpp
+++ b/src/industry_cmd.cpp
@@ -1165,7 +1165,7 @@ static CommandCost CheckNewIndustry_NULL(TileIndex tile)
 static CommandCost CheckNewIndustry_Forest(TileIndex tile)
 {
 	if (_settings_game.game_creation.landscape == LT_ARCTIC) {
-		if (GetTileZ(tile) < HighestSnowLine() + 2U) {
+		if (GetTileZ(tile) < HighestSnowLine() + 2) {
 			return_cmd_error(STR_ERROR_FOREST_CAN_ONLY_BE_PLANTED);
 		}
 	}
diff --git a/src/landscape.cpp b/src/landscape.cpp
index 1c06bb7c7..deff47ba0 100644
--- a/src/landscape.cpp
+++ b/src/landscape.cpp
@@ -337,7 +337,7 @@ void GetSlopePixelZOnEdge(Slope tileh, DiagDirection edge, int *z1, int *z2)
  * @param z returns the z of the foundation slope. (Can be NULL, if not needed)
  * @return The slope on top of the foundation.
  */
-Slope GetFoundationSlope(TileIndex tile, uint *z)
+Slope GetFoundationSlope(TileIndex tile, int *z)
 {
 	Slope tileh = GetTileSlope(tile, z);
 	Foundation f = _tile_type_procs[GetTileType(tile)]->get_foundation_proc(tile, tileh);
@@ -349,7 +349,7 @@ Slope GetFoundationSlope(TileIndex tile, uint *z)
 
 bool HasFoundationNW(TileIndex tile, Slope slope_here, uint z_here)
 {
-	uint z;
+	int z;
 
 	int z_W_here = z_here;
 	int z_N_here = z_here;
@@ -366,7 +366,7 @@ bool HasFoundationNW(TileIndex tile, Slope slope_here, uint z_here)
 
 bool HasFoundationNE(TileIndex tile, Slope slope_here, uint z_here)
 {
-	uint z;
+	int z;
 
 	int z_E_here = z_here;
 	int z_N_here = z_here;
@@ -393,7 +393,7 @@ void DrawFoundation(TileInfo *ti, Foundation f)
 	assert(f != FOUNDATION_STEEP_BOTH);
 
 	uint sprite_block = 0;
-	uint z;
+	int z;
 	Slope slope = GetFoundationPixelSlope(ti->tile, &z);
 
 	/* Select the needed block of foundations sprites
@@ -926,7 +926,7 @@ static void CreateDesertOrRainForest()
  */
 static bool FindSpring(TileIndex tile, void *user_data)
 {
-	uint referenceHeight;
+	int referenceHeight;
 	Slope s = GetTileSlope(tile, &referenceHeight);
 	if (s != SLOPE_FLAT || IsWaterTile(tile)) return false;
 
@@ -988,8 +988,8 @@ static bool FlowsDown(TileIndex begin, TileIndex end)
 {
 	assert(DistanceManhattan(begin, end) == 1);
 
-	uint heightBegin;
-	uint heightEnd;
+	int heightBegin;
+	int heightEnd;
 	Slope slopeBegin = GetTileSlope(begin, &heightBegin);
 	Slope slopeEnd   = GetTileSlope(end, &heightEnd);
 
diff --git a/src/landscape.h b/src/landscape.h
index fc0979b82..c1680d1be 100644
--- a/src/landscape.h
+++ b/src/landscape.h
@@ -36,7 +36,7 @@ byte LowestSnowLine();
 void ClearSnowLine();
 
 int GetSlopeZInCorner(Slope tileh, Corner corner);
-Slope GetFoundationSlope(TileIndex tile, uint *z = NULL);
+Slope GetFoundationSlope(TileIndex tile, int *z = NULL);
 
 uint GetPartialPixelZ(int x, int y, Slope corners);
 int GetSlopePixelZ(int x, int y);
@@ -64,7 +64,7 @@ static inline int GetSlopePixelZInCorner(Slope tileh, Corner corner)
  * @param z returns the z of the foundation slope. (Can be NULL, if not needed)
  * @return The slope on top of the foundation.
  */
-static inline Slope GetFoundationPixelSlope(TileIndex tile, uint *z)
+static inline Slope GetFoundationPixelSlope(TileIndex tile, int *z)
 {
 	assert(z != NULL);
 	Slope s = GetFoundationSlope(tile, z);
diff --git a/src/newgrf_commons.cpp b/src/newgrf_commons.cpp
index e7ef0a01a..443a61e47 100644
--- a/src/newgrf_commons.cpp
+++ b/src/newgrf_commons.cpp
@@ -447,7 +447,7 @@ uint32 GetNearbyTileInformation(TileIndex tile)
 	/* Fake tile type for trees on shore */
 	if (IsTileType(tile, MP_TREES) && GetTreeGround(tile) == TREE_GROUND_SHORE) tile_type = MP_WATER;
 
-	uint z;
+	int z;
 	Slope tileh = GetTilePixelSlope(tile, &z);
 	/* Return 0 if the tile is a land tile */
 	byte terrain_type = (HasTileWaterClass(tile) ? (GetWaterClass(tile) + 1) & 3 : 0) << 5 | GetTerrainType(tile) << 2 | (tile_type == MP_WATER ? 1 : 0) << 1;
diff --git a/src/object_cmd.cpp b/src/object_cmd.cpp
index a023162d6..722cb6893 100644
--- a/src/object_cmd.cpp
+++ b/src/object_cmd.cpp
@@ -230,7 +230,7 @@ CommandCost CmdBuildObject(TileIndex tile, DoCommandFlag flags, uint32 p1, uint3
 
 		/* So, now the surface is checked... check the slope of said surface. */
 		int allowed_z;
-		if (GetTileSlope(tile, (uint*)&allowed_z) != SLOPE_FLAT) allowed_z++;
+		if (GetTileSlope(tile, &allowed_z) != SLOPE_FLAT) allowed_z++;
 
 		TILE_AREA_LOOP(t, ta) {
 			uint16 callback = CALLBACK_FAILED;
@@ -384,7 +384,7 @@ static void DrawTile_Object(TileInfo *ti)
 static uint GetSlopePixelZ_Object(TileIndex tile, uint x, uint y)
 {
 	if (IsOwnedLand(tile)) {
-		uint z;
+		int z;
 		Slope tileh = GetTilePixelSlope(tile, &z);
 
 		return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
@@ -642,7 +642,7 @@ void GenerateObjects()
 	for (uint i = ScaleByMapSize(1000); i != 0 && Object::CanAllocateItem(); i--) {
 		TileIndex tile = RandomTile();
 
-		uint h;
+		int h;
 		if (IsTileType(tile, MP_CLEAR) && GetTileSlope(tile, &h) == SLOPE_FLAT && h >= 4 && !IsBridgeAbove(tile)) {
 			TileIndex t = tile;
 			if (CircularTileSearch(&t, 9, HasTransmitter, NULL)) continue;
@@ -679,7 +679,7 @@ void GenerateObjects()
 		if (!IsTileType(tile, MP_WATER)) continue;
 
 		for (int j = 0; j < 19; j++) {
-			uint h;
+			int h;
 			if (IsTileType(tile, MP_CLEAR) && GetTileSlope(tile, &h) == SLOPE_FLAT && h <= 2 && !IsBridgeAbove(tile)) {
 				BuildObject(OBJECT_LIGHTHOUSE, tile);
 				IncreaseGeneratingWorldProgress(GWP_OBJECT);
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index e799b95c9..b323ad02a 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -2338,7 +2338,7 @@ void DrawTrainDepotSprite(int x, int y, int dir, RailType railtype)
 static uint GetSlopePixelZ_Track(TileIndex tile, uint x, uint y)
 {
 	if (IsPlainRail(tile)) {
-		uint z;
+		int z;
 		Slope tileh = GetTilePixelSlope(tile, &z);
 		if (tileh == SLOPE_FLAT) return z;
 
@@ -2366,7 +2366,7 @@ static void TileLoop_Track(TileIndex tile)
 
 	switch (_settings_game.game_creation.landscape) {
 		case LT_ARCTIC: {
-			uint z;
+			int z;
 			Slope slope = GetTileSlope(tile, &z);
 			bool half = false;
 
@@ -2828,7 +2828,7 @@ static CommandCost TestAutoslopeOnRailTile(TileIndex tile, uint flags, uint z_ol
 
 static CommandCost TerraformTile_Track(TileIndex tile, DoCommandFlag flags, uint z_new, Slope tileh_new)
 {
-	uint z_old;
+	int z_old;
 	Slope tileh_old = GetTileSlope(tile, &z_old);
 	if (IsPlainRail(tile)) {
 		TrackBits rail_bits = GetTrackBits(tile);
diff --git a/src/road_cmd.cpp b/src/road_cmd.cpp
index c45ff7b28..8d0878c04 100644
--- a/src/road_cmd.cpp
+++ b/src/road_cmd.cpp
@@ -1080,7 +1080,7 @@ void DrawTramCatenary(const TileInfo *ti, RoadBits tram)
 
 	/* Don't draw the catenary under a low bridge */
 	if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile) && !IsTransparencySet(TO_CATENARY)) {
-		uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
+		int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
 
 		if (height <= GetTileMaxZ(ti->tile) + 1) return;
 	}
@@ -1187,8 +1187,8 @@ static void DrawRoadBits(TileInfo *ti)
 
 	/* Do not draw details (street lights, trees) under low bridge */
 	if (MayHaveBridgeAbove(ti->tile) && IsBridgeAbove(ti->tile) && (roadside == ROADSIDE_TREES || roadside == ROADSIDE_STREET_LIGHTS)) {
-		uint height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
-		uint minz = GetTileMaxZ(ti->tile) + 2;
+		int height = GetBridgeHeight(GetNorthernBridgeEnd(ti->tile));
+		int minz = GetTileMaxZ(ti->tile) + 2;
 
 		if (roadside == ROADSIDE_TREES) minz++;
 
@@ -1341,7 +1341,7 @@ static uint GetSlopePixelZ_Road(TileIndex tile, uint x, uint y)
 {
 
 	if (IsNormalRoad(tile)) {
-		uint z;
+		int z;
 		Slope tileh = GetTilePixelSlope(tile, &z);
 		if (tileh == SLOPE_FLAT) return z;
 
@@ -1696,7 +1696,7 @@ static CommandCost TerraformTile_Road(TileIndex tile, DoCommandFlag flags, uint
 				if (CheckRoadSlope(tileh_new, &bits_copy, ROAD_NONE, ROAD_NONE).Succeeded()) {
 					/* CheckRoadSlope() sometimes changes the road_bits, if it does not agree with them. */
 					if (bits == bits_copy) {
-						uint z_old;
+						int z_old;
 						Slope tileh_old = GetTileSlope(tile, &z_old);
 
 						/* Get the slope on top of the foundation */
diff --git a/src/slope_func.h b/src/slope_func.h
index d231a4d08..4aff6b9d3 100644
--- a/src/slope_func.h
+++ b/src/slope_func.h
@@ -159,7 +159,7 @@ static inline Corner GetHalftileSlopeCorner(Slope s)
  * @param s The #Slope.
  * @return Relative height of highest corner.
  */
-static inline uint GetSlopeMaxZ(Slope s)
+static inline int GetSlopeMaxZ(Slope s)
 {
 	if (s == SLOPE_FLAT) return 0;
 	if (IsSteepSlope(s)) return 2;
@@ -172,7 +172,7 @@ static inline uint GetSlopeMaxZ(Slope s)
  * @param s The #Slope.
  * @return Relative height of highest corner.
  */
-static inline uint GetSlopeMaxPixelZ(Slope s)
+static inline int GetSlopeMaxPixelZ(Slope s)
 {
 	return GetSlopeMaxZ(s) * TILE_HEIGHT;
 }
diff --git a/src/station_cmd.cpp b/src/station_cmd.cpp
index 8e9beead6..9a930d87c 100644
--- a/src/station_cmd.cpp
+++ b/src/station_cmd.cpp
@@ -664,7 +664,7 @@ CommandCost CheckBuildableTile(TileIndex tile, uint invalid_dirs, int &allowed_z
 	CommandCost ret = EnsureNoVehicleOnGround(tile);
 	if (ret.Failed()) return ret;
 
-	uint z;
+	int z;
 	Slope tileh = GetTileSlope(tile, &z);
 
 	/* Prohibit building if
@@ -2584,7 +2584,7 @@ static void DrawTile_Station(TileInfo *ti)
 			/* Station has custom foundations.
 			 * Check whether the foundation continues beyond the tile's upper sides. */
 			uint edge_info = 0;
-			uint z;
+			int z;
 			Slope slope = GetFoundationPixelSlope(ti->tile, &z);
 			if (!HasFoundationNW(ti->tile, slope, z)) SetBit(edge_info, 0);
 			if (!HasFoundationNE(ti->tile, slope, z)) SetBit(edge_info, 1);
diff --git a/src/terraform_cmd.cpp b/src/terraform_cmd.cpp
index ccdd1505e..adc4108c5 100644
--- a/src/terraform_cmd.cpp
+++ b/src/terraform_cmd.cpp
@@ -292,14 +292,14 @@ CommandCost CmdTerraformLand(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 			if (IsTileType(tile, MP_VOID)) continue;
 
 			/* Find new heights of tile corners */
-			uint z_N = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 0));
-			uint z_W = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 0));
-			uint z_S = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 1));
-			uint z_E = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 1));
+			int z_N = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 0));
+			int z_W = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 0));
+			int z_S = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(1, 1));
+			int z_E = TerraformGetHeightOfTile(&ts, tile + TileDiffXY(0, 1));
 
 			/* Find min and max height of tile */
-			uint z_min = min(min(z_N, z_W), min(z_S, z_E));
-			uint z_max = max(max(z_N, z_W), max(z_S, z_E));
+			int z_min = min(min(z_N, z_W), min(z_S, z_E));
+			int z_max = max(max(z_N, z_W), max(z_S, z_E));
 
 			/* Compute tile slope */
 			Slope tileh = (z_max > z_min + 1 ? SLOPE_STEEP : SLOPE_FLAT);
diff --git a/src/tile_cmd.h b/src/tile_cmd.h
index ab4a8bc35..bdab10621 100644
--- a/src/tile_cmd.h
+++ b/src/tile_cmd.h
@@ -46,7 +46,7 @@ struct TileInfo {
 	uint y;         ///< Y position of the tile in unit coordinates
 	Slope tileh;    ///< Slope of the tile
 	TileIndex tile; ///< Tile index
-	uint z;         ///< Height
+	int z;          ///< Height
 };
 
 /** Tile description for the 'land area information' tool */
diff --git a/src/tile_map.cpp b/src/tile_map.cpp
index 6ac2db3dc..a936b78e7 100644
--- a/src/tile_map.cpp
+++ b/src/tile_map.cpp
@@ -18,7 +18,7 @@
  * @param h    If not \c NULL, pointer to storage of z height
  * @return Slope of the tile, except for the HALFTILE part
  */
-Slope GetTileSlope(TileIndex tile, uint *h)
+Slope GetTileSlope(TileIndex tile, int *h)
 {
 	assert(tile < MapSize());
 
@@ -28,13 +28,13 @@ Slope GetTileSlope(TileIndex tile, uint *h)
 		return SLOPE_FLAT;
 	}
 
-	uint a = TileHeight(tile); // Height of the N corner
-	uint min = a; // Minimal height of all corners examined so far
-	uint b = TileHeight(tile + TileDiffXY(1, 0)); // Height of the W corner
+	int a = TileHeight(tile); // Height of the N corner
+	int min = a; // Minimal height of all corners examined so far
+	int b = TileHeight(tile + TileDiffXY(1, 0)); // Height of the W corner
 	if (min > b) min = b;
-	uint c = TileHeight(tile + TileDiffXY(0, 1)); // Height of the E corner
+	int c = TileHeight(tile + TileDiffXY(0, 1)); // Height of the E corner
 	if (min > c) min = c;
-	uint d = TileHeight(tile + TileDiffXY(1, 1)); // Height of the S corner
+	int d = TileHeight(tile + TileDiffXY(1, 1)); // Height of the S corner
 	if (min > d) min = d;
 
 	/* Due to the fact that tiles must connect with each other without leaving gaps, the
@@ -64,11 +64,11 @@ Slope GetTileSlope(TileIndex tile, uint *h)
  * @param tile Tile to compute height of
  * @return Minimum height of the tile
  */
-uint GetTileZ(TileIndex tile)
+int GetTileZ(TileIndex tile)
 {
 	if (TileX(tile) == MapMaxX() || TileY(tile) == MapMaxY()) return 0;
 
-	uint h = TileHeight(tile); // N corner
+	int h = TileHeight(tile); // N corner
 	h = min(h, TileHeight(tile + TileDiffXY(1, 0))); // W corner
 	h = min(h, TileHeight(tile + TileDiffXY(0, 1))); // E corner
 	h = min(h, TileHeight(tile + TileDiffXY(1, 1))); // S corner
@@ -81,14 +81,14 @@ uint GetTileZ(TileIndex tile)
  * @param t Tile to compute height of
  * @return Maximum height of the tile
  */
-uint GetTileMaxZ(TileIndex t)
+int GetTileMaxZ(TileIndex t)
 {
 	if (TileX(t) == MapMaxX() || TileY(t) == MapMaxY()) return 0;
 
-	uint h = TileHeight(t); // N corner
-	h = max(h, TileHeight(t + TileDiffXY(1, 0))); // W corner
-	h = max(h, TileHeight(t + TileDiffXY(0, 1))); // E corner
-	h = max(h, TileHeight(t + TileDiffXY(1, 1))); // S corner
+	int h = TileHeight(t); // N corner
+	h = max<int>(h, TileHeight(t + TileDiffXY(1, 0))); // W corner
+	h = max<int>(h, TileHeight(t + TileDiffXY(0, 1))); // E corner
+	h = max<int>(h, TileHeight(t + TileDiffXY(1, 1))); // S corner
 
 	return h;
 }
diff --git a/src/tile_map.h b/src/tile_map.h
index 76a3fd75c..8dc4757ba 100644
--- a/src/tile_map.h
+++ b/src/tile_map.h
@@ -226,9 +226,9 @@ static inline void SetAnimationFrame(TileIndex t, byte frame)
 	_me[t].m7 = frame;
 }
 
-Slope GetTileSlope(TileIndex tile, uint *h = NULL);
-uint GetTileZ(TileIndex tile);
-uint GetTileMaxZ(TileIndex tile);
+Slope GetTileSlope(TileIndex tile, int *h = NULL);
+int GetTileZ(TileIndex tile);
+int GetTileMaxZ(TileIndex tile);
 
 /**
  * Return the slope of a given tile
@@ -236,7 +236,7 @@ uint GetTileMaxZ(TileIndex tile);
  * @param h    If not \c NULL, pointer to storage of z height
  * @return Slope of the tile, except for the HALFTILE part
  */
-static inline Slope GetTilePixelSlope(TileIndex tile, uint *h)
+static inline Slope GetTilePixelSlope(TileIndex tile, int *h)
 {
 	Slope s = GetTileSlope(tile, h);
 	if (h != NULL) *h *= TILE_HEIGHT;
@@ -248,7 +248,7 @@ static inline Slope GetTilePixelSlope(TileIndex tile, uint *h)
  * @param tile Tile to compute height of
  * @return Minimum height of the tile
  */
-static inline uint GetTilePixelZ(TileIndex tile)
+static inline int GetTilePixelZ(TileIndex tile)
 {
 	return GetTileZ(tile) * TILE_HEIGHT;
 }
@@ -258,7 +258,7 @@ static inline uint GetTilePixelZ(TileIndex tile)
  * @param t Tile to compute height of
  * @return Maximum height of the tile
  */
-static inline uint GetTileMaxPixelZ(TileIndex tile)
+static inline int GetTileMaxPixelZ(TileIndex tile)
 {
 	return GetTileMaxZ(tile) * TILE_HEIGHT;
 }
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index fcf9852dc..6ea51fcc4 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -2095,7 +2095,7 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
 	/* no house allowed at all, bail out */
 	if (!CanBuildHouseHere(tile, t->index, false)) return false;
 
-	uint z;
+	int z;
 	Slope slope = GetTileSlope(tile, &z);
 
 	/* Get the town zone type of the current tile, as well as the climate.
diff --git a/src/tree_cmd.cpp b/src/tree_cmd.cpp
index e66649dde..61d3bf912 100644
--- a/src/tree_cmd.cpp
+++ b/src/tree_cmd.cpp
@@ -216,7 +216,7 @@ static void PlaceTreeGroups(uint num_groups)
  * @param tile The base tile to add a new tree somewhere around
  * @param height The height (like the one from the tile)
  */
-static void PlaceTreeAtSameHeight(TileIndex tile, uint height)
+static void PlaceTreeAtSameHeight(TileIndex tile, int height)
 {
 	for (uint i = 0; i < DEFAULT_TREE_STEPS; i++) {
 		uint32 r = Random();
@@ -247,7 +247,7 @@ static void PlaceTreeAtSameHeight(TileIndex tile, uint height)
  */
 void PlaceTreesRandomly()
 {
-	uint i, j, ht;
+	int i, j, ht;
 
 	i = ScaleByMapSize(DEFAULT_TREE_STEPS);
 	if (_game_mode == GM_EDITOR) i /= EDITOR_TREE_DIV;
@@ -518,7 +518,7 @@ static void DrawTile_Trees(TileInfo *ti)
 
 static uint GetSlopePixelZ_Trees(TileIndex tile, uint x, uint y)
 {
-	uint z;
+	int z;
 	Slope tileh = GetTilePixelSlope(tile, &z);
 
 	return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
diff --git a/src/tunnel_map.cpp b/src/tunnel_map.cpp
index 799b39000..405e6fb38 100644
--- a/src/tunnel_map.cpp
+++ b/src/tunnel_map.cpp
@@ -23,7 +23,7 @@ TileIndex GetOtherTunnelEnd(TileIndex tile)
 {
 	DiagDirection dir = GetTunnelBridgeDirection(tile);
 	TileIndexDiff delta = TileOffsByDiagDir(dir);
-	uint z = GetTileZ(tile);
+	int z = GetTileZ(tile);
 
 	dir = ReverseDiagDir(dir);
 	do {
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index d07603f16..fd6b5f9c6 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -138,7 +138,7 @@ static inline const PalSpriteID *GetBridgeSpriteTable(int index, BridgePieces ta
  * @param z TileZ corresponding to tileh, gets modified as well
  * @return Error or cost for bridge foundation
  */
-static CommandCost CheckBridgeSlopeNorth(Axis axis, Slope *tileh, uint *z)
+static CommandCost CheckBridgeSlopeNorth(Axis axis, Slope *tileh, int *z)
 {
 	Foundation f = GetBridgeFoundation(*tileh, axis);
 	*z += ApplyFoundationToSlope(f, tileh);
@@ -159,7 +159,7 @@ static CommandCost CheckBridgeSlopeNorth(Axis axis, Slope *tileh, uint *z)
  * @param z TileZ corresponding to tileh, gets modified as well
  * @return Error or cost for bridge foundation
  */
-static CommandCost CheckBridgeSlopeSouth(Axis axis, Slope *tileh, uint *z)
+static CommandCost CheckBridgeSlopeSouth(Axis axis, Slope *tileh, int *z)
 {
 	Foundation f = GetBridgeFoundation(*tileh, axis);
 	*z += ApplyFoundationToSlope(f, tileh);
@@ -267,8 +267,8 @@ CommandCost CmdBuildBridge(TileIndex end_tile, DoCommandFlag flags, uint32 p1, u
 		if (bridge_len > _settings_game.construction.max_bridge_length) return_cmd_error(STR_ERROR_BRIDGE_TOO_LONG);
 	}
 
-	uint z_start;
-	uint z_end;
+	int z_start;
+	int z_end;
 	Slope tileh_start = GetTileSlope(tile_start, &z_start);
 	Slope tileh_end = GetTileSlope(tile_end, &z_end);
 	bool pbs_reservation = false;
@@ -525,8 +525,8 @@ CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1,
 		default: return CMD_ERROR;
 	}
 
-	uint start_z;
-	uint end_z;
+	int start_z;
+	int end_z;
 	Slope start_tileh = GetTileSlope(start_tile, &start_z);
 	DiagDirection direction = GetInclinedSlopeDirection(start_tileh);
 	if (direction == INVALID_DIAGDIR) return_cmd_error(STR_ERROR_SITE_UNSUITABLE_FOR_TUNNEL);
@@ -1361,7 +1361,7 @@ void DrawBridgeMiddle(const TileInfo *ti)
 
 static uint GetSlopePixelZ_TunnelBridge(TileIndex tile, uint x, uint y)
 {
-	uint z;
+	int z;
 	Slope tileh = GetTilePixelSlope(tile, &z);
 
 	x &= 0xF;
@@ -1380,7 +1380,7 @@ static uint GetSlopePixelZ_TunnelBridge(TileIndex tile, uint x, uint y)
 
 		/* On the bridge ramp? */
 		if (5 <= pos && pos <= 10) {
-			uint delta;
+			int delta;
 
 			if (tileh != SLOPE_FLAT) return z + TILE_HEIGHT;
 
@@ -1679,16 +1679,16 @@ static CommandCost TerraformTile_TunnelBridge(TileIndex tile, DoCommandFlag flag
 		DiagDirection direction = GetTunnelBridgeDirection(tile);
 		Axis axis = DiagDirToAxis(direction);
 		CommandCost res;
-		uint z_old;
+		int z_old;
 		Slope tileh_old = GetTileSlope(tile, &z_old);
 
 		/* Check if new slope is valid for bridges in general (so we can safely call GetBridgeFoundation()) */
 		if ((direction == DIAGDIR_NW) || (direction == DIAGDIR_NE)) {
 			CheckBridgeSlopeSouth(axis, &tileh_old, &z_old);
-			res = CheckBridgeSlopeSouth(axis, &tileh_new, &z_new);
+			res = CheckBridgeSlopeSouth(axis, &tileh_new, (int*)&z_new);
 		} else {
 			CheckBridgeSlopeNorth(axis, &tileh_old, &z_old);
-			res = CheckBridgeSlopeNorth(axis, &tileh_new, &z_new);
+			res = CheckBridgeSlopeNorth(axis, &tileh_new, (int*)&z_new);
 		}
 
 		/* Surface slope is valid and remains unchanged? */
diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index 2a91a0a62..b06d5c590 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -149,7 +149,7 @@ void MakeWaterKeepingClass(TileIndex tile, Owner o)
 	WaterClass wc = GetWaterClass(tile);
 
 	/* Autoslope might turn an originally canal or river tile into land */
-	uint z;
+	int z;
 	if (GetTileSlope(tile, &z) != SLOPE_FLAT) wc = WATER_CLASS_INVALID;
 
 	if (wc == WATER_CLASS_SEA && z > 0) wc = WATER_CLASS_CANAL;
@@ -796,7 +796,7 @@ void DrawShipDepotSprite(int x, int y, Axis axis, DepotPart part)
 
 static uint GetSlopePixelZ_Water(TileIndex tile, uint x, uint y)
 {
-	uint z;
+	int z;
 	Slope tileh = GetTilePixelSlope(tile, &z);
 
 	return z + GetPartialPixelZ(x & 0xF, y & 0xF, tileh);
@@ -1079,7 +1079,7 @@ void TileLoop_Water(TileIndex tile)
 				/* do not try to flood water tiles - increases performance a lot */
 				if (IsTileType(dest, MP_WATER)) continue;
 
-				uint z_dest;
+				int z_dest;
 				Slope slope_dest = GetFoundationSlope(dest, &z_dest) & ~SLOPE_HALFTILE_MASK & ~SLOPE_STEEP;
 				if (z_dest > 0) continue;
 
@@ -1109,7 +1109,7 @@ void TileLoop_Water(TileIndex tile)
 
 void ConvertGroundTilesIntoWaterTiles()
 {
-	uint z;
+	int z;
 
 	for (TileIndex tile = 0; tile < MapSize(); ++tile) {
 		Slope slope = GetTileSlope(tile, &z);