(svn r5070) Merged the bridge branch

-Feature: Bridges can now be placed above:
	Any railway track combination (excluding depots and waypoints)
	Any road combination (excluding depots)
	Clear tiles (duh), including fields
	Tunnel entrances
	Bridge heads

Thanks to Tron for idea and implementation, KUDr for the yapf synchronization and many others for hours of testing

There are still a number of visual problems remaining, especially when electric railways are on or under the bridge.
DO NOT REPORT THOSE BUGS FOR THE TIME BEING please.

1 files changed, 45 insertions, 100 deletions

diff --git a/road_cmd.c b/road_cmd.c
index 832ca7a24..30f683b41 100644
--- a/road_cmd.c
+++ b/road_cmd.c
@@ -108,97 +108,70 @@ int32 CmdRemoveRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	if (p1 >> 4) return CMD_ERROR;
 	pieces = p1;
 
-	if (!IsTileType(tile, MP_STREET) && !IsTileType(tile, MP_TUNNELBRIDGE)) return CMD_ERROR;
+	if (!IsTileType(tile, MP_STREET)) return CMD_ERROR;
 
 	owner = IsLevelCrossingTile(tile) ? GetCrossingRoadOwner(tile) : GetTileOwner(tile);
 
 	if (owner == OWNER_TOWN && _game_mode != GM_EDITOR) {
-		if (IsTileType(tile, MP_TUNNELBRIDGE)) { // index of town is not saved for bridge (no space)
-			t = ClosestTownFromTile(tile, _patches.dist_local_authority);
-		} else {
-			t = GetTownByTile(tile);
-		}
+		t = GetTownByTile(tile);
 	} else {
 		t = NULL;
 	}
 
 	if (!CheckAllowRemoveRoad(tile, pieces, &edge_road)) return CMD_ERROR;
 
-	switch (GetTileType(tile)) {
-		case MP_TUNNELBRIDGE:
-			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
-
-			if (!IsBridge(tile) ||
-					!IsBridgeMiddle(tile) ||
-					!IsTransportUnderBridge(tile) ||
-					GetTransportTypeUnderBridge(tile) != TRANSPORT_ROAD ||
-					(pieces & ComplementRoadBits(GetRoadBitsUnderBridge(tile))) != 0) {
-				return CMD_ERROR;
-			}
-
-			if (flags & DC_EXEC) {
-				ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
-				SetClearUnderBridge(tile);
-				MarkTileDirtyByTile(tile);
-			}
-			return _price.remove_road * 2;
+	if (!EnsureNoVehicle(tile)) return CMD_ERROR;
 
-		case MP_STREET:
-			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+	// check if you're allowed to remove the street owned by a town
+	// removal allowance depends on difficulty setting
+	if (!CheckforTownRating(flags, t, ROAD_REMOVE)) return CMD_ERROR;
 
-			// check if you're allowed to remove the street owned by a town
-			// removal allowance depends on difficulty setting
-			if (!CheckforTownRating(flags, t, ROAD_REMOVE)) return CMD_ERROR;
+	switch (GetRoadTileType(tile)) {
+		case ROAD_TILE_NORMAL: {
+			RoadBits present = GetRoadBits(tile);
+			RoadBits c = pieces;
 
-			switch (GetRoadTileType(tile)) {
-				case ROAD_TILE_NORMAL: {
-					RoadBits present = GetRoadBits(tile);
-					RoadBits c = pieces;
-
-					if (GetTileSlope(tile, NULL) != SLOPE_FLAT &&
-							(present == ROAD_Y || present == ROAD_X)) {
-						c |= (c & 0xC) >> 2;
-						c |= (c & 0x3) << 2;
-					}
+			if (GetTileSlope(tile, NULL) != SLOPE_FLAT  &&
+					(present == ROAD_Y || present == ROAD_X)) {
+				c |= (c & 0xC) >> 2;
+				c |= (c & 0x3) << 2;
+			}
 
-					// limit the bits to delete to the existing bits.
-					c &= present;
-					if (c == 0) return CMD_ERROR;
+			// limit the bits to delete to the existing bits.
+			c &= present;
+			if (c == 0) return CMD_ERROR;
 
-					if (flags & DC_EXEC) {
-						ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
+			if (flags & DC_EXEC) {
+				ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
 
-						present ^= c;
-						if (present == 0) {
-							DoClearSquare(tile);
-						} else {
-							SetRoadBits(tile, present);
-							MarkTileDirtyByTile(tile);
-						}
-					}
-					return CountRoadBits(c) * _price.remove_road;
+				present ^= c;
+				if (present == 0) {
+					DoClearSquare(tile);
+				} else {
+					SetRoadBits(tile, present);
+					MarkTileDirtyByTile(tile);
 				}
+			}
+			return CountRoadBits(c) * _price.remove_road;
+		}
 
-				case ROAD_TILE_CROSSING: {
-					if (pieces & ComplementRoadBits(GetCrossingRoadBits(tile))) {
-						return CMD_ERROR;
-					}
-
-					if (flags & DC_EXEC) {
-						ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
+		case ROAD_TILE_CROSSING: {
+			if (pieces & ComplementRoadBits(GetCrossingRoadBits(tile))) {
+				return CMD_ERROR;
+			}
 
-						MakeRailNormal(tile, GetTileOwner(tile), GetCrossingRailBits(tile), GetRailTypeCrossing(tile));
-						MarkTileDirtyByTile(tile);
-					}
-					return _price.remove_road * 2;
-				}
+			if (flags & DC_EXEC) {
+				ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
 
-				default:
-				case ROAD_TILE_DEPOT:
-					return CMD_ERROR;
+				MakeRailNormal(tile, GetTileOwner(tile), GetCrossingRailBits(tile), GetRailTypeCrossing(tile));
+				MarkTileDirtyByTile(tile);
 			}
+			return _price.remove_road * 2;
+		}
 
-		default: return CMD_ERROR;
+		case ROAD_TILE_DEPOT:
+		default:
+			return CMD_ERROR;
 	}
 }
 
@@ -348,37 +321,6 @@ int32 CmdBuildRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 			return _price.build_road * 2;
 		}
 
-		case MP_TUNNELBRIDGE:
-			/* check for flat land */
-			if (IsSteepSlope(tileh)) {
-				return_cmd_error(STR_1000_LAND_SLOPED_IN_WRONG_DIRECTION);
-			}
-
-			if (!IsBridge(tile) || !IsBridgeMiddle(tile)) goto do_clear;
-
-			/* only allow roads pertendicular to bridge */
-			if ((pieces & (GetBridgeAxis(tile) == AXIS_X ? ROAD_X : ROAD_Y)) != 0) {
-				goto do_clear;
-			}
-
-			/* check if clear land under bridge */
-			if (IsTransportUnderBridge(tile)) {
-				switch (GetTransportTypeUnderBridge(tile)) {
-					case TRANSPORT_ROAD: return_cmd_error(STR_1007_ALREADY_BUILT);
-					default: return_cmd_error(STR_1008_MUST_REMOVE_RAILROAD_TRACK);
-				}
-			} else {
-				if (IsWaterUnderBridge(tile)) {
-					return_cmd_error(STR_3807_CAN_T_BUILD_ON_WATER);
-				}
-			}
-
-			if (flags & DC_EXEC) {
-				SetRoadUnderBridge(tile, _current_player);
-				MarkTileDirtyByTile(tile);
-			}
-			return _price.build_road * 2;
-
 		default:
 do_clear:;
 			ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
@@ -575,6 +517,8 @@ int32 CmdBuildRoadDepot(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	cost = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 	if (CmdFailed(cost)) return CMD_ERROR;
 
+	if (MayHaveBridgeAbove(tile) && IsBridgeAbove(tile)) return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
+
 	dep = AllocateDepot();
 	if (dep == NULL) return CMD_ERROR;
 
@@ -798,6 +742,7 @@ static void DrawTile_Road(TileInfo *ti)
 			break;
 		}
 	}
+	DrawBridgeMiddle(ti);
 }
 
 void DrawRoadDepotSprite(int x, int y, int image)