Feature: option to auto remove signals when in the way during rail construction (#8274)

6 files changed, 38 insertions, 10 deletions

diff --git a/src/lang/english.txt b/src/lang/english.txt
index 8d8a12871..c92d03cb6 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -1451,6 +1451,8 @@ STR_CONFIG_SETTING_PERSISTENT_BUILDINGTOOLS                     :Keep building t
 STR_CONFIG_SETTING_PERSISTENT_BUILDINGTOOLS_HELPTEXT            :Keep the building tools for bridges, tunnels, etc. open after use
 STR_CONFIG_SETTING_EXPENSES_LAYOUT                              :Group expenses in company finance window: {STRING2}
 STR_CONFIG_SETTING_EXPENSES_LAYOUT_HELPTEXT                     :Define the layout for the company expenses window
+STR_CONFIG_SETTING_AUTO_REMOVE_SIGNALS                          :Automatically remove signals during rail construction: {STRING2}
+STR_CONFIG_SETTING_AUTO_REMOVE_SIGNALS_HELPTEXT                 :Automatically remove signals during rail construction if the signals are in the way. Note that this can potentially lead to train crashes.
 
 STR_CONFIG_SETTING_SOUND_TICKER                                 :News ticker: {STRING2}
 STR_CONFIG_SETTING_SOUND_TICKER_HELPTEXT                        :Play sound for summarised news messages
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index 34ad07d52..8af7871fc 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -262,10 +262,6 @@ static CommandCost CheckTrackCombination(TileIndex tile, TrackBits to_build, uin
 		return_cmd_error(STR_ERROR_ALREADY_BUILT);
 	}
 
-	/* Let's see if we may build this */
-	if (HasSignals(tile) && future != TRACK_BIT_HORZ && future != TRACK_BIT_VERT) {
-		return_cmd_error(STR_ERROR_MUST_REMOVE_SIGNALS_FIRST);
-	}
 	/* Normally, we may overlap and any combination is valid */
 	return CommandCost();
 }
@@ -432,7 +428,9 @@ static inline bool ValParamTrackOrientation(Track track)
  * @param tile tile  to build on
  * @param flags operation to perform
  * @param p1 railtype of being built piece (normal, mono, maglev)
- * @param p2 rail track to build
+ * @param p2 various bitstuffed elements
+ *           - (bit  0- 2) - track-orientation, valid values: 0-5 (@see Track)
+ *           - (bit  3)    - 0 = error on signal in the way, 1 = auto remove signals when in the way
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -440,6 +438,7 @@ CommandCost CmdBuildSingleRail(TileIndex tile, DoCommandFlag flags, uint32 p1, u
 {
 	RailType railtype = Extract<RailType, 0, 6>(p1);
 	Track track = Extract<Track, 0, 3>(p2);
+	bool auto_remove_signals = HasBit(p2, 3);
 	CommandCost cost(EXPENSES_CONSTRUCTION);
 
 	if (!ValParamRailtype(railtype) || !ValParamTrackOrientation(track)) return CMD_ERROR;
@@ -460,6 +459,19 @@ CommandCost CmdBuildSingleRail(TileIndex tile, DoCommandFlag flags, uint32 p1, u
 			if (ret.Succeeded()) ret = EnsureNoTrainOnTrack(tile, track);
 			if (ret.Failed()) return ret;
 
+			if (HasSignals(tile) && TracksOverlap(GetTrackBits(tile) | TrackToTrackBits(track))) {
+				/* If adding the new track causes any overlap, all signals must be removed first */
+				if (!auto_remove_signals) return_cmd_error(STR_ERROR_MUST_REMOVE_SIGNALS_FIRST);
+
+				for (Track track_it = TRACK_BEGIN; track_it < TRACK_END; track_it++) {
+					if (HasTrack(tile, track_it) && HasSignalOnTrack(tile, track_it)) {
+						CommandCost ret_remove_signals = DoCommand(tile, track_it, 0, flags, CMD_REMOVE_SIGNALS);
+						if (ret_remove_signals.Failed()) return ret_remove_signals;
+						cost.AddCost(ret_remove_signals);
+					}
+				}
+			}
+
 			ret = CheckRailSlope(tileh, trackbit, GetTrackBits(tile), tile);
 			if (ret.Failed()) return ret;
 			cost.AddCost(ret);
@@ -868,6 +880,7 @@ static CommandCost ValidateAutoDrag(Trackdir *trackdir, TileIndex start, TileInd
  * - p2 = (bit 6-8) - track-orientation, valid values: 0-5 (Track enum)
  * - p2 = (bit 9)   - 0 = build, 1 = remove tracks
  * - p2 = (bit 10)  - 0 = build up to an obstacle, 1 = fail if an obstacle is found (used for AIs).
+ * - p2 = (bit 11)  - 0 = error on signal in the way, 1 = auto remove signals when in the way
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -876,6 +889,7 @@ static CommandCost CmdRailTrackHelper(TileIndex tile, DoCommandFlag flags, uint3
 	CommandCost total_cost(EXPENSES_CONSTRUCTION);
 	Track track = Extract<Track, 6, 3>(p2);
 	bool remove = HasBit(p2, 9);
+	bool auto_remove_signals = HasBit(p2, 11);
 	RailType railtype = Extract<RailType, 0, 6>(p2);
 
 	if ((!remove && !ValParamRailtype(railtype)) || !ValParamTrackOrientation(track)) return CMD_ERROR;
@@ -889,7 +903,7 @@ static CommandCost CmdRailTrackHelper(TileIndex tile, DoCommandFlag flags, uint3
 	bool had_success = false;
 	CommandCost last_error = CMD_ERROR;
 	for (;;) {
-		CommandCost ret = DoCommand(tile, remove ? 0 : railtype, TrackdirToTrack(trackdir), flags, remove ? CMD_REMOVE_SINGLE_RAIL : CMD_BUILD_SINGLE_RAIL);
+		CommandCost ret = DoCommand(tile, remove ? 0 : railtype, TrackdirToTrack(trackdir) | (auto_remove_signals << 3), flags, remove ? CMD_REMOVE_SINGLE_RAIL : CMD_BUILD_SINGLE_RAIL);
 
 		if (ret.Failed()) {
 			last_error = ret;
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 788189dcc..7529efcec 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -91,7 +91,7 @@ void CcPlaySound_SPLAT_RAIL(const CommandCost &result, TileIndex tile, uint32 p1
 
 static void GenericPlaceRail(TileIndex tile, int cmd)
 {
-	DoCommandP(tile, _cur_railtype, cmd,
+	DoCommandP(tile, _cur_railtype, cmd | (_settings_client.gui.auto_remove_signals << 3),
 			_remove_button_clicked ?
 			CMD_REMOVE_SINGLE_RAIL | CMD_MSG(STR_ERROR_CAN_T_REMOVE_RAILROAD_TRACK) :
 			CMD_BUILD_SINGLE_RAIL | CMD_MSG(STR_ERROR_CAN_T_BUILD_RAILROAD_TRACK),
@@ -107,10 +107,11 @@ static void GenericPlaceRail(TileIndex tile, int cmd)
  */
 static void PlaceExtraDepotRail(TileIndex tile, DiagDirection dir, Track track)
 {
-	if (GetRailTileType(tile) != RAIL_TILE_NORMAL) return;
+	if (GetRailTileType(tile) == RAIL_TILE_DEPOT) return;
+	if (GetRailTileType(tile) == RAIL_TILE_SIGNALS && !_settings_client.gui.auto_remove_signals) return;
 	if ((GetTrackBits(tile) & DiagdirReachesTracks(dir)) == 0) return;
 
-	DoCommandP(tile, _cur_railtype, track, CMD_BUILD_SINGLE_RAIL);
+	DoCommandP(tile, _cur_railtype, track | (_settings_client.gui.auto_remove_signals << 3), CMD_BUILD_SINGLE_RAIL);
 }
 
 /** Additional pieces of track to add at the entrance of a depot. */
@@ -350,7 +351,8 @@ static void BuildRailClick_Remove(Window *w)
 
 static void DoRailroadTrack(int mode)
 {
-	DoCommandP(TileVirtXY(_thd.selstart.x, _thd.selstart.y), TileVirtXY(_thd.selend.x, _thd.selend.y), _cur_railtype | (mode << 6),
+	uint32 p2 = _cur_railtype | (mode << 6) | (_settings_client.gui.auto_remove_signals << 11);
+	DoCommandP(TileVirtXY(_thd.selstart.x, _thd.selstart.y), TileVirtXY(_thd.selend.x, _thd.selend.y), p2,
 			_remove_button_clicked ?
 			CMD_REMOVE_RAILROAD_TRACK | CMD_MSG(STR_ERROR_CAN_T_REMOVE_RAILROAD_TRACK) :
 			CMD_BUILD_RAILROAD_TRACK  | CMD_MSG(STR_ERROR_CAN_T_BUILD_RAILROAD_TRACK),
diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
index 77be428c9..751cf1a7d 100644
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -1599,6 +1599,7 @@ static SettingsContainer &GetSettingsTree()
 			company->Add(new SettingEntry("gui.default_signal_type"));
 			company->Add(new SettingEntry("gui.cycle_signal_types"));
 			company->Add(new SettingEntry("gui.drag_signals_fixed_distance"));
+			company->Add(new SettingEntry("gui.auto_remove_signals"));
 			company->Add(new SettingEntry("gui.new_nonstop"));
 			company->Add(new SettingEntry("gui.stop_location"));
 			company->Add(new SettingEntry("gui.starting_colour"));
diff --git a/src/settings_type.h b/src/settings_type.h
index 5729a50be..219888a73 100644
--- a/src/settings_type.h
+++ b/src/settings_type.h
@@ -147,6 +147,7 @@ struct GUISettings {
 	uint8  osk_activation;                   ///< Mouse gesture to trigger the OSK.
 	byte   starting_colour;                  ///< default color scheme for the company to start a new game with
 	bool   show_newgrf_name;                 ///< Show the name of the NewGRF in the build vehicle window
+	bool   auto_remove_signals;              ///< automatically remove signals when in the way during rail construction
 
 	uint16 console_backlog_timeout;          ///< the minimum amount of time items should be in the console backlog before they will be removed in ~3 seconds granularity.
 	uint16 console_backlog_length;           ///< the minimum amount of items in the console backlog before items will be removed.
diff --git a/src/table/settings.ini b/src/table/settings.ini
index 517f2fb44..97c892b0b 100644
--- a/src/table/settings.ini
+++ b/src/table/settings.ini
@@ -2859,6 +2859,14 @@ strhelp  = STR_CONFIG_SETTING_COMPANY_STARTING_COLOUR_HELPTEXT
 strval   = STR_COLOUR_DARK_BLUE
 
 [SDTC_BOOL]
+var      = gui.auto_remove_signals
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+def      = false
+str      = STR_CONFIG_SETTING_AUTO_REMOVE_SIGNALS
+strhelp  = STR_CONFIG_SETTING_AUTO_REMOVE_SIGNALS_HELPTEXT
+cat      = SC_ADVANCED
+
+[SDTC_BOOL]
 var      = gui.prefer_teamchat
 flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
 def      = false