(svn r24129) -Feature [FS#3660]: Option to minimise signal distance when dragging over obstacles. (adf88)

6 files changed, 56 insertions, 10 deletions

diff --git a/src/lang/english.txt b/src/lang/english.txt
index 8c341302a..fba9c9790 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -1295,6 +1295,7 @@ STR_CONFIG_SETTING_SMOOTH_ECONOMY                               :{LTBLUE}Enable
 STR_CONFIG_SETTING_ALLOW_SHARES                                 :{LTBLUE}Allow buying shares from other companies: {ORANGE}{STRING1}
 STR_CONFIG_SETTING_FEEDER_PAYMENT_SHARE                         :{LTBLUE}Percentage of leg profit to pay in feeder systems: {ORANGE}{STRING1}%
 STR_CONFIG_SETTING_DRAG_SIGNALS_DENSITY                         :{LTBLUE}When dragging, place signals every: {ORANGE}{STRING1} tile{P 0:1 "" s}
+STR_CONFIG_SETTING_DRAG_SIGNALS_FIXED_DISTANCE                  :{LTBLUE}When dragging, keep fixed distance between signals: {ORANGE}{STRING1}
 STR_CONFIG_SETTING_SEMAPHORE_BUILD_BEFORE_DATE                  :{LTBLUE}Automatically build semaphores before: {ORANGE}{STRING1}
 STR_CONFIG_SETTING_ENABLE_SIGNAL_GUI                            :{LTBLUE}Enable the signal GUI: {ORANGE}{STRING1}
 STR_CONFIG_SETTING_DEFAULT_SIGNAL_TYPE                          :{LTBLUE}Signal type to build by default: {ORANGE}{STRING1}
diff --git a/src/rail_cmd.cpp b/src/rail_cmd.cpp
index 1b60bfc6e..e8f92e51f 100644
--- a/src/rail_cmd.cpp
+++ b/src/rail_cmd.cpp
@@ -1198,6 +1198,7 @@ static bool CheckSignalAutoFill(TileIndex &tile, Trackdir &trackdir, int &signal
  * - p2 = (bit  5)    - 0 = build, 1 = remove signals
  * - p2 = (bit  6)    - 0 = selected stretch, 1 = auto fill
  * - p2 = (bit  7- 9) - default signal type
+ * - p2 = (bit 10)    - 0 = keep fixed distance, 1 = minimise gaps between signals
  * - p2 = (bit 24-31) - user defined signals_density
  * @param text unused
  * @return the cost of this operation or an error
@@ -1212,6 +1213,7 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 	bool semaphores = HasBit(p2, 4);
 	bool remove = HasBit(p2, 5);
 	bool autofill = HasBit(p2, 6);
+	bool minimise_gaps = HasBit(p2, 10);
 	byte signal_density = GB(p2, 24, 8);
 
 	if (p1 >= MapSize() || !ValParamTrackOrientation(track)) return CMD_ERROR;
@@ -1258,7 +1260,11 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 	if (signals & SignalAgainstTrackdir(trackdir)) SetBit(signal_dir, 1);
 
 	/* signal_ctr         - amount of tiles already processed
+	 * last_used_ctr      - amount of tiles before previously placed signal
 	 * signals_density    - setting to put signal on every Nth tile (double space on |, -- tracks)
+	 * last_suitable_ctr  - amount of tiles before last possible signal place
+	 * last_suitable_tile - last tile where it is possible to place a signal
+	 * last_suitable_trackdir - trackdir of the last tile
 	 **********
 	 * trackdir   - trackdir to build with autorail
 	 * semaphores - semaphores or signals
@@ -1266,11 +1272,15 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 	 *              and convert all others to semaphore/signal
 	 * remove     - 1 remove signals, 0 build signals */
 	int signal_ctr = 0;
+	int last_used_ctr = INT_MIN; // initially INT_MIN to force building/removing at the first tile
+	int last_suitable_ctr = 0;
+	TileIndex last_suitable_tile = INVALID_TILE;
+	Trackdir last_suitable_trackdir = INVALID_TRACKDIR;
 	CommandCost last_error = CMD_ERROR;
 	bool had_success = false;
 	for (;;) {
 		/* only build/remove signals with the specified density */
-		if (remove || signal_ctr % signal_density == 0) {
+		if (remove || minimise_gaps || signal_ctr % signal_density == 0) {
 			uint32 p1 = GB(TrackdirToTrack(trackdir), 0, 3);
 			SB(p1, 3, 1, mode);
 			SB(p1, 4, 1, semaphores);
@@ -1282,17 +1292,42 @@ static CommandCost CmdSignalTrackHelper(TileIndex tile, DoCommandFlag flags, uin
 			if (HasBit(signal_dir, 0)) signals |= SignalAlongTrackdir(trackdir);
 			if (HasBit(signal_dir, 1)) signals |= SignalAgainstTrackdir(trackdir);
 
-			CommandCost ret = DoCommand(tile, p1, signals, flags, remove ? CMD_REMOVE_SIGNALS : CMD_BUILD_SIGNALS);
+			/* Test tiles in between for suitability as well if minimising gaps. */
+			bool test_only = minimise_gaps && signal_ctr < (last_used_ctr + signal_density);
+			CommandCost ret = DoCommand(tile, p1, signals, test_only ? flags & ~DC_EXEC : flags, remove ? CMD_REMOVE_SIGNALS : CMD_BUILD_SIGNALS);
 
-			/* Be user-friendly and try placing signals as much as possible */
 			if (ret.Succeeded()) {
-				had_success = true;
-				total_cost.AddCost(ret);
-			} else {
-				/* The "No railway" error is the least important one. */
-				if (ret.GetErrorMessage() != STR_ERROR_THERE_IS_NO_RAILROAD_TRACK ||
-						last_error.GetErrorMessage() == INVALID_STRING_ID) {
-					last_error = ret;
+				/* Remember last track piece where we can place a signal. */
+				last_suitable_ctr = signal_ctr;
+				last_suitable_tile = tile;
+				last_suitable_trackdir = trackdir;
+			} else if (!test_only && last_suitable_tile != INVALID_TILE) {
+				/* If a signal can't be placed, place it at the last possible position. */
+				SB(p1, 0, 3, TrackdirToTrack(last_suitable_trackdir));
+				ClrBit(p1, 17);
+
+				/* Pick the correct orientation for the track direction. */
+				signals = 0;
+				if (HasBit(signal_dir, 0)) signals |= SignalAlongTrackdir(last_suitable_trackdir);
+				if (HasBit(signal_dir, 1)) signals |= SignalAgainstTrackdir(last_suitable_trackdir);
+
+				ret = DoCommand(last_suitable_tile, p1, signals, flags, remove ? CMD_REMOVE_SIGNALS : CMD_BUILD_SIGNALS);
+			}
+
+			/* Collect cost. */
+			if (!test_only) {
+				/* Be user-friendly and try placing signals as much as possible */
+				if (ret.Succeeded()) {
+					had_success = true;
+					total_cost.AddCost(ret);
+					last_used_ctr = last_suitable_ctr;
+					last_suitable_tile = INVALID_TILE;
+				} else {
+					/* The "No railway" error is the least important one. */
+					if (ret.GetErrorMessage() != STR_ERROR_THERE_IS_NO_RAILROAD_TRACK ||
+							last_error.GetErrorMessage() == INVALID_STRING_ID) {
+						last_error = ret;
+					}
 				}
 			}
 		}
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 990812ad8..584622c36 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -390,12 +390,14 @@ static void HandleAutoSignalPlacement()
 		SB(p2,  6, 1, _ctrl_pressed);
 		SB(p2,  7, 3, _cur_signal_type);
 		SB(p2, 24, 8, _settings_client.gui.drag_signals_density);
+		SB(p2, 10, 1, !_settings_client.gui.drag_signals_fixed_distance);
 	} else {
 		SB(p2,  3, 1, 0);
 		SB(p2,  4, 1, (_cur_year < _settings_client.gui.semaphore_build_before ? SIG_SEMAPHORE : SIG_ELECTRIC));
 		SB(p2,  6, 1, _ctrl_pressed);
 		SB(p2,  7, 3, _default_signal_type[_settings_client.gui.default_signal_type]);
 		SB(p2, 24, 8, _settings_client.gui.drag_signals_density);
+		SB(p2, 10, 1, !_settings_client.gui.drag_signals_fixed_distance);
 	}
 
 	/* _settings_client.gui.drag_signals_density is given as a parameter such that each user
diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
index 308839d51..f0d6917b8 100644
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -1451,6 +1451,7 @@ static SettingEntry _settings_construction_signals[] = {
 	SettingEntry("construction.signal_side"),
 	SettingEntry("gui.enable_signal_gui"),
 	SettingEntry("gui.drag_signals_density"),
+	SettingEntry("gui.drag_signals_fixed_distance"),
 	SettingEntry("gui.semaphore_build_before"),
 	SettingEntry("gui.default_signal_type"),
 	SettingEntry("gui.cycle_signal_types"),
diff --git a/src/settings_type.h b/src/settings_type.h
index 1f91a542a..c3825bdcf 100644
--- a/src/settings_type.h
+++ b/src/settings_type.h
@@ -102,6 +102,7 @@ struct GUISettings {
 	bool   quick_goto;                       ///< Allow quick access to 'goto button' in vehicle orders window
 	bool   auto_euro;                        ///< automatically switch to euro in 2002
 	byte   drag_signals_density;             ///< many signals density
+	bool   drag_signals_fixed_distance;      ///< keep fixed distance between signals when dragging
 	Year   semaphore_build_before;           ///< build semaphore signals automatically before this year
 	byte   news_message_timeout;             ///< how much longer than the news message "age" should we keep the message in the history
 	bool   show_track_reservation;           ///< highlight reserved tracks.
diff --git a/src/table/settings.ini b/src/table/settings.ini
index aec498f82..efa70b7f0 100644
--- a/src/table/settings.ini
+++ b/src/table/settings.ini
@@ -2256,6 +2256,12 @@ max      = 20
 str      = STR_CONFIG_SETTING_DRAG_SIGNALS_DENSITY
 proc     = DragSignalsDensityChanged
 
+[SDTC_BOOL]
+var      = gui.drag_signals_fixed_distance
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+def      = false
+str      = STR_CONFIG_SETTING_DRAG_SIGNALS_FIXED_DISTANCE
+
 [SDTC_VAR]
 var      = gui.semaphore_build_before
 type     = SLE_INT32