Add setting to show restricted electric signals using the default sprites.

This is to improve visual distinctiveness of restricted signals when
using signal GRFs.
This defaults to off.

src/gfxinit.cpp

@@ -177,6 +177,11 @@ static void LoadSpriteTables()
 	/* Tracerestrict sprites. */
 	LoadGrfFile("tracerestrict.grf", SPR_TRACERESTRICT_BASE, i++);
 
+	/* Fill duplicate original signal graphics sprite block */
+	for (uint i = 0; i < DUP_ORIGINAL_SIGNALS_SPRITE_COUNT; i++) {
+		DupSprite(SPR_ORIGINAL_SIGNALS_BASE + i, SPR_DUP_ORIGINAL_SIGNALS_BASE + i);
+	}
+
 	/*
 	 * The second basic file always starts at the given location and does
 	 * contain a different amount of sprites depending on the "type"; DOS

src/lang/english.txt

@@ -1287,6 +1287,8 @@ STR_CONFIG_SETTING_POPULATION_IN_LABEL                          :Show town popul
 STR_CONFIG_SETTING_POPULATION_IN_LABEL_HELPTEXT                 :Display the population of towns in their label on the map
 STR_CONFIG_SETTING_GRAPH_LINE_THICKNESS                         :Thickness of lines in graphs: {STRING2}
 STR_CONFIG_SETTING_GRAPH_LINE_THICKNESS_HELPTEXT                :Width of the line in the graphs. A thin line is more precisely readable, a thicker line is easier to see and colours are easier to distinguish
+STR_CONFIG_SETTING_SHOW_RESTRICTED_SIG_DEF                      :Show restricted electric signals using default graphics: {STRING2}
+STR_CONFIG_SETTING_SHOW_RESTRICTED_SIG_DEF_HELPTEXT             :Show electric signals with routing restriction programs using the default signal graphics with a blue signal post, instead of using any NewGRF signal graphics. This is to make it easier to visually distinguish restricted signals.
 
 STR_CONFIG_SETTING_LANDSCAPE                                    :Landscape: {STRING2}
 STR_CONFIG_SETTING_LANDSCAPE_HELPTEXT                           :Landscapes define basic gameplay scenarios with different cargos and town growth requirements. NewGRF and Game Scripts allow finer control though

src/newgrf.cpp

@@ -5671,11 +5671,19 @@ static void GraphicsNew(ByteReader *buf)
 	/* Load <num> sprites starting from <replace>, then skip <skip_num> sprites. */
 	grfmsg(2, "GraphicsNew: Replacing sprites %d to %d of %s (type 0x%02X) at SpriteID 0x%04X", offset, offset + num - 1, action5_type->name, type, replace);
 
-	for (; num > 0; num--) {
+	for (uint16 n = num; n > 0; n--) {
 		_cur.nfo_line++;
 		LoadNextSprite(replace == 0 ? _cur.spriteid++ : replace++, _cur.file_index, _cur.nfo_line, _cur.grf_container_ver);
 	}
 
+	if (type == 0x04 && (_cur.grffile->is_ottdfile || _cur.grfconfig->ident.grfid == BSWAP32(0xFF4F4701))) {
+		/* Signal graphics action 5: Fill duplicate signal sprite block if this is a baseset GRF or OpenGFX */
+		const SpriteID end = offset + num;
+		for (SpriteID i = offset; i < end; i++) {
+			DupSprite(SPR_SIGNALS_BASE + i, SPR_DUP_SIGNALS_BASE + i);
+		}
+	}
+
 	if (type == 0x0D) _loaded_newgrf_features.shore = SHORE_REPLACE_ACTION_5;
 
 	_cur.skip_sprites = skip_num;

src/rail_cmd.cpp

@@ -1862,6 +1862,8 @@ static void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track trac
 	SignalType type       = GetSignalType(tile, track);
 	SignalVariant variant = GetSignalVariant(tile, track);
 
+	bool show_restricted = (variant == SIG_ELECTRIC) && IsRestrictedSignal(tile) && (GetExistingTraceRestrictProgram(tile, track) != NULL);
+
 	SpriteID sprite = GetCustomSignalSprite(rti, tile, type, variant, condition);
 	bool is_custom_sprite = (sprite != 0);
 	if (sprite != 0) {
@@ -1877,7 +1879,14 @@ static void DrawSingleSignal(TileIndex tile, const RailtypeInfo *rti, Track trac
 	extern uint _opengfx_grf_file_index;
 	if (!is_custom_sprite) is_custom_sprite = origin_slot != _opengfx_grf_file_index && (origin_slot >= _first_user_grf_file_index);
 
-	if (!is_custom_sprite && variant == SIG_ELECTRIC && IsRestrictedSignal(tile) && GetExistingTraceRestrictProgram(tile, track) != NULL) {
+	if (is_custom_sprite && show_restricted && _settings_client.gui.show_restricted_signal_default) {
+		/* Use duplicate sprite block, instead of GRF-specified signals */
+		sprite = (type == SIGTYPE_NORMAL && variant == SIG_ELECTRIC) ? SPR_DUP_ORIGINAL_SIGNALS_BASE : SPR_DUP_SIGNALS_BASE - 16;
+		sprite += type * 16 + variant * 64 + image * 2 + condition + (type > SIGTYPE_LAST_NOPBS ? 64 : 0);
+		is_custom_sprite = false;
+	}
+
+	if (!is_custom_sprite && show_restricted) {
 		if (type == SIGTYPE_PBS || type == SIGTYPE_PBS_ONEWAY) {
 			static const SubSprite lower_part = { -50, -10, 50, 50 };
 			static const SubSprite upper_part = { -50, -50, 50, -11 };

src/settings_gui.cpp

@@ -1478,6 +1478,7 @@ static SettingsContainer &GetSettingsTree()
 			graphics->Add(new SettingEntry("gui.zoom_max"));
 			graphics->Add(new SettingEntry("gui.smallmap_land_colour"));
 			graphics->Add(new SettingEntry("gui.graph_line_thickness"));
+			graphics->Add(new SettingEntry("gui.show_restricted_signal_default"));
 		}
 
 		SettingsPage *sound = main->Add(new SettingsPage(STR_CONFIG_SETTING_SOUND));

src/settings_type.h

@@ -135,6 +135,7 @@ struct GUISettings {
 	uint32 last_newgrf_count;                ///< the numbers of NewGRFs we found during the last scan
 	byte   missing_strings_threshold;        ///< the number of missing strings before showing the warning
 	uint8  graph_line_thickness;             ///< the thickness of the lines in the various graph guis
+	bool   show_restricted_signal_default;   ///< Show restricted electric signals using the default sprite
 	uint8  osk_activation;                   ///< Mouse gesture to trigger the OSK.
 
 	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.

src/table/settings.ini

@@ -3133,6 +3133,14 @@ strhelp  = STR_CONFIG_SETTING_GRAPH_LINE_THICKNESS_HELPTEXT
 strval   = STR_JUST_COMMA
 proc     = RedrawScreen
 
+[SDTC_BOOL]
+var      = gui.show_restricted_signal_default
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+def      = false
+str      = STR_CONFIG_SETTING_SHOW_RESTRICTED_SIG_DEF
+strhelp  = STR_CONFIG_SETTING_SHOW_RESTRICTED_SIG_DEF_HELPTEXT
+proc     = RedrawScreen
+
 ; For the dedicated build we'll enable dates in logs by default.
 [SDTC_BOOL]
 ifdef    = DEDICATED

src/table/sprites.h

@@ -300,8 +300,14 @@ static const uint16 PALETTE_SPRITE_COUNT = 1;
 static const SpriteID SPR_TRACERESTRICT_BASE = SPR_PALETTE_BASE + PALETTE_SPRITE_COUNT;
 static const uint16 TRACERESTRICT_SPRITE_COUNT = 2;
 
+/* Duplicated signal sprites */
+static const SpriteID SPR_DUP_ORIGINAL_SIGNALS_BASE = SPR_TRACERESTRICT_BASE + TRACERESTRICT_SPRITE_COUNT;
+static const uint16 DUP_ORIGINAL_SIGNALS_SPRITE_COUNT = 16;
+static const SpriteID SPR_DUP_SIGNALS_BASE = SPR_DUP_ORIGINAL_SIGNALS_BASE + DUP_ORIGINAL_SIGNALS_SPRITE_COUNT;
+static const uint16 DUP_SIGNALS_SPRITE_COUNT = PRESIGNAL_SEMAPHORE_AND_PBS_SPRITE_COUNT;
+
 /* From where can we start putting NewGRFs? */
-static const SpriteID SPR_NEWGRFS_BASE = SPR_TRACERESTRICT_BASE + TRACERESTRICT_SPRITE_COUNT;
+static const SpriteID SPR_NEWGRFS_BASE = SPR_DUP_SIGNALS_BASE + DUP_SIGNALS_SPRITE_COUNT;
 
 /* Manager face sprites */
 static const SpriteID SPR_GRADIENT = 874; // background gradient behind manager face