Add entry direction condition variable.

src/lang/english.txt

@@ -2390,6 +2390,7 @@ STR_TRACE_RESTRICT_VARIABLE_CURRENT_ORDER                       :current order
 STR_TRACE_RESTRICT_VARIABLE_NEXT_ORDER                          :next order
 STR_TRACE_RESTRICT_VARIABLE_LAST_VISITED_STATION                :last visited station
 STR_TRACE_RESTRICT_VARIABLE_CARGO                               :cargo
+STR_TRACE_RESTRICT_VARIABLE_ENTRY_DIRECTION                     :entry direction
 STR_TRACE_RESTRICT_VARIABLE_UNDEFINED                           :undefined
 STR_TRACE_RESTRICT_CONDITIONAL_COMPARE_INTEGER                  :{STRING} {STRING} {STRING} {COMMA} then
 STR_TRACE_RESTRICT_CONDITIONAL_COMPARE_SPEED                    :{STRING} {STRING} {STRING} {VELOCITY} then
@@ -2397,6 +2398,8 @@ STR_TRACE_RESTRICT_CONDITIONAL_ORDER_STATION                    :{STRING} {STRIN
 STR_TRACE_RESTRICT_CONDITIONAL_ORDER_WAYPOINT                   :{STRING} {STRING} {STRING} {WAYPOINT} then
 STR_TRACE_RESTRICT_CONDITIONAL_ORDER_DEPOT                      :{STRING} {STRING} {STRING} {DEPOT} then
 STR_TRACE_RESTRICT_CONDITIONAL_CARGO                            :{STRING} train {STRING} cargo: {STRING} then
+STR_TRACE_RESTRICT_CONDITIONAL_ENTRY_DIRECTION                  :{STRING} train {STRING} entering from {STRING} tile edge then
+STR_TRACE_RESTRICT_CONDITIONAL_ENTRY_SIGNAL_FACE                :{STRING} train {STRING} entering from {STRING} of signal then
 STR_TRACE_RESTRICT_CONDITIONAL_UNDEFINED                        :{STRING} {STRING} {STRING} {RED}undefined {BLACK}{STRING}then
 STR_TRACE_RESTRICT_CONDITIONAL_COMPARE_UNDEFINED                :{STRING} {RED}undefined {BLACK}{STRING}then
 STR_TRACE_RESTRICT_PF_PENALTY_ITEM                              :Add pathfinder penalty: {COMMA}
@@ -2407,6 +2410,12 @@ STR_TRACE_RESTRICT_PF_DENY                                      :Deny
 STR_TRACE_RESTRICT_PF_ALLOW                                     :Allow
 STR_TRACE_RESTRICT_PF_ALLOW_LONG                                :Allow (cancel previous Deny)
 STR_TRACE_RESTRICT_PF_PENALTY                                   :Penalty
+STR_TRACE_RESTRICT_DIRECTION_FRONT                              :front
+STR_TRACE_RESTRICT_DIRECTION_BACK                               :back
+STR_TRACE_RESTRICT_DIRECTION_NE                                 :north-east
+STR_TRACE_RESTRICT_DIRECTION_SE                                 :south-east
+STR_TRACE_RESTRICT_DIRECTION_SW                                 :south-west
+STR_TRACE_RESTRICT_DIRECTION_NW                                 :north-west
 STR_TRACE_RESTRICT_VALUE_CAPTION                                :{WHITE}Value
 STR_TRACE_RESTRICT_CAPTION                                      :{WHITE}Routefinding restriction
 STR_TRACE_RESTRICT_CAPTION_SHARED                               :{WHITE}Routefinding restriction - shared by {COMMA} signals

src/pathfinder/yapf/yapf_costrail.hpp

@@ -194,7 +194,7 @@ private:
 	{
 		const TraceRestrictProgram *prog = GetExistingTraceRestrictProgram(tile, TrackdirToTrack(trackdir));
 		if (prog) {
-			prog->Execute(Yapf().GetVehicle(), out);
+			prog->Execute(Yapf().GetVehicle(), TraceRestrictProgramInput(tile, trackdir), out);
 			if (out.flags & TRPRF_DENY) {
 				n.m_segment->m_end_segment_reason |= ESRB_DEAD_END;
 				return true;

src/tracerestrict.cpp

@@ -211,7 +211,7 @@ static bool TestStationCondition(StationID station, TraceRestrictItem item)
  * @p v may not be NULL
  * @p out should be zero-initialised
  */
-void TraceRestrictProgram::Execute(const Train* v, TraceRestrictProgramResult& out) const
+void TraceRestrictProgram::Execute(const Train* v, const TraceRestrictProgramInput &input, TraceRestrictProgramResult& out) const
 {
 	// static to avoid needing to re-alloc/resize on each execution
 	static std::vector<TraceRestrictCondStackFlags> condstack;
@@ -287,6 +287,32 @@ void TraceRestrictProgram::Execute(const Train* v, TraceRestrictProgramResult& o
 						break;
 					}
 
+					case TRIT_COND_ENTRY_DIRECTION: {
+						bool direction_match;
+						switch (GetTraceRestrictValue(item)) {
+							case TRNTSV_NE:
+							case TRNTSV_SE:
+							case TRNTSV_SW:
+							case TRNTSV_NW:
+								direction_match = (static_cast<DiagDirection>(GetTraceRestrictValue(item)) == TrackdirToExitdir(ReverseTrackdir(input.trackdir)));
+								break;
+
+							case TRDTSV_FRONT:
+								direction_match = IsTileType(input.tile, MP_RAILWAY) && HasSignalOnTrackdir(input.tile, input.trackdir);
+								break;
+
+							case TRDTSV_BACK:
+								direction_match = IsTileType(input.tile, MP_RAILWAY) && !HasSignalOnTrackdir(input.tile, input.trackdir);
+								break;
+
+							default:
+								NOT_REACHED();
+								break;
+						}
+						result = TestBinaryConditionCommon(item, direction_match);
+						break;
+					}
+
 					default:
 						NOT_REACHED();
 				}
@@ -402,6 +428,11 @@ void SetTraceRestrictValueDefault(TraceRestrictItem &item, TraceRestrictValueTyp
 			SetTraceRestrictAuxField(item, 0);
 			break;
 
+		case TRVT_DIRECTION:
+			SetTraceRestrictValue(item, TRDTSV_FRONT);
+			SetTraceRestrictAuxField(item, 0);
+			break;
+
 		default:
 			NOT_REACHED();
 			break;

src/tracerestrict.h

@@ -105,6 +105,7 @@ enum TraceRestrictItemType {
 	TRIT_COND_NEXT_ORDER          = 13,   ///< Test train next order (station, waypoint or depot)
 	TRIT_COND_LAST_STATION        = 14,   ///< Test train last visited station
 	TRIT_COND_CARGO               = 15,   ///< Test if train can carry cargo type
+	TRIT_COND_ENTRY_DIRECTION     = 16,   ///< Test which side of signal/signal tile is being entered from
 	/* space up to 31 */
 };
 
@@ -128,6 +129,18 @@ enum TraceRestrictNullTypeSpecialValue {
 	TRNTSV_END                    = 2,       ///< end tag, generated within GUI
 };
 
+/**
+ * Enumeration of TraceRestrictItemvalue type field when value type is TRVT_DIRECTION
+ */
+enum TraceRestrictDirectionTypeSpecialValue {
+	TRNTSV_NE                     = 0,       ///< DIAGDIR_NE: entering at NE tile edge
+	TRNTSV_SE                     = 1,       ///< DIAGDIR_SE: entering at SE tile edge
+	TRNTSV_SW                     = 2,       ///< DIAGDIR_SW: entering at SW tile edge
+	TRNTSV_NW                     = 3,       ///< DIAGDIR_NW: entering at NW tile edge
+	TRDTSV_FRONT                  = 4,       ///< entering at front face of signal
+	TRDTSV_BACK                   = 5,       ///< entering at rear face of signal
+};
+
 /**
  * TraceRestrictItem condition operator field, only valid with conditional types (IsTraceRestrictTypeConditional() is true)
  */
@@ -159,6 +172,17 @@ enum TraceRestrictProgramResultFlags {
 };
 DECLARE_ENUM_AS_BIT_SET(TraceRestrictProgramResultFlags)
 
+/**
+ * Execution input of a TraceRestrictProgram
+ */
+struct TraceRestrictProgramInput {
+	TileIndex tile;                          ///< Tile of restrict signal, for direction testing
+	Trackdir trackdir;                       ///< Track direction on tile of restrict signal, for direction testing
+
+	TraceRestrictProgramInput(TileIndex tile_, Trackdir trackdir_)
+			: tile(tile_), trackdir(trackdir_) { }
+};
+
 /**
  * Execution result of a TraceRestrictProgram
  */
@@ -181,7 +205,7 @@ struct TraceRestrictProgram : TraceRestrictProgramPool::PoolItem<&_tracerestrict
 	TraceRestrictProgram()
 			: refcount(0) { }
 
-	void Execute(const Train *v, TraceRestrictProgramResult &out) const;
+	void Execute(const Train *v, const TraceRestrictProgramInput &input, TraceRestrictProgramResult &out) const;
 
 	/**
 	 * Increment ref count, only use when creating a mapping
@@ -292,6 +316,7 @@ enum TraceRestrictValueType {
 	TRVT_SPEED                    = 4, ///< takes an integer speed value
 	TRVT_ORDER                    = 5, ///< takes an order target ID, as per the auxiliary field as type: TraceRestrictOrderCondAuxField
 	TRVT_CARGO_ID                 = 6, ///< takes a CargoID
+	TRVT_DIRECTION                = 7, ///< takes a TraceRestrictDirectionTypeSpecialValue
 };
 
 /**
@@ -343,6 +368,11 @@ static inline TraceRestrictTypePropertySet GetTraceRestrictTypeProperties(TraceR
 				out.cond_type = TRCOT_BINARY;
 				break;
 
+			case TRIT_COND_ENTRY_DIRECTION:
+				out.value_type = TRVT_DIRECTION;
+				out.cond_type = TRCOT_BINARY;
+				break;
+
 			default:
 				NOT_REACHED();
 				break;

src/tracerestrict_gui.cpp

@@ -149,6 +149,29 @@ static const TraceRestrictDropDownListSet _deny_value = {
 	_deny_value_str, _deny_value_val,
 };
 
+static const StringID _direction_value_str[] = {
+	STR_TRACE_RESTRICT_DIRECTION_FRONT,
+	STR_TRACE_RESTRICT_DIRECTION_BACK,
+	STR_TRACE_RESTRICT_DIRECTION_NE,
+	STR_TRACE_RESTRICT_DIRECTION_SE,
+	STR_TRACE_RESTRICT_DIRECTION_SW,
+	STR_TRACE_RESTRICT_DIRECTION_NW,
+	INVALID_STRING_ID
+};
+static const uint _direction_value_val[] = {
+	TRDTSV_FRONT,
+	TRDTSV_BACK,
+	TRNTSV_NE,
+	TRNTSV_SE,
+	TRNTSV_SW,
+	TRNTSV_NW,
+};
+
+/** value drop down list for direction type strings and values */
+static const TraceRestrictDropDownListSet _direction_value = {
+	_direction_value_str, _direction_value_val,
+};
+
 /**
  * Get index of @p value in @p list_set
  * if @p value is not present, assert if @p missing_ok is false, otherwise return -1
@@ -201,6 +224,7 @@ static const TraceRestrictDropDownListSet *GetTypeDropDownListSet(TraceRestrictI
 		STR_TRACE_RESTRICT_VARIABLE_NEXT_ORDER,
 		STR_TRACE_RESTRICT_VARIABLE_LAST_VISITED_STATION,
 		STR_TRACE_RESTRICT_VARIABLE_CARGO,
+		STR_TRACE_RESTRICT_VARIABLE_ENTRY_DIRECTION,
 		STR_TRACE_RESTRICT_VARIABLE_UNDEFINED,
 		INVALID_STRING_ID,
 	};
@@ -211,6 +235,7 @@ static const TraceRestrictDropDownListSet *GetTypeDropDownListSet(TraceRestrictI
 		TRIT_COND_NEXT_ORDER,
 		TRIT_COND_LAST_STATION,
 		TRIT_COND_CARGO,
+		TRIT_COND_ENTRY_DIRECTION,
 		TRIT_COND_UNDEFINED,
 	};
 	static const TraceRestrictDropDownListSet set_cond = {
@@ -490,6 +515,17 @@ static void DrawInstructionString(TraceRestrictItem item, int y, bool selected,
 					SetDParam(2, GetCargoStringByID(GetTraceRestrictValue(item)));
 					break;
 
+				case TRVT_DIRECTION:
+					if (GetTraceRestrictValue(item) >= TRDTSV_FRONT) {
+						instruction_string = STR_TRACE_RESTRICT_CONDITIONAL_ENTRY_SIGNAL_FACE;
+					} else {
+						instruction_string = STR_TRACE_RESTRICT_CONDITIONAL_ENTRY_DIRECTION;
+					}
+					SetDParam(0, _program_cond_type[GetTraceRestrictCondFlags(item)]);
+					SetDParam(1, GetDropDownStringByValue(GetCondOpDropDownListSet(properties), GetTraceRestrictCondOp(item)));
+					SetDParam(2, GetDropDownStringByValue(&_direction_value, GetTraceRestrictValue(item)));
+					break;
+
 				default:
 					NOT_REACHED();
 					break;
@@ -706,6 +742,10 @@ public:
 						this->ShowDropDownListWithValue(GetSortedCargoTypeDropDownListSet(), GetTraceRestrictValue(item), true, TR_WIDGET_VALUE_DROPDOWN, 0, 0, 0); // current cargo is permitted to not be in list
 						break;
 
+					case TRVT_DIRECTION:
+						this->ShowDropDownListWithValue(&_direction_value, GetTraceRestrictValue(item), false, TR_WIDGET_VALUE_DROPDOWN, 0, 0, 0);
+						break;
+
 					default:
 						break;
 				}
@@ -1357,6 +1397,13 @@ private:
 									GetCargoStringByID(GetTraceRestrictValue(item));
 							break;
 
+						case TRVT_DIRECTION:
+							right_sel->SetDisplayedPlane(DPR_VALUE_DROPDOWN);
+							this->EnableWidget(TR_WIDGET_VALUE_DROPDOWN);
+							this->GetWidget<NWidgetCore>(TR_WIDGET_VALUE_DROPDOWN)->widget_data =
+									GetDropDownStringByValue(&_direction_value, GetTraceRestrictValue(item));
+							break;
+
 						default:
 							break;
 					}