Improve train speed adaptation with realistic braking

Take into account recorded speeds at signals along the reservation
As noted in the lookahead

See: #613

src/pbs.cpp

@@ -14,6 +14,7 @@
 #include "pathfinder/follow_track.hpp"
 #include "tracerestrict.h"
 #include "newgrf_newsignals.h"
+#include "train_speed_adaptation.h"
 
 #include "safeguards.h"
 
@@ -408,6 +409,14 @@ static uint16 GetTrainSpeedLimitForRailtype(const Train *v, RailType rt, TileInd
 	return speed;
 }
 
+static void AddSignalToLookAhead(const Train *v, TrainReservationLookAhead *lookahead, uint16 signal_speed, uint16 signal_flags, TileIndex signal_tile, uint16 signal_track, int offset, int16 z_pos)
+{
+	lookahead->AddSignal(signal_speed, offset, z_pos, signal_flags);
+	if (_settings_game.vehicle.train_speed_adaptation) {
+		lookahead->AddSpeedAdaptation(signal_tile, signal_track, offset, z_pos);
+	}
+}
+
 /** Follow a reservation starting from a specific tile to the end. */
 static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Trackdir trackdir, FollowReservationFlags flags, const Train *v, TrainReservationLookAhead *lookahead)
 {
@@ -589,7 +598,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					const uint16 signal_flags = GetTunnelBridgeSignalStyle(tile) << 8;
 
 					/* Entrance signal */
-					lookahead->AddSignal(signal_speed, 0, z, signal_flags);
+					AddSignalToLookAhead(v, lookahead, signal_speed, signal_flags, tile, TrackdirToTrack(trackdir), 0, z);
 
 					update_z(tile, trackdir, false);
 
@@ -603,7 +612,8 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 					int offset = start_offset - TILE_SIZE;
 					for (int i = 0; i < signals; i++) {
 						offset += TILE_SIZE * spacing;
-						lookahead->AddSignal(signal_speed, offset, chunnel ? LookaheadTileHeightForChunnel(length, i * spacing) : z, signal_flags);
+						const int signal_z = chunnel ? LookaheadTileHeightForChunnel(length, i * spacing) : z;
+						AddSignalToLookAhead(v, lookahead, signal_speed, signal_flags, tile, 0x100 + i, offset, signal_z);
 					}
 
 					/* Exit signal */
@@ -617,7 +627,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 						if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 					}
 
-					lookahead->AddSignal(signal_speed, end_offset, z, signal_flags);
+					AddSignalToLookAhead(v, lookahead, signal_speed, signal_flags, end, FindFirstTrack(GetAcrossTunnelBridgeTrackBits(end)), end_offset, z);
 
 					lookahead->SetNextExtendPositionIfUnset();
 				} else {
@@ -672,7 +682,7 @@ static PBSTileInfo FollowReservation(Owner o, RailTypes rts, TileIndex tile, Tra
 						SetBit(signal_flags, TRSLAI_COMBINED);
 						UpdateLookaheadCombinedNormalShuntSignalDeferred(tile, trackdir, lookahead->RealEndPosition());
 					}
-					lookahead->AddSignal(signal_speed, 0, z, signal_flags);
+					AddSignalToLookAhead(v, lookahead, signal_speed, signal_flags, tile, TrackdirToTrack(trackdir), 0, z);
 					lookahead->SetNextExtendPositionIfUnset();
 				}
 			}
@@ -1073,7 +1083,8 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 			int offset = -(int)TILE_SIZE;
 			for (int i = 0; i < signals; i++) {
 				offset += TILE_SIZE * spacing;
-				t->lookahead->AddSignal(signal_speed, offset, HasBit(t->lookahead->flags, TRLF_CHUNNEL) ? LookaheadTileHeightForChunnel(length, i * spacing) : z, signal_flags);
+				const int signal_z = HasBit(t->lookahead->flags, TRLF_CHUNNEL) ? LookaheadTileHeightForChunnel(length, i * spacing) : z;
+				AddSignalToLookAhead(t, t->lookahead.get(), signal_speed, signal_flags, t->tile, 0x100 + i, offset, signal_z);
 			}
 
 			/* Exit signal */
@@ -1086,7 +1097,7 @@ void TryCreateLookAheadForTrainInTunnelBridge(Train *t)
 				if (signal_speed == 0 || (bridge_speed != 0 && bridge_speed < signal_speed)) signal_speed = bridge_speed;
 			}
 
-			t->lookahead->AddSignal(signal_speed, end_offset, z, signal_flags);
+			AddSignalToLookAhead(t, t->lookahead.get(), signal_speed, signal_flags, end, FindFirstTrack(GetAcrossTunnelBridgeTrackBits(end)), end_offset, z);
 
 			t->lookahead->SetNextExtendPositionIfUnset();
 		}
@@ -1174,6 +1185,8 @@ void FillTrainReservationLookAhead(Train *v)
 		if (v->lookahead == nullptr) return;
 	}
 
+	int32 old_reservation_end_position = 0;
+
 	if (v->lookahead == nullptr) {
 		v->lookahead.reset(new TrainReservationLookAhead());
 		v->lookahead->current_position = 0;
@@ -1205,6 +1218,7 @@ void FillTrainReservationLookAhead(Train *v)
 			v->lookahead->reservation_end_position += station_offset_tiles * TILE_SIZE;
 		}
 	} else {
+		old_reservation_end_position = v->lookahead->reservation_end_position;
 		tile = v->lookahead->reservation_end_tile;
 		trackdir = v->lookahead->reservation_end_trackdir;
 		if (IsTunnelBridgeSignalSimulationEntranceTile(tile) && TrackdirEntersTunnelBridge(tile, trackdir)) {
@@ -1263,6 +1277,24 @@ void FillTrainReservationLookAhead(Train *v)
 
 	FlushDeferredDetermineCombineNormalShuntMode(v);
 	SetTrainReservationLookaheadEnd(v);
+
+	if (_settings_game.vehicle.train_speed_adaptation && v->signal_speed_restriction > 0 && v->lookahead->reservation_end_position > old_reservation_end_position) {
+		for (const TrainReservationLookAheadItem &item : v->lookahead->items) {
+			if (item.type == TRLIT_SPEED_ADAPTATION && item.end + 1 >= old_reservation_end_position && item.end + 1 < v->lookahead->reservation_end_position) {
+				uint16 signal_speed = GetLowestSpeedTrainAdaptationSpeedAtSignal(item.data_id, item.data_aux);
+
+				if (signal_speed == 0) {
+					/* unrestricted signal ahead, remove current speed adaptation */
+					v->signal_speed_restriction = 0;
+					break;
+				}
+				if (signal_speed > v->signal_speed_restriction) {
+					/* signal ahead with higher speed, increase current speed adaptation */
+					v->signal_speed_restriction = signal_speed;
+				}
+			}
+		}
+	}
 }
 
 /**

src/pbs.h

@@ -57,6 +57,7 @@ enum TrainReservationLookAheadItemType : byte {
 	TRLIT_SPEED_RESTRICTION      = 3,     ///< Speed restriction
 	TRLIT_SIGNAL                 = 4,     ///< Signal
 	TRLIT_CURVE_SPEED            = 5,     ///< Curve speed limit
+	TRLIT_SPEED_ADAPTATION       = 6,     ///< Train speed adaptation ahead
 };
 
 enum TrainReservationSignalLookAheadItemFlags {
@@ -70,9 +71,11 @@ struct TrainReservationLookAheadItem {
 	int32 start;
 	int32 end;
 	int16 z_pos;
-	uint16 data_id;
+	/* gap: 2 bytes */
+	uint32 data_id;
 	uint16 data_aux;
 	TrainReservationLookAheadItemType type;
+	/* gap: 1 byte */
 };
 
 struct TrainReservationLookAheadCurve {
@@ -145,6 +148,12 @@ struct TrainReservationLookAhead {
 		this->items.push_back({ end + offset, end + offset, z_pos, target_speed, 0, TRLIT_CURVE_SPEED });
 	}
 
+	void AddSpeedAdaptation(TileIndex signal_tile, uint16 signal_track, int offset, int16 z_pos)
+	{
+		int end = this->RealEndPosition();
+		this->items.push_back({ end + offset, end + offset, z_pos, signal_tile, signal_track, TRLIT_SPEED_ADAPTATION });
+	}
+
 	void SetNextExtendPosition();
 
 	void SetNextExtendPositionIfUnset()

src/sl/extended_ver_sl.cpp

@@ -157,7 +157,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_ANIMATED_TILE_EXTRA,              XSCF_NULL,                1,   1, "animated_tile_extra",              nullptr, nullptr, nullptr          },
 	{ XSLFI_NEWGRF_INFO_EXTRA,                XSCF_NULL,                1,   1, "newgrf_info_extra",                nullptr, nullptr, nullptr          },
 	{ XSLFI_INDUSTRY_CARGO_ADJ,               XSCF_IGNORABLE_UNKNOWN,   1,   1, "industry_cargo_adj",               nullptr, nullptr, nullptr          },
-	{ XSLFI_REALISTIC_TRAIN_BRAKING,          XSCF_NULL,                9,   9, "realistic_train_braking",          nullptr, nullptr, "VLKA"           },
+	{ XSLFI_REALISTIC_TRAIN_BRAKING,          XSCF_NULL,               10,  10, "realistic_train_braking",          nullptr, nullptr, "VLKA"           },
 	{ XSLFI_INFLATION_FIXED_DATES,            XSCF_IGNORABLE_ALL,       1,   1, "inflation_fixed_dates",            nullptr, nullptr, nullptr          },
 	{ XSLFI_WATER_FLOODING,                   XSCF_NULL,                2,   2, "water_flooding",                   nullptr, nullptr, nullptr          },
 	{ XSLFI_MORE_HOUSES,                      XSCF_NULL,                2,   2, "more_houses",                      nullptr, nullptr, nullptr          },

src/sl/vehicle_sl.cpp

@@ -1513,7 +1513,8 @@ const SaveLoadTable GetVehicleLookAheadItemDescription()
 		     SLE_VAR(TrainReservationLookAheadItem, start,                    SLE_INT32),
 		     SLE_VAR(TrainReservationLookAheadItem, end,                      SLE_INT32),
 		     SLE_VAR(TrainReservationLookAheadItem, z_pos,                    SLE_INT16),
-		     SLE_VAR(TrainReservationLookAheadItem, data_id,                  SLE_UINT16),
+		SLE_CONDVAR_X(TrainReservationLookAheadItem, data_id, SLE_FILE_U16 | SLE_VAR_U32,  SL_MIN_VERSION, SL_MAX_VERSION, SlXvFeatureTest(XSLFTO_AND, XSLFI_REALISTIC_TRAIN_BRAKING, 0, 9)),
+		SLE_CONDVAR_X(TrainReservationLookAheadItem, data_id,                 SLE_UINT32,  SL_MIN_VERSION, SL_MAX_VERSION, SlXvFeatureTest(XSLFTO_AND, XSLFI_REALISTIC_TRAIN_BRAKING, 10)),
 		SLE_CONDVAR_X(TrainReservationLookAheadItem, data_aux,                SLE_UINT16,  SL_MIN_VERSION, SL_MAX_VERSION, SlXvFeatureTest(XSLFTO_AND, XSLFI_REALISTIC_TRAIN_BRAKING, 9)),
 		     SLE_VAR(TrainReservationLookAheadItem, type,                     SLE_UINT8),
 	};

src/table/newgrf_debug_data.h

@@ -401,6 +401,15 @@ class NIHVehicle : public NIHelper {
 							if (_settings_game.vehicle.train_acceleration_model != AM_ORIGINAL) print_braking_speed(item.start, item.data_id, item.z_pos);
 
 							break;
+						case TRLIT_SPEED_ADAPTATION: {
+							TileIndex tile = item.data_id;
+							uint16 td = item.data_aux;
+							b += seprintf(b, lastof(buffer), "speed adaptation: tile: %X, trackdir: %X", tile, td);
+							if (item.end + 1 < l.reservation_end_position) {
+								b += seprintf(b, lastof(buffer), " --> %u", GetLowestSpeedTrainAdaptationSpeedAtSignal(tile, td));
+							}
+							break;
+						}
 					}
 					output.print(buffer);
 				}
@@ -1411,17 +1420,17 @@ class NIHSignals : public NIHelper {
 			DumpTunnelBridgeSignalsInfo(buffer, lastof(buffer), index, output);
 		}
 		if (_settings_game.vehicle.train_speed_adaptation) {
-			for (const auto &it : _signal_speeds) {
-				if (it.first.signal_tile == index) {
-					char *b = buffer + seprintf(buffer, lastof(buffer), "Speed adaptation: Track: %X, last dir: %X --> speed: %u",
-							it.first.signal_track, it.first.last_passing_train_dir, it.second.train_speed);
-					if (it.second.IsOutOfDate()) {
-						b += seprintf(b, lastof(buffer), ", expired");
-					} else {
-						b += seprintf(b, lastof(buffer), ", expires in %u ticks", (uint)(it.second.time_stamp - _scaled_date_ticks));
-					}
-					output.print(buffer);
+			SignalSpeedKey speed_key = { index, 0, (Trackdir)0 };
+			for (auto iter = _signal_speeds.lower_bound(speed_key); iter != _signal_speeds.end() && iter->first.signal_tile == index; ++iter) {
+				const auto &it = *iter;
+				char *b = buffer + seprintf(buffer, lastof(buffer), "Speed adaptation: Track: %X, last dir: %X --> speed: %u",
+						it.first.signal_track, it.first.last_passing_train_dir, it.second.train_speed);
+				if (it.second.IsOutOfDate()) {
+					b += seprintf(b, lastof(buffer), ", expired");
+				} else {
+					b += seprintf(b, lastof(buffer), ", expires in %u ticks", (uint)(it.second.time_stamp - _scaled_date_ticks));
 				}
+				output.print(buffer);
 			}
 		}
 	}

src/train_cmd.cpp

@@ -81,7 +81,7 @@ enum ChooseTrainTrackFlags {
 };
 DECLARE_ENUM_AS_BIT_SET(ChooseTrainTrackFlags)
 
-std::unordered_map<SignalSpeedKey, SignalSpeedValue, SignalSpeedKeyHashFunc> _signal_speeds(1 << 16);
+btree::btree_map<SignalSpeedKey, SignalSpeedValue> _signal_speeds;
 
 static void TryLongReserveChooseTrainTrackFromReservationEnd(Train *v, bool no_reserve_vehicle_tile = false);
 static Track ChooseTrainTrack(Train *v, TileIndex tile, DiagDirection enterdir, TrackBits tracks, ChooseTrainTrackFlags flags, bool *p_got_reservation, ChooseTrainTrackLookAheadState lookahead_state = {});
@@ -966,6 +966,9 @@ static void ApplyLookAheadItem(const Train *v, const TrainReservationLookAheadIt
 		case TRLIT_CURVE_SPEED:
 			if (_settings_game.vehicle.train_acceleration_model != AM_ORIGINAL) limit_speed(item.start, item.data_id, item.z_pos);
 			break;
+
+		case TRLIT_SPEED_ADAPTATION:
+			break;
 	}
 }
 
@@ -7566,27 +7569,70 @@ void SetSignalTrainAdaptationSpeed(const Train *v, TileIndex tile, uint16 track)
 	_signal_speeds[speed_key] = speed_value;
 }
 
-void ApplySignalTrainAdaptationSpeed(Train *v, TileIndex tile, uint16 track)
+static uint16 GetTrainAdaptationSpeed(TileIndex tile, uint16 track, Trackdir last_passing_train_dir)
 {
 	SignalSpeedKey speed_key = {
 		speed_key.signal_tile = tile,
 		speed_key.signal_track = track,
-		speed_key.last_passing_train_dir = v->GetVehicleTrackdir()
+		speed_key.last_passing_train_dir = last_passing_train_dir
 	};
 	const auto found_speed_restriction = _signal_speeds.find(speed_key);
 
 	if (found_speed_restriction != _signal_speeds.end()) {
 		if (found_speed_restriction->second.IsOutOfDate()) {
 			_signal_speeds.erase(found_speed_restriction);
-			v->signal_speed_restriction = 0;
+			return 0;
 		} else {
-			v->signal_speed_restriction = std::max<uint16>(25, found_speed_restriction->second.train_speed);
+			return std::max<uint16>(25, found_speed_restriction->second.train_speed);
 		}
 	} else {
-		v->signal_speed_restriction = 0;
+		return 0;
 	}
 }
 
+void ApplySignalTrainAdaptationSpeed(Train *v, TileIndex tile, uint16 track)
+{
+	uint16 speed = GetTrainAdaptationSpeed(tile, track, v->GetVehicleTrackdir());
+
+	if (speed > 0 && v->lookahead != nullptr) {
+		for (const TrainReservationLookAheadItem &item : v->lookahead->items) {
+			if (item.type == TRLIT_SPEED_ADAPTATION && item.end + 1 < v->lookahead->reservation_end_position) {
+				uint16 signal_speed = GetLowestSpeedTrainAdaptationSpeedAtSignal(item.data_id, item.data_aux);
+
+				if (signal_speed == 0) {
+					/* unrestricted signal ahead, disregard speed adaptation at earlier signal */
+					v->signal_speed_restriction = 0;
+					return;
+				}
+				if (signal_speed > speed) {
+					/* signal ahead with higher speed adaptation speed, override speed adaptation at earlier signal */
+					speed = signal_speed;
+				}
+			}
+		}
+	}
+
+	v->signal_speed_restriction = speed;
+}
+
+uint16 GetLowestSpeedTrainAdaptationSpeedAtSignal(TileIndex tile, uint16 track)
+{
+	uint16 lowest_speed = 0;
+
+	SignalSpeedKey speed_key = { tile, track, (Trackdir)0 };
+	for (auto iter = _signal_speeds.lower_bound(speed_key); iter != _signal_speeds.end() && iter->first.signal_tile == tile && iter->first.signal_track == track;) {
+		if (iter->second.IsOutOfDate()) {
+			iter = _signal_speeds.erase(iter);
+		} else {
+			uint16 adapt_speed = std::max<uint16>(25, iter->second.train_speed);
+			if (lowest_speed == 0 || adapt_speed < lowest_speed) lowest_speed = adapt_speed;
+			++iter;
+		}
+	}
+
+	return lowest_speed;
+}
+
 uint16 Train::GetMaxWeight() const
 {
 	uint16 weight = CargoSpec::Get(this->cargo_type)->WeightOfNUnitsInTrain(this->GetEngine()->DetermineCapacity(this));

src/train_speed_adaptation.h

@@ -14,8 +14,7 @@
 #include "date_func.h"
 #include "track_type.h"
 #include "tile_type.h"
-
-#include <unordered_map>
+#include "3rdparty/cpp-btree/btree_map.h"
 
 struct SignalSpeedKey {
 	TileIndex signal_tile;
@@ -28,6 +27,11 @@ struct SignalSpeedKey {
 			signal_track == other.signal_track &&
 			last_passing_train_dir == other.last_passing_train_dir;
 	}
+
+	bool operator<(const SignalSpeedKey& other) const
+	{
+		return std::tie(this->signal_tile, this->signal_track, this->last_passing_train_dir) < std::tie(other.signal_tile, other.signal_track, other.last_passing_train_dir);
+	}
 };
 
 struct SignalSpeedValue {
@@ -41,21 +45,11 @@ struct SignalSpeedValue {
 	}
 };
 
-struct SignalSpeedKeyHashFunc {
-	std::size_t operator() (const SignalSpeedKey &key) const
-	{
-		const std::size_t h1 = std::hash<TileIndex>()(key.signal_tile);
-		const std::size_t h2 = std::hash<Trackdir>()(key.last_passing_train_dir);
-		const std::size_t h3 = std::hash<uint16>()(key.signal_track);
-
-		return (h1 ^ h2) ^ h3;
-	}
-};
-
-extern std::unordered_map<SignalSpeedKey, SignalSpeedValue, SignalSpeedKeyHashFunc> _signal_speeds;
+extern btree::btree_map<SignalSpeedKey, SignalSpeedValue> _signal_speeds;
 
 struct Train;
 void SetSignalTrainAdaptationSpeed(const Train *v, TileIndex tile, uint16 track);
 void ApplySignalTrainAdaptationSpeed(Train *v, TileIndex tile, uint16 track);
+uint16 GetLowestSpeedTrainAdaptationSpeedAtSignal(TileIndex tile, uint16 track);
 
 #endif /* TRAIN_SPEED_ADAPTATION_H */