Proper Propa

- Improvements to graph building
- Fixed a number of issues caused by junctions and inconsistent track propagation
- Trains no longer disassemble with reversed carriage spacing
- Trains can no longer jump to perpendicular tracks on an intersection

src/main/java/com/simibubi/create/content/logistics/trains/ITrackBlock.java

@@ -1,9 +1,18 @@
 package com.simibubi.create.content.logistics.trains;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+
+import javax.annotation.Nullable;
 
 import com.jozufozu.flywheel.core.PartialModel;
 import com.mojang.blaze3d.vertex.PoseStack;
+import com.simibubi.create.content.logistics.trains.TrackNodeLocation.DiscoveredLocation;
+import com.simibubi.create.content.logistics.trains.track.TrackBlock;
+import com.simibubi.create.content.logistics.trains.track.TrackShape;
 import com.simibubi.create.foundation.utility.Iterate;
 import com.simibubi.create.foundation.utility.Pair;
 
@@ -32,6 +41,67 @@ public interface ITrackBlock {
 		return existing;
 	}
 
+	public default double getElevationAtCenter(BlockGetter world, BlockPos pos, BlockState state) {
+		return isSlope(world, pos, state) ? .5 : 0;
+	}
+
+	public static Collection<DiscoveredLocation> walkConnectedTracks(BlockGetter world, TrackNodeLocation location,
+		boolean linear) {
+		List<DiscoveredLocation> list = new ArrayList<>();
+		for (BlockPos blockPos : location.allAdjacent()) {
+			BlockState blockState = world.getBlockState(blockPos);
+			if (blockState.getBlock()instanceof ITrackBlock track)
+				list.addAll(track.getConnected(world, blockPos, blockState, linear, location));
+		}
+		return list;
+	}
+
+	public default Collection<DiscoveredLocation> getConnected(BlockGetter world, BlockPos pos, BlockState state,
+		boolean linear, @Nullable TrackNodeLocation connectedTo) {
+		Vec3 center = Vec3.atBottomCenterOf(pos)
+			.add(0, getElevationAtCenter(world, pos, state), 0);
+		List<DiscoveredLocation> list = new ArrayList<>();
+		TrackShape shape = state.getValue(TrackBlock.SHAPE);
+		getTrackAxes(world, pos, state).forEach(axis -> {
+			addToListIfConnected(connectedTo, list, (d, b) -> axis.scale(b ? d : -d)
+				.add(center), b -> shape.getNormal(), null);
+		});
+
+		return list;
+	}
+
+	public static void addToListIfConnected(@Nullable TrackNodeLocation fromEnd, Collection<DiscoveredLocation> list,
+		BiFunction<Double, Boolean, Vec3> offsetFactory, Function<Boolean, Vec3> normalFactory,
+		BezierConnection viaTurn) {
+
+		DiscoveredLocation firstLocation = new DiscoveredLocation(offsetFactory.apply(0.5d, true)).viaTurn(viaTurn)
+			.withNormal(normalFactory.apply(true));
+		DiscoveredLocation secondLocation = new DiscoveredLocation(offsetFactory.apply(0.5d, false)).viaTurn(viaTurn)
+			.withNormal(normalFactory.apply(false));
+
+		boolean skipFirst = false;
+		boolean skipSecond = false;
+
+		if (fromEnd != null) {
+			boolean equalsFirst = firstLocation.equals(fromEnd);
+			boolean equalsSecond = secondLocation.equals(fromEnd);
+
+			// not reachable from this end
+			if (!equalsFirst && !equalsSecond)
+				return;
+
+			if (equalsFirst)
+				skipFirst = true;
+			if (equalsSecond)
+				skipSecond = true;
+		}
+
+		if (!skipFirst)
+			list.add(firstLocation);
+		if (!skipSecond)
+			list.add(secondLocation);
+	}
+
 	@OnlyIn(Dist.CLIENT)
 	public PartialModel prepareStationOverlay(BlockGetter world, BlockPos pos, BlockState state,
 		AxisDirection direction, PoseStack transform);

src/main/java/com/simibubi/create/content/logistics/trains/TrackGraph.java

@@ -409,11 +409,12 @@ public class TrackGraph {
 			if (location.distanceTo(camera) > 50)
 				continue;
 
-			Vec3 v1 = location.add(0, 3 / 16f, 0);
+			Vec3 yOffset = new Vec3(0, 3 / 16f, 0);
-			Vec3 v2 = v1.add(node.normal.scale(0.75f));
+			Vec3 v1 = location.add(yOffset);
+			Vec3 v2 = v1.add(node.normal.scale(0.125f));
 			CreateClient.OUTLINER.showLine(Integer.valueOf(node.netId), v1, v2)
 				.colored(Color.mixColors(Color.WHITE, color, 1))
-				.lineWidth(1 / 8f);
+				.lineWidth(1 / 4f);
 
 			Map<TrackNode, TrackEdge> map = connectionsByNode.get(node);
 			if (map == null)
@@ -428,8 +429,10 @@ public class TrackGraph {
 
 				TrackEdge edge = entry.getValue();
 				if (!edge.isTurn()) {
-					CreateClient.OUTLINER
+					CreateClient.OUTLINER.showLine(edge, edge.getPosition(node, other, 0)
-						.showLine(edge, edge.getPosition(node, other, 0), edge.getPosition(node, other, 1))
+						.add(yOffset),
+						edge.getPosition(node, other, 1)
+							.add(yOffset))
 						.colored(color)
 						.lineWidth(1 / 16f);
 					continue;
@@ -440,7 +443,7 @@ public class TrackGraph {
 				for (int i = 0; i <= turn.getSegmentCount(); i++) {
 					Vec3 current = edge.getPosition(node, other, i * 1f / turn.getSegmentCount());
 					if (previous != null)
-						CreateClient.OUTLINER.showLine(previous, previous, current)
+						CreateClient.OUTLINER.showLine(previous, previous.add(yOffset), current.add(yOffset))
 							.colored(color)
 							.lineWidth(1 / 16f);
 					previous = current;

src/main/java/com/simibubi/create/content/logistics/trains/TrackGraphHelper.java

@@ -1,12 +1,13 @@
 package com.simibubi.create.content.logistics.trains;
 
-import java.util.List;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
 
 import com.simibubi.create.Create;
 import com.simibubi.create.content.logistics.trains.TrackNodeLocation.DiscoveredLocation;
 import com.simibubi.create.content.logistics.trains.management.GraphLocation;
 import com.simibubi.create.foundation.utility.Couple;
-import com.simibubi.create.foundation.utility.Pair;
 
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction.AxisDirection;
@@ -24,48 +25,88 @@ public class TrackGraphHelper {
 
 		Vec3 axis = targetAxis.scale(targetDirection.getStep());
 		double length = axis.length();
-
-		List<Pair<BlockPos, DiscoveredLocation>> ends =
-			TrackPropagator.getEnds(level, pos, trackBlockState, true, null, null);
-
 		TrackGraph graph = null;
+
+		// Case 1: Centre of block lies on a node
+
+		TrackNodeLocation location = new TrackNodeLocation(Vec3.atBottomCenterOf(pos)
+			.add(0, track.getElevationAtCenter(level, pos, trackBlockState), 0));
+		graph = Create.RAILWAYS.getGraph(level, location);
+		if (graph != null) {
+			TrackNode node = graph.locateNode(location);
+			if (node != null) {
+				Map<TrackNode, TrackEdge> connectionsFrom = graph.getConnectionsFrom(node);
+				for (Entry<TrackNode, TrackEdge> entry : connectionsFrom.entrySet()) {
+					TrackNode backNode = entry.getKey();
+					Vec3 direction = entry.getValue()
+						.getDirection(node, backNode, true);
+					if (direction.scale(length)
+						.distanceToSqr(axis.scale(-1)) > 1 / 4096f)
+						continue;
+
+					GraphLocation graphLocation = new GraphLocation();
+					graphLocation.edge = Couple.create(node.getLocation(), backNode.getLocation());
+					graphLocation.position = 0;
+					graphLocation.graph = graph;
+					return graphLocation;
+				}
+			}
+		}
+
+		// Case 2: Center of block is between two nodes
+
+		Collection<DiscoveredLocation> ends = track.getConnected(level, pos, trackBlockState, true, null);
+		Vec3 start = Vec3.atBottomCenterOf(pos)
+			.add(0, track.getElevationAtCenter(level, pos, trackBlockState), 0);
+
 		TrackNode frontNode = null;
 		TrackNode backNode = null;
 		double position = 0;
 
-		for (Pair<BlockPos, DiscoveredLocation> pair : ends) {
+		for (DiscoveredLocation current : ends) {
-			DiscoveredLocation current = pair.getSecond();
+			Vec3 offset = current.getLocation()
-			BlockPos currentPos = pair.getFirst();
+				.subtract(start)
-			Vec3 offset = Vec3.atLowerCornerOf(currentPos.subtract(pos));
+				.normalize()
+				.scale(length);
+
 			boolean forward = offset.distanceToSqr(axis.scale(-1)) < 1 / 4096f;
 			boolean backwards = offset.distanceToSqr(axis) < 1 / 4096f;
 
 			if (!forward && !backwards)
 				continue;
 
-			for (int i = 0; i < 32; i++) {
+			DiscoveredLocation previous = null;
+			double distance = 0;
+			for (int i = 0; i < 100 && distance < 32; i++) {
 				DiscoveredLocation loc = current;
-				List<Pair<BlockPos, DiscoveredLocation>> list =
-					TrackPropagator.getEnds(level, currentPos, level.getBlockState(currentPos), true, current, null);
-				if (!list.isEmpty()) {
-					currentPos = list.get(0)
-						.getFirst();
-					current = list.get(0)
-						.getSecond();
-				}
-
 				if (graph == null)
 					graph = Create.RAILWAYS.getGraph(level, loc);
-				if (graph == null)
+
+				if (graph == null || graph.locateNode(loc) == null) {
+					Collection<DiscoveredLocation> list = ITrackBlock.walkConnectedTracks(level, loc, true);
+					for (DiscoveredLocation discoveredLocation : list) {
+						if (discoveredLocation == previous)
 							continue;
+						Vec3 diff = discoveredLocation.getLocation()
+							.subtract(loc.getLocation());
+						if ((forward ? axis.scale(-1) : axis).distanceToSqr(diff.normalize()
+							.scale(length)) > 1 / 4096f)
+							continue;
+
+						previous = current;
+						current = discoveredLocation;
+						distance += diff.length();
+						break;
+					}
+					continue;
+				}
+
 				TrackNode node = graph.locateNode(loc);
-				if (node == null)
-					continue;
 				if (forward)
 					frontNode = node;
 				if (backwards) {
 					backNode = node;
-					position = (i + .5) * length;
+					position = distance + .5;
 				}
 				break;
 			}

src/main/java/com/simibubi/create/content/logistics/trains/TrackNodeLocation.java

@@ -1,5 +1,11 @@
 package com.simibubi.create.content.logistics.trains;
 
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+import com.simibubi.create.foundation.utility.Iterate;
+
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Vec3i;
 import net.minecraft.world.phys.Vec3;
@@ -36,9 +42,21 @@ public class TrackNodeLocation extends Vec3i {
 		return (this.getY() + this.getZ() * 31) * 31 + this.getX();
 	}
 
+	public Collection<BlockPos> allAdjacent() {
+		Set<BlockPos> set = new HashSet<>();
+		Vec3 vec3 = getLocation();
+		double step = 1 / 8f;
+		for (int x : Iterate.positiveAndNegative)
+			for (int y : Iterate.positiveAndNegative)
+				for (int z : Iterate.positiveAndNegative)
+					set.add(new BlockPos(vec3.add(x * step, y * step, z * step)));
+		return set;
+	}
+
 	public static class DiscoveredLocation extends TrackNodeLocation {
 
 		BezierConnection turn = null;
+		boolean forceNode = false;
 		Vec3 normal;
 
 		public DiscoveredLocation(double p_121865_, double p_121866_, double p_121867_) {
@@ -51,6 +69,13 @@ public class TrackNodeLocation extends Vec3i {
 
 		public DiscoveredLocation viaTurn(BezierConnection turn) {
 			this.turn = turn;
+			if (turn != null)
+				forceNode();
+			return this;
+		}
+		
+		public DiscoveredLocation forceNode() {
+			forceNode = true;
 			return this;
 		}
 		
@@ -67,6 +92,10 @@ public class TrackNodeLocation extends Vec3i {
 			return turn;
 		}
 		
+		public boolean shouldForceNode() {
+			return forceNode;
+		}
+
 	}
 
 }

src/main/java/com/simibubi/create/content/logistics/trains/TrackPropagator.java

@@ -1,101 +1,89 @@
 package com.simibubi.create.content.logistics.trains;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
-import java.util.function.BiFunction;
-import java.util.function.Function;
-
-import javax.annotation.Nullable;
 
 import com.simibubi.create.Create;
 import com.simibubi.create.content.logistics.trains.TrackNodeLocation.DiscoveredLocation;
-import com.simibubi.create.content.logistics.trains.track.TrackBlock;
-import com.simibubi.create.content.logistics.trains.track.TrackShape;
-import com.simibubi.create.content.logistics.trains.track.TrackTileEntity;
-import com.simibubi.create.foundation.utility.Pair;
-import com.simibubi.create.foundation.utility.VecHelper;
 
 import net.minecraft.core.BlockPos;
 import net.minecraft.util.Mth;
 import net.minecraft.world.level.LevelAccessor;
-import net.minecraft.world.level.LevelReader;
-import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.phys.Vec3;
 
 public class TrackPropagator {
 
 	static class FrontierEntry {
-		BlockPos prevPos;
 		DiscoveredLocation prevNode;
-		BlockPos currentPos;
 		DiscoveredLocation currentNode;
 		DiscoveredLocation parentNode;
 
-		public FrontierEntry(BlockPos previousPos, BlockPos pos, DiscoveredLocation location) {
+		public FrontierEntry(DiscoveredLocation parent, DiscoveredLocation previousNode, DiscoveredLocation location) {
-			this(null, previousPos, null, pos, location);
-		}
-
-		public FrontierEntry(DiscoveredLocation parent, BlockPos previousPos, DiscoveredLocation previousNode,
-			BlockPos pos, DiscoveredLocation location) {
 			parentNode = parent;
-			prevPos = previousPos;
 			prevNode = previousNode;
-			currentPos = pos;
 			currentNode = location;
 		}
 	}
 
 	public static void onRailRemoved(LevelAccessor reader, BlockPos pos, BlockState state) {
-		List<Pair<BlockPos, DiscoveredLocation>> ends = getEnds(reader, pos, state, false, null, null);
+		if (!(state.getBlock()instanceof ITrackBlock track))
-		TrackGraph foundGraph = null;
+			return;
+
+		Collection<DiscoveredLocation> ends = track.getConnected(reader, pos, state, false, null);
 		GlobalRailwayManager manager = Create.RAILWAYS;
 		TrackGraphSync sync = manager.sync;
+		TrackGraph foundGraph = null;
 
-		for (Pair<BlockPos, DiscoveredLocation> removedEnd : ends) {
+		// 1. Remove any nodes this rail was part of
-			DiscoveredLocation removedLocation = removedEnd.getSecond();
+		
+		for (DiscoveredLocation removedLocation : ends) {
 			if (foundGraph == null)
 				foundGraph = manager.getGraph(reader, removedLocation);
-			if (foundGraph != null) {
+			if (foundGraph == null)
+				continue;
 			TrackNode removedNode = foundGraph.locateNode(removedLocation);
 			if (removedNode != null) {
 				foundGraph.removeNode(reader, removedLocation);
 				sync.nodeRemoved(foundGraph, removedNode);
 			}
 		}
-		}
 
 		if (foundGraph != null && foundGraph.isEmpty()) {
 			manager.removeGraph(foundGraph);
 			sync.graphRemoved(foundGraph);
 		}
 
+		Set<BlockPos> positionsToUpdate = new HashSet<>();
+		for (DiscoveredLocation removedEnd : ends)
+			positionsToUpdate.addAll(removedEnd.allAdjacent());
+
+		// 2. Re-run railAdded for any track that was disconnected from this track
+		
 		Set<TrackGraph> toUpdate = new HashSet<>();
-		for (Pair<BlockPos, DiscoveredLocation> removedEnd : ends) {
+		for (BlockPos blockPos : positionsToUpdate)
-			BlockPos adjPos = removedEnd.getFirst();
+			if (!blockPos.equals(pos)) {
-			BlockState adjState = reader.getBlockState(adjPos);
+				TrackGraph onRailAdded = onRailAdded(reader, blockPos, reader.getBlockState(blockPos));
-			List<Pair<BlockPos, DiscoveredLocation>> adjEnds =
+				if (onRailAdded != null)
-				getEnds(reader, adjPos, adjState, true, removedEnd.getSecond(), null);
+					toUpdate.add(onRailAdded);
-			if (adjEnds.isEmpty())
-				continue;
-			Vec3 filter = adjEnds.get(0)
-				.getSecond()
-				.getLocation()
-				.subtract(removedEnd.getSecond()
-					.getLocation());
-			toUpdate.add(onRailAdded(reader, adjPos, adjState, filter.normalize()));
 			}
 		
+		// 3. Ensure any affected graph gets checked for segmentation
+
 		for (TrackGraph railGraph : toUpdate)
 			manager.updateSplitGraph(railGraph);
 
 		manager.markTracksDirty();
 	}
 
-	public static TrackGraph onRailAdded(LevelAccessor reader, BlockPos pos, BlockState state, Vec3 axisFilter) {
+	public static TrackGraph onRailAdded(LevelAccessor reader, BlockPos pos, BlockState state) {
+		if (!(state.getBlock()instanceof ITrackBlock track))
+			return null;
+
 		// 1. Remove all immediately reachable node locations
 
 		GlobalRailwayManager manager = Create.RAILWAYS;
@@ -103,7 +91,7 @@ public class TrackPropagator {
 		List<FrontierEntry> frontier = new ArrayList<>();
 		Set<DiscoveredLocation> visited = new HashSet<>();
 		Set<TrackGraph> connectedGraphs = new HashSet<>();
-		addInitialEndsOf(reader, pos, state, frontier, false, axisFilter);
+		addInitialEndsOf(reader, pos, state, track, frontier, false);
 
 		int emergencyExit = 1000;
 		while (!frontier.isEmpty()) {
@@ -111,7 +99,6 @@ public class TrackPropagator {
 				break;
 
 			FrontierEntry entry = frontier.remove(0);
-			List<Pair<BlockPos, DiscoveredLocation>> ends = findReachableEnds(reader, entry);
 			TrackGraph graph = manager.getGraph(reader, entry.currentNode);
 			if (graph != null) {
 				TrackNode node = graph.locateNode(entry.currentNode);
@@ -121,6 +108,9 @@ public class TrackPropagator {
 				continue;
 			}
 
+			Collection<DiscoveredLocation> ends = ITrackBlock.walkConnectedTracks(reader, entry.currentNode, false);
+			if (entry.prevNode != null)
+				ends.remove(entry.prevNode);
 			continueSearch(frontier, visited, entry, ends);
 		}
 
@@ -157,11 +147,10 @@ public class TrackPropagator {
 			manager.putGraph(graph = new TrackGraph());
 
 		DiscoveredLocation startNode = null;
-		List<BlockPos> startPositions = new ArrayList<>();
 
 		// 2. Find the first graph node candidate nearby
 
-		addInitialEndsOf(reader, pos, state, frontier, true, axisFilter);
+		addInitialEndsOf(reader, pos, state, track, frontier, true);
 
 		emergencyExit = 1000;
 		while (!frontier.isEmpty()) {
@@ -169,26 +158,12 @@ public class TrackPropagator {
 				break;
 
 			FrontierEntry entry = frontier.remove(0);
-
+			Collection<DiscoveredLocation> ends = ITrackBlock.walkConnectedTracks(reader, entry.currentNode, false);
-//			CreateClient.OUTLINER
+			boolean first = entry.prevNode == null;
-//				.showAABB(entry.currentNode, new AABB(entry.currentNode.getLocation(), entry.currentNode.getLocation()
+			if (!first)
-//					.add(0, 2, 0)), 120)
+				ends.remove(entry.prevNode);
-//				.colored(Color.GREEN)
+			if (isValidGraphNodeLocation(entry.currentNode, ends, first)) {
-//				.lineWidth(1 / 16f);
-//			CreateClient.OUTLINER.showAABB(entry.currentPos, new AABB(entry.currentPos).contract(0, 1, 0), 120)
-//				.colored(0x7777ff)
-//				.lineWidth(1 / 16f);
-//			if (entry.prevPos != null) {
-//				CreateClient.OUTLINER.showAABB(entry.prevPos, new AABB(entry.prevPos).contract(0, 1, 0), 120)
-//					.colored(0x3333aa)
-//					.lineWidth(1 / 16f);
-//			}
-
-			List<Pair<BlockPos, DiscoveredLocation>> ends = findReachableEnds(reader, entry);
-			if (isValidGraphNodeLocation(entry.currentNode, ends)) {
 				startNode = entry.currentNode;
-				startPositions.add(entry.prevPos);
-				startPositions.add(entry.currentPos);
 				break;
 			}
 
@@ -199,12 +174,7 @@ public class TrackPropagator {
 		if (graph.createNode(startNode))
 			sync.nodeAdded(graph, graph.locateNode(startNode));
 
-//		CreateClient.OUTLINER.showAABB(graph, new AABB(startNode.getLocation(), startNode.getLocation()
+		frontier.add(new FrontierEntry(startNode, null, startNode));
-//			.add(0, 2, 0)), 20)
-//			.lineWidth(1 / 32f);
-
-		for (BlockPos position : startPositions)
-			frontier.add(new FrontierEntry(startNode, null, null, position, startNode));
 
 		// 3. Build up the graph via all connected nodes
 
@@ -215,9 +185,12 @@ public class TrackPropagator {
 
 			FrontierEntry entry = frontier.remove(0);
 			DiscoveredLocation parentNode = entry.parentNode;
-			List<Pair<BlockPos, DiscoveredLocation>> ends = findReachableEnds(reader, entry);
+			Collection<DiscoveredLocation> ends = ITrackBlock.walkConnectedTracks(reader, entry.currentNode, false);
+			boolean first = entry.prevNode == null;
+			if (!first)
+				ends.remove(entry.prevNode);
 
-			if (isValidGraphNodeLocation(entry.currentNode, ends) && entry.currentNode != startNode) {
+			if (isValidGraphNodeLocation(entry.currentNode, ends, first) && entry.currentNode != startNode) {
 				boolean nodeIsNew = graph.createNode(entry.currentNode);
 				if (nodeIsNew)
 					sync.nodeAdded(graph, graph.locateNode(entry.currentNode));
@@ -234,70 +207,35 @@ public class TrackPropagator {
 		return graph;
 	}
 
-	private static void addInitialEndsOf(LevelAccessor reader, BlockPos pos, BlockState state,
+	private static void addInitialEndsOf(LevelAccessor reader, BlockPos pos, BlockState state, ITrackBlock track,
-		List<FrontierEntry> frontier, boolean ignoreTurns, Vec3 axisFilter) {
+		List<FrontierEntry> frontier, boolean ignoreTurns) {
-		for (Pair<BlockPos, DiscoveredLocation> initial : getEnds(reader, pos, state, ignoreTurns, null, axisFilter))
+		for (DiscoveredLocation initial : track.getConnected(reader, pos, state, ignoreTurns, null)) {
-			frontier.add(new FrontierEntry(initial.getFirst(), pos, initial.getSecond()));
+			frontier.add(new FrontierEntry(null, null, initial));
 		}
-
-	private static List<Pair<BlockPos, DiscoveredLocation>> findReachableEnds(LevelAccessor reader,
-		FrontierEntry entry) {
-		BlockState currentState = reader.getBlockState(entry.currentPos);
-		List<Pair<BlockPos, DiscoveredLocation>> ends = new ArrayList<>();
-
-		if (entry.prevNode != null) {
-			BlockPos prevPos = entry.prevPos;
-
-			// PrevPos correction after a turn
-			if (entry.currentNode.connectedViaTurn()) {
-				boolean slope = false;
-				if (currentState.getBlock()instanceof ITrackBlock track)
-					slope = track.isSlope(reader, entry.currentPos, currentState);
-				BlockPos offset = new BlockPos(VecHelper.getCenterOf(entry.currentPos)
-					.subtract(entry.currentNode.getLocation()
-						.add(0, slope ? 0 : .5f, 0))
-					.scale(-2));
-				prevPos = entry.currentPos.offset(offset);
-			}
-
-			for (Pair<BlockPos, DiscoveredLocation> pair : getEnds(reader, prevPos, reader.getBlockState(prevPos),
-				false, entry.currentNode, null))
-				if (!pair.getSecond()
-					.equals(entry.prevNode))
-					ends.add(pair);
-		}
-
-		ends.addAll(getEnds(reader, entry.currentPos, currentState, false, entry.currentNode, null));
-		return ends;
 	}
 
 	private static void continueSearch(List<FrontierEntry> frontier, Set<DiscoveredLocation> visited,
-		FrontierEntry entry, List<Pair<BlockPos, DiscoveredLocation>> ends) {
+		FrontierEntry entry, Collection<DiscoveredLocation> ends) {
-		for (Pair<BlockPos, DiscoveredLocation> pair : ends)
+		for (DiscoveredLocation location : ends)
-			if (visited.add(pair.getSecond()))
+			if (visited.add(location))
-				frontier.add(
+				frontier.add(new FrontierEntry(null, entry.currentNode, location));
-					new FrontierEntry(null, entry.currentPos, entry.currentNode, pair.getFirst(), pair.getSecond()));
 	}
 
 	private static void continueSearchWithParent(List<FrontierEntry> frontier, FrontierEntry entry,
-		DiscoveredLocation parentNode, List<Pair<BlockPos, DiscoveredLocation>> ends) {
+		DiscoveredLocation parentNode, Collection<DiscoveredLocation> ends) {
-		for (Pair<BlockPos, DiscoveredLocation> pair : ends)
+		for (DiscoveredLocation location : ends)
-			frontier.add(
+			frontier.add(new FrontierEntry(parentNode, entry.currentNode, location));
-				new FrontierEntry(parentNode, entry.currentPos, entry.currentNode, pair.getFirst(), pair.getSecond()));
 	}
 
-	public static boolean isValidGraphNodeLocation(DiscoveredLocation location,
+	public static boolean isValidGraphNodeLocation(DiscoveredLocation location, Collection<DiscoveredLocation> next,
-		List<Pair<BlockPos, DiscoveredLocation>> next) {
+		boolean first) {
-		if (next.size() != 1)
+		int size = next.size() - (first ? 1 : 0);
+		if (size != 1)
 			return true;
-		if (location.connectedViaTurn())
+		if (location.shouldForceNode())
 			return true;
-
+		if (next.stream()
-		DiscoveredLocation nextLocation = next.iterator()
+			.anyMatch(DiscoveredLocation::connectedViaTurn))
-			.next()
-			.getSecond();
-
-		if (nextLocation.connectedViaTurn())
 			return true;
 
 		Vec3 vec = location.getLocation();
@@ -308,86 +246,4 @@ public class TrackPropagator {
 		return ((int) Math.round(vec.x)) % 16 == 0;
 	}
 
-	// TODO ITrackBlock
-	public static List<Pair<BlockPos, DiscoveredLocation>> getEnds(LevelReader reader, BlockPos pos, BlockState state,
-		boolean ignoreTurns, @Nullable DiscoveredLocation fromEnd, @Nullable Vec3 axisFilter) {
-		Vec3 center = VecHelper.getCenterOf(pos);
-		List<Pair<BlockPos, DiscoveredLocation>> list = new ArrayList<>();
-
-		if (!(state.getBlock() instanceof TrackBlock))
-			return list;
-
-		BlockEntity blockEntity = reader.getBlockEntity(pos);
-		if (state.getValue(TrackBlock.HAS_TURN) && blockEntity instanceof TrackTileEntity && !ignoreTurns) {
-			TrackTileEntity trackTileEntity = (TrackTileEntity) blockEntity;
-			trackTileEntity.getConnections()
-				.forEach((connectedPos, bc) -> {
-					Vec3 curveHandle = bc.axes.getFirst();
-					if (axisFilter != null && !testAxisFilter(curveHandle.normalize(), axisFilter))
-						return;
-					addToSet(fromEnd, list,
-						(d, b) -> d == 1 ? Vec3.atLowerCornerOf(bc.tePositions.get(b)) : bc.starts.get(b),
-						bc.normals::get, bc);
-				});
-		}
-
-		TrackShape shape = state.getValue(TrackBlock.SHAPE);
-		if (shape == TrackShape.NONE)
-			return list;
-
-		shape.getAxes()
-			.forEach(axis -> {
-				if (axisFilter != null && !testAxisFilter(axis.normalize(), axisFilter))
-					return;
-				addToSet(fromEnd, list, (d, b) -> axis.scale(b ? d : -d)
-					.add(center)
-					.add(0, axis.y == 0 ? -.5 : 0, 0), b -> shape.getNormal(), null);
-			});
-
-		return list;
-	}
-
-	private static boolean testAxisFilter(Vec3 axis, Vec3 filter) {
-		return Mth.equal(axis.distanceToSqr(filter), 0) || Mth.equal(axis.distanceToSqr(filter.scale(-1)), 0);
-	}
-
-	private static void addToSet(DiscoveredLocation fromEnd, List<Pair<BlockPos, DiscoveredLocation>> list,
-		BiFunction<Double, Boolean, Vec3> offsetFactory, Function<Boolean, Vec3> normalFactory,
-		BezierConnection viaTurn) {
-
-		DiscoveredLocation firstLocation = new DiscoveredLocation(offsetFactory.apply(0.5d, true));
-		DiscoveredLocation secondLocation = new DiscoveredLocation(offsetFactory.apply(0.5d, false));
-
-		Pair<BlockPos, DiscoveredLocation> firstNode =
-			Pair.of(new BlockPos(offsetFactory.apply(1.0d, true)), firstLocation.viaTurn(viaTurn)
-				.withNormal(normalFactory.apply(true)));
-		Pair<BlockPos, DiscoveredLocation> secondNode =
-			Pair.of(new BlockPos(offsetFactory.apply(1.0d, false)), secondLocation.viaTurn(viaTurn)
-				.withNormal(normalFactory.apply(false)));
-
-		boolean skipFirst = false;
-		boolean skipSecond = false;
-
-		if (fromEnd != null) {
-			boolean equalsFirst = firstNode.getSecond()
-				.equals(fromEnd);
-			boolean equalsSecond = secondNode.getSecond()
-				.equals(fromEnd);
-
-			// not reachable from this end, crossover rail
-			if (!equalsFirst && !equalsSecond)
-				return;
-
-			if (equalsFirst)
-				skipFirst = true;
-			if (equalsSecond)
-				skipSecond = true;
-		}
-
-		if (!skipFirst)
-			list.add(firstNode);
-		if (!skipSecond)
-			list.add(secondNode);
-	}
-
 }

src/main/java/com/simibubi/create/content/logistics/trains/entity/Train.java

@@ -338,7 +338,7 @@ public class Train {
 			offset += carriage.bogeySpacing;
 
 			if (i < carriageSpacing.size())
-				offset += carriageSpacing.get(carriageSpacing.size() - i - 1);
+				offset += carriageSpacing.get(backwards ? carriageSpacing.size() - i - 1 : i);
 		}
 
 		GlobalStation currentStation = getCurrentStation();

src/main/java/com/simibubi/create/content/logistics/trains/entity/TravellingPoint.java

@@ -159,7 +159,7 @@ public class TravellingPoint {
 					TrackEdge newEdge = entry.getValue();
 					Vec3 currentDirection = edge.getDirection(node1, node2, false);
 					Vec3 newDirection = newEdge.getDirection(node2, newNode, true);
-					if (currentDirection.dot(newDirection) < 0)
+					if (currentDirection.dot(newDirection) < 3 / 4f)
 						continue;
 
 					validTargets.add(entry);
@@ -197,7 +197,7 @@ public class TravellingPoint {
 						.get(node1);
 					Vec3 currentDirection = edge.getDirection(node1, node2, true);
 					Vec3 newDirection = newEdge.getDirection(newNode, node1, false);
-					if (currentDirection.dot(newDirection) < 0)
+					if (currentDirection.dot(newDirection) < 3 / 4f)
 						continue;
 
 					validTargets.add(entry);

src/main/java/com/simibubi/create/content/logistics/trains/management/StationTileEntity.java

@@ -2,6 +2,7 @@ package com.simibubi.create.content.logistics.trains.management;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -16,7 +17,6 @@ import com.simibubi.create.content.logistics.trains.TrackEdge;
 import com.simibubi.create.content.logistics.trains.TrackGraph;
 import com.simibubi.create.content.logistics.trains.TrackNode;
 import com.simibubi.create.content.logistics.trains.TrackNodeLocation.DiscoveredLocation;
-import com.simibubi.create.content.logistics.trains.TrackPropagator;
 import com.simibubi.create.content.logistics.trains.entity.Carriage;
 import com.simibubi.create.content.logistics.trains.entity.Carriage.CarriageBogey;
 import com.simibubi.create.content.logistics.trains.entity.CarriageContraption;
@@ -26,7 +26,6 @@ import com.simibubi.create.foundation.tileEntity.SmartTileEntity;
 import com.simibubi.create.foundation.tileEntity.TileEntityBehaviour;
 import com.simibubi.create.foundation.utility.Iterate;
 import com.simibubi.create.foundation.utility.Lang;
-import com.simibubi.create.foundation.utility.Pair;
 import com.simibubi.create.foundation.utility.WorldAttached;
 
 import net.minecraft.core.BlockPos;
@@ -325,12 +324,15 @@ public class StationTileEntity extends SmartTileEntity {
 		BlockPos bogeyOffset = new BlockPos(track.getUpNormal(level, trackPosition, trackState));
 
 		DiscoveredLocation location = null;
-		List<Pair<BlockPos, DiscoveredLocation>> ends =
+		Vec3 centre = Vec3.atBottomCenterOf(trackPosition)
-			TrackPropagator.getEnds(level, trackPosition, trackState, true, null, null);
+			.add(0, track.getElevationAtCenter(level, trackPosition, trackState), 0);
-		for (Pair<BlockPos, DiscoveredLocation> pair : ends)
+		Collection<DiscoveredLocation> ends = track.getConnected(level, trackPosition, trackState, true, null);
-			if (trackPosition.relative(assemblyDirection)
+		Vec3 targetOffset = Vec3.atLowerCornerOf(assemblyDirection.getNormal());
-				.equals(pair.getFirst()))
+		for (DiscoveredLocation end : ends)
-				location = pair.getSecond();
+			if (Mth.equal(0, targetOffset.distanceToSqr(end.getLocation()
+				.subtract(centre)
+				.normalize())))
+				location = end;
 		if (location == null)
 			return;
 
@@ -349,13 +351,14 @@ public class StationTileEntity extends SmartTileEntity {
 		TrackGraph graph = null;
 		TrackNode secondNode = null;
 
-		for (int i = 0; i < assemblyLength + 20; i++) {
+		for (int j = 0; j < assemblyLength * 2 + 40; j++) {
+			double i = j / 2d;
 			if (points.size() == pointOffsets.size())
 				break;
 
 			DiscoveredLocation currentLocation = location;
 			location = new DiscoveredLocation(location.getLocation()
-				.add(directionVec));
+				.add(directionVec.scale(.5)));
 
 			if (graph == null)
 				graph = Create.RAILWAYS.getGraph(level, currentLocation);

src/main/java/com/simibubi/create/content/logistics/trains/track/StandardBogeyBlock.java

@@ -99,7 +99,7 @@ public class StandardBogeyBlock extends Block implements IBogeyBlock, ITE<Standa
 				ms.mulPose(Vector3f.YP.rotationDegrees(90));
 		}
 
-		ms.translate(0, -1.5, 0);
+		ms.translate(0, -1.5 - 1 / 128f, 0);
 
 		VertexConsumer vb = buffers.getBuffer(RenderType.cutoutMipped());
 		BlockState air = Blocks.AIR.defaultBlockState();

src/main/java/com/simibubi/create/content/logistics/trains/track/TrackBlock.java

@@ -1,6 +1,9 @@
 package com.simibubi.create.content.logistics.trains.track;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
+import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Random;
 
@@ -15,7 +18,10 @@ import com.simibubi.create.Create;
 import com.simibubi.create.CreateClient;
 import com.simibubi.create.content.contraptions.wrench.IWrenchable;
 import com.simibubi.create.content.curiosities.girder.GirderBlock;
+import com.simibubi.create.content.logistics.trains.BezierConnection;
 import com.simibubi.create.content.logistics.trains.ITrackBlock;
+import com.simibubi.create.content.logistics.trains.TrackNodeLocation;
+import com.simibubi.create.content.logistics.trains.TrackNodeLocation.DiscoveredLocation;
 import com.simibubi.create.content.logistics.trains.TrackPropagator;
 import com.simibubi.create.content.logistics.trains.management.StationTileEntity;
 import com.simibubi.create.foundation.utility.AngleHelper;
@@ -144,8 +150,41 @@ public class TrackBlock extends Block implements EntityBlock, IWrenchable, ITrac
 
 	@Override
 	public void tick(BlockState p_60462_, ServerLevel p_60463_, BlockPos p_60464_, Random p_60465_) {
-		for (Vec3 axis : getTrackAxes(p_60463_, p_60464_, p_60462_))
+		TrackPropagator.onRailAdded(p_60463_, p_60464_, p_60462_);
-			TrackPropagator.onRailAdded(p_60463_, p_60464_, p_60462_, axis.normalize());
+	}
+
+	@Override
+	public Collection<DiscoveredLocation> getConnected(BlockGetter world, BlockPos pos, BlockState state,
+		boolean linear, TrackNodeLocation connectedTo) {
+		Collection<DiscoveredLocation> list;
+
+		if (getTrackAxes(world, pos, state).size() > 1) {
+			Vec3 center = Vec3.atBottomCenterOf(pos)
+				.add(0, getElevationAtCenter(world, pos, state), 0);
+			TrackShape shape = state.getValue(TrackBlock.SHAPE);
+			list = new ArrayList<>();
+			for (Vec3 axis : getTrackAxes(world, pos, state))
+				for (boolean fromCenter : Iterate.trueAndFalse)
+					ITrackBlock.addToListIfConnected(connectedTo, list,
+						(d, b) -> axis.scale(b ? 0 : fromCenter ? -d : d)
+							.add(center),
+						b -> shape.getNormal(), null);
+		} else
+			list = ITrackBlock.super.getConnected(world, pos, state, linear, connectedTo);
+
+		if (!state.getValue(HAS_TURN))
+			return list;
+		if (linear)
+			return list;
+
+		BlockEntity blockEntity = world.getBlockEntity(pos);
+		if (!(blockEntity instanceof TrackTileEntity trackTE))
+			return list;
+
+		Map<BlockPos, BezierConnection> connections = trackTE.getConnections();
+		connections.forEach((connectedPos, bc) -> ITrackBlock.addToListIfConnected(connectedTo, list,
+			(d, b) -> d == 1 ? Vec3.atLowerCornerOf(bc.tePositions.get(b)) : bc.starts.get(b), bc.normals::get, bc));
+		return list;
 	}
 
 	@Override