Traffic Frights

- Fixed Trains ignoring their signal when nearby graph nodes are changed
- Fixed Trains not being notified of new signal blocks if they share an edge with the added/removed signal
- Fixed Navigation reserving chained signal blocks before verifying that it can be fully traversed
- Fixed Track placement requiring much shallower slopes for diagonal tracks
- Fixed long range navigation choosing detours near the beginning
- Temporarily patched and highlighted a problem with track traversal and long distances

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

@@ -176,9 +176,9 @@ public class GlobalRailwayManager {
 		for (TrackGraph graph : trackNetworks.values())
 			graph.tickPoints(false);
 
-//		if (AllKeys.isKeyDown(GLFW.GLFW_KEY_K))
-//			trackNetworks.values()
-//				.forEach(TrackGraph::debugViewReserved);
+		if (AllKeys.isKeyDown(GLFW.GLFW_KEY_K))
+			trackNetworks.values()
+				.forEach(TrackGraph::debugViewReserved);
 //		if (AllKeys.isKeyDown(GLFW.GLFW_KEY_J) && AllKeys.altDown())
 //			trackNetworks.values()
 //				.forEach(TrackGraph::debugViewNodes);

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

@@ -44,8 +44,9 @@ public class TrackEdge {
 	}
 
 	public double incrementT(TrackNode node1, TrackNode node2, double currentT, double distance) {
+		boolean tooFar = Math.abs(distance) > 5; 
 		distance = distance / getLength(node1, node2);
-		return isTurn() ? turn.incrementT(currentT, distance) : currentT + distance;
+		return !tooFar && isTurn() ? turn.incrementT(currentT, distance) : currentT + distance;
 	}
 
 	public Vec3 getPosition(TrackNode node1, TrackNode node2, double t) {

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

@@ -1,6 +1,7 @@
 package com.simibubi.create.content.logistics.trains.entity;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.IdentityHashMap;
 import java.util.List;
@@ -39,6 +40,7 @@ import net.minecraft.core.BlockPos;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.NbtUtils;
 import net.minecraft.nbt.Tag;
+import net.minecraft.util.Mth;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.phys.Vec3;
 
@@ -53,7 +55,7 @@ public class Navigation {
 
 	private TravellingPoint signalScout;
 	public Pair<UUID, Boolean> waitingForSignal;
-	private Set<UUID> waitingForChainedGroups;
+	private Map<UUID, SignalBoundary> waitingForChainedGroups;
 	public double distanceToSignal;
 	public int ticksWaitingForSignal;
 
@@ -61,7 +63,7 @@ public class Navigation {
 		this.train = train;
 		currentPath = new ArrayList<>();
 		signalScout = new TravellingPoint();
-		waitingForChainedGroups = new HashSet<>();
+		waitingForChainedGroups = new HashMap<>();
 	}
 
 	public void tick(Level level) {
@@ -101,11 +103,11 @@ public class Navigation {
 		// Signals
 		if (train.graph != null) {
 			if (waitingForSignal != null && currentSignalResolved()) {
-				SignalBoundary signal = train.graph.getPoint(EdgePointType.SIGNAL, waitingForSignal.getFirst());
-				if (signal.types.get(waitingForSignal.getSecond()) == SignalType.CROSS_SIGNAL)
-					train.reservedSignalBlocks.addAll(waitingForChainedGroups);
+				UUID signalId = waitingForSignal.getFirst();
+				SignalBoundary signal = train.graph.getPoint(EdgePointType.SIGNAL, signalId);
+				if (signal != null && signal.types.get(waitingForSignal.getSecond()) == SignalType.CROSS_SIGNAL)
+					waitingForChainedGroups.clear();
 				waitingForSignal = null;
-				waitingForChainedGroups.clear();
 			}
 
 			TravellingPoint leadingPoint = !destinationBehindTrain ? train.carriages.get(0)
@@ -126,16 +128,15 @@ public class Navigation {
 				signalScout.edge = leadingPoint.edge;
 				signalScout.position = leadingPoint.position;
 
-				double brakingDistanceNoFlicker =
-					Math.max(preDepartureLookAhead, brakingDistance + 3 - (brakingDistance % 3));
-				double scanDistance = Math.min(distanceToDestination, brakingDistanceNoFlicker);
+				double brakingDistanceNoFlicker = brakingDistance + 3 - (brakingDistance % 3);
+				double scanDistance = Mth.clamp(brakingDistanceNoFlicker, preDepartureLookAhead, distanceToDestination);
 
 				MutableDouble crossSignalDistanceTracker = new MutableDouble(-1);
 				MutableObject<Pair<UUID, Boolean>> trackingCrossSignal = new MutableObject<>(null);
 				waitingForChainedGroups.clear();
-//				train.reservedSignalBlocks.clear();
 
-				signalScout.travel(train.graph, distanceToDestination * speedMod, controlSignalScout(),
+				// Adding 50 to the distance due to unresolved inaccuracies in TravellingPoint::travel
+				signalScout.travel(train.graph, (distanceToDestination + 50) * speedMod, controlSignalScout(),
 					(distance, couple) -> {
 						// > scanDistance and not following down a cross signal
 						boolean crossSignalTracked = trackingCrossSignal.getValue() != null;
@@ -158,15 +159,11 @@ public class Navigation {
 						boolean crossSignal = signal.types.get(primary) == SignalType.CROSS_SIGNAL;
 						boolean occupied = signalEdgeGroup.isOccupiedUnless(train);
 
-						if (!occupied && distance < distanceToSignal + .25)
-							signalEdgeGroup.reserved = signal; // Reserve group for traversal, unless waiting at an
-																// earlier cross signal
-
 						if (!crossSignalTracked) {
 							if (crossSignal) { // Now entering cross signal path
 								trackingCrossSignal.setValue(Pair.of(boundary.id, primary));
 								crossSignalDistanceTracker.setValue(distance);
-								waitingForChainedGroups.add(entering);
+								waitingForChainedGroups.put(entering, signal);
 							}
 							if (occupied) { // Section is occupied
 								waitingForSignal = Pair.of(boundary.id, primary);
@@ -174,8 +171,14 @@ public class Navigation {
 								if (!crossSignal)
 									return true; // Standard entry signal, do not collect any further segments
 							}
-						} else {
-							waitingForChainedGroups.add(entering); // Add group to chain
+							if (!occupied && !crossSignal && distance < distanceToSignal + .25
+								&& distance < brakingDistanceNoFlicker)
+								signalEdgeGroup.reserved = signal; // Reserve group for traversal
+							return false;
+						}
+
+						if (crossSignalTracked) {
+							waitingForChainedGroups.put(entering, signal); // Add group to chain
 							if (occupied) { // Section is occupied, but wait at the cross signal that started the chain
 								waitingForSignal = trackingCrossSignal.getValue();
 								distanceToSignal = crossSignalDistanceTracker.doubleValue();
@@ -186,8 +189,7 @@ public class Navigation {
 								if (distance < distanceToSignal + .25) {
 									// Collect and reset the signal chain because none were blocked
 									trackingCrossSignal.setValue(null);
-									train.reservedSignalBlocks.addAll(waitingForChainedGroups);
-									waitingForChainedGroups.clear();
+									reserveChain();
 									return false;
 								} else
 									return true; // End of a blocked signal chain
@@ -202,20 +204,13 @@ public class Navigation {
 							curveDistanceTracker.setValue(distance);
 					});
 
-				if (trackingCrossSignal.getValue() != null) {
-					if (waitingForSignal == null) {
-						train.reservedSignalBlocks.addAll(waitingForChainedGroups);
-						waitingForChainedGroups.clear();
-					}
-				}
+				if (trackingCrossSignal.getValue() != null && waitingForSignal == null)
+					reserveChain();
 
 				distanceToNextCurve = curveDistanceTracker.floatValue();
 
-			} else {
+			} else
 				ticksWaitingForSignal++;
-				// if chain signal try finding new path/destination every x ticks
-			}
-
 		}
 
 		double targetDistance = waitingForSignal != null ? distanceToSignal : distanceToDestination;
@@ -265,6 +260,16 @@ public class Navigation {
 		train.approachTargetSpeed(1);
 	}
 
+	private void reserveChain() {
+		train.reservedSignalBlocks.addAll(waitingForChainedGroups.keySet());
+		waitingForChainedGroups.forEach((groupId, boundary) -> {
+			SignalEdgeGroup signalEdgeGroup = Create.RAILWAYS.signalEdgeGroups.get(groupId);
+			if (signalEdgeGroup != null)
+				signalEdgeGroup.reserved = boundary;
+		});
+		waitingForChainedGroups.clear();
+	}
+
 	private boolean currentSignalResolved() {
 		if (distanceToDestination < .5f)
 			return true;
@@ -274,10 +279,12 @@ public class Navigation {
 
 		// Cross Signal
 		if (signal.types.get(waitingForSignal.getSecond()) == SignalType.CROSS_SIGNAL) {
-			for (UUID groupId : waitingForChainedGroups) {
+			for (UUID groupId : waitingForChainedGroups.keySet()) {
 				SignalEdgeGroup signalEdgeGroup = Create.RAILWAYS.signalEdgeGroups.get(groupId);
-				if (signalEdgeGroup == null)
-					continue;
+				if (signalEdgeGroup == null) { // Migration, re-initialize chain
+					waitingForSignal.setFirst(null);
+					return true;
+				}
 				if (signalEdgeGroup.isOccupiedUnless(train))
 					return false;
 			}
@@ -629,7 +636,7 @@ public class Navigation {
 				TrackEdge newEdge = target.getValue();
 				double newDistance = newEdge.getLength(node2, newNode) + distance;
 				int newPenalty = penalty;
-				reachedVia.put(newEdge, Pair.of(validTargets.size() > 1, Couple.create(node1, node2)));
+				reachedVia.putIfAbsent(newEdge, Pair.of(validTargets.size() > 1, Couple.create(node1, node2)));
 				frontier.add(new FrontierEntry(newDistance, newPenalty, node2, newNode, newEdge));
 			}
 		}

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

@@ -123,16 +123,17 @@ public class Train {
 		status.tick(level);
 		if (graph == null && !migratingPoints.isEmpty())
 			reattachToTracks(level);
-
-		addToSignalGroups(occupiedSignalBlocks.keySet());
-
-		if (graph == null)
+		if (graph == null) {
+			addToSignalGroups(occupiedSignalBlocks.keySet());
 			return;
+		}
+		
 		if (updateSignalBlocks) {
 			updateSignalBlocks = false;
 			collectInitiallyOccupiedSignalBlocks();
 		}
 
+		addToSignalGroups(occupiedSignalBlocks.keySet());
 		addToSignalGroups(reservedSignalBlocks);
 	}
 

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

@@ -187,6 +187,15 @@ public class TravellingPoint {
 		double currentT = position / edgeLength;
 		double incrementT = edge.incrementT(node1, node2, currentT, distance);
 		position = incrementT * edgeLength;
+
+		// FIXME: using incrementT like this becomes inaccurate at medium-long distances
+		// travelling points would travel only 50m instead of 100m due to the low
+		// incrementT at their starting position (e.g. bezier turn)
+		// In an ideal scenario the amount added to position would iterate the traversed
+		// edges for context first
+		
+		// A workaround was added in TrackEdge::incrementT
+
 		List<Entry<TrackNode, TrackEdge>> validTargets = new ArrayList<>();
 
 		boolean forward = distance > 0;

src/main/java/com/simibubi/create/content/logistics/trains/management/edgePoint/signal/SignalBoundary.java

@@ -42,7 +42,7 @@ public class SignalBoundary extends TrackEdgePoint {
 		groups = Couple.create(null, null);
 		sidesToUpdate = Couple.create(true, true);
 		types = Couple.create(() -> SignalType.ENTRY_SIGNAL);
-		cachedStates = Couple.create(() -> SignalState.GREEN);
+		cachedStates = Couple.create(() -> SignalState.INVALID);
 	}
 
 	public void setGroup(TrackNode side, UUID groupId) {

src/main/java/com/simibubi/create/content/logistics/trains/management/edgePoint/signal/SignalPropagator.java

@@ -115,15 +115,16 @@ public class SignalPropagator {
 		if (startEdge == null)
 			return;
 
-		if (!forCollection)
+		if (!forCollection) {
+			notifyTrains(graph, startEdge, oppositeEdge);
 			Create.RAILWAYS.sync.edgeDataChanged(graph, node1, node2, startEdge, oppositeEdge);
+		}
 
 		// Check for signal on the same edge
 		SignalBoundary immediateBoundary = startEdge.getEdgeData()
 			.next(EdgePointType.SIGNAL, node1, node2, startEdge, signal.getLocationOn(node1, node2, startEdge));
 		if (immediateBoundary != null) {
-			if (boundaryCallback.test(Pair.of(node1, immediateBoundary)))
-				notifyTrains(graph, startEdge, oppositeEdge);
+			boundaryCallback.test(Pair.of(node1, immediateBoundary));
 			return;
 		}
 

src/main/java/com/simibubi/create/content/logistics/trains/management/edgePoint/signal/SignalRenderer.java

@@ -34,7 +34,7 @@ public class SignalRenderer extends SafeTileEntityRenderer<SignalTileEntity> {
 		if (signalState.isRedLight(renderTime))
 			CachedBufferer.partial(AllBlockPartials.SIGNAL_ON, blockState)
 				.renderInto(ms, buffer.getBuffer(RenderType.solid()));
-		else if (signalState.isGreenLight(renderTime))
+		else
 			CachedBufferer.partial(AllBlockPartials.SIGNAL_OFF, blockState)
 				.renderInto(ms, buffer.getBuffer(RenderType.solid()));
 

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

@@ -247,7 +247,7 @@ public class TrackPlacement {
 			int hDistance = info.end1Extent;
 			if (axis1.y == 0 || !Mth.equal(absAscend + 1, dist / axis1.length())) {
 				info.end1Extent = 0;
-				double minHDistance = Math.max(absAscend < 4 ? absAscend * 4 : absAscend * 3, 6);
+				double minHDistance = Math.max(absAscend < 4 ? absAscend * 4 : absAscend * 3, 6) / axis1.length();
 				if (hDistance < minHDistance)
 					return info.withMessage("too_steep");
 				if (hDistance > minHDistance) {