Persistence is key

src/main/java/com/simibubi/create/content/contraptions/base/KineticTileEntity.java

@@ -4,6 +4,7 @@ import static net.minecraft.ChatFormatting.GOLD;
 import static net.minecraft.ChatFormatting.GRAY;
 
 import java.util.List;
+import java.util.Optional;
 
 import javax.annotation.Nullable;
 
@@ -78,14 +79,6 @@ public class KineticTileEntity extends SmartTileEntity
 		}
 	}
 
-	private void addToSolver() {
-		KineticSolver.getSolver(level).addNode(this);
-	}
-
-	private void removeFromSolver() {
-		KineticSolver.getSolver(level).removeNode(this);
-	}
-
 	public KineticConnections getConnections() {
 		return connections;
 	}
@@ -102,6 +95,10 @@ public class KineticTileEntity extends SmartTileEntity
 		return getDefaultStressCapacity();
 	}
 
+	public boolean isStressConstant() {
+		return false;
+	}
+
 	public float getDefaultStressImpact() {
 		return (float) BlockStressValues.getImpact(getStressConfigKey());
 	}
@@ -110,11 +107,18 @@ public class KineticTileEntity extends SmartTileEntity
 		return (float) BlockStressValues.getCapacity(getStressConfigKey());
 	}
 
+	public Optional<Float> isConnected(BlockPos to) {
+		return KineticSolver.getSolver(level).isConnected(this.getBlockPos(), to);
+	}
+
+	public boolean isStressOnlyConnected(BlockPos to) {
+		return KineticSolver.getSolver(level).isStressOnlyConnected(this.getBlockPos(), to);
+	}
 
 	@Override
 	public void initialize() {
 		if (!level.isClientSide) {
-			addToSolver();
+			KineticSolver.getSolver(level).addNode(this);
 		}
 
 		super.initialize();
@@ -125,7 +129,7 @@ public class KineticTileEntity extends SmartTileEntity
 		super.tick();
 		effects.tick();
 
-		if (!level.isClientSide && !isRemoved()) {
+		if (!level.isClientSide) {
 			KineticSolver.getSolver(level).updateNode(this);
 		}
 
@@ -144,6 +148,29 @@ public class KineticTileEntity extends SmartTileEntity
 			flickerTally = getFlickerScore() - 1;
 	}
 
+	@Override
+	protected void setRemovedNotDueToChunkUnload() {
+		if (!level.isClientSide) {
+			KineticSolver.getSolver(level).removeNode(this);
+		}
+		super.setRemovedNotDueToChunkUnload();
+	}
+
+	@Override
+	public void onChunkUnloaded() {
+		super.onChunkUnloaded();
+		if (!level.isClientSide) {
+			preKineticsUnloaded();
+			KineticSolver solver = KineticSolver.getSolver(level);
+			solver.updateNode(this);
+			solver.unloadNode(this);
+		}
+	}
+
+	public void preKineticsUnloaded() {}
+
+
+
 	private void validateKinetics() {
 //		if (hasSource()) {
 //			if (!hasNetwork()) {
@@ -215,14 +242,6 @@ public class KineticTileEntity extends SmartTileEntity
 		super.setRemoved();
 	}
 
-	@Override
-	protected void setRemovedNotDueToChunkUnload() {
-		if (!level.isClientSide) {
-			removeFromSolver();
-		}
-		super.setRemovedNotDueToChunkUnload();
-	}
-
 	@Override
 	protected void write(CompoundTag compound, boolean clientPacket) {
 		compound.putFloat("Speed", speed);

src/main/java/com/simibubi/create/content/contraptions/relays/elementary/SimpleKineticTileEntity.java

@@ -29,10 +29,10 @@ public class SimpleKineticTileEntity extends KineticTileEntity {
 
 	@Override
 	public float getGeneratedSpeed() {
-		Block block = getBlockState().getBlock();
-		BlockEntity below = level.getBlockEntity(getBlockPos().below());
-		if (block instanceof ICogWheel cog && cog.isLargeCog()
-				&& below instanceof SpeedControllerTileEntity controller && controller.getSpeed() != 0)
+		BlockPos belowPos = getBlockPos().below();
+		if (isStressOnlyConnected(belowPos)
+				&& level.getBlockEntity(belowPos) instanceof SpeedControllerTileEntity controller
+				&& controller.getSpeed() != 0)
 			return controller.getTargetSpeed();
 		return 0;
 	}

src/main/java/com/simibubi/create/content/contraptions/solver/AllConnections.java

@@ -1,40 +1,24 @@
 package com.simibubi.create.content.contraptions.solver;
 
+import com.google.common.collect.Interner;
+import com.google.common.collect.Interners;
 import com.simibubi.create.foundation.utility.DirectionHelper;
 import com.simibubi.create.foundation.utility.LazyMap;
 import com.simibubi.create.content.contraptions.solver.KineticConnections.Type;
+import com.simibubi.create.content.contraptions.solver.KineticConnections.Types;
 import com.simibubi.create.content.contraptions.solver.KineticConnections.Entry;
 
 import net.minecraft.core.Direction;
 import net.minecraft.core.Direction.Axis;
 import net.minecraft.core.Vec3i;
+import net.minecraft.util.StringRepresentable;
 
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Optional;
 
-import static net.minecraft.world.level.block.state.properties.BlockStateProperties.AXIS;
-
 public class AllConnections {
 
-	public static record ValueType(Object value) implements Type {
-		@Override
-		public boolean compatible(Type other) {
-			return this == other;
-		}
-
-		public static <T> LazyMap<T, Type> map() {
-			return new LazyMap<>(ValueType::new);
-		}
-	}
-
-	public static final LazyMap<Axis, Type>
-			TYPE_SHAFT = ValueType.map(),
-			TYPE_LARGE_COG = ValueType.map(),
-			TYPE_SMALL_COG = ValueType.map(),
-			TYPE_SPEED_CONTROLLER_TOP = ValueType.map();
-
-
 	private static Direction pos(Axis axis) {
 		return Direction.get(Direction.AxisDirection.POSITIVE, axis);
 	}
@@ -47,7 +31,7 @@ public class AllConnections {
 		int fromDiff = from.choose(diff.getX(), diff.getY(), diff.getZ());
 		int toDiff = to.choose(diff.getX(), diff.getY(), diff.getZ());
 		float ratio = fromDiff > 0 ^ toDiff > 0 ? -1 : 1;
-		return new Entry(diff, TYPE_LARGE_COG.apply(from), TYPE_LARGE_COG.apply(to), ratio);
+		return new Entry(diff, Type.of(Types.LARGE_COG, from), Type.of(Types.LARGE_COG, to), ratio);
 	}
 
 	private static Optional<Axis> oppAxis(Axis axis) {
@@ -63,14 +47,14 @@ public class AllConnections {
 
 	public static final LazyMap<Direction, KineticConnections>
 			HALF_SHAFT = new LazyMap<>(dir ->
-				new KineticConnections(new Entry(dir.getNormal(), TYPE_SHAFT.apply(dir.getAxis()))));
+				new KineticConnections(new Entry(dir.getNormal(), Type.of(Types.SHAFT, dir.getAxis()))));
 
 	public static final LazyMap<Axis, KineticConnections>
 			FULL_SHAFT = new LazyMap<>(axis -> HALF_SHAFT.apply(pos(axis)).merge(HALF_SHAFT.apply(neg(axis)))),
 
 			LARGE_COG = new LazyMap<>(axis -> {
-				Type large = TYPE_LARGE_COG.apply(axis);
-				Type small = TYPE_SMALL_COG.apply(axis);
+				Type large = Type.of(Types.LARGE_COG, axis);
+				Type small = Type.of(Types.SMALL_COG, axis);
 
 				List<Entry> out = new LinkedList<>();
 				Direction cur = DirectionHelper.getPositivePerpendicular(axis);
@@ -83,15 +67,15 @@ public class AllConnections {
 				}
 
 				oppAxis(axis).ifPresent(opp -> {
-					Type sc = TYPE_SPEED_CONTROLLER_TOP.apply(opp);
+					Type sc = Type.of(Types.SPEED_CONTROLLER_TOP, opp);
 					out.add(new Entry(Direction.DOWN.getNormal(), large, sc).stressOnly());
 				});
 				return new KineticConnections(out);
 			}),
 
 			SMALL_COG = new LazyMap<>(axis -> {
-				Type large = TYPE_LARGE_COG.apply(axis);
-				Type small = TYPE_SMALL_COG.apply(axis);
+				Type large = Type.of(Types.LARGE_COG, axis);
+				Type small = Type.of(Types.SMALL_COG, axis);
 
 				List<Entry> out = new LinkedList<>();
 				Direction cur = DirectionHelper.getPositivePerpendicular(axis);
@@ -110,8 +94,8 @@ public class AllConnections {
 			SMALL_COG_FULL_SHAFT = new LazyMap<>(axis -> SMALL_COG.apply(axis).merge(FULL_SHAFT.apply(axis))),
 
 			SPEED_CONTROLLER = new LazyMap<>(axis -> {
-				Type sc = TYPE_SPEED_CONTROLLER_TOP.apply(axis);
-				Type large = TYPE_LARGE_COG.apply(oppAxis(axis).get());
+				Type sc = Type.of(Types.SPEED_CONTROLLER_TOP, axis);
+				Type large = Type.of(Types.LARGE_COG, oppAxis(axis).get());
 				Vec3i up = Direction.UP.getNormal();
 				return new KineticConnections(new Entry(up, sc, large).stressOnly()).merge(FULL_SHAFT.apply(axis));
 			});

src/main/java/com/simibubi/create/content/contraptions/solver/KineticConnections.java

@@ -1,7 +1,15 @@
 package com.simibubi.create.content.contraptions.solver;
 
+import com.google.common.collect.Interner;
+import com.google.common.collect.Interners;
+import com.simibubi.create.foundation.utility.NBTHelper;
+
 import net.minecraft.core.Vec3i;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.ListTag;
+import net.minecraft.nbt.Tag;
 import net.minecraft.util.Mth;
+import net.minecraft.util.StringRepresentable;
 
 import java.util.Arrays;
 import java.util.Collection;
@@ -15,8 +23,51 @@ import java.util.stream.Stream;
 
 public class KineticConnections {
 
-	public interface Type {
-		boolean compatible(Type other);
+	public enum Types {
+		SHAFT, LARGE_COG, SMALL_COG, SPEED_CONTROLLER_TOP
+	}
+
+	public static class Type {
+		private final Types name;
+		private final String value;
+
+		private Type(Types name, String value) {
+			this.name = name;
+			this.value = value;
+		}
+
+		private final static Interner<Type> cachedTypes = Interners.newStrongInterner();
+
+		public static Type of(Types name, String value) {
+			return cachedTypes.intern(new Type(name, value));
+		}
+
+		public static Type of(Types name, StringRepresentable value) {
+			return of(name, value.getSerializedName());
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (this == o) return true;
+			if (o == null || getClass() != o.getClass()) return false;
+			Type type1 = (Type) o;
+			return name == type1.name && Objects.equals(value, type1.value);
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash(name, value);
+		}
+
+		public CompoundTag save(CompoundTag tag) {
+			NBTHelper.writeEnum(tag, "Name", name);
+			tag.putString("Value", value);
+			return tag;
+		}
+
+		public static Type load(CompoundTag tag) {
+			return Type.of(NBTHelper.readEnum(tag, "Name", Types.class), tag.getString("Value"));
+		}
 	}
 
 	public static record Entry(Vec3i offset, Value value) {
@@ -74,7 +125,7 @@ public class KineticConnections {
 
 		if (fromValue.isStressOnly() || toValue.isStressOnly()) return Optional.empty();
 
-		if (fromValue.from.compatible(toValue.to) && fromValue.to.compatible(toValue.from)
+		if (fromValue.from.equals(toValue.to) && fromValue.to.equals(toValue.from)
 				&& (Mth.equal(fromValue.ratio, 1/toValue.ratio) || (Mth.equal(toValue.ratio, 1/fromValue.ratio))))
 			return Optional.of(fromValue.ratio);
 		return Optional.empty();
@@ -89,7 +140,7 @@ public class KineticConnections {
 
 		if (!fromValue.isStressOnly() || !toValue.isStressOnly()) return false;
 
-		return fromValue.from.compatible(toValue.to) && fromValue.to.compatible(toValue.from);
+		return fromValue.from.equals(toValue.to) && fromValue.to.equals(toValue.from);
 	}
 
 	@Override
@@ -116,5 +167,32 @@ public class KineticConnections {
 		return connections.values().stream().anyMatch(Value::isStressOnly);
 	}
 
+	public CompoundTag save(CompoundTag tag) {
+		ListTag connectionsTags = new ListTag();
+		for (Map.Entry<Vec3i, Value> entry : connections.entrySet()) {
+			CompoundTag entryTag = new CompoundTag();
+			entryTag.put("Off", NBTHelper.writeVec3i(entry.getKey()));
+			entryTag.put("From", entry.getValue().from().save(new CompoundTag()));
+			entryTag.put("To", entry.getValue().to().save(new CompoundTag()));
+			entryTag.putFloat("Ratio", entry.getValue().ratio());
+			connectionsTags.add(entryTag);
+		}
+		tag.put("Connections", connectionsTags);
+		return tag;
+	}
+
+	public static KineticConnections load(CompoundTag tag) {
+		Map<Vec3i, Value> connections = new HashMap<>();
+		tag.getList("Connections", Tag.TAG_COMPOUND).forEach(c -> {
+			CompoundTag comp = (CompoundTag) c;
+			Vec3i offset = NBTHelper.readVec3i(comp.getList("Off", Tag.TAG_INT));
+			Type from = Type.load(comp.getCompound("From"));
+			Type to = Type.load(comp.getCompound("To"));
+			float ratio = comp.getFloat("Ratio");
+			connections.put(offset, new Value(from, to, ratio));
+		});
+		return new KineticConnections(connections);
+	}
+
 }
 

src/main/java/com/simibubi/create/content/contraptions/solver/KineticNetwork.java

@@ -47,12 +47,15 @@ public class KineticNetwork {
 		if (node.isGenerator() && !generators.contains(node)) {
 			generators.add(node);
 			rootSpeedDirty = true;
-			rootSpeedChanged = true;
 		}
 		if (node.hasStressImpact()) onMemberStressImpactUpdated();
 		if (node.hasStressCapacity()) onMemberStressCapacityUpdated();
 	}
 
+	public void onMemberLoaded(KineticNode node) {
+		potentialNewBranches.add(node);
+	}
+
 	public void onMemberGeneratedSpeedUpdated(KineticNode node) {
 		if (node.isGenerator()) {
 			generators.add(node);
@@ -60,7 +63,7 @@ public class KineticNetwork {
 			generators.remove(node);
 		}
 		rootSpeedDirty = true;
-		rootSpeedChanged = true;
+		onMemberStressCapacityUpdated();
 	}
 
 	public void onMemberStressImpactUpdated() {
@@ -75,7 +78,6 @@ public class KineticNetwork {
 		if (node.isGenerator() && generators.contains(node)) {
 			generators.remove(node);
 			rootSpeedDirty = true;
-			rootSpeedChanged = true;
 		}
 		if (node.hasStressImpact()) onMemberStressImpactUpdated();
 		if (node.hasStressCapacity()) onMemberStressCapacityUpdated();
@@ -131,7 +133,11 @@ public class KineticNetwork {
 			}
 		}
 
-		rootTheoreticalSpeed = newSpeed * sign;
+		if (rootTheoreticalSpeed != newSpeed * sign) {
+			rootTheoreticalSpeed = newSpeed * sign;
+			onRootSpeedChanged();
+		}
+
 		mainGenerator = newGenerator;
 		rootSpeedDirty = false;
 
@@ -150,6 +156,11 @@ public class KineticNetwork {
 		return isStopped() ? 0 : rootTheoreticalSpeed;
 	}
 
+	private void onRootSpeedChanged() {
+		rootSpeedChanged = true;
+		onMemberStressImpactUpdated();
+	}
+
 	public void untick() {
 		ticked = false;
 	}
@@ -180,13 +191,13 @@ public class KineticNetwork {
 			} else if (nowOverstressed) {
 				if (!cur.overstressed) {
 					cur.overstressed = true;
-					rootSpeedChanged = true;
+					cur.onRootSpeedChanged();
 					cur.members.forEach(KineticNode::stop);
 				}
 			} else {
 				if (cur.overstressed) {
 					cur.overstressed = false;
-					rootSpeedChanged = true;
+					cur.onRootSpeedChanged();
 					cur.bulldozeContradictingMembers(newNetworks);
 					cur.updateMemberSpeeds(newNetworks);
 				}
@@ -201,16 +212,16 @@ public class KineticNetwork {
 	 * @param newNetworks 	a List that any new networks created during this call will be added to
 	 */
 	private void updateMemberSpeeds(List<KineticNetwork> newNetworks) {
+		SolveResult recalculateSpeedResult = tryRecalculateSpeed();
+		// generators should not be turning against each other or have conflicting cycles by now
+		assert(recalculateSpeedResult.isOk());
+
 		// if we're stopped, then all members' speeds will be 0, so no need to check for speeding nodes
 		if (isStopped()) {
 			members.forEach(KineticNode::stop);
 			return;
 		}
 
-		SolveResult recalculateSpeedResult = tryRecalculateSpeed();
-		// generators should not be turning against each other or have conflicting cycles by now
-		assert(recalculateSpeedResult.isOk());
-
 		if (rootSpeedChanged) {
 			// root speed changed, update all nodes starting from the main generator
 			rootSpeedChanged = false;
@@ -220,8 +231,8 @@ public class KineticNetwork {
 			potentialNewBranches.stream()
 					.filter(n -> !potentialNewBranches.contains(n.getSource()))
 					.forEach(n -> bfs(n, newNetworks, true));
-			potentialNewBranches.clear();
 		}
+		potentialNewBranches.clear();
 	}
 
 	private void bfs(KineticNode root, List<KineticNetwork> newNetworks, boolean followSource) {

src/main/java/com/simibubi/create/content/contraptions/solver/KineticNode.java

@@ -5,6 +5,8 @@ import com.simibubi.create.foundation.config.AllConfigs;
 import com.simibubi.create.foundation.utility.Pair;
 
 import net.minecraft.core.BlockPos;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.NbtUtils;
 import net.minecraft.util.Mth;
 
 import javax.annotation.Nullable;
@@ -12,39 +14,90 @@ import javax.annotation.Nullable;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Optional;
-import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 public class KineticNode {
 
-	private final Function<BlockPos, Optional<KineticNode>> nodeAccessor;
-	private final KineticTileEntity entity;
+	private final KineticSolver solver;
+	private @Nullable KineticTileEntity entity;
 
 	private @Nullable KineticNode source;
 	private KineticNetwork network;
 	private float speedRatio = 1;
+	private float speedCur;
+	private float speedNext;
 
+	private final BlockPos pos;
 	private final KineticConnections connections;
 	private float generatedSpeed;
 	private float stressCapacity;
 	private float stressImpact;
+	private final boolean constantStress;
 
-	private float speedCur;
-	private float speedNext;
-
-	public KineticNode(KineticTileEntity entity, Function<BlockPos, Optional<KineticNode>> nodeAccessor) {
-		this.nodeAccessor = nodeAccessor;
+	public KineticNode(KineticSolver solver, KineticTileEntity entity) {
+		this.solver = solver;
 		this.entity = entity;
 
+		this.pos = entity.getBlockPos();
 		this.connections = entity.getConnections();
 		this.generatedSpeed = entity.getGeneratedSpeed();
 		this.stressImpact = entity.getStressImpact();
 		this.stressCapacity = entity.getStressCapacity();
+		this.constantStress = entity.isStressConstant();
 
 		this.network = new KineticNetwork(this);
 	}
 
+	private KineticNode(KineticSolver solver, BlockPos pos, KineticConnections connections, float generatedSpeed,
+						float stressCapacity, float stressImpact, boolean constantStress) {
+		this.solver = solver;
+
+		this.pos = pos;
+		this.connections = connections;
+		this.generatedSpeed = generatedSpeed;
+		this.stressImpact = stressImpact;
+		this.stressCapacity = stressCapacity;
+		this.constantStress = constantStress;
+
+		this.network = new KineticNetwork(this);
+	}
+
+	public CompoundTag save(CompoundTag tag) {
+		tag.put("Pos", NbtUtils.writeBlockPos(pos));
+		tag.put("Connections", connections.save(new CompoundTag()));
+		tag.putFloat("Generated", generatedSpeed);
+		tag.putFloat("Capacity", stressCapacity);
+		tag.putFloat("Impact", stressImpact);
+		if (constantStress)
+			tag.putBoolean("ConstantStress", true);
+		return tag;
+	}
+
+	public static KineticNode load(KineticSolver solver, CompoundTag tag) {
+		BlockPos pos = NbtUtils.readBlockPos(tag.getCompound("Pos"));
+		KineticConnections connections = KineticConnections.load(tag.getCompound("Connections"));
+		float generatedSpeed = tag.getFloat("Generated");
+		float stressCapacity = tag.getFloat("Capacity");
+		float stressImpact = tag.getFloat("Impact");
+		boolean constantStress = tag.getBoolean("ConstantStress");
+		return new KineticNode(solver, pos, connections, generatedSpeed, stressCapacity, stressImpact, constantStress);
+	}
+
+	public boolean isLoaded() {
+		return entity != null;
+	}
+
+	public void onLoaded(KineticTileEntity entity) {
+		this.entity = entity;
+		network.onMemberLoaded(this);
+		if (speedCur != 0) entity.setSpeed(speedCur);
+	}
+
+	public void onUnloaded() {
+		this.entity = null;
+	}
+
 	public KineticConnections getConnections() {
 		return connections;
 	}
@@ -53,13 +106,17 @@ public class KineticNode {
 		return network;
 	}
 
+	public BlockPos getPos() {
+		return pos;
+	}
+
 	/**
 	 * @return 	a Stream containing a pair for each compatible connection with this node, where the first value is
 	 * 			the connecting node and the second value is the speed ratio of the connection
 	 */
 	public Stream<Pair<KineticNode, Float>> getActiveConnections() {
 		return connections.getDirections().stream()
-				.map(d -> nodeAccessor.apply(entity.getBlockPos().offset(d))
+				.map(d -> solver.getNode(pos.offset(d))
 						.map(n -> connections.checkConnection(n.connections, d)
 								.map(r -> Pair.of(n, r))))
 				.flatMap(Optional::stream)
@@ -72,7 +129,7 @@ public class KineticNode {
 
 	public Stream<KineticNetwork> getActiveStressOnlyConnections() {
 		return connections.getDirections().stream()
-				.map(d -> nodeAccessor.apply(entity.getBlockPos().offset(d))
+				.map(d -> solver.getNode(pos.offset(d))
 						.filter(n -> connections.checkStressOnlyConnection(n.connections, d)))
 				.flatMap(Optional::stream)
 				.map(KineticNode::getNetwork);
@@ -86,10 +143,15 @@ public class KineticNode {
 		return generatedSpeed != 0;
 	}
 
-	public void onUpdated() {
+	public boolean onUpdated() {
+		if (entity == null) return false;
+
+		boolean changed = false;
+
 		float generatedSpeedNew = entity.getGeneratedSpeed();
 		if (this.generatedSpeed != generatedSpeedNew) {
 			this.generatedSpeed = generatedSpeedNew;
+			changed = true;
 			network.onMemberGeneratedSpeedUpdated(this);
 			if (network.tryRecalculateSpeed().isContradiction()) {
 				popBlock();
@@ -99,14 +161,18 @@ public class KineticNode {
 		float stressImpactNew = entity.getStressImpact();
 		if (this.stressImpact != stressImpactNew) {
 			this.stressImpact = stressImpactNew;
+			changed = true;
 			network.onMemberStressImpactUpdated();
 		}
 
 		float stressCapacityNew = entity.getStressCapacity();
 		if (this.stressCapacity != stressCapacityNew) {
 			this.stressCapacity = stressCapacityNew;
+			changed = true;
 			network.onMemberStressCapacityUpdated();
 		}
+
+		return changed;
 	}
 
 	public boolean hasStressCapacity() {
@@ -122,11 +188,11 @@ public class KineticNode {
 	}
 
 	public float getStressCapacity() {
-		return Math.abs(stressCapacity * generatedSpeed);
+		return constantStress ? stressCapacity : stressCapacity * Math.abs(generatedSpeed);
 	}
 
 	public float getTotalStressImpact(float speedAtRoot) {
-		return Math.abs(stressImpact * getTheoreticalSpeed(speedAtRoot));
+		return constantStress ? stressImpact : stressImpact * Math.abs(getTheoreticalSpeed(speedAtRoot));
 	}
 
 	private SolveResult setNetwork(KineticNetwork network) {
@@ -233,13 +299,18 @@ public class KineticNode {
 	public void flushChangedSpeed() {
 		if (speedCur != speedNext) {
 			speedCur = speedNext;
-			entity.setSpeed(speedCur);
+			if (entity != null) {
+				entity.setSpeed(speedCur);
+			}
 		}
 	}
 
 	public void popBlock() {
-		// this should cause the node to get removed from the solver and lead to onRemoved() being called
-		entity.getLevel().destroyBlock(entity.getBlockPos(), true);
+		if (entity != null) {
+			solver.removeAndPopNow(entity);
+		} else {
+			solver.removeAndQueuePop(pos);
+		}
 	}
 
 }

src/main/java/com/simibubi/create/content/contraptions/solver/KineticSolver.java

@@ -10,30 +10,108 @@ import java.util.Set;
 import java.util.stream.Collectors;
 
 import com.simibubi.create.content.contraptions.base.KineticTileEntity;
+import com.simibubi.create.foundation.utility.Pair;
 import com.simibubi.create.foundation.utility.WorldAttached;
 
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Vec3i;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.ListTag;
+import net.minecraft.nbt.NbtUtils;
+import net.minecraft.nbt.Tag;
+import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.level.Level;
+import net.minecraft.world.level.LevelAccessor;
+import net.minecraft.world.level.block.Block;
+import net.minecraft.world.level.saveddata.SavedData;
 
-public class KineticSolver {
+import org.checkerframework.checker.units.qual.C;
+import org.jetbrains.annotations.NotNull;
 
-	private static final WorldAttached<KineticSolver> SOLVERS = new WorldAttached<>($ -> new KineticSolver());
+public class KineticSolver extends SavedData {
+
+	public static final String DATA_FILE_NAME = "kinetics";
+
+	private static final WorldAttached<KineticSolver> SOLVERS = new WorldAttached<>(levelAccessor -> {
+		if (levelAccessor instanceof ServerLevel level)
+			return level.getDataStorage().computeIfAbsent(KineticSolver::load, KineticSolver::new, DATA_FILE_NAME);
+		return new KineticSolver();
+	});
 
 	public static KineticSolver getSolver(Level level) {
 		return SOLVERS.get(level);
 	}
 
 	private final Map<BlockPos, KineticNode> nodes = new HashMap<>();
+	private final Set<BlockPos> popQueue = new HashSet<>();
+
+	@Override
+	public @NotNull CompoundTag save(@NotNull CompoundTag tag) {
+		ListTag popQueueTag = new ListTag();
+		for (BlockPos pos : popQueue) {
+			popQueueTag.add(NbtUtils.writeBlockPos(pos));
+		}
+		tag.put("PopQueue", popQueueTag);
+
+		ListTag nodesTag = new ListTag();
+		for (KineticNode node : nodes.values()) {
+			nodesTag.add(node.save(new CompoundTag()));
+		}
+		tag.put("Nodes", nodesTag);
+
+		return tag;
+	}
+
+	private static KineticSolver load(CompoundTag tag) {
+		KineticSolver out = new KineticSolver();
+
+		tag.getList("PopQueue", Tag.TAG_COMPOUND).forEach(c ->
+				out.popQueue.add(NbtUtils.readBlockPos((CompoundTag) c)));
+
+		tag.getList("Nodes", Tag.TAG_COMPOUND).forEach(c ->
+				out.addUnloadedNode(KineticNode.load(out, (CompoundTag) c)));
+
+		return out;
+	}
+
+	private void addUnloadedNode(KineticNode node) {
+		KineticNode nodePrev = nodes.remove(node.getPos());
+		if (nodePrev != null) nodePrev.onRemoved();
+
+		nodes.put(node.getPos(), node);
+		node.onAdded();
+	}
 
 	public void addNode(KineticTileEntity entity) {
-		removeNode(entity);
-		KineticNode node = new KineticNode(entity, this::getNode);
-		nodes.put(entity.getBlockPos(), node);
+		BlockPos pos = entity.getBlockPos();
+		if (popQueue.contains(pos)) {
+			popQueue.remove(pos);
+			popBlock(entity.getLevel(), pos);
+			setDirty();
+			return;
+		}
+
+		KineticNode nodePrev = nodes.get(pos);
+		if (nodePrev != null) {
+			if (nodePrev.isLoaded()) {
+				nodes.remove(pos);
+				nodePrev.onRemoved();
+			} else {
+				// a node exists here but is unloaded, so just load it with this entity instead of replacing
+				nodePrev.onLoaded(entity);
+				return;
+			}
+		}
+
+		KineticNode node = new KineticNode(this, entity);
+		nodes.put(pos, node);
 		node.onAdded();
+		setDirty();
 	}
 
 	public void updateNode(KineticTileEntity entity) {
 		KineticNode node = nodes.get(entity.getBlockPos());
+		if (node == null) return;
 
 		if (!node.getConnections().equals(entity.getConnections())) {
 			// connections changed, so things could've been disconnected
@@ -41,17 +119,49 @@ public class KineticSolver {
 			addNode(entity);
 		} else {
 			// connections are the same, so just update in case other properties changed
-			node.onUpdated();
+			if (node.onUpdated()) {
+				setDirty();
+			}
 		}
 	}
 
+	public void unloadNode(KineticTileEntity entity) {
+		KineticNode node = nodes.get(entity.getBlockPos());
+		if (node != null) node.onUnloaded();
+	}
+
 	protected Optional<KineticNode> getNode(BlockPos pos) {
 		return Optional.ofNullable(nodes.get(pos));
 	}
 
 	public void removeNode(KineticTileEntity entity) {
 		KineticNode node = nodes.remove(entity.getBlockPos());
-		if (node != null) node.onRemoved();
+		if (node != null) {
+			node.onRemoved();
+			setDirty();
+		}
+	}
+
+	protected void removeAndQueuePop(BlockPos pos) {
+		KineticNode node = nodes.remove(pos);
+		if (node != null) {
+			popQueue.add(pos);
+			node.onRemoved();
+			setDirty();
+		}
+	}
+
+	protected void removeAndPopNow(KineticTileEntity entity) {
+		KineticNode node = nodes.remove(entity.getBlockPos());
+		if (node != null) {
+			popBlock(entity.getLevel(), entity.getBlockPos());
+			node.onRemoved();
+			setDirty();
+		}
+	}
+
+	private void popBlock(Level level, BlockPos pos) {
+		level.destroyBlock(pos, true);
 	}
 
 	public void tick() {
@@ -69,4 +179,18 @@ public class KineticSolver {
 		}
 	}
 
+	public Optional<Float> isConnected(BlockPos from, BlockPos to) {
+		return getNode(from).flatMap(fromNode ->
+				getNode(to).flatMap(toNode ->
+						fromNode.getConnections()
+								.checkConnection(toNode.getConnections(), to.subtract(from))));
+	}
+
+	public boolean isStressOnlyConnected(BlockPos from, BlockPos to) {
+		return getNode(from).flatMap(fromNode ->
+				getNode(to).map(toNode ->
+						fromNode.getConnections()
+								.checkStressOnlyConnection(toNode.getConnections(), to.subtract(from)))
+		).orElse(false);
+	}
 }