Add ComputerCraft integration to Nixie Tubes

- Makes computer-controlled Nixie Tubes unable to be changed by external
  factors (but can still be used as a Display Link source)
- Add CC setText(text[, colour]) function
- Add CC setTextColour(colour) function
- Add CC setSignal(first, second) function taking 2 tables describing
  the appearance of the first and second tube as custom train signals

src/main/java/com/simibubi/create/AllPartialModels.java

@@ -156,6 +156,10 @@ public class AllPartialModels {
 		SIGNAL_RED_CUBE = block("track_signal/red_cube"), SIGNAL_RED_GLOW = block("track_signal/red_glow"),
 		SIGNAL_RED = block("track_signal/red_tube"), SIGNAL_YELLOW_CUBE = block("track_signal/yellow_cube"),
 		SIGNAL_YELLOW_GLOW = block("track_signal/yellow_glow"), SIGNAL_YELLOW = block("track_signal/yellow_tube"),
+		SIGNAL_COMPUTER_WHITE_CUBE = block("track_signal/computer_white_cube"),
+		SIGNAL_COMPUTER_WHITE_GLOW = block("track_signal/computer_white_glow"),
+		SIGNAL_COMPUTER_WHITE = block("track_signal/computer_white_tube"),
+		SIGNAL_COMPUTER_WHITE_BASE = block("track_signal/computer_white_tube_base"),
 
 		BLAZE_INERT = block("blaze_burner/blaze/inert"), BLAZE_SUPER_ACTIVE = block("blaze_burner/blaze/super_active"),
 		BLAZE_GOGGLES = block("blaze_burner/goggles"), BLAZE_GOGGLES_SMALL = block("blaze_burner/goggles_small"),

src/main/java/com/simibubi/create/compat/computercraft/implementation/ComputerBehaviour.java

@@ -2,6 +2,7 @@ package com.simibubi.create.compat.computercraft.implementation;
 
 import com.simibubi.create.compat.computercraft.AbstractComputerBehaviour;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.DisplayLinkPeripheral;
+import com.simibubi.create.compat.computercraft.implementation.peripherals.NixieTubePeripheral;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.SequencedGearshiftPeripheral;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.SpeedControllerPeripheral;
 import com.simibubi.create.compat.computercraft.implementation.peripherals.SpeedGaugePeripheral;
@@ -12,6 +13,7 @@ import com.simibubi.create.content.kinetics.gauge.StressGaugeBlockEntity;
 import com.simibubi.create.content.kinetics.speedController.SpeedControllerBlockEntity;
 import com.simibubi.create.content.kinetics.transmission.sequencer.SequencedGearshiftBlockEntity;
 import com.simibubi.create.content.redstone.displayLink.DisplayLinkBlockEntity;
+import com.simibubi.create.content.redstone.nixieTube.NixieTubeBlockEntity;
 import com.simibubi.create.content.trains.station.StationBlockEntity;
 import com.simibubi.create.foundation.blockEntity.SmartBlockEntity;
 
@@ -40,6 +42,8 @@ public class ComputerBehaviour extends AbstractComputerBehaviour {
 			return () -> new SpeedControllerPeripheral(scbe, scbe.targetSpeed);
 		if (be instanceof DisplayLinkBlockEntity dlbe)
 			return () -> new DisplayLinkPeripheral(dlbe);
+		if (be instanceof NixieTubeBlockEntity ntbe)
+			return () -> new NixieTubePeripheral(ntbe);
 		if (be instanceof SequencedGearshiftBlockEntity sgbe)
 			return () -> new SequencedGearshiftPeripheral(sgbe);
 		if (be instanceof SpeedGaugeBlockEntity sgbe)

src/main/java/com/simibubi/create/compat/computercraft/implementation/peripherals/NixieTubePeripheral.java

@@ -0,0 +1,169 @@
+package com.simibubi.create.compat.computercraft.implementation.peripherals;
+
+import java.util.Map;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+
+import com.simibubi.create.content.redstone.nixieTube.NixieTubeBlock;
+import com.simibubi.create.content.redstone.nixieTube.NixieTubeBlockEntity;
+import com.simibubi.create.foundation.utility.Components;
+
+import dan200.computercraft.api.lua.IArguments;
+import dan200.computercraft.api.lua.LuaException;
+import dan200.computercraft.api.lua.LuaFunction;
+import dan200.computercraft.api.lua.LuaValues;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.item.DyeColor;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.state.BlockState;
+
+public class NixieTubePeripheral extends SyncedPeripheral<NixieTubeBlockEntity> {
+
+	private static final String EMPTY_COMPONENT_JSON = Component.Serializer.toJson(Components.literal(""));
+
+	public NixieTubePeripheral(NixieTubeBlockEntity blockEntity) {
+		super(blockEntity);
+	}
+
+	@Override
+	protected void onFirstAttach() {
+		// When first attaching to a computer, clear out the entire nixie tube row.
+		super.onFirstAttach();
+		Level world = blockEntity.getLevel();
+		if (world == null)
+			return;
+		NixieTubeBlock.walkNixies(world, blockEntity.getBlockPos(), true,
+				(currentPos, rowPosition) -> {
+					if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+						ntbe.displayCustomText(EMPTY_COMPONENT_JSON, rowPosition);
+				});
+	}
+
+	@Override
+	protected void onLastDetach() {
+		// When detaching from the last computer, reset the entire nixie tube row back to redstone display,
+		// except if it's still being controlled from some other tube. onLastDetach runs after the
+		// hasAttachedComputer flag is reset, so we can use walkNixies()'s computer control rejection for that.
+		super.onLastDetach();
+		Level world = blockEntity.getLevel();
+		if (world == null)
+			return;
+		// Check if the nixie tube block is still there; if it isn't then the nixie was removed/destroyed
+		// and the row reset is handled in NixieTubeBlock::remove.
+		BlockState state = world.getBlockState(blockEntity.getBlockPos());
+		if (!(state.getBlock() instanceof NixieTubeBlock))
+			return;
+		NixieTubeBlock.walkNixies(world, blockEntity.getBlockPos(), false,
+				(currentPos, rowPosition) -> {
+					if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe) {
+						NixieTubeBlock.updateDisplayedRedstoneValue(ntbe, true);
+					}
+				});
+	}
+
+	@LuaFunction(mainThread = true)
+	public void setText(IArguments arguments) throws LuaException {
+		Level world = blockEntity.getLevel();
+		if (world == null)
+			return;
+		blockEntity.computerSignal = null;
+
+		String tagElement = Component.Serializer.toJson(Components.literal(arguments.getString(0)));
+
+		@Nullable String colour = arguments.optString(1, null);
+		BlockState state = null;
+		DyeColor dye = null;
+		if (colour != null) {
+			state = blockEntity.getLevel().getBlockState(blockEntity.getBlockPos());
+			dye = LuaValues.checkEnum(1, DyeColor.class, colour.equals("grey") ? "gray" : colour);
+		}
+
+		changeTextNixie(tagElement, state, dye);
+	}
+
+	@LuaFunction(mainThread = true)
+	public void setTextColour(String colour) throws LuaException {
+		Level world = blockEntity.getLevel();
+		if (world == null)
+			return;
+		BlockState state = blockEntity.getLevel().getBlockState(blockEntity.getBlockPos());
+		DyeColor dye = LuaValues.checkEnum(1, DyeColor.class, colour.equals("grey") ? "gray" : colour);
+		changeTextNixie(null, state, dye);
+	}
+
+	@LuaFunction(mainThread = true)
+	public void setTextColor(String color) throws LuaException {
+		setTextColour(color);
+	}
+
+	private void changeTextNixie(@Nullable String tagElement, @Nullable BlockState state, @Nullable DyeColor dye) {
+		Level world = blockEntity.getLevel();
+		if (world == null)
+			return;
+		NixieTubeBlock.walkNixies(world, blockEntity.getBlockPos(), true, (currentPos, rowPosition) -> {
+			if (tagElement != null)
+				((NixieTubeBlock) blockEntity.getBlockState().getBlock()).withBlockEntityDo(
+						world, currentPos, be -> be.displayCustomText(tagElement, rowPosition));
+			if (state != null && dye != null)
+				world.setBlockAndUpdate(currentPos, NixieTubeBlock.withColor(state, dye));
+		});
+	}
+
+	@LuaFunction(mainThread = true)
+	public void setSignal(IArguments arguments) throws LuaException {
+		if (arguments.optTable(0).isPresent())
+			setSignal(signal().first, arguments.getTable(0));
+		if (arguments.optTable(1).isPresent())
+			setSignal(signal().second, arguments.getTable(1));
+	}
+
+	private void setSignal(NixieTubeBlockEntity.ComputerSignal.TubeDisplay display, @NotNull Map<?, ?> attrs)
+			throws LuaException {
+		if (attrs.containsKey("r"))
+			display.r = constrainByte("r", 0, 255, attrs.get("r"));
+		if (attrs.containsKey("g"))
+			display.g = constrainByte("g", 0, 255, attrs.get("g"));
+		if (attrs.containsKey("b"))
+			display.b = constrainByte("r", 0, 255, attrs.get("b"));
+		if (attrs.containsKey("glowWidth"))
+			display.glowWidth = constrainByte("glowWidth", 1, 4, attrs.get("glowWidth"));
+		if (attrs.containsKey("glowHeight"))
+			display.glowHeight = constrainByte("glowHeight", 1, 4, attrs.get("glowHeight"));
+		if (attrs.containsKey("blinkPeriod"))
+			display.blinkPeriod = constrainByte("blinkPeriod", 0, 255, attrs.get("blinkPeriod"));
+		if (attrs.containsKey("blinkOffTime"))
+			display.blinkOffTime = constrainByte("blinkOffTime", 0, 255, attrs.get("blinkOffTime"));
+		if (display.r == 0 && display.g == 0 && display.b == 0) {
+			display.blinkPeriod = 0;
+			display.blinkOffTime = 0;
+		} else if (display.blinkPeriod == 0) {
+			display.blinkPeriod = 1;
+			display.blinkOffTime = 0;
+		}
+		blockEntity.notifyUpdate();
+	}
+
+	private byte constrainByte(String name, int min, int max, Object rawValue) throws LuaException {
+		if (!(rawValue instanceof Number))
+			throw LuaValues.badField(name, "number", LuaValues.getType(rawValue));
+		int value = ((Number) rawValue).intValue();
+		if (value < min || value > max)
+			throw new LuaException("field " + name + " must be in range " + min + "-" + max);
+		return (byte) value;
+	}
+
+	private NixieTubeBlockEntity.ComputerSignal signal() {
+		if (blockEntity.computerSignal == null)
+			blockEntity.computerSignal = new NixieTubeBlockEntity.ComputerSignal();
+		return blockEntity.computerSignal;
+	}
+
+	@NotNull
+	@Override
+	public String getType() {
+		return "Create_NixieTube";
+	}
+
+}

src/main/java/com/simibubi/create/compat/computercraft/implementation/peripherals/SyncedPeripheral.java

@@ -1,6 +1,9 @@
 package com.simibubi.create.compat.computercraft.implementation.peripherals;
 
-import java.util.concurrent.atomic.AtomicInteger;
+import java.util.ArrayList;
+import java.util.List;
+
+import com.simibubi.create.compat.computercraft.events.ComputerEvent;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -17,7 +20,7 @@ import net.minecraftforge.network.PacketDistributor;
 public abstract class SyncedPeripheral<T extends SmartBlockEntity> implements IPeripheral {
 
 	protected final T blockEntity;
-	private final AtomicInteger computers = new AtomicInteger();
+	private final List<@NotNull IComputerAccess> computers = new ArrayList<>();
 
 	public SyncedPeripheral(T blockEntity) {
 		this.blockEntity = blockEntity;
@@ -25,21 +28,34 @@ public abstract class SyncedPeripheral<T extends SmartBlockEntity> implements IP
 
 	@Override
 	public void attach(@NotNull IComputerAccess computer) {
-		computers.incrementAndGet();
-		updateBlockEntity();
+		synchronized (computers) {
+			computers.add(computer);
+			if (computers.size() == 1)
+				onFirstAttach();
+			updateBlockEntity();
+		}
 	}
 
+	protected void onFirstAttach() {}
+
 	@Override
 	public void detach(@NotNull IComputerAccess computer) {
-		computers.decrementAndGet();
-		updateBlockEntity();
+		synchronized (computers) {
+			computers.remove(computer);
+			updateBlockEntity();
+			if (computers.isEmpty())
+				onLastDetach();
+		}
 	}
 
+	protected void onLastDetach() {}
+
 	private void updateBlockEntity() {
-		boolean hasAttachedComputer = computers.get() > 0;
+		boolean hasAttachedComputer = !computers.isEmpty();
 
 		blockEntity.getBehaviour(ComputerBehaviour.TYPE).setHasAttachedComputer(hasAttachedComputer);
-		AllPackets.getChannel().send(PacketDistributor.ALL.noArg(), new AttachedComputerPacket(blockEntity.getBlockPos(), hasAttachedComputer));
+		AllPackets.getChannel().send(PacketDistributor.ALL.noArg(),
+				new AttachedComputerPacket(blockEntity.getBlockPos(), hasAttachedComputer));
 	}
 
 	@Override

src/main/java/com/simibubi/create/content/redstone/displayLink/target/NixieTubeDisplayTarget.java

@@ -22,7 +22,7 @@ public class NixieTubeDisplayTarget extends SingleLineDisplayTarget {
 	@Override
 	protected void acceptLine(MutableComponent text, DisplayLinkContext context) {
 		String tagElement = Component.Serializer.toJson(text);
-		NixieTubeBlock.walkNixies(context.level(), context.getTargetPos(), (currentPos, rowPosition) -> {
+		NixieTubeBlock.walkNixies(context.level(), context.getTargetPos(), false, (currentPos, rowPosition) -> {
 			BlockEntity blockEntity = context.level()
 				.getBlockEntity(currentPos);
 			if (blockEntity instanceof NixieTubeBlockEntity nixie)
@@ -33,7 +33,8 @@ public class NixieTubeDisplayTarget extends SingleLineDisplayTarget {
 	@Override
 	protected int getWidth(DisplayLinkContext context) {
 		MutableInt count = new MutableInt(0);
-		NixieTubeBlock.walkNixies(context.level(), context.getTargetPos(), (currentPos, rowPosition) -> count.add(2));
+		NixieTubeBlock.walkNixies(context.level(), context.getTargetPos(), false,
+				(currentPos, rowPosition) -> count.add(2));
 		return count.intValue();
 	}
 
@@ -42,7 +43,7 @@ public class NixieTubeDisplayTarget extends SingleLineDisplayTarget {
 	public AABB getMultiblockBounds(LevelAccessor level, BlockPos pos) {
 		MutableObject<BlockPos> start = new MutableObject<>(null);
 		MutableObject<BlockPos> end = new MutableObject<>(null);
-		NixieTubeBlock.walkNixies(level, pos, (currentPos, rowPosition) -> {
+		NixieTubeBlock.walkNixies(level, pos, true, (currentPos, rowPosition) -> {
 			end.setValue(currentPos);
 			if (start.getValue() == null)
 				start.setValue(currentPos);

src/main/java/com/simibubi/create/content/redstone/nixieTube/NixieTubeBlock.java

@@ -6,9 +6,14 @@ import java.util.List;
 import java.util.Random;
 import java.util.function.BiConsumer;
 
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+
 import com.simibubi.create.AllBlockEntityTypes;
 import com.simibubi.create.AllBlocks;
 import com.simibubi.create.AllShapes;
+import com.simibubi.create.compat.Mods;
 import com.simibubi.create.content.equipment.clipboard.ClipboardEntry;
 import com.simibubi.create.content.equipment.wrench.IWrenchable;
 import com.simibubi.create.content.schematics.requirement.ISpecialBlockItemRequirement;
@@ -71,6 +76,11 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 
 		if (nixie == null)
 			return InteractionResult.PASS;
+
+		// Refuse interaction if nixie tube is in a computer-controlled row
+		if (isInComputerControlledRow(world, pos))
+			return InteractionResult.PASS;
+
 		if (heldItem.isEmpty()) {
 			if (nixie.reactsToRedstone())
 				return InteractionResult.PASS;
@@ -101,7 +111,8 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 			return InteractionResult.SUCCESS;
 
 		String tagUsed = tagElement;
-		walkNixies(world, pos, (currentPos, rowPosition) -> {
+		// Skip computer check in this walk since it was already performed at the start.
+		walkNixies(world, pos, true, (currentPos, rowPosition) -> {
 			if (display)
 				withBlockEntityDo(world, currentPos, be -> be.displayCustomText(tagUsed, rowPosition));
 			if (dye != null)
@@ -111,40 +122,98 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 		return InteractionResult.SUCCESS;
 	}
 
-	public static void walkNixies(LevelAccessor world, BlockPos start, BiConsumer<BlockPos, Integer> callback) {
-		BlockState state = world.getBlockState(start);
-		if (!(state.getBlock() instanceof NixieTubeBlock))
-			return;
-
-		BlockPos currentPos = start;
-		Direction left = state.getValue(FACING)
-			.getOpposite();
-
+	public static Direction getLeftNixieDirection(@NotNull BlockState state) {
+		Direction left = state.getValue(FACING).getOpposite();
 		if (state.getValue(FACE) == DoubleAttachFace.WALL)
 			left = Direction.UP;
 		if (state.getValue(FACE) == DoubleAttachFace.WALL_REVERSED)
 			left = Direction.DOWN;
+		return left;
+	}
 
+	public static Direction getRightNixieDirection(@NotNull BlockState state) {
+		return getLeftNixieDirection(state).getOpposite();
+	}
+
+	public static boolean isInComputerControlledRow(@NotNull LevelAccessor world, @NotNull BlockPos pos) {
+		return Mods.COMPUTERCRAFT.isLoaded() && !walkNixies(world, pos, false, null);
+	}
+
+	/**
+	 * Walk down a nixie tube row and execute a callback on each tube in said row.
+	 * @param world The world the tubes are in.
+	 * @param start Start position for the walk.
+	 * @param allowComputerControlled Allow or disallow running callbacks if the row is computer-controlled.
+	 * @param callback Callback to run for each tube.
+	 * @return True if the row was walked, false if the walk was aborted because it is computer-controlled.
+	 */
+	public static boolean walkNixies(@NotNull LevelAccessor world, @NotNull BlockPos start,
+									 boolean allowComputerControlled,
+									 @Nullable BiConsumer<BlockPos, Integer> callback) {
+		BlockState state = world.getBlockState(start);
+		if (!(state.getBlock() instanceof NixieTubeBlock))
+			return false;
+
+		// If ComputerCraft is not installed, ignore allowComputerControlled since
+		// nixies can't be computer-controlled
+		if (!Mods.COMPUTERCRAFT.isLoaded())
+			allowComputerControlled = true;
+
+		BlockPos currentPos = start;
+		Direction left = getLeftNixieDirection(state);
 		Direction right = left.getOpposite();
 
 		while (true) {
 			BlockPos nextPos = currentPos.relative(left);
 			if (!areNixieBlocksEqual(world.getBlockState(nextPos), state))
 				break;
+			// If computer-controlled nixie walking is disallowed, presence of any (same-color)
+			// controlled nixies aborts the entire nixie walk.
+			if (!allowComputerControlled && world.getBlockEntity(nextPos) instanceof NixieTubeBlockEntity ntbe &&
+					ntbe.computerBehaviour.hasAttachedComputer()) {
+				return false;
+			}
 			currentPos = nextPos;
 		}
 
+		// As explained above, a controlled nixie in the row aborts the walk if they are disallowed,
+		// and that includes those down the chain too.
+		if (!allowComputerControlled) {
+			// Check the start block itself
+			if (world.getBlockEntity(start) instanceof NixieTubeBlockEntity ntbe &&
+					ntbe.computerBehaviour.hasAttachedComputer()) {
+				return false;
+			}
+			BlockPos leftmostPos = currentPos;
+			// No need to iterate over the nixies to the left again
+			currentPos = start;
+			while (true) {
+				BlockPos nextPos = currentPos.relative(right);
+				if (!areNixieBlocksEqual(world.getBlockState(nextPos), state))
+					break;
+				if (world.getBlockEntity(nextPos) instanceof NixieTubeBlockEntity ntbe &&
+						ntbe.computerBehaviour.hasAttachedComputer()) {
+					return false;
+				}
+				currentPos = nextPos;
+			}
+			currentPos = leftmostPos;
+		}
+
 		int index = 0;
 
 		while (true) {
 			final int rowPosition = index;
-			callback.accept(currentPos, rowPosition);
+			if (callback != null)
+				callback.accept(currentPos, rowPosition);
 			BlockPos nextPos = currentPos.relative(right);
 			if (!areNixieBlocksEqual(world.getBlockState(nextPos), state))
 				break;
 			currentPos = nextPos;
 			index++;
 		}
+
+		return true;
 	}
 
 	@Override
@@ -153,10 +222,41 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 	}
 
 	@Override
-	public void onRemove(BlockState p_196243_1_, Level p_196243_2_, BlockPos p_196243_3_, BlockState p_196243_4_,
-		boolean p_196243_5_) {
-		if (!(p_196243_4_.getBlock() instanceof NixieTubeBlock))
-			p_196243_2_.removeBlockEntity(p_196243_3_);
+	public void onRemove(BlockState state, Level world, BlockPos pos, BlockState newState, boolean isMoving) {
+		if (newState.getBlock() instanceof NixieTubeBlock)
+			return;
+		world.removeBlockEntity(pos);
+		if (Mods.COMPUTERCRAFT.isLoaded()) {
+			// A computer-controlled nixie tube row may have been broken in the middle.
+			Direction left = getLeftNixieDirection(state);
+			BlockPos leftPos = pos.relative(left);
+			if (areNixieBlocksEqual(world.getBlockState(leftPos), state)) {
+				boolean leftRowComputerControlled = isInComputerControlledRow(world, leftPos);
+				walkNixies(world, leftPos, true, leftRowComputerControlled ?
+						(currentPos, rowPosition) -> {
+							if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+								ntbe.displayCustomText("{\"text\":\"\"}", rowPosition);
+						} :
+						(currentPos, rowPosition) -> {
+							if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+								NixieTubeBlock.updateDisplayedRedstoneValue(ntbe, true);
+						});
+			}
+			Direction right = left.getOpposite();
+			BlockPos rightPos = pos.relative(right);
+			if (areNixieBlocksEqual(world.getBlockState(rightPos), state)) {
+				boolean rightRowComputerControlled = isInComputerControlledRow(world, rightPos);
+				walkNixies(world, rightPos, true, rightRowComputerControlled ?
+						(currentPos, rowPosition) -> {
+							if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+								ntbe.displayCustomText("{\"text\":\"\"}", rowPosition);
+						} :
+						(currentPos, rowPosition) -> {
+							if (world.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+								NixieTubeBlock.updateDisplayedRedstoneValue(ntbe, true);
+						});
+			}
+		}
 	}
 
 	@Override
@@ -237,18 +337,30 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 
 	@Override
 	public void onPlace(BlockState state, Level worldIn, BlockPos pos, BlockState oldState, boolean isMoving) {
-		if (state.getBlock() == oldState.getBlock() || isMoving)
+		if (state.getBlock() == oldState.getBlock() || isMoving || oldState.getBlock() instanceof NixieTubeBlock)
 			return;
+		if (Mods.COMPUTERCRAFT.isLoaded() && isInComputerControlledRow(worldIn, pos)) {
+			// The nixie tube has been placed in a computer-controlled row.
+			walkNixies(worldIn, pos, true, (currentPos, rowPosition) -> {
+				if (worldIn.getBlockEntity(currentPos) instanceof NixieTubeBlockEntity ntbe)
+					ntbe.displayCustomText("{\"text\":\"\"}", rowPosition);
+			});
+			return;
+		}
 		updateDisplayedRedstoneValue(state, worldIn, pos);
 	}
 
+	public static void updateDisplayedRedstoneValue(NixieTubeBlockEntity be, boolean force) {
+		if (be.getLevel() == null || be.getLevel().isClientSide)
+			return;
+		if (be.reactsToRedstone() || force)
+			be.updateRedstoneStrength(getPower(be.getLevel(), be.getBlockPos()));
+	}
+
 	private void updateDisplayedRedstoneValue(BlockState state, Level worldIn, BlockPos pos) {
 		if (worldIn.isClientSide)
 			return;
-		withBlockEntityDo(worldIn, pos, be -> {
-			if (be.reactsToRedstone())
-				be.updateRedstoneStrength(getPower(worldIn, pos));
-		});
+		withBlockEntityDo(worldIn, pos, be -> NixieTubeBlock.updateDisplayedRedstoneValue(be, false));
 	}
 
 	static boolean isValidBlock(BlockGetter world, BlockPos pos, boolean above) {
@@ -257,7 +369,7 @@ public class NixieTubeBlock extends DoubleFaceAttachedBlock
 			.isEmpty();
 	}
 
-	private int getPower(Level worldIn, BlockPos pos) {
+	private static int getPower(Level worldIn, BlockPos pos) {
 		int power = 0;
 		for (Direction direction : Iterate.directions)
 			power = Math.max(worldIn.getSignal(pos.relative(direction), direction), power);

src/main/java/com/simibubi/create/content/redstone/nixieTube/NixieTubeBlockEntity.java

@@ -4,6 +4,14 @@ import java.lang.ref.WeakReference;
 import java.util.List;
 import java.util.Optional;
 
+import com.simibubi.create.Create;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+
+import com.simibubi.create.compat.computercraft.AbstractComputerBehaviour;
+import com.simibubi.create.compat.computercraft.ComputerCraftProxy;
 import com.simibubi.create.content.redstone.displayLink.DisplayLinkBlock;
 import com.simibubi.create.content.trains.signal.SignalBlockEntity;
 import com.simibubi.create.content.trains.signal.SignalBlockEntity.SignalState;
@@ -13,6 +21,8 @@ import com.simibubi.create.foundation.utility.Components;
 import com.simibubi.create.foundation.utility.Couple;
 import com.simibubi.create.foundation.utility.DynamicComponent;
 
+import net.minecraftforge.common.capabilities.Capability;
+import net.minecraftforge.common.util.LazyOptional;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
@@ -23,15 +33,62 @@ import net.minecraft.world.level.block.state.BlockState;
 
 public class NixieTubeBlockEntity extends SmartBlockEntity {
 
+	public static final class ComputerSignal {
+		public static final class TubeDisplay {
+			public static final int ENCODED_SIZE = 7;
+
+			public byte r = 63, g = 63, b = 63;
+			public byte blinkPeriod = 0, blinkOffTime = 0;
+			public byte glowWidth = 1, glowHeight = 1;
+
+			public void decode(byte[] data, int offset) {
+				r = data[offset];
+				g = data[offset + 1];
+				b = data[offset + 2];
+				blinkPeriod = data[offset + 3];
+				blinkOffTime = data[offset + 4];
+				glowWidth = data[offset + 5];
+				glowHeight = data[offset + 6];
+			}
+
+			public void encode(byte[] data, int offset) {
+				data[offset] = r;
+				data[offset + 1] = g;
+				data[offset + 2] = b;
+				data[offset + 3] = blinkPeriod;
+				data[offset + 4] = blinkOffTime;
+				data[offset + 5] = glowWidth;
+				data[offset + 6] = glowHeight;
+			}
+		}
+
+		public @NotNull TubeDisplay first = new TubeDisplay();
+		public @NotNull TubeDisplay second = new TubeDisplay();
+
+		public void decode(byte[] encoded) {
+			first.decode(encoded, 0);
+			second.decode(encoded, TubeDisplay.ENCODED_SIZE);
+		}
+
+		public byte[] encode() {
+			byte[] encoded = new byte[TubeDisplay.ENCODED_SIZE * 2];
+			first.encode(encoded, 0);
+			second.encode(encoded, TubeDisplay.ENCODED_SIZE);
+			return encoded;
+		}
+	}
+
 	private static final Couple<String> EMPTY = Couple.create("", "");
 
 	private int redstoneStrength;
 	private Optional<DynamicComponent> customText;
 	private int nixieIndex;
 	private Couple<String> displayedStrings;
+	public AbstractComputerBehaviour computerBehaviour;
 
 	private WeakReference<SignalBlockEntity> cachedSignalTE;
-	public SignalState signalState;
+	public @Nullable SignalState signalState;
+	public @Nullable ComputerSignal computerSignal;
 
 	public NixieTubeBlockEntity(BlockEntityType<?> type, BlockPos pos, BlockState state) {
 		super(type, pos, state);
@@ -47,6 +104,13 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 			return;
 
 		signalState = null;
+		if (computerBehaviour.hasAttachedComputer()) {
+			if (level.isClientSide && cachedSignalTE.get() != null) {
+				cachedSignalTE = new WeakReference<>(null);
+			}
+			return;
+		}
+
 		SignalBlockEntity signalBlockEntity = cachedSignalTE.get();
 
 		if (signalBlockEntity == null || signalBlockEntity.isRemoved()) {
@@ -71,7 +135,7 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 	//
 
 	public boolean reactsToRedstone() {
-		return customText.isEmpty();
+		return !computerBehaviour.hasAttachedComputer() && customText.isEmpty();
 	}
 
 	public Couple<String> getDisplayedStrings() {
@@ -108,7 +172,7 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 	}
 
 	public void updateDisplayedStrings() {
-		if (signalState != null)
+		if (signalState != null || computerSignal != null)
 			return;
 		customText.map(DynamicComponent::resolve)
 			.ifPresentOrElse(
@@ -144,12 +208,25 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 				customText = Optional.empty();
 				nixieIndex = 0;
 			}
+		} else {
+			customText = Optional.empty();
+			nixieIndex = 0;
 		}
 
 		if (customText.isEmpty())
 			redstoneStrength = nbt.getInt("RedstoneStrength");
-		if (clientPacket)
+		if (clientPacket) {
+			if (nbt.contains("ComputerSignal")) {
+				byte[] encodedComputerSignal = nbt.getByteArray("ComputerSignal");
+				if (computerSignal == null)
+					computerSignal = new ComputerSignal();
+				computerSignal.decode(encodedComputerSignal);
+			} else {
+				computerSignal = null;
+			}
+
 			updateDisplayedStrings();
+		}
 	}
 
 	@Override
@@ -162,6 +239,8 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 				.write(nbt);
 		} else
 			nbt.putInt("RedstoneStrength", redstoneStrength);
+		if (clientPacket && computerSignal != null)
+			nbt.putByteArray("ComputerSignal", computerSignal.encode());
 	}
 
 	private String charOrEmpty(String string, int index) {
@@ -169,6 +248,21 @@ public class NixieTubeBlockEntity extends SmartBlockEntity {
 	}
 
 	@Override
-	public void addBehaviours(List<BlockEntityBehaviour> behaviours) {}
+	public void addBehaviours(List<BlockEntityBehaviour> behaviours) {
+		behaviours.add(computerBehaviour = ComputerCraftProxy.behaviour(this));
+	}
+
+	@Override
+	public <T> @NotNull LazyOptional<T> getCapability(@NotNull Capability<T> cap, Direction side) {
+		if (computerBehaviour.isPeripheralCap(cap))
+			return computerBehaviour.getPeripheralCapability();
+		return super.getCapability(cap, side);
+	}
+
+	@Override
+	public void invalidateCaps() {
+		super.invalidateCaps();
+		computerBehaviour.removePeripheral();
+	}
 
 }

src/main/java/com/simibubi/create/content/redstone/nixieTube/NixieTubeRenderer.java

@@ -32,6 +32,7 @@ import net.minecraft.world.phys.Vec3;
 
 public class NixieTubeRenderer extends SafeBlockEntityRenderer<NixieTubeBlockEntity> {
 
+	private static final int GLOW_VIEW_DISTANCE = 96;
 	private static Random r = new Random();
 
 	public NixieTubeRenderer(BlockEntityRendererProvider.Context context) {}
@@ -52,7 +53,7 @@ public class NixieTubeRenderer extends SafeBlockEntityRenderer<NixieTubeBlockEnt
 			.rotateZ(xRot)
 			.unCentre();
 
-		if (be.signalState != null) {
+		if (be.signalState != null || be.computerSignal != null) {
 			renderAsSignal(be, partialTicks, ms, buffer, light, overlay);
 			ms.popPose();
 			return;
@@ -144,55 +145,111 @@ public class NixieTubeRenderer extends SafeBlockEntityRenderer<NixieTubeBlockEnt
 		ms.pushPose();
 		ms.translate(1 / 2f, 7.5f / 16f, 1 / 2f);
 		float renderTime = AnimationTickHolder.getRenderTime(be.getLevel());
+		Vec3 lampVec = Vec3.atCenterOf(be.getBlockPos());
+		Vec3 diff = lampVec.subtract(observerVec);
 
-		for (boolean first : Iterate.trueAndFalse) {
-			Vec3 lampVec = Vec3.atCenterOf(be.getBlockPos());
-			Vec3 diff = lampVec.subtract(observerVec);
+		if (be.signalState != null) {
+			for (boolean first : Iterate.trueAndFalse) {
+				if (first && !be.signalState.isRedLight(renderTime))
+					continue;
+				if (!first && !be.signalState.isGreenLight(renderTime) && !be.signalState.isYellowLight(renderTime))
+					continue;
 
-			if (first && !be.signalState.isRedLight(renderTime))
-				continue;
-			if (!first && !be.signalState.isGreenLight(renderTime) && !be.signalState.isYellowLight(renderTime))
-				continue;
+				boolean flip = first == invertTubes;
+				boolean yellow = be.signalState.isYellowLight(renderTime);
 
-			boolean flip = first == invertTubes;
-			boolean yellow = be.signalState.isYellowLight(renderTime);
+				ms.pushPose();
+				ms.translate(flip ? 4 / 16f : -4 / 16f, 0, 0);
 
-			ms.pushPose();
-			ms.translate(flip ? 4 / 16f : -4 / 16f, 0, 0);
+				if (diff.lengthSqr() < GLOW_VIEW_DISTANCE * GLOW_VIEW_DISTANCE) {
+					boolean vert = first ^ facing.getAxis()
+							.isHorizontal();
+					float longSide = yellow ? 1 : 4;
+					float longSideGlow = yellow ? 2 : 5.125f;
 
-			if (diff.lengthSqr() < 96 * 96) {
-				boolean vert = first ^ facing.getAxis()
-					.isHorizontal();
-				float longSide = yellow ? 1 : 4;
-				float longSideGlow = yellow ? 2 : 5.125f;
+					CachedBufferer.partial(AllPartialModels.SIGNAL_WHITE_CUBE, blockState)
+							.light(0xf000f0)
+							.disableDiffuse()
+							.scale(vert ? longSide : 1, vert ? 1 : longSide, 1)
+							.renderInto(ms, buffer.getBuffer(RenderType.translucent()));
 
-				CachedBufferer.partial(AllPartialModels.SIGNAL_WHITE_CUBE, blockState)
-					.light(0xf000f0)
-					.disableDiffuse()
-					.scale(vert ? longSide : 1, vert ? 1 : longSide, 1)
-					.renderInto(ms, buffer.getBuffer(RenderType.translucent()));
+					CachedBufferer
+							.partial(
+									first ? AllPartialModels.SIGNAL_RED_GLOW
+											: yellow ? AllPartialModels.SIGNAL_YELLOW_GLOW : AllPartialModels.SIGNAL_WHITE_GLOW,
+									blockState)
+							.light(0xf000f0)
+							.disableDiffuse()
+							.scale(vert ? longSideGlow : 2, vert ? 2 : longSideGlow, 2)
+							.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+				}
 
 				CachedBufferer
-					.partial(
-						first ? AllPartialModels.SIGNAL_RED_GLOW
-							: yellow ? AllPartialModels.SIGNAL_YELLOW_GLOW : AllPartialModels.SIGNAL_WHITE_GLOW,
-						blockState)
-					.light(0xf000f0)
-					.disableDiffuse()
-					.scale(vert ? longSideGlow : 2, vert ? 2 : longSideGlow, 2)
-					.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+						.partial(first ? AllPartialModels.SIGNAL_RED
+								: yellow ? AllPartialModels.SIGNAL_YELLOW : AllPartialModels.SIGNAL_WHITE, blockState)
+						.light(0xF000F0)
+						.disableDiffuse()
+						.scale(1 + 1 / 16f)
+						.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+
+				ms.popPose();
 			}
+		} else if (be.computerSignal != null) {
+			for (boolean first : Iterate.trueAndFalse) {
+				NixieTubeBlockEntity.ComputerSignal.TubeDisplay tubeDisplay = first ?
+						be.computerSignal.first : be.computerSignal.second;
+				if (tubeDisplay.blinkPeriod == 0 || tubeDisplay.blinkPeriod > 1 && renderTime % tubeDisplay.blinkPeriod < tubeDisplay.blinkOffTime)
+					continue;
 
-			CachedBufferer
-				.partial(first ? AllPartialModels.SIGNAL_RED
-					: yellow ? AllPartialModels.SIGNAL_YELLOW : AllPartialModels.SIGNAL_WHITE, blockState)
-				.light(0xF000F0)
-				.disableDiffuse()
-				.scale(1 + 1 / 16f)
-				.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+				boolean flip = first == invertTubes;
 
-			ms.popPose();
+				ms.pushPose();
+				ms.translate(flip ? 4 / 16f : -4 / 16f, 0, 0);
+
+				if (diff.lengthSqr() < GLOW_VIEW_DISTANCE * GLOW_VIEW_DISTANCE) {
+					boolean horiz = facing.getAxis().isHorizontal();
+					float width = horiz ? tubeDisplay.glowWidth : tubeDisplay.glowHeight;
+					float height = horiz ? tubeDisplay.glowHeight : tubeDisplay.glowWidth;
+
+					CachedBufferer.partial(AllPartialModels.SIGNAL_COMPUTER_WHITE_CUBE, blockState)
+							.light(0xf000f0)
+							.disableDiffuse()
+							.scale(width, height,  1)
+							.renderInto(ms, buffer.getBuffer(RenderType.translucent()));
+
+					CachedBufferer
+							.partial(AllPartialModels.SIGNAL_COMPUTER_WHITE_GLOW, blockState)
+							.light(0xf000f0)
+							.color(
+									Math.min(((tubeDisplay.r & 0xFF) * 6 + 256) >> 3, 255),
+									Math.min(((tubeDisplay.g & 0xFF) * 6 + 256) >> 3, 255),
+									Math.min(((tubeDisplay.b & 0xFF) * 6 + 256) >> 3, 255),
+									255)
+							.disableDiffuse()
+							.scale(width + 1.125f, height + 1.125f, 2)
+							.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+				}
+
+				CachedBufferer
+						.partial(AllPartialModels.SIGNAL_COMPUTER_WHITE_BASE, blockState)
+						.light(0xF000F0)
+						.color(12, 12, 12, 255)
+						.disableDiffuse()
+						.scale(1 + 1.25f / 16f)
+						.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+
+				CachedBufferer
+						.partial(AllPartialModels.SIGNAL_COMPUTER_WHITE, blockState)
+						.light(0xF000F0)
+						.color(tubeDisplay.r, tubeDisplay.g, tubeDisplay.b, 255)
+						.disableDiffuse()
+						.scale(1 + 1 / 16f)
+						.renderInto(ms, buffer.getBuffer(RenderTypes.getAdditive()));
+
+				ms.popPose();
+			}
 		}
+
 		ms.popPose();
 
 	}

src/main/resources/assets/create/models/block/track_signal/computer_white_cube.json

@@ -0,0 +1,20 @@
+{
+  "textures": {
+    "0": "create:block/signal_glow_3",
+    "particle": "create:block/signal_glow_3"
+  },
+  "elements": [
+    {
+      "from": [-0.5, -0.5, -0.5],
+      "to": [0.5, 0.5, 0.5],
+      "faces": {
+        "north": {"uv": [1, 1, 2, 2], "texture": "#0"},
+        "east": {"uv": [1, 1, 2, 2], "texture": "#0"},
+        "south": {"uv": [1, 1, 2, 2], "texture": "#0"},
+        "west": {"uv": [1, 1, 2, 2], "texture": "#0"},
+        "up": {"uv": [1, 1, 2, 2], "texture": "#0"},
+        "down": {"uv": [1, 1, 2, 2], "texture": "#0"}
+      }
+    }
+  ]
+}

src/main/resources/assets/create/models/block/track_signal/computer_white_glow.json

@@ -0,0 +1,20 @@
+{
+  "textures": {
+    "0": "create:block/signal_glow_3",
+    "particle": "create:block/signal_glow_3"
+  },
+  "elements": [
+    {
+      "from": [-0.5, -0.5, -0.5],
+      "to": [0.5, 0.5, 0.5],
+      "faces": {
+        "north": {"uv": [1, 0, 2, 1], "texture": "#0"},
+        "east": {"uv": [1, 0, 2, 1], "texture": "#0"},
+        "south": {"uv": [1, 0, 2, 1], "texture": "#0"},
+        "west": {"uv": [1, 0, 2, 1], "texture": "#0"},
+        "up": {"uv": [1, 0, 2, 1], "texture": "#0"},
+        "down": {"uv": [1, 0, 2, 1], "texture": "#0"}
+      }
+    }
+  ]
+}

src/main/resources/assets/create/models/block/track_signal/computer_white_tube.json

@@ -0,0 +1,24 @@
+{
+  "parent": "block/block",
+  "ambientocclusion": false,
+  "textures": {
+    "1": "create:block/signal_glow_3",
+    "particle": "create:block/signal_glow_3"
+  },
+  "elements": [
+    {
+      "name": "tube3",
+      "from": [-3, -4.5, -3],
+      "to": [3, 4.5, 3],
+      "rotation": {"angle": 0, "axis": "z", "origin": [8, 8, 8]},
+      "faces": {
+        "north": {"uv": [10, 7, 16, 16], "texture": "#1"},
+        "east": {"uv": [10, 7, 16, 16], "texture": "#1"},
+        "south": {"uv": [10, 7, 16, 16], "texture": "#1"},
+        "west": {"uv": [10, 7, 16, 16], "texture": "#1"},
+        "up": {"uv": [10, 0, 16, 6], "rotation": 90, "texture": "#1"},
+        "down": {"uv": [10, 0, 16, 6], "rotation": 90, "texture": "#1"}
+      }
+    }
+  ]
+}

src/main/resources/assets/create/models/block/track_signal/computer_white_tube_base.json

@@ -0,0 +1,24 @@
+{
+  "parent": "block/block",
+  "ambientocclusion": false,
+  "textures": {
+    "1": "create:block/signal_glow_3",
+    "particle": "create:block/signal_glow_3"
+  },
+  "elements": [
+    {
+      "name": "tube3",
+      "from": [-3, -4.5, -3],
+      "to": [3, 4.5, 3],
+      "rotation": {"angle": 0, "axis": "z", "origin": [8, 8, 8]},
+      "faces": {
+        "north": {"uv": [3, 7, 9, 16], "texture": "#1"},
+        "east": {"uv": [3, 7, 9, 16], "texture": "#1"},
+        "south": {"uv": [3, 7, 9, 16], "texture": "#1"},
+        "west": {"uv": [3, 7, 9, 16], "texture": "#1"},
+        "up": {"uv": [3, 0, 9, 6], "rotation": 90, "texture": "#1"},
+        "down": {"uv": [3, 0, 9, 6], "rotation": 90, "texture": "#1"}
+      }
+    }
+  ]
+}