Create persistent runtime Ages

src/main/java/net/dnorberg/rivencraft/Rivencraft.java

@@ -9,6 +9,7 @@ import net.dnorberg.rivencraft.registry.ModBlockEntities;
 import net.dnorberg.rivencraft.event.BookStandConversionHandler;
 import net.dnorberg.rivencraft.network.ModNetworking;
 import net.dnorberg.rivencraft.config.RivencraftConfig;
+import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.fml.ModContainer;
 import net.neoforged.fml.common.Mod;
@@ -22,6 +23,7 @@ public final class Rivencraft {
     public static final Logger LOGGER = LogUtils.getLogger();
 
     public Rivencraft(IEventBus modEventBus, ModContainer modContainer) {
+        AgeDimensionService.register();
         modContainer.registerConfig(ModConfig.Type.SERVER, RivencraftConfig.SPEC);
         modEventBus.addListener(ModNetworking::register);
         ModDataComponents.register(modEventBus);

src/main/java/net/dnorberg/rivencraft/book/AgeDefinition.java

@@ -3,6 +3,7 @@ package net.dnorberg.rivencraft.book;
 import java.util.Objects;
 import java.util.UUID;
 import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.BlockPos;
 import net.minecraft.resources.ResourceLocation;
 
 /** Immutable, server-owned generation definition for one Age. */
@@ -12,7 +13,9 @@ public record AgeDefinition(
         long seed,
         ResourceLocation generationProfile,
         int generationVersion,
-        long createdGameTime
+        long createdGameTime,
+        ResourceLocation dimensionId,
+        BlockPos spawn
 ) {
     public static final ResourceLocation RANDOM_VANILLA_PROFILE = ResourceLocation.fromNamespaceAndPath(
             Rivencraft.MOD_ID, "random_vanilla"
@@ -23,5 +26,15 @@ public record AgeDefinition(
         Objects.requireNonNull(id, "id");
         Objects.requireNonNull(name, "name");
         Objects.requireNonNull(generationProfile, "generationProfile");
+        Objects.requireNonNull(dimensionId, "dimensionId");
+    }
+
+    public static ResourceLocation dimensionId(UUID ageId) {
+        return ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "age/" + ageId);
+    }
+
+    public AgeDefinition withSpawn(BlockPos spawn) {
+        return new AgeDefinition(id, name, seed, generationProfile, generationVersion,
+                createdGameTime, dimensionId, spawn.immutable());
     }
 }

src/main/java/net/dnorberg/rivencraft/book/AgeDimensionService.java

@@ -0,0 +1,171 @@
+package net.dnorberg.rivencraft.book;
+
+import dev.galacticraft.dynamicdimensions.api.DynamicDimensionRegistry;
+import dev.galacticraft.dynamicdimensions.api.event.DynamicDimensionLoadCallback;
+import java.util.Optional;
+import java.util.OptionalLong;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.BlockPos;
+import net.minecraft.core.GlobalPos;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.tags.BlockTags;
+import net.minecraft.util.valueproviders.UniformInt;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.level.dimension.BuiltinDimensionTypes;
+import net.minecraft.world.level.dimension.DimensionType;
+import net.minecraft.world.level.levelgen.Heightmap;
+
+/** Creates, reloads, and resolves Rivencraft's runtime Age dimensions. */
+public final class AgeDimensionService {
+    private static final int PLATFORM_RADIUS = 2;
+    private static final int SURFACE_SEARCH_RADIUS = 16;
+    private static final int FALLBACK_PLATFORM_Y = 63;
+
+    private AgeDimensionService() {
+    }
+
+    public static void register() {
+        DynamicDimensionLoadCallback.register((server, loader) -> {
+            ServerLevel overworld = server.overworld();
+            for (AgeDefinition age : AgeRegistrySavedData.get(overworld).definitions()) {
+                loader.loadDynamicDimension(
+                        age.dimensionId(),
+                        overworld.getChunkSource().getGenerator(),
+                        createDimensionType()
+                );
+            }
+        });
+    }
+
+    public static Optional<LinkTarget> resolve(ServerPlayer player, AgeReference reference) {
+        AgeDefinition definition = AgeRegistrySavedData.resolveOrCreate(player.serverLevel(), reference);
+        ServerLevel level = ensureLoaded(player.getServer(), definition);
+        if (level == null) {
+            return Optional.empty();
+        }
+
+        BlockPos spawn = definition.spawn();
+        if (spawn == null) {
+            spawn = createSafeSpawn(level);
+            definition = AgeRegistrySavedData.get(level).setSpawn(definition.id(), spawn);
+        }
+        return Optional.of(new LinkTarget(
+                GlobalPos.of(dimensionKey(definition), spawn),
+                level.getSharedSpawnAngle(),
+                0.0F
+        ));
+    }
+
+    public static ServerLevel ensureLoaded(MinecraftServer server, AgeDefinition definition) {
+        ResourceKey<Level> key = dimensionKey(definition);
+        ServerLevel existing = server.getLevel(key);
+        if (existing != null) {
+            return existing;
+        }
+
+        ServerLevel overworld = server.overworld();
+        ServerLevel loaded = DynamicDimensionRegistry.from(server).loadDynamicDimension(
+                definition.dimensionId(),
+                overworld.getChunkSource().getGenerator(),
+                createDimensionType()
+        );
+        if (loaded == null) {
+            Rivencraft.LOGGER.error("Failed to load Age {} as {}", definition.id(), definition.dimensionId());
+        }
+        return loaded;
+    }
+
+    public static ResourceKey<Level> dimensionKey(AgeDefinition definition) {
+        return ResourceKey.create(net.minecraft.core.registries.Registries.DIMENSION, definition.dimensionId());
+    }
+
+    private static BlockPos createSafeSpawn(ServerLevel level) {
+        BlockPos floorCenter = isNetherStyle(level)
+                ? netherSpawnFloor(level)
+                : highestFootedSurface(level).orElseGet(() -> fallbackSpawnFloor(level));
+
+        for (int x = -PLATFORM_RADIUS; x <= PLATFORM_RADIUS; x++) {
+            for (int z = -PLATFORM_RADIUS; z <= PLATFORM_RADIUS; z++) {
+                BlockPos floor = floorCenter.offset(x, 0, z);
+                level.setBlock(floor, Blocks.COBBLESTONE.defaultBlockState(), 2);
+                for (int y = 1; y <= 4; y++) {
+                    level.setBlock(floor.above(y), Blocks.AIR.defaultBlockState(), 2);
+                }
+            }
+        }
+
+        BlockPos spawn = floorCenter.above();
+        level.setDefaultSpawnPos(spawn, 0.0F);
+        return spawn;
+    }
+
+    private static boolean isNetherStyle(ServerLevel level) {
+        DimensionType type = level.dimensionType();
+        return type.ultraWarm() || type.effectsLocation().equals(BuiltinDimensionTypes.NETHER_EFFECTS);
+    }
+
+    private static BlockPos netherSpawnFloor(ServerLevel level) {
+        int surfaceY = level.getHeight(Heightmap.Types.WORLD_SURFACE, 0, 0);
+        int floorY = Math.clamp(surfaceY - 1, level.getMinBuildHeight(), level.getMaxBuildHeight() - 5);
+        return new BlockPos(0, floorY, 0);
+    }
+
+    /** Selects the highest nearby terrain column that can naturally support a player. */
+    private static Optional<BlockPos> highestFootedSurface(ServerLevel level) {
+        BlockPos best = null;
+        int maximumFloorY = level.getMaxBuildHeight() - 5;
+
+        for (int x = -SURFACE_SEARCH_RADIUS; x <= SURFACE_SEARCH_RADIUS; x++) {
+            for (int z = -SURFACE_SEARCH_RADIUS; z <= SURFACE_SEARCH_RADIUS; z++) {
+                int floorY = level.getHeight(Heightmap.Types.MOTION_BLOCKING_NO_LEAVES, x, z) - 1;
+                if (floorY < level.getMinBuildHeight() || floorY > maximumFloorY) {
+                    continue;
+                }
+
+                BlockPos candidate = new BlockPos(x, floorY, z);
+                if (!level.getFluidState(candidate).isEmpty()
+                        || !level.getBlockState(candidate).isFaceSturdy(level, candidate, net.minecraft.core.Direction.UP)) {
+                    continue;
+                }
+
+                if (best == null || candidate.getY() > best.getY()
+                        || (candidate.getY() == best.getY()
+                        && candidate.distSqr(BlockPos.ZERO) < best.distSqr(BlockPos.ZERO))) {
+                    best = candidate;
+                }
+            }
+        }
+
+        return Optional.ofNullable(best);
+    }
+
+    private static BlockPos fallbackSpawnFloor(ServerLevel level) {
+        int floorY = Math.clamp(FALLBACK_PLATFORM_Y,
+                level.getMinBuildHeight(), level.getMaxBuildHeight() - 5);
+        return new BlockPos(0, floorY, 0);
+    }
+
+    private static DimensionType createDimensionType() {
+        return new DimensionType(
+                OptionalLong.empty(),
+                true,
+                false,
+                false,
+                true,
+                1.0D,
+                false,
+                false,
+                -64,
+                384,
+                384,
+                BlockTags.INFINIBURN_OVERWORLD,
+                BuiltinDimensionTypes.OVERWORLD_EFFECTS,
+                0.0F,
+                new DimensionType.MonsterSettings(false, true, UniformInt.of(0, 7), 0)
+        );
+    }
+}

src/main/java/net/dnorberg/rivencraft/book/AgeRegistrySavedData.java

@@ -4,6 +4,8 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
 import java.util.UUID;
+import java.util.List;
+import net.minecraft.core.BlockPos;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.nbt.ListTag;
@@ -22,6 +24,10 @@ public final class AgeRegistrySavedData extends SavedData {
     private static final String PROFILE_TAG = "GenerationProfile";
     private static final String VERSION_TAG = "GenerationVersion";
     private static final String CREATED_TIME_TAG = "CreatedGameTime";
+    private static final String DIMENSION_TAG = "Dimension";
+    private static final String SPAWN_X_TAG = "SpawnX";
+    private static final String SPAWN_Y_TAG = "SpawnY";
+    private static final String SPAWN_Z_TAG = "SpawnZ";
     private static final Factory<AgeRegistrySavedData> FACTORY = new Factory<>(
             AgeRegistrySavedData::new,
             AgeRegistrySavedData::load,
@@ -44,6 +50,21 @@ public final class AgeRegistrySavedData extends SavedData {
         return Optional.ofNullable(ages.get(ageId));
     }
 
+    public List<AgeDefinition> definitions() {
+        return List.copyOf(ages.values());
+    }
+
+    public AgeDefinition setSpawn(UUID ageId, BlockPos spawn) {
+        AgeDefinition existing = ages.get(ageId);
+        if (existing == null) {
+            throw new IllegalArgumentException("Unknown Age " + ageId);
+        }
+        AgeDefinition updated = existing.withSpawn(spawn);
+        ages.put(ageId, updated);
+        setDirty();
+        return updated;
+    }
+
     private AgeDefinition getOrCreate(AgeReference reference, long worldSeed, long createdGameTime) {
         AgeDefinition existing = ages.get(reference.id());
         if (existing != null) {
@@ -56,7 +77,9 @@ public final class AgeRegistrySavedData extends SavedData {
                 ageSeed(worldSeed, reference.id()),
                 AgeDefinition.RANDOM_VANILLA_PROFILE,
                 AgeDefinition.CURRENT_GENERATION_VERSION,
-                createdGameTime
+                createdGameTime,
+                AgeDefinition.dimensionId(reference.id()),
+                null
         );
         ages.put(created.id(), created);
         setDirty();
@@ -76,13 +99,22 @@ public final class AgeRegistrySavedData extends SavedData {
                 profile = AgeDefinition.RANDOM_VANILLA_PROFILE;
             }
             UUID id = entry.getUUID(ID_TAG);
+            ResourceLocation dimensionId = ResourceLocation.tryParse(entry.getString(DIMENSION_TAG));
+            if (dimensionId == null) {
+                dimensionId = AgeDefinition.dimensionId(id);
+            }
+            BlockPos spawn = entry.contains(SPAWN_Y_TAG)
+                    ? new BlockPos(entry.getInt(SPAWN_X_TAG), entry.getInt(SPAWN_Y_TAG), entry.getInt(SPAWN_Z_TAG))
+                    : null;
             data.ages.put(id, new AgeDefinition(
                     id,
                     normalizedName(entry.getString(NAME_TAG)),
                     entry.getLong(SEED_TAG),
                     profile,
                     entry.contains(VERSION_TAG) ? entry.getInt(VERSION_TAG) : 1,
-                    entry.getLong(CREATED_TIME_TAG)
+                    entry.getLong(CREATED_TIME_TAG),
+                    dimensionId,
+                    spawn
             ));
         }
         return data;
@@ -101,6 +133,12 @@ public final class AgeRegistrySavedData extends SavedData {
                     entry.putString(PROFILE_TAG, age.generationProfile().toString());
                     entry.putInt(VERSION_TAG, age.generationVersion());
                     entry.putLong(CREATED_TIME_TAG, age.createdGameTime());
+                    entry.putString(DIMENSION_TAG, age.dimensionId().toString());
+                    if (age.spawn() != null) {
+                        entry.putInt(SPAWN_X_TAG, age.spawn().getX());
+                        entry.putInt(SPAWN_Y_TAG, age.spawn().getY());
+                        entry.putInt(SPAWN_Z_TAG, age.spawn().getZ());
+                    }
                     serializedAges.add(entry);
                 });
         tag.put(AGES_TAG, serializedAges);
@@ -113,15 +151,8 @@ public final class AgeRegistrySavedData extends SavedData {
     }
 
     private static long ageSeed(long worldSeed, UUID ageId) {
-        long value = worldSeed ^ ageId.getMostSignificantBits();
-        value = mix64(value + ageId.getLeastSignificantBits());
-        return mix64(value ^ 0x524956454E435241L);
-    }
-
-    /** SplitMix64 finalizer, used only to derive a stable seed from world and Age identities. */
-    private static long mix64(long value) {
-        value = (value ^ (value >>> 30)) * 0xBF58476D1CE4E5B9L;
-        value = (value ^ (value >>> 27)) * 0x94D049BB133111EBL;
-        return value ^ (value >>> 31);
+        // Dynamic Dimensions AR derives each level seed from the primary world
+        // seed and the dimension key. Persist the same value as Age metadata.
+        return worldSeed + AgeDefinition.dimensionId(ageId).hashCode();
     }
 }

src/main/java/net/dnorberg/rivencraft/book/VanillaAgeResolver.java

@@ -1,55 +0,0 @@
-package net.dnorberg.rivencraft.book;
-
-import java.util.List;
-import java.util.Optional;
-import java.util.UUID;
-import net.minecraft.core.GlobalPos;
-import net.minecraft.resources.ResourceKey;
-import net.minecraft.server.level.ServerLevel;
-import net.minecraft.server.level.ServerPlayer;
-import net.minecraft.world.level.Level;
-
-/**
- * Temporary Milestone 2 destination resolver.
- *
- * <p>Until Ages own generated dimensions, an Age UUID deterministically selects
- * one of the three vanilla dimensions. Milestone 3 will replace this with the
- * persistent Age-to-dimension mapping without changing book identities.</p>
- */
-public final class VanillaAgeResolver {
-    private static final List<ResourceKey<Level>> VANILLA_DIMENSIONS = List.of(
-            Level.OVERWORLD,
-            Level.NETHER,
-            Level.END
-    );
-    private static final List<AgeReference> DEMO_AGES = List.of(
-            new AgeReference(new UUID(0L, 0L), "Overworld Age"),
-            new AgeReference(new UUID(0L, 1L), "Nether Age"),
-            new AgeReference(new UUID(0L, 2L), "End Age")
-    );
-
-    private VanillaAgeResolver() {
-    }
-
-    public static Optional<LinkTarget> resolve(ServerPlayer player, AgeReference age) {
-        // Milestone 3 owns Age identity and generation data even while this
-        // temporary adapter continues to provide a vanilla travel destination.
-        AgeRegistrySavedData.resolveOrCreate(player.serverLevel(), age);
-        ResourceKey<Level> dimension = VANILLA_DIMENSIONS.get(Math.floorMod(age.id().hashCode(), VANILLA_DIMENSIONS.size()));
-        ServerLevel level = player.getServer().getLevel(dimension);
-        if (level == null) {
-            return Optional.empty();
-        }
-
-        return Optional.of(new LinkTarget(
-                GlobalPos.of(dimension, level.getSharedSpawnPos()),
-                level.getSharedSpawnAngle(),
-                0.0F
-        ));
-    }
-
-    /** Written sample books exposed in the creative tab until the writing system exists. */
-    public static List<AgeReference> demoAges() {
-        return DEMO_AGES;
-    }
-}

src/main/java/net/dnorberg/rivencraft/client/screen/DescriptiveBookScreen.java

@@ -2,6 +2,8 @@ package net.dnorberg.rivencraft.client.screen;
 
 import net.dnorberg.rivencraft.book.AgeReference;
 import net.dnorberg.rivencraft.network.UseDescriptiveBookPayload;
+import net.dnorberg.rivencraft.network.BindDescriptiveBookPayload;
+import net.dnorberg.rivencraft.network.ModNetworking;
 import net.dnorberg.rivencraft.network.RequestLinkPreviewPayload;
 import net.dnorberg.rivencraft.network.LinkPreviewPayload;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
@@ -10,6 +12,8 @@ import net.dnorberg.rivencraft.client.preview.PonderDestinationPreviewRenderer;
 import net.minecraft.core.BlockPos;
 import net.minecraft.client.gui.GuiGraphics;
 import net.minecraft.client.gui.screens.Screen;
+import net.minecraft.client.gui.components.Button;
+import net.minecraft.client.gui.components.EditBox;
 import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.util.FormattedCharSequence;
@@ -35,6 +39,7 @@ public final class DescriptiveBookScreen extends Screen {
     private final InteractionHand hand;
     private final BlockPos bookStandPos;
     private DestinationPreviewRenderer preview;
+    private EditBox titleInput;
 
     public DescriptiveBookScreen(InteractionHand hand, ItemStack book) {
         super(book.getHoverName());
@@ -52,7 +57,23 @@ public final class DescriptiveBookScreen extends Screen {
 
     @Override
     protected void init() {
-        if (age != null) {
+        int left = (width - BOOK_WIDTH) / 2;
+        int top = (height - BOOK_HEIGHT) / 2;
+        if (age == null) {
+            int rightPage = left + 177;
+            titleInput = new EditBox(font, rightPage, top + 69, 124, 20,
+                    Component.translatable("screen.rivencraft.age.title"));
+            titleInput.setMaxLength(ModNetworking.MAX_BOOK_TITLE_LENGTH);
+            titleInput.setHint(Component.translatable("screen.rivencraft.age.title_hint"));
+            addRenderableWidget(titleInput);
+            setInitialFocus(titleInput);
+            addRenderableWidget(Button.builder(Component.translatable("screen.rivencraft.age.create"), button -> createAge())
+                    .bounds(rightPage, top + 100, 59, 20)
+                    .build());
+            addRenderableWidget(Button.builder(Component.translatable("gui.cancel"), button -> onClose())
+                    .bounds(rightPage + 65, top + 100, 59, 20)
+                    .build());
+        } else {
             preview = new PonderDestinationPreviewRenderer();
             PacketDistributor.sendToServer(new RequestLinkPreviewPayload(
                     true,
@@ -83,7 +104,7 @@ public final class DescriptiveBookScreen extends Screen {
                 TEXTURE_WIDTH, TEXTURE_HEIGHT, TEXTURE_WIDTH, TEXTURE_HEIGHT);
 
         if (age == null) {
-            drawWrappedWithoutShadow(graphics, Component.translatable("screen.rivencraft.book.unwritten"),
+            drawWrappedWithoutShadow(graphics, Component.translatable("screen.rivencraft.age.name_prompt"),
                     left + 177, top + 45, 124);
         } else {
             preview.render(graphics, left + LINK_PANEL_X, top + LINK_PANEL_Y, LINK_PANEL_WIDTH, LINK_PANEL_HEIGHT, partialTick);
@@ -129,6 +150,20 @@ public final class DescriptiveBookScreen extends Screen {
         onClose();
     }
 
+    private void createAge() {
+        String name = titleInput.getValue().strip();
+        if (name.isEmpty()) {
+            return;
+        }
+        PacketDistributor.sendToServer(new BindDescriptiveBookPayload(
+                bookStandPos != null,
+                bookStandPos == null && hand == InteractionHand.OFF_HAND,
+                bookStandPos == null ? BlockPos.ZERO : bookStandPos,
+                name
+        ));
+        onClose();
+    }
+
     private void drawWrappedWithoutShadow(GuiGraphics graphics, Component text, int x, int y, int maxWidth) {
         for (FormattedCharSequence line : font.split(text, maxWidth)) {
             graphics.drawString(font, line, x, y, BOOK_TEXT_COLOR, false);

src/main/java/net/dnorberg/rivencraft/gametest/LinkingGameTests.java

@@ -2,6 +2,7 @@ package net.dnorberg.rivencraft.gametest;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.book.AgeDefinition;
+import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.book.AgeReference;
 import net.dnorberg.rivencraft.book.AgeRegistrySavedData;
 import net.dnorberg.rivencraft.book.LinkTarget;
@@ -102,6 +103,25 @@ public final class LinkingGameTests {
         helper.succeed();
     }
 
+    @GameTest(template = "empty", timeoutTicks = 100)
+    public static void descriptiveBookAgeCreatesRuntimeDimensionAndSafeSpawn(GameTestHelper helper) {
+        ServerPlayer player = helper.makeMockServerPlayerInLevel();
+        AgeReference reference = new AgeReference(UUID.randomUUID(), "Generated Test Age");
+        LinkTarget target = AgeDimensionService.resolve(player, reference).orElse(null);
+
+        helper.assertTrue(target != null, "A page-free Descriptive Book must create a runtime Age destination");
+        helper.runAfterDelay(1, () -> {
+            var ageLevel = player.getServer().getLevel(target.location().dimension());
+            helper.assertTrue(ageLevel != null, "The generated Age must be registered with the server");
+            BlockPos spawn = target.location().pos();
+            helper.assertTrue(ageLevel.getBlockState(spawn.below()).is(Blocks.COBBLESTONE),
+                    "The generated Age must have a cobblestone arrival platform");
+            helper.assertTrue(ageLevel.getBlockState(spawn).isAir() && ageLevel.getBlockState(spawn.above()).isAir(),
+                    "The generated Age arrival must have clear headroom");
+            helper.succeed();
+        });
+    }
+
     @GameTest(template = "empty")
     public static void travelUsesLeafyDestinationWithoutFloor(GameTestHelper helper) {
         helper.setBlock(ORIGIN.below(), Blocks.AIR);

src/main/java/net/dnorberg/rivencraft/item/DescriptiveBookItem.java

@@ -5,7 +5,7 @@ import net.dnorberg.rivencraft.book.AgeReference;
 import net.dnorberg.rivencraft.book.AgeVisitSavedData;
 import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.LinkingService;
-import net.dnorberg.rivencraft.book.VanillaAgeResolver;
+import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.config.RivencraftConfig;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
 import net.dnorberg.rivencraft.registry.ModItems;
@@ -45,7 +45,7 @@ public final class DescriptiveBookItem extends Item {
         }
 
         LinkTarget returnTarget = LinkTarget.from(player);
-        LinkTarget ageTarget = VanillaAgeResolver.resolve(player, age).orElse(null);
+        LinkTarget ageTarget = AgeDimensionService.resolve(player, age).orElse(null);
         if (ageTarget == null) {
             player.displayClientMessage(Component.translatable("message.rivencraft.descriptive_book.unavailable"), true);
             return false;

src/main/java/net/dnorberg/rivencraft/network/BindDescriptiveBookPayload.java

@@ -0,0 +1,29 @@
+package net.dnorberg.rivencraft.network;
+
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.core.BlockPos;
+import net.minecraft.network.RegistryFriendlyByteBuf;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.network.protocol.common.custom.CustomPacketPayload;
+import net.minecraft.resources.ResourceLocation;
+
+/** Requests creation of a randomly generated Age for an unwritten Descriptive Book. */
+public record BindDescriptiveBookPayload(boolean fromStand, boolean offhand, BlockPos standPos, String title)
+        implements CustomPacketPayload {
+    public static final Type<BindDescriptiveBookPayload> TYPE = new Type<>(
+            ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "bind_descriptive_book")
+    );
+    public static final StreamCodec<RegistryFriendlyByteBuf, BindDescriptiveBookPayload> STREAM_CODEC = StreamCodec.composite(
+            ByteBufCodecs.BOOL, BindDescriptiveBookPayload::fromStand,
+            ByteBufCodecs.BOOL, BindDescriptiveBookPayload::offhand,
+            BlockPos.STREAM_CODEC, BindDescriptiveBookPayload::standPos,
+            ByteBufCodecs.STRING_UTF8, BindDescriptiveBookPayload::title,
+            BindDescriptiveBookPayload::new
+    );
+
+    @Override
+    public Type<? extends CustomPacketPayload> type() {
+        return TYPE;
+    }
+}

src/main/java/net/dnorberg/rivencraft/network/ModNetworking.java

@@ -2,7 +2,7 @@ package net.dnorberg.rivencraft.network;
 
 import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.AgeReference;
-import net.dnorberg.rivencraft.book.VanillaAgeResolver;
+import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.block.entity.BookStandBlockEntity;
 import net.dnorberg.rivencraft.client.ClientLinkPreviewHandler;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
@@ -26,6 +26,7 @@ import net.neoforged.neoforge.network.registration.PayloadRegistrar;
 import net.neoforged.neoforge.network.PacketDistributor;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 
 public final class ModNetworking {
     public static final int MAX_BOOK_TITLE_LENGTH = 32;
@@ -34,8 +35,10 @@ public final class ModNetworking {
     }
 
     public static void register(RegisterPayloadHandlersEvent event) {
-        PayloadRegistrar registrar = event.registrar("5");
+        PayloadRegistrar registrar = event.registrar("6");
         registrar.playToServer(BindLinkingBookPayload.TYPE, BindLinkingBookPayload.STREAM_CODEC, ModNetworking::bindBook);
+        registrar.playToServer(BindDescriptiveBookPayload.TYPE, BindDescriptiveBookPayload.STREAM_CODEC,
+                ModNetworking::bindDescriptiveBook);
         registrar.playToServer(UseLinkingBookPayload.TYPE, UseLinkingBookPayload.STREAM_CODEC, ModNetworking::useBook);
         registrar.playToServer(UseDescriptiveBookPayload.TYPE, UseDescriptiveBookPayload.STREAM_CODEC,
                 ModNetworking::useDescriptiveBook);
@@ -46,6 +49,33 @@ public final class ModNetworking {
                 ClientLinkPreviewHandler::handle);
     }
 
+    private static void bindDescriptiveBook(BindDescriptiveBookPayload payload, IPayloadContext context) {
+        if (!(context.player() instanceof ServerPlayer player)) {
+            return;
+        }
+
+        BookAccess access = descriptiveBookAccess(player, payload.fromStand(), payload.offhand(), payload.standPos());
+        if (access == null || access.stack().has(ModDataComponents.AGE_REFERENCE.get())) {
+            return;
+        }
+        String title = normalizeTitle(payload.title());
+        if (title.isEmpty()) {
+            return;
+        }
+
+        AgeReference reference = new AgeReference(UUID.randomUUID(), title);
+        if (AgeDimensionService.resolve(player, reference).isEmpty()) {
+            player.displayClientMessage(Component.translatable("message.rivencraft.descriptive_book.unavailable"), true);
+            return;
+        }
+
+        access.stack().set(ModDataComponents.AGE_REFERENCE.get(), reference);
+        access.stack().set(DataComponents.CUSTOM_NAME, Component.literal(title));
+        access.sync().run();
+        player.level().playSound(null, player.blockPosition(), SoundEvents.BOOK_PAGE_TURN, SoundSource.PLAYERS, 1.0F, 1.0F);
+        player.displayClientMessage(Component.translatable("message.rivencraft.descriptive_book.created", title), true);
+    }
+
     private static void bindBook(BindLinkingBookPayload payload, IPayloadContext context) {
         if (!(context.player() instanceof ServerPlayer player)) {
             return;
@@ -131,7 +161,7 @@ public final class ModNetworking {
         LinkTarget target;
         if (payload.descriptiveBook() && stack.is(ModItems.DESCRIPTIVE_BOOK.get())) {
             AgeReference age = stack.get(ModDataComponents.AGE_REFERENCE.get());
-            target = age == null ? null : VanillaAgeResolver.resolve(player, age).orElse(null);
+            target = age == null ? null : AgeDimensionService.resolve(player, age).orElse(null);
         } else if (!payload.descriptiveBook() && stack.is(ModItems.LINKING_BOOK.get())) {
             target = stack.get(ModDataComponents.LINK_TARGET.get());
         } else {
@@ -186,4 +216,25 @@ public final class ModNetworking {
                 ? normalized
                 : normalized.substring(0, MAX_BOOK_TITLE_LENGTH).stripTrailing();
     }
+
+    private static BookAccess descriptiveBookAccess(
+            ServerPlayer player,
+            boolean fromStand,
+            boolean offhand,
+            BlockPos standPos
+    ) {
+        if (fromStand) {
+            if (player.distanceToSqr(Vec3.atCenterOf(standPos)) > 64.0D
+                    || !(player.level().getBlockEntity(standPos) instanceof BookStandBlockEntity stand)
+                    || !stand.getBook().is(ModItems.DESCRIPTIVE_BOOK.get())) {
+                return null;
+            }
+            return new BookAccess(stand.getBook(), () -> stand.setBook(stand.getBook()));
+        }
+        ItemStack stack = player.getItemInHand(hand(offhand));
+        return stack.is(ModItems.DESCRIPTIVE_BOOK.get()) ? new BookAccess(stack, () -> { }) : null;
+    }
+
+    private record BookAccess(ItemStack stack, Runnable sync) {
+    }
 }

src/main/java/net/dnorberg/rivencraft/registry/ModCreativeTabs.java

@@ -1,12 +1,9 @@
 package net.dnorberg.rivencraft.registry;
 
 import net.dnorberg.rivencraft.Rivencraft;
-import net.dnorberg.rivencraft.book.VanillaAgeResolver;
-import net.minecraft.core.component.DataComponents;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.network.chat.Component;
 import net.minecraft.world.item.CreativeModeTab;
-import net.minecraft.world.item.ItemStack;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.neoforge.registries.DeferredHolder;
 import net.neoforged.neoforge.registries.DeferredRegister;
@@ -21,12 +18,6 @@ public final class ModCreativeTabs {
                     .icon(() -> ModItems.DESCRIPTIVE_BOOK.get().getDefaultInstance())
                     .displayItems((parameters, output) -> {
                         output.accept(ModItems.DESCRIPTIVE_BOOK.get());
-                        VanillaAgeResolver.demoAges().forEach(age -> {
-                            ItemStack book = new ItemStack(ModItems.DESCRIPTIVE_BOOK.get());
-                            book.set(ModDataComponents.AGE_REFERENCE.get(), age);
-                            book.set(DataComponents.CUSTOM_NAME, Component.literal(age.name()));
-                            output.accept(book);
-                        });
                         output.accept(ModItems.LINKING_BOOK.get());
                     })
                     .build());

src/main/resources/assets/rivencraft/lang/en_us.json

@@ -13,6 +13,7 @@
   "message.rivencraft.linking_book.missing_dimension": "That dimension is unavailable",
   "message.rivencraft.linking_book.unsafe": "No safe destination was found near the link",
   "message.rivencraft.descriptive_book.unwritten": "This Descriptive Book is unwritten",
+  "message.rivencraft.descriptive_book.created": "Created Age: %s",
   "message.rivencraft.descriptive_book.unavailable": "That Age is unavailable",
   "message.rivencraft.descriptive_book.unsafe": "No safe destination was found in that Age",
   "message.rivencraft.descriptive_book.linked_first": "Linked to %s — a Return Link was created",
@@ -23,6 +24,10 @@
   "screen.rivencraft.book.bind": "Bind",
   "screen.rivencraft.book.link": "Link",
   "screen.rivencraft.book.unwritten": "This Descriptive Book is unwritten",
+  "screen.rivencraft.age.title": "Age name",
+  "screen.rivencraft.age.title_hint": "Name this Age",
+  "screen.rivencraft.age.name_prompt": "Name this Age before writing the Descriptive Book",
+  "screen.rivencraft.age.create": "Create",
   "screen.rivencraft.book.preview_pending": "Loading destination...",
   "screen.rivencraft.book.click_to_link": "Click the panel to link",
   "itemGroup.rivencraft": "Rivencraft"

src/main/templates/META-INF/neoforge.mods.toml

@@ -93,6 +93,13 @@ A spiritual successor and modern port of Mystcraft for Minecraft 1.21.1 on NeoFo
     ordering="AFTER"
     side="CLIENT"
 
+[[dependencies.${mod_id}]]
+    modId="dynamicdimensions"
+    type="required"
+    versionRange="[0.9.1,1.0.0)"
+    ordering="AFTER"
+    side="BOTH"
+
 # Features are specific properties of the game environment, that you may want to declare you require. This example declares
 # that your mod requires GL version 3.2 or higher. Other features will be added. They are side aware so declaring this won't
 # stop your mod loading on the server for example.