Bug Fix: Enviromental Audio from Immersive Portals

README.md

@@ -4,10 +4,17 @@ Rivencraft is a clean, incremental port of the ideas and gameplay of
 [Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) to Minecraft
 1.21.1 on NeoForge.
 
-The bootstrap, books/linking, and Ages milestones are complete. The project
-currently provides functional Linking Books and randomly seeded, persistent
-vanilla-like Ages created from page-free Descriptive Books. Symbols,
-instability, and the full writing mechanics have not been ported yet.
+The bootstrap, books/linking, and Ages milestones are complete. Milestone 4 is
+building the writing system on a data-pack symbol catalog and persistent
+ordered-writing model. The project currently provides functional Linking Books
+and randomly seeded, persistent vanilla-like Ages created from page-free
+Descriptive Books. Instability and full symbol-to-world grammar interpretation
+have not been ported yet.
+
+Milestone 4 now includes stackable blank Pages plus server-created symbol,
+unresolved-symbol, and baseline link-panel states. Page visuals follow the
+legacy runtime-composition rules; written-page creation will become available
+through the Writing Desk work that follows.
 
 ## Linking Book
 

docs/ASSET_PROVENANCE.md

@@ -0,0 +1,16 @@
+# Asset provenance
+
+Rivencraft reuses selected assets from
+[Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) under that
+project's GNU LGPL v3 license. Rivencraft itself uses the same license.
+
+| Rivencraft asset | Upstream asset | Upstream revision | Changes |
+| --- | --- | --- | --- |
+| `assets/rivencraft/textures/item/page.png` | `assets/mystcraft/textures/items/page_background.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/item/linking_book_unwritten.png` | `assets/mystcraft/textures/items/unlinked.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/item/page_link_panel.png` | `page_background.png` and `PageBuilder.BasicPageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Reproduces the legacy 160 px scale, black panel at `(25,30)`–`(135,75)`, and 128 px resample |
+| `assets/rivencraft/textures/item/page_symbol*.png` and `page_unresolved.png` | `page_background.png`, `textures/symbolcomponents.png`, `WordData`, `ModSymbols`, and `PageBuilder.PageSprite` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Static 1.21.1 renditions of the legacy runtime-composed four-word symbol pages; `normal_time` uses the legacy Full Length poem |
+
+Mystcraft Legacy identifies XCompWiz as its project developer and includes the
+full LGPL v3 text in its root `LICENSE` file. Rivencraft's root `LICENSE`
+provides the same license terms.

docs/PORTING.md

@@ -34,6 +34,7 @@ acceptance issue and all required implementation issues are complete.
    renderer compatibility. **Complete.** See
    [Milestone 3](https://gitea.tail180fb1.ts.net/dnorberg/rivencraft/milestone/8).
 4. **Writing system** — pages, symbols, notebooks, desks, and book assembly.
+   **In progress.**
 5. **Age grammar** — translate symbol combinations into modern biome, noise,
    dimension-type, and world-generation configuration. Optional integrations
    may add composable biome regions and seasonal behavior.
@@ -61,9 +62,15 @@ The writing system and Age grammar will build on the existing page-free Age
 path. Page-free books remain a useful deterministic fallback and test fixture
 after written symbol combinations become available.
 
+Milestone 4 begins with a versioned, data-pack-defined symbol catalog and an
+immutable ordered-writing model. See [WRITING_DATA.md](WRITING_DATA.md). These
+contracts preserve unknown symbol identifiers and store author intent; they do
+not interpret symbols into Age generation, which remains Milestone 5 work.
+
 ## Provenance rules
 
 - New code uses the `net.dnorberg.rivencraft` package.
+- Reused legacy art is recorded in [ASSET_PROVENANCE.md](ASSET_PROVENANCE.md).
 - Adapted Mystcraft code retains its upstream copyright notice and is tracked
   in a nearby source comment or commit.
 - Generated, binary, and third-party dependency content is not copied from the

docs/WRITING_DATA.md

@@ -0,0 +1,66 @@
+# Writing and symbol data
+
+Milestone 4 stores what a player wrote without deciding what that writing does
+to an Age. Milestone 5 owns grammar validation, symbol interaction, instability,
+and translation into biome, noise, dimension-type, and other world-generation
+configuration.
+
+## Symbol catalog
+
+The authoritative server catalog loads JSON resources from
+`data/<namespace>/rivencraft/symbols/<path>.json`. The resource ID is the
+symbol ID. For example, `data/rivencraft/rivencraft/symbols/terrain/standard.json`
+defines `rivencraft:terrain/standard`.
+
+Schema version 1 contains display metadata only:
+
+```json
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.terrain.standard",
+  "description": "symbol.rivencraft.terrain.standard.description",
+  "category": "rivencraft:terrain"
+}
+```
+
+`name` and `description` are translation keys, not arbitrary formatted text or
+executable behavior. `category` is a namespaced organizational identifier.
+Invalid definitions are logged and excluded by the server. Menus and future
+page synchronization must obtain resolved display metadata from the server;
+clients never make a symbol valid by naming it.
+
+Rivencraft ships a small catalog covering terrain, biomes, lighting, weather,
+celestial behavior, and features. It exists to exercise the complete writing
+workflow before Milestone 5 implements the full legacy grammar.
+
+## Persistent writing
+
+`SymbolReference` stores only a namespaced symbol ID. `WritingEntry` is either
+a symbol reference or a baseline link-panel marker. `OrderedWriting` retains up
+to 256 entries in exact player-authored order. All three contracts have both
+persistent codecs and bounded network codecs.
+
+Removing a data pack never removes its IDs from saved writing. A missing ID is
+resolved as client-safe **Unresolved Symbol** display metadata while retaining
+the original namespaced ID for diagnostics and later restoration. This is
+deliberately different from treating an unknown symbol as valid grammar.
+
+## Pages
+
+The single stackable `rivencraft:page` item has a bounded, persistent
+`rivencraft:page_content` component. Its explicit states are blank, symbol,
+unresolved symbol, and baseline link panel. Symbol and unresolved-symbol pages
+retain their namespaced symbol reference; unresolved pages can be inspected and
+removed but are rejected as usable writing until their data pack returns.
+
+Only server-side writing operations may turn a blank page into a known symbol
+page or link panel. The shared `PageItem` creation and validation gates reject
+new pages for identifiers absent from the server catalog. Later Writing Desk
+and Book Binder packets must call these gates rather than accepting page
+contents supplied by a client.
+
+The item model uses server-assigned custom-model data derived from the symbol
+identifier. Built-in pages reproduce Mystcraft Legacy's four-word poem
+composition from its page background and symbol-component sheet. Data-pack
+symbols without a bundled resource-pack model use the legacy question-mark
+fallback while keeping their real identifier and display metadata.

gradle.properties

@@ -35,7 +35,7 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. Rivencraft uses the x.y.z.b policy documented in README.md.
-mod_version=0.3.0.0
+mod_version=0.3.2.3
 immersive_portals_version=6.0.7
 # The group ID for the mod. It is only important when publishing as an artifact to a Maven repository.
 # This should match the base package used for the mod sources.

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

@@ -18,6 +18,7 @@ import net.dnorberg.rivencraft.config.RivencraftClientConfig;
 import net.dnorberg.rivencraft.book.AgeDimensionService;
 import net.dnorberg.rivencraft.book.AgeWeatherService;
 import net.dnorberg.rivencraft.book.AgeRuntimeProfiles;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.fml.ModContainer;
 import net.neoforged.fml.common.Mod;
@@ -50,6 +51,7 @@ public final class Rivencraft {
         NeoForge.EVENT_BUS.addListener(AgeLifecycleEvents::onServerStopping);
         NeoForge.EVENT_BUS.addListener(RivencraftCommands::register);
         NeoForge.EVENT_BUS.addListener(AgeRuntimeProfiles::register);
+        NeoForge.EVENT_BUS.addListener(SymbolCatalog::register);
         LOGGER.info("Initializing Rivencraft");
     }
 }

src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java

@@ -2,6 +2,10 @@ package net.dnorberg.rivencraft.client;
 
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.registry.ModBlockEntities;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.client.renderer.item.ItemProperties;
+import net.minecraft.resources.ResourceLocation;
 import net.neoforged.api.distmarker.Dist;
 import net.neoforged.bus.api.SubscribeEvent;
 import net.neoforged.fml.common.EventBusSubscriber;
@@ -21,6 +25,11 @@ public final class ClientEvents {
 
     @SubscribeEvent
     public static void clientSetup(FMLClientSetupEvent event) {
+        event.enqueueWork(() -> ItemProperties.register(
+                ModItems.LINKING_BOOK.get(),
+                ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "bound"),
+                (stack, level, entity, seed) -> stack.has(ModDataComponents.LINK_TARGET.get()) ? 1.0F : 0.0F
+        ));
         NeoForge.EVENT_BUS.addListener(ClientBookInteractionHandler::onRightClickItem);
         NeoForge.EVENT_BUS.addListener(ClientBookInteractionHandler::onRightClickBlock);
         NeoForge.EVENT_BUS.addListener(ClientBookExploreOverlay::onClientTickPre);

src/main/java/net/dnorberg/rivencraft/client/preview/ImmersivePortalsDestinationPreviewRenderer.java

@@ -42,7 +42,11 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
 
     @Override
     public void accept(LinkPreviewPayload payload) {
+        if (destination != null) {
+            ImmersivePortalsPreviewAudioGuard.clear(destination.dimension());
+        }
         destination = payload;
+        ImmersivePortalsPreviewAudioGuard.mute(payload.dimension());
         resetView();
     }
 
@@ -118,6 +122,7 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
         FRAMEBUFFER.clear(true);
         minecraft.getMainRenderTarget().bindWrite(true);
         MyRenderHelper.restoreViewPort();
+        ImmersivePortalsPreviewAudioGuard.markCameraRestorePending();
         GuiPortalRendering.submitNextFrameRendering(info, FRAMEBUFFER);
         hasCompletedFrame = true;
         graphics.renderOutline(left, top, width, height, exploring ? 0xFFE0C36A : 0xFF7B6AA8);
@@ -234,5 +239,8 @@ public final class ImmersivePortalsDestinationPreviewRenderer implements Destina
     public void close() {
         clearMovement();
         hasCompletedFrame = false;
+        if (destination != null) {
+            ImmersivePortalsPreviewAudioGuard.clear(destination.dimension());
+        }
     }
 }

src/main/java/net/dnorberg/rivencraft/client/preview/ImmersivePortalsPreviewAudioGuard.java

@@ -0,0 +1,62 @@
+package net.dnorberg.rivencraft.client.preview;
+
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.Camera;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.world.level.Level;
+
+/** Prevents an Immersive Portals preview world from contributing sounds to a book screen. */
+public final class ImmersivePortalsPreviewAudioGuard {
+    private static ResourceKey<Level> mutedDimension;
+    private static boolean cameraRestorePending;
+
+    private ImmersivePortalsPreviewAudioGuard() {
+    }
+
+    public static void mute(ResourceKey<Level> dimension) {
+        mutedDimension = dimension;
+    }
+
+    public static void clear(ResourceKey<Level> dimension) {
+        if (dimension.equals(mutedDimension)) {
+            mutedDimension = null;
+        }
+    }
+
+    public static boolean shouldMute(ClientLevel level) {
+        Minecraft minecraft = Minecraft.getInstance();
+        return mutedDimension != null
+                && level.dimension().equals(mutedDimension)
+                && (minecraft.player == null || level != minecraft.player.level());
+    }
+
+    public static void markCameraRestorePending() {
+        cameraRestorePending = true;
+    }
+
+    /**
+     * Immersive Portals' GUI renderer leaves the shared main camera in the
+     * remote world after its end-of-frame render. Restore it before the next
+     * frame uses that camera for rain effects and the sound listener.
+     */
+    public static void restorePlayerCamera() {
+        Minecraft minecraft = Minecraft.getInstance();
+        if (!cameraRestorePending) {
+            return;
+        }
+        cameraRestorePending = false;
+        if (minecraft.level == null || minecraft.getCameraEntity() == null) {
+            return;
+        }
+
+        Camera camera = minecraft.gameRenderer.getMainCamera();
+        camera.setup(
+                minecraft.level,
+                minecraft.getCameraEntity(),
+                !minecraft.options.getCameraType().isFirstPerson(),
+                minecraft.options.getCameraType().isMirrored(),
+                camera.getPartialTickTime()
+        );
+    }
+}

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

@@ -0,0 +1,124 @@
+package net.dnorberg.rivencraft.gametest;
+
+import com.mojang.serialization.JsonOps;
+import io.netty.buffer.Unpooled;
+import java.util.List;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.dnorberg.rivencraft.writing.OrderedWriting;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.dnorberg.rivencraft.writing.WritingEntry;
+import net.dnorberg.rivencraft.item.PageItem;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.minecraft.gametest.framework.GameTest;
+import net.minecraft.gametest.framework.GameTestHelper;
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.world.item.ItemStack;
+import net.neoforged.neoforge.gametest.GameTestHolder;
+import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
+
+/** Acceptance coverage for Milestone 4's persistent writing contracts. */
+@GameTestHolder(Rivencraft.MOD_ID)
+@PrefixGameTestTemplate(false)
+public final class WritingDataGameTests {
+    private WritingDataGameTests() {
+    }
+
+    @GameTest(template = "empty")
+    public static void orderedWritingPreservesKnownUnknownAndLinkPanelEntries(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:removed_symbol");
+        OrderedWriting original = new OrderedWriting(List.of(
+                WritingEntry.symbol(known),
+                WritingEntry.symbol(unknown),
+                WritingEntry.linkPanel()
+        ));
+
+        var json = OrderedWriting.CODEC.encodeStart(JsonOps.INSTANCE, original).result().orElseThrow();
+        OrderedWriting persistentCopy = OrderedWriting.CODEC.parse(JsonOps.INSTANCE, json).result().orElseThrow();
+        helper.assertValueEqual(persistentCopy, original,
+                "Persistent writing codec must retain entry order and unknown symbol IDs");
+
+        FriendlyByteBuf buffer = new FriendlyByteBuf(Unpooled.buffer());
+        OrderedWriting.STREAM_CODEC.encode(buffer, original);
+        OrderedWriting networkCopy = OrderedWriting.STREAM_CODEC.decode(buffer);
+        helper.assertValueEqual(networkCopy, original,
+                "Network writing codec must retain entry order and unknown symbol IDs");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void serverCatalogResolvesBuiltinsAndKeepsUnknownReferencesReadable(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:removed_symbol");
+        helper.assertTrue(SymbolCatalog.symbols().size() >= 6,
+                "The built-in catalog must exercise every Milestone 4 writing workflow");
+        helper.assertTrue(SymbolCatalog.isKnown(known),
+                "The built-in Standard Terrain symbol must be server-authoritative");
+        helper.assertFalse(SymbolCatalog.isKnown(unknown),
+                "An absent data-pack symbol must remain unresolved");
+        var unresolved = SymbolCatalog.display(unknown);
+        helper.assertFalse(unresolved.resolved(),
+                "Unknown symbol display metadata must be marked unresolved");
+        helper.assertValueEqual(unresolved.id(), unknown.id(),
+                "Unresolved display metadata must preserve the original namespaced ID");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void pageStatesPersistAndNetworkRoundTrip(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference removed = reference("example:removed_symbol");
+        List<PageContent> states = List.of(
+                PageContent.BLANK,
+                PageContent.symbol(known),
+                PageContent.unresolved(removed),
+                PageContent.LINK_PANEL
+        );
+
+        for (PageContent state : states) {
+            var json = PageContent.CODEC.encodeStart(JsonOps.INSTANCE, state).result().orElseThrow();
+            PageContent persistentCopy = PageContent.CODEC.parse(JsonOps.INSTANCE, json).result().orElseThrow();
+            helper.assertValueEqual(persistentCopy, state, "Page content must persist exactly");
+
+            FriendlyByteBuf buffer = new FriendlyByteBuf(Unpooled.buffer());
+            PageContent.STREAM_CODEC.encode(buffer, state);
+            helper.assertValueEqual(PageContent.STREAM_CODEC.decode(buffer), state,
+                    "Page content must network-sync exactly");
+        }
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void pageItemPreservesContentAndRejectsForgedUnknownSymbols(GameTestHelper helper) {
+        SymbolReference known = reference("rivencraft:terrain/standard");
+        SymbolReference unknown = reference("example:forged_symbol");
+        ItemStack page = PageItem.createSymbolPage(known);
+        CompoundTag serialized = (CompoundTag) page.saveOptional(helper.getLevel().registryAccess());
+        ItemStack restored = ItemStack.parseOptional(helper.getLevel().registryAccess(), serialized);
+        helper.assertValueEqual(restored.get(ModDataComponents.PAGE_CONTENT.get()), PageContent.symbol(known),
+                "Symbol page content must survive an ItemStack save/load");
+        helper.assertValueEqual(
+                restored.get(ModDataComponents.PAGE_SYMBOL_DISPLAY.get()),
+                SymbolCatalog.display(known),
+                "Server-selected display metadata must survive for remote clients"
+        );
+
+        ItemStack recovered = PageItem.createRecoveredPage(unknown);
+        helper.assertFalse(PageItem.isUsableWriting(recovered),
+                "An unresolved page must remain recoverable without becoming valid writing");
+        try {
+            PageItem.createSymbolPage(unknown);
+            helper.fail("The server must reject new pages for unknown symbols");
+        } catch (IllegalArgumentException expected) {
+            helper.succeed();
+        }
+    }
+
+    private static SymbolReference reference(String id) {
+        return new SymbolReference(ResourceLocation.parse(id));
+    }
+}

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

@@ -0,0 +1,131 @@
+package net.dnorberg.rivencraft.item;
+
+import java.util.List;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolCatalog;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
+import net.dnorberg.rivencraft.writing.SymbolReference;
+import net.minecraft.ChatFormatting;
+import net.minecraft.core.component.DataComponents;
+import net.minecraft.network.chat.Component;
+import net.minecraft.world.item.component.CustomModelData;
+import net.minecraft.world.item.Item;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.TooltipFlag;
+
+/** One stackable Page item whose server-owned component identifies its writing state. */
+public final class PageItem extends Item {
+    public PageItem(Properties properties) {
+        super(properties);
+    }
+
+    public static ItemStack createSymbolPage(SymbolReference reference) {
+        if (!SymbolCatalog.isKnown(reference)) {
+            throw new IllegalArgumentException("Cannot create a page for unknown symbol " + reference.id());
+        }
+        return create(PageContent.symbol(reference));
+    }
+
+    public static ItemStack createLinkPanelPage() {
+        return create(PageContent.LINK_PANEL);
+    }
+
+    /** Restores saved unknown references without granting them validity for new writing operations. */
+    public static ItemStack createRecoveredPage(SymbolReference reference) {
+        return create(PageContent.unresolved(reference));
+    }
+
+    public static PageContent content(ItemStack stack) {
+        PageContent content = stack.get(ModDataComponents.PAGE_CONTENT.get());
+        return content == null ? PageContent.BLANK : content;
+    }
+
+    /** Server-side gate for Desk and Binder inputs; unresolved pages remain removable but not usable. */
+    public static boolean isUsableWriting(ItemStack stack) {
+        if (!stack.is(ModItems.PAGE.get())) {
+            return false;
+        }
+        PageContent resolved = content(stack).resolve();
+        return resolved.kind() == PageContent.Kind.BLANK
+                || resolved.kind() == PageContent.Kind.LINK_PANEL
+                || resolved.isResolvedSymbol();
+    }
+
+    @Override
+    public Component getName(ItemStack stack) {
+        PageContent content = content(stack);
+        return switch (content.kind()) {
+            case BLANK -> Component.translatable("item.rivencraft.page.blank");
+            case LINK_PANEL -> Component.translatable("item.rivencraft.page.link_panel");
+            case UNRESOLVED_SYMBOL -> Component.translatable("item.rivencraft.page.unresolved");
+            case SYMBOL -> symbolName(stack, content.symbol().orElseThrow());
+        };
+    }
+
+    @Override
+    public void appendHoverText(ItemStack stack, TooltipContext context,
+                                List<Component> tooltipComponents, TooltipFlag tooltipFlag) {
+        PageContent content = content(stack);
+        if (content.kind() == PageContent.Kind.BLANK) {
+            tooltipComponents.add(Component.translatable("item.rivencraft.page.blank.description")
+                    .withStyle(ChatFormatting.GRAY));
+            return;
+        }
+        if (content.kind() == PageContent.Kind.LINK_PANEL) {
+            tooltipComponents.add(Component.translatable("item.rivencraft.page.link_panel.description")
+                    .withStyle(ChatFormatting.GRAY));
+            return;
+        }
+        SymbolReference reference = content.symbol().orElseThrow();
+        SymbolDisplayMetadata metadata = content.kind() == PageContent.Kind.SYMBOL
+                ? stack.getOrDefault(ModDataComponents.PAGE_SYMBOL_DISPLAY.get(), SymbolCatalog.display(reference))
+                : SymbolDisplayMetadata.unresolved(reference);
+        if (metadata.resolved()) {
+            tooltipComponents.add(Component.translatable(metadata.descriptionTranslationKey())
+                    .withStyle(ChatFormatting.GRAY));
+        } else {
+            tooltipComponents.add(Component.translatable(
+                    "symbol.rivencraft.unresolved.description", reference.unresolvedName())
+                    .withStyle(ChatFormatting.RED));
+        }
+        tooltipComponents.add(Component.literal(reference.id().toString()).withStyle(ChatFormatting.DARK_GRAY));
+    }
+
+    private static ItemStack create(PageContent content) {
+        ItemStack stack = new ItemStack(ModItems.PAGE.get());
+        stack.set(ModDataComponents.PAGE_CONTENT.get(), content);
+        stack.set(DataComponents.CUSTOM_MODEL_DATA, new CustomModelData(modelIndex(content)));
+        if (content.kind() == PageContent.Kind.SYMBOL) {
+            stack.set(ModDataComponents.PAGE_SYMBOL_DISPLAY.get(),
+                    SymbolCatalog.display(content.symbol().orElseThrow()));
+        }
+        return stack;
+    }
+
+    private static Component symbolName(ItemStack stack, SymbolReference reference) {
+        SymbolDisplayMetadata metadata = stack.getOrDefault(
+                ModDataComponents.PAGE_SYMBOL_DISPLAY.get(), SymbolCatalog.display(reference));
+        return metadata.resolved()
+                ? Component.translatable(metadata.nameTranslationKey())
+                : Component.translatable("item.rivencraft.page.unresolved");
+    }
+
+    private static int modelIndex(PageContent content) {
+        return switch (content.kind()) {
+            case BLANK -> 0;
+            case LINK_PANEL -> 1;
+            case UNRESOLVED_SYMBOL -> 2;
+            case SYMBOL -> switch (content.symbol().orElseThrow().id().toString()) {
+                case "rivencraft:terrain/standard" -> 100;
+                case "rivencraft:biome/native" -> 101;
+                case "rivencraft:lighting/normal" -> 102;
+                case "rivencraft:weather/normal" -> 103;
+                case "rivencraft:celestial/normal_time" -> 104;
+                case "rivencraft:feature/caves" -> 105;
+                default -> 3;
+            };
+        };
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/ClientLevelSoundMixin.java

@@ -0,0 +1,59 @@
+package net.dnorberg.rivencraft.mixin.client;
+
+import net.dnorberg.rivencraft.client.preview.ImmersivePortalsPreviewAudioGuard;
+import net.minecraft.client.multiplayer.ClientLevel;
+import net.minecraft.core.Holder;
+import net.minecraft.sounds.SoundEvent;
+import net.minecraft.sounds.SoundSource;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.entity.player.Player;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/** Mutes only the remote client world displayed by a Rivencraft book preview. */
+@Mixin(value = ClientLevel.class, priority = 2000)
+public abstract class ClientLevelSoundMixin {
+    @Inject(
+            method = "playSound(DDDLnet/minecraft/sounds/SoundEvent;Lnet/minecraft/sounds/SoundSource;FFZJ)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewPositionSound(
+            double x, double y, double z, SoundEvent sound, SoundSource source,
+            float volume, float pitch, boolean distanceDelay, long seed, CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    @Inject(
+            method = "playLocalSound(Lnet/minecraft/world/entity/Entity;Lnet/minecraft/sounds/SoundEvent;Lnet/minecraft/sounds/SoundSource;FF)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewLocalEntitySound(
+            Entity entity, SoundEvent sound, SoundSource source, float volume, float pitch,
+            CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    @Inject(
+            method = "playSeededSound(Lnet/minecraft/world/entity/player/Player;Lnet/minecraft/world/entity/Entity;Lnet/minecraft/core/Holder;Lnet/minecraft/sounds/SoundSource;FFJ)V",
+            at = @At("HEAD"),
+            cancellable = true
+    )
+    private void rivencraft$mutePreviewSeededEntitySound(
+            Player player, Entity entity, Holder<SoundEvent> sound, SoundSource source,
+            float volume, float pitch, long seed, CallbackInfo callback
+    ) {
+        rivencraft$cancelPreviewSound(callback);
+    }
+
+    private void rivencraft$cancelPreviewSound(CallbackInfo callback) {
+        if (ImmersivePortalsPreviewAudioGuard.shouldMute((ClientLevel)(Object)this)) {
+            callback.cancel();
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/mixin/client/ImmersivePortalsGuiRenderingMixin.java

@@ -0,0 +1,18 @@
+package net.dnorberg.rivencraft.mixin.client;
+
+import net.dnorberg.rivencraft.client.preview.ImmersivePortalsPreviewAudioGuard;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Pseudo;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+/** Restores the player camera after Immersive Portals finishes GUI-world rendering. */
+@Pseudo
+@Mixin(targets = "qouteall.imm_ptl.core.render.GuiPortalRendering", remap = false)
+public abstract class ImmersivePortalsGuiRenderingMixin {
+    @Inject(method = "_onGameRenderEnd", at = @At("RETURN"), remap = false)
+    private static void rivencraft$restorePlayerCamera(CallbackInfo callback) {
+        ImmersivePortalsPreviewAudioGuard.restorePlayerCamera();
+    }
+}

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

@@ -19,6 +19,7 @@ public final class ModCreativeTabs {
                     .displayItems((parameters, output) -> {
                         output.accept(ModItems.DESCRIPTIVE_BOOK.get());
                         output.accept(ModItems.LINKING_BOOK.get());
+                        output.accept(ModItems.PAGE.get());
                     })
                     .build());
 

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

@@ -3,6 +3,8 @@ package net.dnorberg.rivencraft.registry;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.book.LinkTarget;
 import net.dnorberg.rivencraft.book.AgeReference;
+import net.dnorberg.rivencraft.writing.PageContent;
+import net.dnorberg.rivencraft.writing.SymbolDisplayMetadata;
 import net.minecraft.core.component.DataComponentType;
 import net.minecraft.core.registries.Registries;
 import net.minecraft.resources.ResourceLocation;
@@ -39,6 +41,18 @@ public final class ModDataComponents {
                     .networkSynchronized(ByteBufCodecs.STRING_UTF8)
                     .cacheEncoding()
                     .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<PageContent>> PAGE_CONTENT =
+            DATA_COMPONENTS.register("page_content", () -> DataComponentType.<PageContent>builder()
+                    .persistent(PageContent.CODEC)
+                    .networkSynchronized(PageContent.STREAM_CODEC)
+                    .cacheEncoding()
+                    .build());
+    public static final DeferredHolder<DataComponentType<?>, DataComponentType<SymbolDisplayMetadata>> PAGE_SYMBOL_DISPLAY =
+            DATA_COMPONENTS.register("page_symbol_display", () -> DataComponentType.<SymbolDisplayMetadata>builder()
+                    .persistent(SymbolDisplayMetadata.CODEC)
+                    .networkSynchronized(SymbolDisplayMetadata.STREAM_CODEC)
+                    .cacheEncoding()
+                    .build());
 
     private ModDataComponents() {
     }

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

@@ -3,6 +3,7 @@ package net.dnorberg.rivencraft.registry;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.item.DescriptiveBookItem;
 import net.dnorberg.rivencraft.item.LinkingBookItem;
+import net.dnorberg.rivencraft.item.PageItem;
 import net.minecraft.world.item.Item;
 import net.neoforged.bus.api.IEventBus;
 import net.neoforged.neoforge.registries.DeferredItem;
@@ -21,6 +22,11 @@ public final class ModItems {
             LinkingBookItem::new,
             new Item.Properties().stacksTo(1)
     );
+    public static final DeferredItem<PageItem> PAGE = ITEMS.registerItem(
+            "page",
+            PageItem::new,
+            new Item.Properties().stacksTo(64)
+    );
 
     private ModItems() {
     }

src/main/java/net/dnorberg/rivencraft/writing/OrderedWriting.java

@@ -0,0 +1,47 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import io.netty.buffer.ByteBuf;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** Immutable ordered writing shared by pages, notebooks, desks, and books. */
+public record OrderedWriting(List<WritingEntry> entries) {
+    public static final int MAX_ENTRIES = 256;
+    public static final OrderedWriting EMPTY = new OrderedWriting(List.of());
+    public static final Codec<OrderedWriting> CODEC = WritingEntry.CODEC.listOf()
+            .validate(entries -> entries.size() <= MAX_ENTRIES
+                    ? DataResult.success(entries)
+                    : DataResult.error(() -> "Writing exceeds " + MAX_ENTRIES + " entries"))
+            .xmap(OrderedWriting::new, OrderedWriting::entries);
+    public static final StreamCodec<ByteBuf, OrderedWriting> STREAM_CODEC = StreamCodec.of(
+            OrderedWriting::encode, OrderedWriting::decode);
+
+    public OrderedWriting {
+        entries = List.copyOf(Objects.requireNonNull(entries, "entries"));
+        if (entries.size() > MAX_ENTRIES) {
+            throw new IllegalArgumentException("Writing exceeds " + MAX_ENTRIES + " entries");
+        }
+    }
+
+    private static void encode(ByteBuf buffer, OrderedWriting writing) {
+        ByteBufCodecs.VAR_INT.encode(buffer, writing.entries.size());
+        writing.entries.forEach(entry -> WritingEntry.STREAM_CODEC.encode(buffer, entry));
+    }
+
+    private static OrderedWriting decode(ByteBuf buffer) {
+        int size = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (size < 0 || size > MAX_ENTRIES) {
+            throw new IllegalArgumentException("Invalid writing entry count " + size);
+        }
+        List<WritingEntry> entries = new ArrayList<>(size);
+        for (int index = 0; index < size; index++) {
+            entries.add(WritingEntry.STREAM_CODEC.decode(buffer));
+        }
+        return new OrderedWriting(entries);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/PageContent.java

@@ -0,0 +1,95 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import java.util.Locale;
+import java.util.Objects;
+import java.util.Optional;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** Persistent contents of a Page item. Unknown symbols remain explicit and recoverable. */
+public record PageContent(Kind kind, Optional<SymbolReference> symbol) {
+    public static final PageContent BLANK = new PageContent(Kind.BLANK, Optional.empty());
+    public static final PageContent LINK_PANEL = new PageContent(Kind.LINK_PANEL, Optional.empty());
+    private static final Codec<Kind> KIND_CODEC = Codec.STRING.comapFlatMap(
+            value -> {
+                try {
+                    return DataResult.success(Kind.valueOf(value.toUpperCase(Locale.ROOT)));
+                } catch (IllegalArgumentException exception) {
+                    return DataResult.error(() -> "Unknown page content kind: " + value);
+                }
+            },
+            value -> value.name().toLowerCase(Locale.ROOT)
+    );
+    private static final Codec<PageContent> RECORD_CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            KIND_CODEC.fieldOf("kind").forGetter(PageContent::kind),
+            SymbolReference.CODEC.optionalFieldOf("symbol").forGetter(PageContent::symbol)
+    ).apply(instance, PageContent::new));
+    public static final Codec<PageContent> CODEC = RECORD_CODEC.flatXmap(PageContent::validate, PageContent::validate);
+    public static final StreamCodec<ByteBuf, PageContent> STREAM_CODEC = StreamCodec.of(
+            PageContent::encode, PageContent::decode);
+
+    public PageContent {
+        Objects.requireNonNull(kind, "kind");
+        symbol = Objects.requireNonNull(symbol, "symbol");
+        boolean needsSymbol = kind == Kind.SYMBOL || kind == Kind.UNRESOLVED_SYMBOL;
+        if (needsSymbol != symbol.isPresent()) {
+            throw new IllegalArgumentException("Page contents do not match kind " + kind);
+        }
+    }
+
+    public static PageContent symbol(SymbolReference symbol) {
+        return new PageContent(Kind.SYMBOL, Optional.of(symbol));
+    }
+
+    public static PageContent unresolved(SymbolReference symbol) {
+        return new PageContent(Kind.UNRESOLVED_SYMBOL, Optional.of(symbol));
+    }
+
+    /** Re-resolves persisted data against the authoritative current server catalog. */
+    public PageContent resolve() {
+        if (kind != Kind.SYMBOL && kind != Kind.UNRESOLVED_SYMBOL) {
+            return this;
+        }
+        SymbolReference reference = symbol.orElseThrow();
+        return SymbolCatalog.isKnown(reference) ? symbol(reference) : unresolved(reference);
+    }
+
+    public boolean isResolvedSymbol() {
+        return kind == Kind.SYMBOL;
+    }
+
+    private static DataResult<PageContent> validate(PageContent content) {
+        boolean needsSymbol = content.kind == Kind.SYMBOL || content.kind == Kind.UNRESOLVED_SYMBOL;
+        return needsSymbol == content.symbol.isPresent()
+                ? DataResult.success(content)
+                : DataResult.error(() -> "Page contents do not match kind " + content.kind);
+    }
+
+    private static void encode(ByteBuf buffer, PageContent content) {
+        ByteBufCodecs.VAR_INT.encode(buffer, content.kind.ordinal());
+        content.symbol.ifPresent(reference -> SymbolReference.STREAM_CODEC.encode(buffer, reference));
+    }
+
+    private static PageContent decode(ByteBuf buffer) {
+        int ordinal = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (ordinal < 0 || ordinal >= Kind.values().length) {
+            throw new IllegalArgumentException("Unknown page content kind ordinal " + ordinal);
+        }
+        Kind kind = Kind.values()[ordinal];
+        Optional<SymbolReference> symbol = kind == Kind.SYMBOL || kind == Kind.UNRESOLVED_SYMBOL
+                ? Optional.of(SymbolReference.STREAM_CODEC.decode(buffer))
+                : Optional.empty();
+        return new PageContent(kind, symbol);
+    }
+
+    public enum Kind {
+        BLANK,
+        SYMBOL,
+        UNRESOLVED_SYMBOL,
+        LINK_PANEL
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolCatalog.java

@@ -0,0 +1,67 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import com.mojang.serialization.JsonOps;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.packs.resources.ResourceManager;
+import net.minecraft.server.packs.resources.SimpleJsonResourceReloadListener;
+import net.minecraft.util.profiling.ProfilerFiller;
+import net.neoforged.neoforge.event.AddReloadListenerEvent;
+
+/** Authoritative server catalog loaded from data/<namespace>/rivencraft/symbols. */
+public final class SymbolCatalog {
+    private static final Gson GSON = new GsonBuilder().create();
+    private static final String DIRECTORY = "rivencraft/symbols";
+    private static volatile Map<ResourceLocation, SymbolDefinition> symbols = Map.of();
+
+    private SymbolCatalog() {
+    }
+
+    public static void register(AddReloadListenerEvent event) {
+        event.addListener(new Loader());
+    }
+
+    public static Optional<SymbolDefinition> find(SymbolReference reference) {
+        return Optional.ofNullable(symbols.get(reference.id()));
+    }
+
+    public static boolean isKnown(SymbolReference reference) {
+        return symbols.containsKey(reference.id());
+    }
+
+    public static SymbolDisplayMetadata display(SymbolReference reference) {
+        SymbolDefinition definition = symbols.get(reference.id());
+        return definition == null
+                ? SymbolDisplayMetadata.unresolved(reference)
+                : definition.display(reference.id());
+    }
+
+    public static Map<ResourceLocation, SymbolDefinition> symbols() {
+        return symbols;
+    }
+
+    private static final class Loader extends SimpleJsonResourceReloadListener {
+        private Loader() {
+            super(GSON, DIRECTORY);
+        }
+
+        @Override
+        protected void apply(Map<ResourceLocation, JsonElement> resources,
+                             ResourceManager resourceManager,
+                             ProfilerFiller profiler) {
+            Map<ResourceLocation, SymbolDefinition> loaded = new HashMap<>();
+            resources.forEach((id, json) -> SymbolDefinition.CODEC.parse(JsonOps.INSTANCE, json)
+                    .resultOrPartial(error -> Rivencraft.LOGGER.error(
+                            "Ignoring invalid writing symbol {}: {}", id, error))
+                    .ifPresent(definition -> loaded.put(id, definition)));
+            symbols = Map.copyOf(loaded);
+            Rivencraft.LOGGER.info("Loaded {} writing symbols", loaded.size());
+        }
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolDefinition.java

@@ -0,0 +1,47 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import java.util.Objects;
+import java.util.regex.Pattern;
+import net.minecraft.resources.ResourceLocation;
+
+/** Server-loaded, non-executable display metadata for a writing symbol. */
+public record SymbolDefinition(
+        int schemaVersion,
+        String nameTranslationKey,
+        String descriptionTranslationKey,
+        ResourceLocation category
+) {
+    public static final int CURRENT_SCHEMA_VERSION = 1;
+    private static final Pattern TRANSLATION_KEY = Pattern.compile("[a-z0-9_.-]+");
+    private static final Codec<String> TRANSLATION_KEY_CODEC = Codec.STRING.comapFlatMap(
+            value -> TRANSLATION_KEY.matcher(value).matches()
+                    ? DataResult.success(value)
+                    : DataResult.error(() -> "Invalid translation key: " + value),
+            value -> value
+    );
+    public static final Codec<SymbolDefinition> CODEC = RecordCodecBuilder.<SymbolDefinition>create(instance -> instance.group(
+            Codec.INT.fieldOf("schema_version").forGetter(SymbolDefinition::schemaVersion),
+            TRANSLATION_KEY_CODEC.fieldOf("name").forGetter(SymbolDefinition::nameTranslationKey),
+            TRANSLATION_KEY_CODEC.fieldOf("description").forGetter(SymbolDefinition::descriptionTranslationKey),
+            ResourceLocation.CODEC.fieldOf("category").forGetter(SymbolDefinition::category)
+    ).apply(instance, SymbolDefinition::new)).flatXmap(SymbolDefinition::validate, SymbolDefinition::validate);
+
+    public SymbolDefinition {
+        Objects.requireNonNull(nameTranslationKey, "nameTranslationKey");
+        Objects.requireNonNull(descriptionTranslationKey, "descriptionTranslationKey");
+        Objects.requireNonNull(category, "category");
+    }
+
+    public SymbolDisplayMetadata display(ResourceLocation id) {
+        return new SymbolDisplayMetadata(id, nameTranslationKey, descriptionTranslationKey, category, true);
+    }
+
+    private static DataResult<SymbolDefinition> validate(SymbolDefinition definition) {
+        return definition.schemaVersion == CURRENT_SCHEMA_VERSION
+                ? DataResult.success(definition)
+                : DataResult.error(() -> "Unsupported symbol schema_version " + definition.schemaVersion);
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolDisplayMetadata.java

@@ -0,0 +1,44 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import net.dnorberg.rivencraft.Rivencraft;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.resources.ResourceLocation;
+
+/** Client-safe symbol presentation selected by the authoritative server catalog. */
+public record SymbolDisplayMetadata(
+        ResourceLocation id,
+        String nameTranslationKey,
+        String descriptionTranslationKey,
+        ResourceLocation category,
+        boolean resolved
+) {
+    public static final Codec<SymbolDisplayMetadata> CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            ResourceLocation.CODEC.fieldOf("id").forGetter(SymbolDisplayMetadata::id),
+            Codec.STRING.fieldOf("name").forGetter(SymbolDisplayMetadata::nameTranslationKey),
+            Codec.STRING.fieldOf("description").forGetter(SymbolDisplayMetadata::descriptionTranslationKey),
+            ResourceLocation.CODEC.fieldOf("category").forGetter(SymbolDisplayMetadata::category),
+            Codec.BOOL.fieldOf("resolved").forGetter(SymbolDisplayMetadata::resolved)
+    ).apply(instance, SymbolDisplayMetadata::new));
+    public static final StreamCodec<ByteBuf, SymbolDisplayMetadata> STREAM_CODEC = StreamCodec.composite(
+            ResourceLocation.STREAM_CODEC, SymbolDisplayMetadata::id,
+            ByteBufCodecs.STRING_UTF8, SymbolDisplayMetadata::nameTranslationKey,
+            ByteBufCodecs.STRING_UTF8, SymbolDisplayMetadata::descriptionTranslationKey,
+            ResourceLocation.STREAM_CODEC, SymbolDisplayMetadata::category,
+            ByteBufCodecs.BOOL, SymbolDisplayMetadata::resolved,
+            SymbolDisplayMetadata::new
+    );
+
+    public static SymbolDisplayMetadata unresolved(SymbolReference reference) {
+        return new SymbolDisplayMetadata(
+                reference.id(),
+                "symbol.rivencraft.unresolved",
+                "symbol.rivencraft.unresolved.description",
+                ResourceLocation.fromNamespaceAndPath(Rivencraft.MOD_ID, "unresolved"),
+                false
+        );
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/SymbolReference.java

@@ -0,0 +1,24 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import io.netty.buffer.ByteBuf;
+import java.util.Objects;
+import net.minecraft.network.codec.StreamCodec;
+import net.minecraft.resources.ResourceLocation;
+
+/** Stable namespaced identity for one writing symbol. */
+public record SymbolReference(ResourceLocation id) {
+    public static final Codec<SymbolReference> CODEC = ResourceLocation.CODEC.xmap(
+            SymbolReference::new, SymbolReference::id);
+    public static final StreamCodec<ByteBuf, SymbolReference> STREAM_CODEC = ResourceLocation.STREAM_CODEC.map(
+            SymbolReference::new, SymbolReference::id);
+
+    public SymbolReference {
+        Objects.requireNonNull(id, "id");
+    }
+
+    /** Remains useful when the defining data pack has been removed. */
+    public String unresolvedName() {
+        return id.toString();
+    }
+}

src/main/java/net/dnorberg/rivencraft/writing/WritingEntry.java

@@ -0,0 +1,82 @@
+package net.dnorberg.rivencraft.writing;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.DataResult;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+import io.netty.buffer.ByteBuf;
+import java.util.Locale;
+import java.util.Objects;
+import java.util.Optional;
+import net.minecraft.network.codec.ByteBufCodecs;
+import net.minecraft.network.codec.StreamCodec;
+
+/** One ordered unit of book writing. Interpretation belongs to Milestone 5. */
+public record WritingEntry(Kind kind, Optional<SymbolReference> symbol) {
+    private static final Codec<Kind> KIND_CODEC = Codec.STRING.comapFlatMap(
+            value -> {
+                try {
+                    return DataResult.success(Kind.valueOf(value.toUpperCase(Locale.ROOT)));
+                } catch (IllegalArgumentException exception) {
+                    return DataResult.error(() -> "Unknown writing entry kind: " + value);
+                }
+            },
+            value -> value.name().toLowerCase(Locale.ROOT)
+    );
+    private static final Codec<WritingEntry> RECORD_CODEC = RecordCodecBuilder.create(instance -> instance.group(
+            KIND_CODEC.fieldOf("kind").forGetter(WritingEntry::kind),
+            SymbolReference.CODEC.optionalFieldOf("symbol").forGetter(WritingEntry::symbol)
+    ).apply(instance, WritingEntry::new));
+    public static final Codec<WritingEntry> CODEC = RECORD_CODEC.flatXmap(
+            WritingEntry::validate, WritingEntry::validate);
+    public static final StreamCodec<ByteBuf, WritingEntry> STREAM_CODEC = StreamCodec.of(
+            WritingEntry::encode, WritingEntry::decode);
+
+    public WritingEntry {
+        Objects.requireNonNull(kind, "kind");
+        symbol = Objects.requireNonNull(symbol, "symbol");
+        if (kind == Kind.SYMBOL && symbol.isEmpty()) {
+            throw new IllegalArgumentException("Symbol writing entries require a symbol reference");
+        }
+        if (kind == Kind.LINK_PANEL && symbol.isPresent()) {
+            throw new IllegalArgumentException("Link-panel writing entries cannot contain a symbol reference");
+        }
+    }
+
+    public static WritingEntry symbol(SymbolReference symbol) {
+        return new WritingEntry(Kind.SYMBOL, Optional.of(symbol));
+    }
+
+    public static WritingEntry linkPanel() {
+        return new WritingEntry(Kind.LINK_PANEL, Optional.empty());
+    }
+
+    private static DataResult<WritingEntry> validate(WritingEntry entry) {
+        return entry.kind == Kind.SYMBOL && entry.symbol.isEmpty()
+                || entry.kind == Kind.LINK_PANEL && entry.symbol.isPresent()
+                ? DataResult.error(() -> "Writing entry contents do not match kind " + entry.kind)
+                : DataResult.success(entry);
+    }
+
+    private static void encode(ByteBuf buffer, WritingEntry entry) {
+        ByteBufCodecs.VAR_INT.encode(buffer, entry.kind.ordinal());
+        if (entry.kind == Kind.SYMBOL) {
+            SymbolReference.STREAM_CODEC.encode(buffer, entry.symbol.orElseThrow());
+        }
+    }
+
+    private static WritingEntry decode(ByteBuf buffer) {
+        int ordinal = ByteBufCodecs.VAR_INT.decode(buffer);
+        if (ordinal < 0 || ordinal >= Kind.values().length) {
+            throw new IllegalArgumentException("Unknown writing entry kind ordinal " + ordinal);
+        }
+        Kind kind = Kind.values()[ordinal];
+        return kind == Kind.SYMBOL
+                ? symbol(SymbolReference.STREAM_CODEC.decode(buffer))
+                : linkPanel();
+    }
+
+    public enum Kind {
+        SYMBOL,
+        LINK_PANEL
+    }
+}

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

@@ -6,6 +6,12 @@
   "item.rivencraft.linking_book.unbound": "Unbound — sneak-use to bind",
   "item.rivencraft.linking_book.destination": "%s (%s, %s, %s)",
   "item.rivencraft.linking_book.return": "Return Link",
+  "item.rivencraft.page": "Page",
+  "item.rivencraft.page.blank": "Blank Page",
+  "item.rivencraft.page.blank.description": "Ready for writing at a Writing Desk.",
+  "item.rivencraft.page.link_panel": "Link Panel Page",
+  "item.rivencraft.page.link_panel.description": "The baseline panel required to assemble a Descriptive Book.",
+  "item.rivencraft.page.unresolved": "Unresolved Symbol Page",
   "message.rivencraft.linking_book.bind_hint": "Sneak-use to bind this book to your current location",
   "message.rivencraft.linking_book.unbound": "This Linking Book is unbound",
   "message.rivencraft.linking_book.bound": "Linking Book bound as %s",
@@ -57,6 +63,20 @@
   "trait.rivencraft.weather.snow": "Snow",
   "trait.rivencraft.weather.storm": "Storm",
   "trait.rivencraft.day_length.stopped": "Stopped",
+  "symbol.rivencraft.unresolved": "Unresolved Symbol",
+  "symbol.rivencraft.unresolved.description": "Missing symbol: %s",
+  "symbol.rivencraft.terrain.standard": "Standard Terrain",
+  "symbol.rivencraft.terrain.standard.description": "A familiar continental terrain foundation.",
+  "symbol.rivencraft.biome.native": "Native Biomes",
+  "symbol.rivencraft.biome.native.description": "Use the terrain profile's native biome climate.",
+  "symbol.rivencraft.lighting.normal": "Normal Lighting",
+  "symbol.rivencraft.lighting.normal.description": "Use normal skylight and ambient brightness.",
+  "symbol.rivencraft.weather.normal": "Normal Weather",
+  "symbol.rivencraft.weather.normal.description": "Use the normal weather cycle.",
+  "symbol.rivencraft.celestial.normal_time": "Normal Time",
+  "symbol.rivencraft.celestial.normal_time.description": "Use a normal-length celestial cycle.",
+  "symbol.rivencraft.feature.caves": "Caves",
+  "symbol.rivencraft.feature.caves.description": "Describe underground cave features.",
   "generator.rivencraft.standard": "Standard",
   "generator.rivencraft.amplified": "Amplified",
   "generator.rivencraft.island": "Island",

src/main/resources/assets/rivencraft/models/item/linking_book.json

@@ -1,6 +1,14 @@
 {
   "parent": "minecraft:item/generated",
   "textures": {
-    "layer0": "rivencraft:item/linking_book"
-  }
+    "layer0": "rivencraft:item/linking_book_unwritten"
+  },
+  "overrides": [
+    {
+      "predicate": {
+        "rivencraft:bound": 1.0
+      },
+      "model": "rivencraft:item/linking_book_bound"
+    }
+  ]
 }

src/main/resources/assets/rivencraft/models/item/linking_book_bound.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/linking_book"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page.json

@@ -0,0 +1,17 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page"
+  },
+  "overrides": [
+    { "predicate": { "custom_model_data": 1 }, "model": "rivencraft:item/page_link_panel" },
+    { "predicate": { "custom_model_data": 2 }, "model": "rivencraft:item/page_unresolved" },
+    { "predicate": { "custom_model_data": 3 }, "model": "rivencraft:item/page_symbol" },
+    { "predicate": { "custom_model_data": 100 }, "model": "rivencraft:item/page_symbol_terrain_standard" },
+    { "predicate": { "custom_model_data": 101 }, "model": "rivencraft:item/page_symbol_biome_native" },
+    { "predicate": { "custom_model_data": 102 }, "model": "rivencraft:item/page_symbol_lighting_normal" },
+    { "predicate": { "custom_model_data": 103 }, "model": "rivencraft:item/page_symbol_weather_normal" },
+    { "predicate": { "custom_model_data": 104 }, "model": "rivencraft:item/page_symbol_celestial_normal_time" },
+    { "predicate": { "custom_model_data": 105 }, "model": "rivencraft:item/page_symbol_feature_caves" }
+  ]
+}

src/main/resources/assets/rivencraft/models/item/page_link_panel.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_link_panel"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_symbol"
+  }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_biome_native.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_biome_native" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_celestial_normal_time.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_celestial_normal_time" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_feature_caves.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_feature_caves" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_lighting_normal.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_lighting_normal" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_terrain_standard.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_terrain_standard" }
+}

src/main/resources/assets/rivencraft/models/item/page_symbol_weather_normal.json

@@ -0,0 +1,4 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": { "layer0": "rivencraft:item/page_symbol_weather_normal" }
+}

src/main/resources/assets/rivencraft/models/item/page_unresolved.json

@@ -0,0 +1,6 @@
+{
+  "parent": "minecraft:item/generated",
+  "textures": {
+    "layer0": "rivencraft:item/page_unresolved"
+  }
+}

src/main/resources/data/rivencraft/recipe/page.json

@@ -0,0 +1,13 @@
+{
+  "type": "minecraft:crafting_shapeless",
+  "category": "misc",
+  "ingredients": [
+    {
+      "item": "minecraft:paper"
+    }
+  ],
+  "result": {
+    "count": 1,
+    "id": "rivencraft:page"
+  }
+}

src/main/resources/data/rivencraft/rivencraft/symbols/biome/native.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.biome.native",
+  "description": "symbol.rivencraft.biome.native.description",
+  "category": "rivencraft:biome"
+}

src/main/resources/data/rivencraft/rivencraft/symbols/celestial/normal_time.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.celestial.normal_time",
+  "description": "symbol.rivencraft.celestial.normal_time.description",
+  "category": "rivencraft:celestial"
+}

src/main/resources/data/rivencraft/rivencraft/symbols/feature/caves.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.feature.caves",
+  "description": "symbol.rivencraft.feature.caves.description",
+  "category": "rivencraft:feature"
+}

src/main/resources/data/rivencraft/rivencraft/symbols/lighting/normal.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.lighting.normal",
+  "description": "symbol.rivencraft.lighting.normal.description",
+  "category": "rivencraft:lighting"
+}

src/main/resources/data/rivencraft/rivencraft/symbols/terrain/standard.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.terrain.standard",
+  "description": "symbol.rivencraft.terrain.standard.description",
+  "category": "rivencraft:terrain"
+}

src/main/resources/data/rivencraft/rivencraft/symbols/weather/normal.json

@@ -0,0 +1,6 @@
+{
+  "schema_version": 1,
+  "name": "symbol.rivencraft.weather.normal",
+  "description": "symbol.rivencraft.weather.normal.description",
+  "category": "rivencraft:weather"
+}

src/main/resources/rivencraft.mixins.json

@@ -4,6 +4,8 @@
   "package": "net.dnorberg.rivencraft.mixin",
   "compatibilityLevel": "JAVA_21",
   "client": [
+    "client.ClientLevelSoundMixin",
+    "client.ImmersivePortalsGuiRenderingMixin",
     "client.LevelRendererMixin"
   ],
   "injectors": {