worked on getting writing desk model to match legacy

BUILDING.txt

@@ -0,0 +1,113 @@
+Rivencraft Build Instructions
+============================
+
+These instructions apply when source code, models, textures, data, or other
+resources have been changed.
+
+Requirements
+------------
+
+- Java 21 JDK
+- A working Gradle wrapper
+- The project dependencies available in the Gradle cache, or network access
+  for Gradle to download them
+
+The project targets Minecraft 1.21.1 and NeoForge 21.1.251.
+
+1. Open the project directory
+--------------------------------
+
+    cd /path/to/rivencraft
+
+2. Check the changed files
+--------------------------
+
+Confirm that model, texture, and other resource files are inside
+`src/main/resources`. Java source files belong under `src/main/java`.
+
+For example, block models are normally stored under:
+
+    src/main/resources/assets/rivencraft/models/block/
+
+Resource files placed under `src/main/resources` are automatically included in
+the finished mod JAR by Gradle.
+
+3. Update the version when appropriate
+---------------------------------------
+
+Rivencraft uses the version format `x.y.z.b`:
+
+- `x`: major release
+- `y`: milestone completion
+- `z`: release slice
+- `b`: bug fixes and additional work within that slice
+
+Edit `mod_version` in `gradle.properties` before creating a new release. Do
+not reuse a version that has already been published.
+
+4. Build the mod
+----------------
+
+From the project directory, run:
+
+    ./gradlew build --offline
+
+If the required dependencies are not cached locally, remove `--offline`:
+
+    ./gradlew build
+
+On systems using mise-managed Java and Gradle, use:
+
+    mise exec -- ./gradlew build --offline
+
+5. Run the automated tests
+--------------------------
+
+To build and run the GameTest suite:
+
+    ./gradlew build runGameTestServer --offline
+
+Or, with mise:
+
+    mise exec -- ./gradlew build runGameTestServer --offline
+
+All required GameTests should pass before distributing a build.
+
+6. Locate and inspect the JAR
+-----------------------------
+
+Build outputs are written to:
+
+    build/libs/
+
+The filename uses the configured version, for example:
+
+    build/libs/rivencraft-0.3.6.9.jar
+
+To verify that changed resource files are packaged:
+
+    unzip -l build/libs/rivencraft-VERSION.jar | rg 'models|textures|data'
+
+Replace `VERSION` with the actual version number.
+
+To create a checksum for distribution:
+
+    sha256sum build/libs/rivencraft-VERSION.jar
+
+7. Stop the Gradle daemon when finished
+----------------------------------------
+
+This is optional, but useful after a long test run:
+
+    ./gradlew --stop
+
+Release checklist
+-----------------
+
+- Confirm the version was incremented when required.
+- Confirm the build completed successfully.
+- Confirm all required GameTests passed.
+- Confirm changed resources are present in the JAR.
+- Generate and record the SHA-256 checksum.
+- Test the JAR in the target Minecraft 1.21.1 NeoForge instance.
+- Publish the JAR only after client-side testing is complete.

NOTICE

@@ -14,6 +14,8 @@ The Writing Desk item texture is copied from Legacy's
 assets/mystcraft/textures/items/writingdesk.png under the same license.
 The Writing Desk block texture is copied from Legacy's
 assets/mystcraft/textures/entity/desk.png under the same license.
+The Writing Desk GUI atlas is copied from Legacy's assets/mystcraft/gui/writingdesk.png
+under the same license; desk wood and inlay textures are cropped from desk.png.
 
 The initial build layout is derived from the official NeoForge 1.21.1
 ModDevGradle MDK: https://github.com/NeoForgeMDKs/MDK-1.21.1-ModDevGradle

README.md

@@ -21,17 +21,41 @@ The spent vial returns a glass bottle. Server owners can adjust the symbol-copy
 and link-panel costs in the `writing` section of `rivencraft-server.toml`.
 The Writing Desk can copy a selected written page from its collection tabs.
 The Writing Desk is now craftable from planks, a glass bottle, and a feather.
-Its four collection tabs, paper input, ink vial input, empty glass-bottle return,
+It occupies two adjacent blocks, with one shared inventory; loaded paper and
+the selected page appear on its Legacy-inspired model.
+Desks placed before 0.3.6.1 keep their old one-block footprint until broken
+and placed again; leave an adjacent space when replacing one.
+Its 88 collection tabs, paper input, ink vial input, empty glass-bottle return,
 16-unit ink meter, and inventory persist
 through world saves; breaking it drops stored contents. The desk screen is a
-functional foundation styled after Legacy's left tabs, central writing surface,
+functional foundation using Legacy's original desk and scrollbar textures.
-and right inventory. Put vanilla paper in the
+Four tabs are visible at once; the controls above and below them move by four
+(1–4, 5–8, through 85–88). Each viewer can browse a different group. Existing
+four-tab desks retain their collections and supplies when upgraded.
+With a notebook selected, pick up a Page from your inventory and click an empty
+position on the left surface to store one page there. Clear search/filter/sort
+and turn off `ALL` to place pages at specific positions; occupied positions are
+never overwritten. A notebook tab exposes all 27 notebook positions (scroll to
+reach the rest); a loose-page tab exposes only its one occupied position.
+Empty tabs have no page storage until a notebook or page is put in the tab slot.
+Click a page on the desk surface to select it for copying. Drag a page from one
+notebook position to an empty position to move it, or onto another page to swap
+their positions. This also works between notebooks shown in the `ALL` view.
+Drag a page out of the panel to turn it back into an item. Drop it over a player
+inventory slot or desk tab to place it there; a tab with a notebook adds it to
+the first open position. Dropping elsewhere leaves the page on the cursor for
+normal inventory placement. The source notebook or tab loses the page only after
+a valid drop.
+Put vanilla paper in the
 upper-left slot and Ink Vials in the upper-right; a copy appears in the
 lower-left result slot when the selected page is valid. Taking it consumes one
-paper and, by default, one ink. An empty meter consumes a vial to refill and
+paper and, by default, one ink. An available vial refills an empty ink meter
-returns a vanilla glass bottle to the lower-right slot. The ALL browser searches
+when inserted or when copying uses its last ink, and returns a vanilla glass
-and filters symbols held in the desk's loose pages and Notebooks; selection
+bottle to the lower-right slot. Removing a bottle also retries a blocked refill.
-is validated against the server's current symbol catalog.
+Refilling waits if that slot is full or contains another item. The `AZ` control sorts
+visible pages by name; `ALL` shows pages held across every desk tab. Search and
+category filtering narrow the view without granting new pages, and cross-tab
+copy selection is checked by the server.
 Selecting a stored page on the desk surface shows its Legacy-proportioned
 portrait preview and name above the player inventory.
 

docs/ASSET_PROVENANCE.md

@@ -9,7 +9,10 @@ project's GNU LGPL v3 license. Rivencraft itself uses the same license.
 | `assets/rivencraft/textures/item/page.png` | `assets/mystcraft/textures/items/page_background.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
 | `assets/rivencraft/textures/gui/notebook_pages.png` | `assets/mystcraft/gui/bookui_pagel.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; Notebook draws the native 30×40 page at atlas coordinates `(156, 0)` |
 | `assets/rivencraft/textures/item/writing_desk.png` | `assets/mystcraft/textures/items/writingdesk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
-| `assets/rivencraft/textures/block/writing_desk.png` | `assets/mystcraft/textures/entity/desk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; single-block model adapts the desk geometry and UV regions from `ModelWritingDesk` |
+| `assets/rivencraft/textures/block/writing_desk.png` | `assets/mystcraft/textures/entity/desk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only |
+| `assets/rivencraft/textures/block/writing_desk_wood.png` and `writing_desk_inlay.png` | `assets/mystcraft/textures/entity/desk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Cropped opaque wood and red inlay regions for the two-block model |
+| `assets/rivencraft/textures/gui/writing_desk_legacy.png` | `assets/mystcraft/gui/writingdesk.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; full desk panel, tabs, and cycling controls at original atlas coordinates |
+| `assets/rivencraft/textures/gui/scrollbar.png` | `assets/mystcraft/gui/scrollbar.png` | `9bc8ddc061845df0cd5ea47f4fdef773cff786ae` | Namespace/path rename only; tiled track and normal/pressed thumb |
 | `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 |

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=0.3.6.0
+mod_version=0.3.6.9
 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/block/WritingDeskBlock.java

@@ -5,6 +5,7 @@ import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
 import net.dnorberg.rivencraft.menu.WritingDeskMenu;
 import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.network.chat.Component;
 import net.minecraft.server.level.ServerPlayer;
 import net.minecraft.world.Containers;
@@ -19,48 +20,72 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.block.state.StateDefinition;
 import net.minecraft.world.level.block.state.properties.BlockStateProperties;
 import net.minecraft.world.level.block.state.properties.DirectionProperty;
+import net.minecraft.world.level.block.state.properties.BooleanProperty;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.entity.LivingEntity;
+import org.jetbrains.annotations.Nullable;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.phys.BlockHitResult;
 
 public final class WritingDeskBlock extends BaseEntityBlock {
     public static final MapCodec<WritingDeskBlock> CODEC = simpleCodec(WritingDeskBlock::new);
     public static final DirectionProperty FACING = BlockStateProperties.HORIZONTAL_FACING;
+    public static final BooleanProperty EXTENSION = BooleanProperty.create("extension");
 
     public WritingDeskBlock(Properties properties) {
         super(properties);
-        registerDefaultState(stateDefinition.any().setValue(FACING, net.minecraft.core.Direction.NORTH));
+        registerDefaultState(stateDefinition.any().setValue(FACING, Direction.NORTH).setValue(EXTENSION, false));
     }
 
     @Override public MapCodec<? extends BaseEntityBlock> codec() { return CODEC; }
     @Override protected void createBlockStateDefinition(StateDefinition.Builder<net.minecraft.world.level.block.Block, BlockState> builder) {
-        builder.add(FACING);
+        builder.add(FACING, EXTENSION);
     }
     @Override public BlockState getStateForPlacement(BlockPlaceContext context) {
-        return defaultBlockState().setValue(FACING, context.getHorizontalDirection().getOpposite());
+        Direction facing = context.getHorizontalDirection().getOpposite();
+        BlockPos extension = context.getClickedPos().relative(facing.getClockWise());
+        return context.getLevel().getBlockState(extension).canBeReplaced(context)
+                ? defaultBlockState().setValue(FACING, facing) : null;
+    }
+    @Override public void setPlacedBy(Level level, BlockPos pos, BlockState state,
+                                      @Nullable LivingEntity placer, ItemStack stack) {
+        super.setPlacedBy(level, pos, state, placer, stack);
+        level.setBlock(pos.relative(state.getValue(FACING).getClockWise()),
+                state.setValue(EXTENSION, true), 3);
     }
     @Override protected RenderShape getRenderShape(BlockState state) { return RenderShape.MODEL; }
     @Override public BlockEntity newBlockEntity(BlockPos pos, BlockState state) {
-        return new WritingDeskBlockEntity(pos, state);
+        return state.getValue(EXTENSION) ? null : new WritingDeskBlockEntity(pos, state);
     }
     @Override protected InteractionResult useWithoutItem(BlockState state, Level level, BlockPos pos,
                                                           Player player, BlockHitResult hit) {
+        BlockPos controller = state.getValue(EXTENSION)
+                ? pos.relative(state.getValue(FACING).getCounterClockWise()) : pos;
         if (!level.isClientSide && player instanceof ServerPlayer serverPlayer
-                && level.getBlockEntity(pos) instanceof WritingDeskBlockEntity desk) {
+                && level.getBlockEntity(controller) instanceof WritingDeskBlockEntity desk) {
             serverPlayer.openMenu(new SimpleMenuProvider(
                     (id, inventory, ignored) -> new WritingDeskMenu(id, inventory, desk),
                     Component.translatable("container.rivencraft.writing_desk")),
                     buffer -> {
-                        buffer.writeBlockPos(pos);
+                        buffer.writeBlockPos(controller);
                         WritingDeskCatalog.write(buffer, WritingDeskCatalog.available(desk));
                     });
         }
         return InteractionResult.sidedSuccess(level.isClientSide);
     }
     @Override protected void onRemove(BlockState state, Level level, BlockPos pos, BlockState replacement, boolean moving) {
-        if (!state.is(replacement.getBlock()) && !level.isClientSide
+        if (!state.is(replacement.getBlock())) {
-                && level.getBlockEntity(pos) instanceof WritingDeskBlockEntity desk) {
+            if (!level.isClientSide && !state.getValue(EXTENSION)
-            Containers.dropContents(level, pos, desk);
+                    && level.getBlockEntity(pos) instanceof WritingDeskBlockEntity desk) {
-            level.updateNeighbourForOutputSignal(pos, this);
+                Containers.dropContents(level, pos, desk);
+                level.updateNeighbourForOutputSignal(pos, this);
+            }
+            BlockPos other = pos.relative(state.getValue(FACING).getClockWise(),
+                    state.getValue(EXTENSION) ? -1 : 1);
+            BlockState otherState = level.getBlockState(other);
+            if (otherState.is(this) && otherState.getValue(EXTENSION) != state.getValue(EXTENSION)) {
+                level.setBlock(other, net.minecraft.world.level.block.Blocks.AIR.defaultBlockState(), 35);
+            }
         }
         super.onRemove(state, level, pos, replacement, moving);
     }

src/main/java/net/dnorberg/rivencraft/block/entity/WritingDeskBlockEntity.java

@@ -8,26 +8,31 @@ import net.minecraft.core.BlockPos;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.core.NonNullList;
 import net.minecraft.nbt.CompoundTag;
+import net.minecraft.network.protocol.Packet;
+import net.minecraft.network.protocol.game.ClientGamePacketListener;
+import net.minecraft.network.protocol.game.ClientboundBlockEntityDataPacket;
 import net.minecraft.world.Container;
 import net.minecraft.world.ContainerHelper;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.Items;
+import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.entity.BlockEntity;
 import net.minecraft.world.level.block.state.BlockState;
 
-/** Four collection tabs, paper, ink vials and empty-vial return are owned by the block. */
+/** Collection tabs, paper, ink vials and empty-vial return are owned by the block. */
 public final class WritingDeskBlockEntity extends BlockEntity implements Container {
-    public static final int COLLECTIONS = 4;
+    public static final int COLLECTIONS = 88;
-    public static final int INK = 4;
+    public static final int INK = COLLECTIONS;
-    public static final int RETURN = 5;
+    public static final int RETURN = INK + 1;
-    public static final int PAPER = 6;
+    public static final int PAPER = INK + 2;
     /** Unused by new desks; retained so old saves cannot silently lose slot contents. */
-    public static final int LEGACY_OUTPUT = 7;
+    public static final int LEGACY_OUTPUT = INK + 3;
-    public static final int SIZE = 8;
+    public static final int SIZE = INK + 4;
     private NonNullList<ItemStack> items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
     private int activeCollection;
     private int inkRemaining;
+    private ItemStack displayPage = ItemStack.EMPTY;
 
     public WritingDeskBlockEntity(BlockPos pos, BlockState state) {
         super(ModBlockEntities.WRITING_DESK.get(), pos, state);
@@ -35,6 +40,14 @@ public final class WritingDeskBlockEntity extends BlockEntity implements Contain
 
     public int activeCollection() { return activeCollection; }
     public int inkRemaining() { return inkRemaining; }
+    public ItemStack displayPage() { return displayPage; }
+    public void setDisplayPage(ItemStack page) {
+        ItemStack next = page.isEmpty() ? ItemStack.EMPTY : page.copyWithCount(1);
+        if (!ItemStack.matches(displayPage, next)) {
+            displayPage = next;
+            setChanged();
+        }
+    }
     public void setActiveCollection(int index) {
         if (index >= 0 && index < COLLECTIONS && activeCollection != index) {
             activeCollection = index;
@@ -47,14 +60,20 @@ public final class WritingDeskBlockEntity extends BlockEntity implements Contain
     @Override public ItemStack getItem(int slot) { return items.get(slot); }
     @Override public ItemStack removeItem(int slot, int amount) {
         ItemStack removed = ContainerHelper.removeItem(items, slot, amount);
-        if (!removed.isEmpty()) setChanged();
+        if (!removed.isEmpty()) {
+            if (slot < COLLECTIONS) displayPage = ItemStack.EMPTY;
+            setChanged();
+            if (slot == RETURN) refillEmptyInkBar();
+        }
         return removed;
     }
     @Override public ItemStack removeItemNoUpdate(int slot) { return ContainerHelper.takeItem(items, slot); }
     @Override public void setItem(int slot, ItemStack stack) {
         items.set(slot, stack);
         if (stack.getCount() > getMaxStackSize()) stack.setCount(getMaxStackSize());
+        if (slot < COLLECTIONS) displayPage = ItemStack.EMPTY;
         setChanged();
+        if (slot == INK || slot == RETURN) refillEmptyInkBar();
     }
     @Override public boolean stillValid(Player player) {
         return level != null && level.isLoaded(worldPosition)
@@ -73,6 +92,28 @@ public final class WritingDeskBlockEntity extends BlockEntity implements Contain
         };
     }
 
+    private boolean hasBottleSpace() {
+        ItemStack returned = items.get(RETURN);
+        return returned.isEmpty() || returned.is(Items.GLASS_BOTTLE)
+                && returned.getCount() < returned.getMaxStackSize();
+    }
+
+    /** Consume one vial only when the empty meter can return its glass bottle. */
+    private void refillEmptyInkBar() {
+        if (level == null || level.isClientSide || inkRemaining != 0 || !hasBottleSpace()) return;
+        ItemStack vial = items.get(INK);
+        if (!vial.is(ModItems.INK_VIAL.get())) return;
+        int ink = Math.clamp(InkVialItem.remaining(vial), 0, InkVialItem.CAPACITY);
+        if (ink == 0) return;
+        inkRemaining = ink;
+        vial.shrink(1);
+        if (vial.isEmpty()) items.set(INK, ItemStack.EMPTY);
+        ItemStack returned = items.get(RETURN);
+        if (returned.isEmpty()) items.set(RETURN, new ItemStack(Items.GLASS_BOTTLE));
+        else returned.grow(1);
+        setChanged();
+    }
+
     /** The output is virtual; inputs are committed only after a result can be given to a player. */
     public boolean canConsumeCopyMaterials() {
         ItemStack paper = items.get(PAPER);
@@ -80,10 +121,8 @@ public final class WritingDeskBlockEntity extends BlockEntity implements Contain
         int cost = WritingInkService.symbolCopyCost();
         if (inkRemaining >= cost) return true;
         ItemStack vial = items.get(INK);
-        ItemStack returned = items.get(RETURN);
         return vial.is(ModItems.INK_VIAL.get()) && inkRemaining + InkVialItem.remaining(vial) >= cost
-                && (returned.isEmpty() || returned.is(Items.GLASS_BOTTLE)
+                && hasBottleSpace();
-                && returned.getCount() < returned.getMaxStackSize());
     }
 
     public boolean consumeCopyMaterials() {
@@ -101,25 +140,57 @@ public final class WritingDeskBlockEntity extends BlockEntity implements Contain
         inkRemaining -= cost;
         removeItem(PAPER, 1);
         setChanged();
+        if (inkRemaining == 0) refillEmptyInkBar();
         return true;
     }
+    @Override public void setLevel(Level level) {
+        super.setLevel(level);
+        refillEmptyInkBar();
+    }
     @Override public void clearContent() {
         items.clear();
         items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
         inkRemaining = 0;
+        displayPage = ItemStack.EMPTY;
         setChanged();
     }
     @Override protected void loadAdditional(CompoundTag tag, HolderLookup.Provider registries) {
         super.loadAdditional(tag, registries);
         items = NonNullList.withSize(SIZE, ItemStack.EMPTY);
         ContainerHelper.loadAllItems(tag, items, registries);
+        // Pre-88-tab desks stored materials in slots 4..7. Move them once;
+        // never interpret those stacks as newly added collection tabs.
+        if (tag.getInt("InventoryVersion") < 1) {
+            for (int i = 0; i < 4; i++) {
+                items.set(INK + i, items.get(4 + i));
+                items.set(4 + i, ItemStack.EMPTY);
+            }
+        }
         activeCollection = Math.clamp(tag.getInt("ActiveCollection"), 0, COLLECTIONS - 1);
         inkRemaining = Math.clamp(tag.getInt("InkRemaining"), 0, InkVialItem.CAPACITY);
+        displayPage = tag.contains("DisplayPage", CompoundTag.TAG_COMPOUND)
+                ? ItemStack.parse(registries, tag.getCompound("DisplayPage")).orElse(ItemStack.EMPTY)
+                : ItemStack.EMPTY;
+        refillEmptyInkBar();
     }
     @Override protected void saveAdditional(CompoundTag tag, HolderLookup.Provider registries) {
         super.saveAdditional(tag, registries);
         ContainerHelper.saveAllItems(tag, items, registries);
+        tag.putInt("InventoryVersion", 1);
         tag.putInt("ActiveCollection", activeCollection);
         tag.putInt("InkRemaining", inkRemaining);
+        if (!displayPage.isEmpty()) tag.put("DisplayPage", displayPage.save(registries));
+    }
+    @Override public Packet<ClientGamePacketListener> getUpdatePacket() {
+        return ClientboundBlockEntityDataPacket.create(this);
+    }
+    @Override public CompoundTag getUpdateTag(HolderLookup.Provider registries) {
+        return saveWithoutMetadata(registries);
+    }
+    @Override public void setChanged() {
+        super.setChanged();
+        if (level != null && !level.isClientSide) {
+            level.sendBlockUpdated(worldPosition, getBlockState(), getBlockState(), 2);
+        }
     }
 }

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

@@ -25,6 +25,7 @@ public final class ClientEvents {
     @SubscribeEvent
     public static void registerRenderers(EntityRenderersEvent.RegisterRenderers event) {
         event.registerBlockEntityRenderer(ModBlockEntities.BOOK_STAND.get(), BookStandRenderer::new);
+        event.registerBlockEntityRenderer(ModBlockEntities.WRITING_DESK.get(), WritingDeskRenderer::new);
     }
 
     @SubscribeEvent

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

@@ -0,0 +1,55 @@
+package net.dnorberg.rivencraft.client;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.math.Axis;
+import net.dnorberg.rivencraft.block.WritingDeskBlock;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.minecraft.client.Minecraft;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.blockentity.BlockEntityRenderer;
+import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
+import net.minecraft.world.item.ItemDisplayContext;
+import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.item.Items;
+
+/** Visible selected page and loaded paper, as on the Legacy desk. */
+public final class WritingDeskRenderer implements BlockEntityRenderer<WritingDeskBlockEntity> {
+    public WritingDeskRenderer(BlockEntityRendererProvider.Context context) {}
+
+    @Override public void render(WritingDeskBlockEntity desk, float partialTick, PoseStack pose,
+                                 MultiBufferSource buffers, int light, int overlay) {
+        int paper = desk.getItem(WritingDeskBlockEntity.PAPER).getCount();
+        ItemStack page = desk.displayPage();
+        if (paper == 0 && page.isEmpty()) return;
+        pose.pushPose();
+        pose.translate(0.5, 0, 0.5);
+        pose.mulPose(Axis.YP.rotationDegrees(
+                180.0F - desk.getBlockState().getValue(WritingDeskBlock.FACING).toYRot()));
+        if (paper > 0) {
+            ItemStack sheet = new ItemStack(Items.PAPER);
+            int layers = Math.min(4, 1 + paper / 16);
+            for (int i = 0; i < layers; i++) {
+                drawFlat(desk, sheet, pose, buffers, light, overlay, 1.22, 0.27 + i * 0.008, -0.14, 0.55F);
+            }
+        }
+        if (!page.isEmpty()) {
+            drawFlat(desk, page, pose, buffers, light, overlay, 1.0, 0.572, 0.0, 0.8F);
+        }
+        pose.popPose();
+    }
+
+    private static void drawFlat(WritingDeskBlockEntity desk, ItemStack stack, PoseStack pose,
+                                 MultiBufferSource buffers, int light, int overlay,
+                                 double x, double y, double z, float scale) {
+        pose.pushPose();
+        pose.translate(x, y, z);
+        pose.mulPose(Axis.XP.rotationDegrees(90));
+        pose.scale(scale, scale, scale);
+        Minecraft.getInstance().getItemRenderer().renderStatic(stack, ItemDisplayContext.FIXED,
+                light, overlay, pose, buffers, desk.getLevel(), 0);
+        pose.popPose();
+    }
+
+    @Override public boolean shouldRenderOffScreen(WritingDeskBlockEntity blockEntity) { return true; }
+    @Override public int getViewDistance() { return 64; }
+}

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

@@ -2,10 +2,12 @@ package net.dnorberg.rivencraft.client.screen;
 
 import java.util.List;
 import java.util.Locale;
-import java.util.Objects;
+import java.util.ArrayList;
+import java.util.Comparator;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.item.PageItem;
 import net.dnorberg.rivencraft.menu.WritingDeskMenu;
+import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
 import net.dnorberg.rivencraft.registry.ModDataComponents;
 import net.dnorberg.rivencraft.registry.ModItems;
 import net.dnorberg.rivencraft.writing.NotebookContents;
@@ -17,123 +19,197 @@ import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen;
 import net.minecraft.network.chat.Component;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.world.entity.player.Inventory;
+import net.minecraft.world.inventory.Slot;
 import net.minecraft.world.item.ItemStack;
 
-/** Functional storage surface; full Legacy transcription controls are a later Milestone 4 slice. */
+/** Legacy desk atlas layout, with four visible tabs out of the desk's 88 collections. */
 public final class WritingDeskScreen extends AbstractContainerScreen<WritingDeskMenu> {
     private static final ResourceLocation PAGE_ATLAS = ResourceLocation.fromNamespaceAndPath(
             Rivencraft.MOD_ID, "textures/gui/notebook_pages.png");
+    private static final ResourceLocation LEGACY_DESK = ResourceLocation.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "textures/gui/writing_desk_legacy.png");
+    private static final ResourceLocation SCROLLBAR = ResourceLocation.fromNamespaceAndPath(
+            Rivencraft.MOD_ID, "textures/gui/scrollbar.png");
     private int lastCollection = -1;
     private int selectedPage;
     private int scrollRows;
     private boolean allMode;
-    private ResourceLocation selectedSymbol;
+    private boolean sortAlphabetically;
+    private int selectedCollection = -1;
     private ResourceLocation selectedCategory;
     private EditBox search;
     private Button categoryButton;
+    private Button allButton;
+    private Button sortButton;
+    private boolean draggingScrollbar;
+    private record DisplayPage(int collection, int index, ItemStack stack) {}
+    private DisplayPage pageDragSource;
+    private double pageDragStartX;
+    private double pageDragStartY;
+    private boolean draggingPage;
+
+    private boolean isPhysicalPageView() {
+        return !allMode && !sortAlphabetically && selectedCategory == null
+                && (search == null || search.getValue().isBlank());
+    }
 
     public WritingDeskScreen(WritingDeskMenu menu, Inventory inventory, Component title) {
         super(menu, inventory, title);
-        imageWidth = 398;
+        imageWidth = 409;
-        imageHeight = 176;
+        imageHeight = 186;
         titleLabelX = 222;
-        inventoryLabelX = 224;
-        inventoryLabelY = 79;
     }
 
     @Override protected void init() {
         super.init();
-        addRenderableWidget(Button.builder(Component.literal("ALL"), button -> {
+        sortButton = addRenderableWidget(Button.builder(Component.literal("AZ"), button -> {
-            allMode = true;
+            sortAlphabetically = !sortAlphabetically;
             scrollRows = 0;
-        }).bounds(leftPos + 48, topPos - 18, 29, 18).build());
+        }).bounds(leftPos + 58, topPos, 20, 18).build());
-        categoryButton = addRenderableWidget(Button.builder(Component.literal("All types"), button -> {
+        allButton = addRenderableWidget(Button.builder(Component.literal("ALL"), button -> {
+            allMode = !allMode;
+            scrollRows = 0;
+            if (!allMode) {
+                selectedCollection = -1;
+                selectedPage = 0;
+                if (minecraft != null && minecraft.gameMode != null)
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId, WritingDeskMenu.PAGE_BUTTON_BASE);
+            }
+        }).bounds(leftPos + 80, topPos, 28, 18).build());
+        search = new EditBox(font, leftPos + 110, topPos, 101, 18,
+                Component.translatable("screen.rivencraft.writing_desk.search"));
+        search.setMaxLength(64);
+        search.setHint(Component.translatable("screen.rivencraft.writing_desk.search"));
+        search.setResponder(value -> scrollRows = 0);
+        addRenderableWidget(search);
+        categoryButton = addRenderableWidget(Button.builder(Component.literal("C"), button -> {
             List<ResourceLocation> categories = menu.catalog().stream()
                     .map(SymbolDisplayMetadata::category).distinct().sorted().toList();
             int next = selectedCategory == null ? 0 : categories.indexOf(selectedCategory) + 1;
             selectedCategory = next >= categories.size() ? null : categories.get(next);
-            categoryButton.setMessage(Component.literal(selectedCategory == null
+            categoryButton.setMessage(Component.literal(selectedCategory == null ? "C" : "C*"));
-                    ? "All types" : selectedCategory.getPath()));
-            allMode = true;
             scrollRows = 0;
-        }).bounds(leftPos + 79, topPos - 18, 66, 18).build());
+        }).bounds(leftPos + 213, topPos, 18, 18).build());
-        search = new EditBox(font, leftPos + 147, topPos - 18, 69, 18,
-                Component.translatable("screen.rivencraft.writing_desk.search"));
-        search.setMaxLength(64);
-        search.setHint(Component.translatable("screen.rivencraft.writing_desk.search"));
-        search.setResponder(value -> {
-            allMode = true;
-            scrollRows = 0;
-        });
-        addRenderableWidget(search);
     }
 
-    private List<SymbolDisplayMetadata> filteredCatalog() {
+    private List<DisplayPage> filteredPages() {
         String query = search == null ? "" : search.getValue().trim().toLowerCase(Locale.ROOT);
-        return menu.catalog().stream()
+        List<DisplayPage> entries = new ArrayList<>();
-                .filter(entry -> selectedCategory == null || selectedCategory.equals(entry.category()))
+        int from = allMode ? 0 : menu.activeCollection();
-                .filter(entry -> query.isEmpty()
+        int until = allMode ? WritingDeskBlockEntity.COLLECTIONS : from + 1;
-                        || entry.id().toString().toLowerCase(Locale.ROOT).contains(query)
+        for (int collection = from; collection < until; collection++) {
-                        || Component.translatable(entry.nameTranslationKey()).getString()
+            List<ItemStack> pages = pages(collection);
-                        .toLowerCase(Locale.ROOT).contains(query))
+            int last = -1;
-                .toList();
+            for (int i = 0; i < pages.size(); i++) if (!pages.get(i).isEmpty()) last = i;
+            // A notebook has exactly its normal GUI capacity; a loose page has one position.
+            if (isPhysicalPageView()) last = menu.pageCapacity(collection) - 1;
+            for (int i = 0; i <= last; i++) {
+                ItemStack page = i < pages.size() ? pages.get(i) : ItemStack.EMPTY;
+                if (page.isEmpty() && (allMode || sortAlphabetically || !query.isEmpty() || selectedCategory != null)) continue;
+                if (!page.isEmpty() && !query.isEmpty()
+                        && !page.getHoverName().getString().toLowerCase(Locale.ROOT).contains(query)
+                        && !PageItem.content(page).symbol().map(symbol -> symbol.id().toString()
+                        .toLowerCase(Locale.ROOT).contains(query)).orElse(false)) continue;
+                if (!page.isEmpty() && selectedCategory != null) {
+                    ResourceLocation id = PageItem.content(page).symbol().map(symbol -> symbol.id()).orElse(null);
+                    if (menu.catalog().stream().noneMatch(metadata -> metadata.id().equals(id)
+                            && metadata.category().equals(selectedCategory))) continue;
+                }
+                entries.add(new DisplayPage(collection, i, page));
+            }
+        }
+        if (sortAlphabetically) entries.sort(Comparator
+                .comparing((DisplayPage entry) -> entry.stack().getHoverName().getString(), String.CASE_INSENSITIVE_ORDER)
+                .thenComparingInt(DisplayPage::collection).thenComparingInt(DisplayPage::index));
+        return entries;
     }
 
     @Override public void renderBackground(GuiGraphics graphics, int mouseX, int mouseY, float partialTick) {
-        // Legacy leaves the world visible around the desk instead of dimming it.
+        // Keep the world visible, but still draw our GUI backing. The vanilla
+        // container implementation normally calls renderBg from this method.
+        renderBg(graphics, partialTick, mouseX, mouseY);
     }
 
     @Override protected void renderBg(GuiGraphics graphics, float partialTick, int mouseX, int mouseY) {
         int x = leftPos;
         int y = topPos;
-        graphics.fill(x + 4, y + 8, x + 216, y + 174, 0xFF383230);
+        // Legacy GuiWritingDesk draws the entire 176x166 panel, not a stretched swatch.
-        graphics.fill(x + 44, y + 14, x + 210, y + 170, 0xFF221B1A);
+        graphics.blit(LEGACY_DESK, x + 233, y + 20, 0, 0, 176, 166);
-        graphics.fill(x + 218, y + 4, x + 396, y + 174, 0xFF555454);
+        drawTabControl(graphics, 20, 203, menu.firstVisibleTab() > 0);
-        graphics.fill(x + 220, y + 6, x + 394, y + 172, 0xFFB7B7B7);
         for (int i = 0; i < 4; i++) {
-            graphics.fill(x + 6, y + 16 + i * 37, x + 40, y + 48 + i * 37,
+            int tab = menu.firstVisibleTab() + i;
-                    i == menu.activeCollection() ? 0xFF7777B6 : 0xFF999999);
+            int tabY = y + 29 + i * 37;
-            slotFrame(graphics, 12, 20 + i * 37);
+            if (tab == menu.activeCollection() && !allMode) graphics.setColor(0.5F, 0.5F, 1F, 1F);
+            graphics.blit(LEGACY_DESK, x, tabY, 0, 166, 58, 37);
+            graphics.setColor(1F, 1F, 1F, 1F);
+            graphics.drawString(font, Integer.toString(tab + 1), x + 8, tabY + 8, 0xFF181818, false);
+            ItemStack collection = menu.getSlot(tab).getItem();
+            if (!collection.isEmpty()) {
+                String name = collection.getHoverName().getString();
+                float scale = Math.min(1F, 50F / Math.max(1, font.width(name)));
+                graphics.pose().pushPose();
+                graphics.pose().translate(x + 4, tabY + 25, 0);
+                graphics.pose().scale(scale, scale, 1);
+                graphics.drawString(font, name, 0, 0, 0xFF404040, false);
+                graphics.pose().popPose();
+            }
         }
-        slotFrame(graphics, 370, 20);
+        drawTabControl(graphics, 177, 212, menu.firstVisibleTab() < WritingDeskBlockEntity.COLLECTIONS - 4);
-        slotFrame(graphics, 228, 20);
+        // GuiElementVSlider: 4-pixel caps, repeated 22-pixel track, 12x15 thumb.
-        slotFrame(graphics, 228, 57);
+        graphics.blit(SCROLLBAR, x + 213, y + 20, 0, 0, 20, 4, 32, 32);
-        slotFrame(graphics, 370, 57);
+        for (int offset = 4; offset < 162; offset += 22)
-        graphics.fill(x + 350, y + 20, x + 364, y + 75, 0xFF303035);
+            graphics.blit(SCROLLBAR, x + 213, y + 20 + offset, 0, 4, 20, Math.min(22, 162 - offset), 32, 32);
-        graphics.fill(x + 352, y + 22, x + 362, y + 73, 0xFF15151B);
+        graphics.blit(SCROLLBAR, x + 213, y + 182, 0, 26, 20, 4, 32, 32);
-        int filled = 51 * menu.inkRemaining() / 16;
+        int totalRows = (filteredPages().size() + 4) / 5;
-        if (filled > 0) graphics.fill(x + 352, y + 73 - filled, x + 362, y + 73, 0xFF6666AA);
+        int maxScroll = Math.max(0, totalRows - 4);
-        graphics.renderOutline(x + 350, y + 20, 14, 55, 0xFF484848);
+        scrollRows = Math.clamp(scrollRows, 0, maxScroll);
-        for (int row = 0; row < 3; row++) {
+        int thumbY = y + 24 + (maxScroll == 0 ? 0 : scrollRows * 143 / maxScroll);
-            for (int column = 0; column < 9; column++) slotFrame(graphics, 224 + column * 18, 91 + row * 18);
+        graphics.blit(SCROLLBAR, x + 217, thumbY, 20, draggingScrollbar ? 15 : 0, 12, 15, 32, 32);
-        }
+        graphics.fill(x + 365, y + 27, x + 381, y + 97, 0xFF303035);
-        for (int column = 0; column < 9; column++) slotFrame(graphics, 224 + column * 18, 149);
+        graphics.fill(x + 366, y + 28, x + 380, y + 96, 0xFF6666AA);
+        int filled = 68 * menu.inkRemaining() / 16;
+        if (filled > 0) graphics.fill(x + 366, y + 96 - filled, x + 380, y + 96, 0xFF15151B);
     }
 
-    private void slotFrame(GuiGraphics graphics, int x, int y) {
+    private void drawTabControl(GuiGraphics graphics, int y, int textureY, boolean enabled) {
-        graphics.fill(leftPos + x - 1, topPos + y - 1,
+        if (!enabled) graphics.setColor(0.4F, 0.4F, 0.4F, 1F);
-                leftPos + x + 17, topPos + y + 17, 0xFF4D4D4D);
+        graphics.blit(LEGACY_DESK, leftPos, topPos + y, 0, textureY, 58, 9);
-        graphics.fill(leftPos + x, topPos + y,
+        graphics.setColor(1F, 1F, 1F, 1F);
-                leftPos + x + 16, topPos + y + 16, 0xFF858585);
     }
 
     @Override protected void renderLabels(GuiGraphics graphics, int mouseX, int mouseY) {
-        graphics.drawString(font, playerInventoryTitle, inventoryLabelX, inventoryLabelY, 0x404040, false);
+        // Legacy leaves the inventory grid unlabeled.
     }
 
     @Override public void render(GuiGraphics graphics, int mouseX, int mouseY, float partialTick) {
         super.render(graphics, mouseX, mouseY, partialTick);
+        if (sortAlphabetically) graphics.renderOutline(leftPos + 58, topPos, 20, 18, 0xFFFFD061);
+        if (allMode) graphics.renderOutline(leftPos + 80, topPos, 28, 18, 0xFFFFD061);
         renderCollection(graphics);
+        if (draggingPage && pageDragSource != null) {
+            DisplayPage target = pageAtMouse(mouseX, mouseY);
+            if (target != null && canMovePage(pageDragSource, target)) {
+                int x = leftPos + 58 + ((int) mouseX - leftPos - 58) / 31 * 31;
+                int y = topPos + 20 + ((int) mouseY - topPos - 20) / 41 * 41;
+                graphics.renderOutline(x, y, 30, 40, 0xFF57D478);
+            }
+            graphics.renderItem(pageDragSource.stack(), mouseX - 8, mouseY - 8);
+        }
         renderTooltip(graphics, mouseX, mouseY);
-        if (mouseX >= leftPos + 350 && mouseX < leftPos + 364
+        if (mouseX >= leftPos + 365 && mouseX < leftPos + 381
-                && mouseY >= topPos + 20 && mouseY < topPos + 75) {
+                && mouseY >= topPos + 27 && mouseY < topPos + 97) {
             graphics.renderTooltip(font, Component.translatable("screen.rivencraft.writing_desk.ink",
                     menu.inkRemaining(), 16), mouseX, mouseY);
         }
+        if (mouseX >= leftPos + 213 && mouseX < leftPos + 231
+                && mouseY >= topPos && mouseY < topPos + 18) {
+            graphics.renderTooltip(font, Component.literal(selectedCategory == null
+                    ? "All categories" : selectedCategory.toString()), mouseX, mouseY);
+        }
     }
 
-    private List<ItemStack> pages() {
+    private List<ItemStack> pages(int collectionIndex) {
-        ItemStack collection = menu.getSlot(menu.activeCollection()).getItem();
+        ItemStack collection = menu.getSlot(collectionIndex).getItem();
         if (collection.is(ModItems.PAGE.get())) return List.of(collection);
         if (collection.is(ModItems.NOTEBOOK.get())) {
             return collection.getOrDefault(ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
@@ -142,73 +218,34 @@ public final class WritingDeskScreen extends AbstractContainerScreen<WritingDesk
     }
 
     private void renderCollection(GuiGraphics graphics) {
-        if (allMode) {
-            renderCatalog(graphics);
-            return;
-        }
-        List<ItemStack> pages = pages();
         if (lastCollection != menu.activeCollection()) {
             lastCollection = menu.activeCollection();
             scrollRows = 0;
             selectedPage = 0;
+            selectedCollection = -1;
         }
-        int last = -1;
+        List<DisplayPage> entries = filteredPages();
-        for (int i = 0; i < pages.size(); i++) if (!pages.get(i).isEmpty()) last = i;
+        for (int i = scrollRows * 5; i < entries.size() && i < scrollRows * 5 + 20; i++) {
-        for (int i = scrollRows * 5; i <= last && i < scrollRows * 5 + 15; i++) {
             int column = i % 5;
             int row = i / 5 - scrollRows;
-            ItemStack page = pages.get(i);
+            DisplayPage entry = entries.get(i);
-            int x = leftPos + 48 + column * 31;
+            ItemStack page = entry.stack();
-            int y = topPos + 18 + row * 41;
+            int x = leftPos + 58 + column * 31;
+            int y = topPos + 20 + row * 41;
             drawPage(graphics, page, x, y);
             if (page.isEmpty()) graphics.fill(x, y, x + 30, y + 40, 0xB8000000);
-            if (i == selectedPage && !page.isEmpty()) graphics.renderOutline(x, y, 30, 40, 0xFFFFD061);
+            int active = selectedCollection >= 0 ? selectedCollection : menu.activeCollection();
-        }
+            if (entry.collection() == active && entry.index() == selectedPage && !page.isEmpty())
-        if (selectedPage >= pages.size() || pages.get(selectedPage).isEmpty()) return;
-        ItemStack selected = pages.get(selectedPage);
-        graphics.pose().pushPose();
-        graphics.pose().translate(leftPos + 294, topPos + 12, 0);
-        graphics.pose().scale(1.35F, 1.35F, 1.0F);
-        drawPage(graphics, selected, 0, 0);
-        graphics.pose().popPose();
-        String title = font.plainSubstrByWidth(selected.getHoverName().getString(), 112);
-        graphics.fill(leftPos + 251, topPos + 64, leftPos + 365, topPos + 77, 0xFF202020);
-        graphics.drawString(font, title, leftPos + 254, topPos + 67, 0xFFE0E0E0, false);
-    }
-
-    private void renderCatalog(GuiGraphics graphics) {
-        List<SymbolDisplayMetadata> filtered = filteredCatalog();
-        if (filtered.isEmpty()) {
-            graphics.drawString(font, Component.translatable("screen.rivencraft.writing_desk.no_symbols"),
-                    leftPos + 52, topPos + 24, 0xFFC4B8A3, false);
-        }
-        for (int i = scrollRows * 5; i < filtered.size() && i < scrollRows * 5 + 15; i++) {
-            SymbolDisplayMetadata entry = filtered.get(i);
-            int x = leftPos + 48 + (i % 5) * 31;
-            int y = topPos + 18 + (i / 5 - scrollRows) * 41;
-            drawSymbolPage(graphics, entry.id(), x, y);
-            if (Objects.equals(entry.id(), selectedSymbol)) {
                 graphics.renderOutline(x, y, 30, 40, 0xFFFFD061);
-            }
         }
-        SymbolDisplayMetadata selected = menu.catalog().stream()
+        int active = selectedCollection >= 0 ? selectedCollection : menu.activeCollection();
-                .filter(entry -> Objects.equals(entry.id(), selectedSymbol)).findFirst().orElse(null);
+        List<ItemStack> source = pages(active);
-        if (selected == null) return;
+        if (selectedPage >= source.size() || source.get(selectedPage).isEmpty()) return;
-        graphics.pose().pushPose();
+        ItemStack selected = source.get(selectedPage);
-        graphics.pose().translate(leftPos + 294, topPos + 12, 0);
+        drawPage(graphics, selected, leftPos + 265, topPos + 26);
-        graphics.pose().scale(1.35F, 1.35F, 1.0F);
+        String title = font.plainSubstrByWidth(selected.getHoverName().getString(), 95);
-        drawSymbolPage(graphics, selected.id(), 0, 0);
+        graphics.fill(leftPos + 261, topPos + 81, leftPos + 360, topPos + 95, 0xFF202020);
-        graphics.pose().popPose();
+        graphics.drawString(font, title, leftPos + 263, topPos + 84, 0xFFE0E0E0, false);
-        String title = font.plainSubstrByWidth(
-                Component.translatable(selected.nameTranslationKey()).getString(), 112);
-        graphics.fill(leftPos + 251, topPos + 64, leftPos + 365, topPos + 77, 0xFF202020);
-        graphics.drawString(font, title, leftPos + 254, topPos + 67, 0xFFE0E0E0, false);
-    }
-
-    private void drawSymbolPage(GuiGraphics graphics, ResourceLocation id, int x, int y) {
-        graphics.blit(PAGE_ATLAS, x, y, 30, 40, 156, 0, 30, 40, 256, 256);
-        graphics.blit(NotebookScreen.symbolTexture(id), x + 1, y + 6,
-                28, 28, 16, 16, 96, 96, 128, 128);
     }
 
     private void drawPage(GuiGraphics graphics, ItemStack page, int x, int y) {
@@ -222,45 +259,116 @@ public final class WritingDeskScreen extends AbstractContainerScreen<WritingDesk
         }
     }
 
+    private DisplayPage pageAtMouse(double mouseX, double mouseY) {
+        int x = (int) Math.floor(mouseX - leftPos - 58);
+        int y = (int) Math.floor(mouseY - topPos - 20);
+        if (x < 0 || x >= 155 || y < 0 || y >= 164 || x % 31 >= 30 || y % 41 >= 40) return null;
+        int index = (y / 41 + scrollRows) * 5 + x / 31;
+        List<DisplayPage> entries = filteredPages();
+        return index < entries.size() ? entries.get(index) : null;
+    }
+
+    private boolean canMovePage(DisplayPage source, DisplayPage target) {
+        return !source.stack().isEmpty()
+                && (menu.getSlot(source.collection()).getItem().is(ModItems.NOTEBOOK.get())
+                    || menu.getSlot(source.collection()).getItem().is(ModItems.PAGE.get()))
+                && (menu.getSlot(target.collection()).getItem().is(ModItems.NOTEBOOK.get())
+                    || menu.getSlot(target.collection()).getItem().is(ModItems.PAGE.get()))
+                && (source.collection() != target.collection() || source.index() != target.index());
+    }
+
+    private int extractTargetSlot(double mouseX, double mouseY) {
+        for (Slot slot : menu.slots) {
+            int index = slot.index;
+            if (index >= WritingDeskBlockEntity.COLLECTIONS && index <= WritingDeskMenu.COPY_RESULT) continue;
+            if (!slot.isActive() || !isHovering(slot.x, slot.y, 16, 16, mouseX, mouseY)) continue;
+            ItemStack held = pageDragSource.stack();
+            if (!slot.mayPlace(held)) return -1;
+            ItemStack current = slot.getItem();
+            if (current.isEmpty()) return index;
+            if (index < WritingDeskBlockEntity.COLLECTIONS && current.is(ModItems.NOTEBOOK.get())) {
+                List<ItemStack> pages = current.getOrDefault(
+                        ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
+                if (pages.size() < NotebookContents.MAX_PAGES || pages.stream().anyMatch(ItemStack::isEmpty))
+                    return index;
+            } else if (index > WritingDeskMenu.COPY_RESULT && ItemStack.isSameItemSameComponents(current, held)
+                    && current.getCount() < slot.getMaxStackSize(held)) return index;
+            return -1;
+        }
+        return -1;
+    }
+
     @Override public boolean mouseClicked(double mouseX, double mouseY, int button) {
         if (button == 0) {
-            int x = (int) mouseX - leftPos - 48;
+            pageDragSource = null;
-            int y = (int) mouseY - topPos - 18;
+            draggingPage = false;
-            if (x >= 0 && x < 155 && y >= 0 && y < 123) {
+        }
-                int column = x / 31;
+        int surfaceX = (int) Math.floor(mouseX - leftPos - 58);
-                int row = y / 41;
+        int surfaceY = (int) Math.floor(mouseY - topPos - 20);
-                int index = (row + scrollRows) * 5 + column;
+        if ((button == 0 || button == 1) && !menu.getCarried().isEmpty()
-                if (allMode) {
+                && surfaceX >= 0 && surfaceX < 155 && surfaceY >= 0 && surfaceY < 164) {
-                    List<SymbolDisplayMetadata> filtered = filteredCatalog();
+            if (menu.getCarried().is(ModItems.PAGE.get()) && surfaceX % 31 < 30 && surfaceY % 41 < 40) {
-                    if (x % 31 < 30 && y % 41 < 40 && index < filtered.size()) {
+                int index = (surfaceY / 41 + scrollRows) * 5 + surfaceX / 31;
-                        SymbolDisplayMetadata entry = filtered.get(index);
+                List<DisplayPage> entries = filteredPages();
-                        selectedSymbol = entry.id();
+                // Only displayed positions are addressable. Filtering never turns
-                        int serverIndex = menu.catalog().indexOf(entry);
+                // empty screen space into additional storage for a loose-page tab.
-                        if (serverIndex >= 0 && minecraft != null && minecraft.gameMode != null) {
+                int collection = index < entries.size() ? entries.get(index).collection() : menu.activeCollection();
-                            minecraft.gameMode.handleInventoryButtonClick(menu.containerId, 100 + serverIndex);
+                int page = index < entries.size() ? entries.get(index).index() : index;
-                        }
+                if (index < entries.size() && page < menu.pageCapacity(collection)
+                        && minecraft != null && minecraft.gameMode != null) {
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + collection * NotebookContents.MAX_PAGES + page);
+                }
+            }
+            return true;
+        }
+        if (button == 0) {
+            if (mouseX >= leftPos && mouseX < leftPos + 58) {
+                int y = (int) mouseY - topPos;
+                if (y >= 20 && y < 29 || y >= 177 && y < 186) {
+                    if (minecraft != null && minecraft.gameMode != null)
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                                y < 29 ? WritingDeskMenu.PREVIOUS_TABS : WritingDeskMenu.NEXT_TABS);
+                    return true;
+                }
+            }
+            if (mouseX >= leftPos + 213 && mouseX < leftPos + 233
+                    && mouseY >= topPos + 20 && mouseY < topPos + 186) {
+                draggingScrollbar = true;
+                setScrollFromMouse(mouseY);
+                return true;
+            }
+            int x = (int) Math.floor(mouseX - leftPos - 58);
+            int y = (int) Math.floor(mouseY - topPos - 20);
+            if (x >= 0 && x < 155 && y >= 0 && y < 164) {
+                DisplayPage entry = pageAtMouse(mouseX, mouseY);
+                if (entry != null && !entry.stack().isEmpty()) {
+                    selectedCollection = entry.collection();
+                    selectedPage = entry.index();
+                    if (menu.getCarried().isEmpty()) {
+                        pageDragSource = entry;
+                        pageDragStartX = mouseX;
+                        pageDragStartY = mouseY;
                     }
-                } else {
+                    if (minecraft != null && minecraft.gameMode != null) {
-                    List<ItemStack> pages = pages();
+                        int id = WritingDeskMenu.ALL_PAGE_BUTTON_BASE
-                    if (x % 31 < 30 && y % 41 < 40 && index < pages.size()
+                                + entry.collection() * NotebookContents.MAX_PAGES + entry.index();
-                            && !pages.get(index).isEmpty()) {
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId, id);
-                        selectedPage = index;
-                        if (minecraft != null && minecraft.gameMode != null) {
-                            minecraft.gameMode.handleInventoryButtonClick(menu.containerId, 16 + index);
-                        }
                     }
                 }
                 return true;
             }
         }
-        if (button == 0 && mouseX >= leftPos + 29 && mouseX < leftPos + 40) {
+        if (button == 0 && mouseX >= leftPos && mouseX < leftPos + 58) {
             for (int i = 0; i < 4; i++) {
-                int top = topPos + 16 + i * 37;
+                int top = topPos + 29 + i * 37;
-                if (mouseY >= top && mouseY < top + 32) {
+                boolean overSlot = mouseX >= leftPos + 36 && mouseX < leftPos + 54
+                        && mouseY >= top + 4 && mouseY < top + 22;
+                if (mouseY >= top && mouseY < top + 37 && !overSlot) {
                     allMode = false;
-                    selectedSymbol = null;
+                    selectedCollection = -1;
                     if (minecraft != null && minecraft.gameMode != null) {
-                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId, i);
+                        minecraft.gameMode.handleInventoryButtonClick(menu.containerId, menu.firstVisibleTab() + i);
                     }
                     return true;
                 }
@@ -270,15 +378,63 @@ public final class WritingDeskScreen extends AbstractContainerScreen<WritingDesk
     }
 
     @Override public boolean mouseScrolled(double mouseX, double mouseY, double scrollX, double scrollY) {
-        if (mouseX >= leftPos + 48 && mouseX < leftPos + 203
+        if (mouseX >= leftPos + 58 && mouseX < leftPos + 233
-                && mouseY >= topPos + 18 && mouseY < topPos + 141) {
+                && mouseY >= topPos + 20 && mouseY < topPos + 186) {
-            int rows = ((allMode ? filteredCatalog().size() : pages().size()) + 4) / 5;
+            int rows = (filteredPages().size() + 4) / 5;
-            scrollRows = Math.clamp(scrollRows - (int) Math.signum(scrollY), 0, Math.max(0, rows - 3));
+            scrollRows = Math.clamp(scrollRows - (int) Math.signum(scrollY), 0, Math.max(0, rows - 4));
             return true;
         }
         return super.mouseScrolled(mouseX, mouseY, scrollX, scrollY);
     }
 
+    private void setScrollFromMouse(double mouseY) {
+        int rows = (filteredPages().size() + 4) / 5;
+        int max = Math.max(0, rows - 4);
+        scrollRows = Math.clamp((int) Math.round((mouseY - topPos - 31.5) * max / 143.0), 0, max);
+    }
+
+    @Override public boolean mouseDragged(double mouseX, double mouseY, int button, double dragX, double dragY) {
+        if (button == 0 && pageDragSource != null) {
+            if (Math.abs(mouseX - pageDragStartX) >= 4 || Math.abs(mouseY - pageDragStartY) >= 4)
+                draggingPage = true;
+            return true;
+        }
+        if (button == 0 && draggingScrollbar) {
+            setScrollFromMouse(mouseY);
+            return true;
+        }
+        return super.mouseDragged(mouseX, mouseY, button, dragX, dragY);
+    }
+
+    @Override public boolean mouseReleased(double mouseX, double mouseY, int button) {
+        if (button == 0 && pageDragSource != null) {
+            if (draggingPage) {
+                DisplayPage target = pageAtMouse(mouseX, mouseY);
+                if (target != null && canMovePage(pageDragSource, target)
+                        && minecraft != null && minecraft.gameMode != null) {
+                    selectedCollection = target.collection();
+                    selectedPage = target.index();
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.movePageButtonId(pageDragSource.collection(), pageDragSource.index(),
+                                    target.collection(), target.index()));
+                } else if (target == null && minecraft != null && minecraft.gameMode != null) {
+                    int targetSlot = extractTargetSlot(mouseX, mouseY);
+                    minecraft.gameMode.handleInventoryButtonClick(menu.containerId,
+                            WritingDeskMenu.extractPageButtonId(pageDragSource.collection(), pageDragSource.index(),
+                                    targetSlot));
+                }
+            }
+            pageDragSource = null;
+            draggingPage = false;
+            return true;
+        }
+        if (button == 0 && draggingScrollbar) {
+            draggingScrollbar = false;
+            return true;
+        }
+        return super.mouseReleased(mouseX, mouseY, button);
+    }
+
     @Override public boolean keyPressed(int keyCode, int scanCode, int modifiers) {
         if (search != null && search.isFocused()) {
             if (keyCode == 256) {

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

@@ -3,6 +3,7 @@ package net.dnorberg.rivencraft.gametest;
 import java.util.List;
 import net.dnorberg.rivencraft.Rivencraft;
 import net.dnorberg.rivencraft.block.entity.WritingDeskBlockEntity;
+import net.dnorberg.rivencraft.block.WritingDeskBlock;
 import net.dnorberg.rivencraft.menu.WritingDeskMenu;
 import net.dnorberg.rivencraft.item.PageItem;
 import net.dnorberg.rivencraft.registry.ModBlocks;
@@ -12,6 +13,7 @@ import net.dnorberg.rivencraft.writing.NotebookContents;
 import net.dnorberg.rivencraft.writing.SymbolReference;
 import net.dnorberg.rivencraft.writing.WritingDeskCatalog;
 import net.minecraft.core.BlockPos;
+import net.minecraft.core.Direction;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraft.gametest.framework.GameTest;
 import net.minecraft.gametest.framework.GameTestHelper;
@@ -59,10 +61,10 @@ public final class WritingDeskGameTests {
         helper.getLevel().setBlock(pos, Blocks.AIR.defaultBlockState(), 3);
         var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(2));
         int notebooks = drops.stream().filter(e -> e.getItem().is(ModItems.NOTEBOOK.get())).mapToInt(e -> e.getItem().getCount()).sum();
-        int ink = drops.stream().filter(e -> e.getItem().is(ModItems.INK_VIAL.get())).mapToInt(e -> e.getItem().getCount()).sum();
+        int bottles = drops.stream().filter(e -> e.getItem().is(Items.GLASS_BOTTLE)).mapToInt(e -> e.getItem().getCount()).sum();
         int pages = drops.stream().filter(e -> e.getItem().is(Items.PAPER)).mapToInt(e -> e.getItem().getCount()).sum();
         helper.assertValueEqual(notebooks, 1, "Notebook must drop exactly once");
-        helper.assertValueEqual(ink, 1, "Ink must drop exactly once");
+        helper.assertValueEqual(bottles, 1, "Consumed vial must return one glass bottle on break");
         helper.assertValueEqual(pages, 12, "Pages must drop without loss");
         helper.succeed();
     }
@@ -79,7 +81,7 @@ public final class WritingDeskGameTests {
         helper.assertTrue(menu.stillValid(player), "Placed desk must keep its menu valid");
         helper.assertTrue(menu.clickMenuButton(player, 3), "Active collection control must accept a valid tab");
         helper.assertValueEqual(desk.activeCollection(), 3, "Selected tab must be stored on the desk");
-        menu.quickMoveStack(player, 9);
+        menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT + 1);
         helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 12, "Shift-click must deposit all pages");
         helper.assertTrue(player.getInventory().getItem(9).isEmpty(), "Shift-click must consume player source stack");
         menu.quickMoveStack(player, WritingDeskBlockEntity.PAPER);
@@ -109,12 +111,12 @@ public final class WritingDeskGameTests {
                 "A source page with paper and ink must preview one copy");
         helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 2,
                 "Previewing must not consume paper");
-        helper.assertValueEqual(desk.inkRemaining(), 0, "Previewing must not consume ink");
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Inserting a vial must fill the empty bar before copying");
         menu.clicked(WritingDeskMenu.COPY_RESULT, 0, ClickType.PICKUP, player);
         helper.assertTrue(menu.getCarried().is(ModItems.PAGE.get()), "Taking result must give the copied page");
         helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 1,
                 "Taking a copy must consume one paper");
-        helper.assertValueEqual(desk.inkRemaining(), 15, "First copy must refill to 16 and consume one ink");
+        helper.assertValueEqual(desk.inkRemaining(), 15, "First copy must consume one ink");
         helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(), "Refill must consume one vial");
         helper.assertTrue(desk.getItem(WritingDeskBlockEntity.RETURN).is(Items.GLASS_BOTTLE),
                 "Refill must return a vanilla glass bottle");
@@ -133,6 +135,48 @@ public final class WritingDeskGameTests {
         helper.succeed();
     }
 
+    @GameTest(template = "empty")
+    public static void emptyDeskInkBarRefillsWithoutCopying(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get(), 2));
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Inserting a vial must refill immediately");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.INK).getCount(), 1,
+                "Refill must consume exactly one vial");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.RETURN).is(Items.GLASS_BOTTLE),
+                "Refill must put a vanilla glass bottle in the return slot");
+        helper.runAfterDelay(2, () -> {
+            helper.assertValueEqual(desk.inkRemaining(), 16, "Full bar must not refill again");
+            helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.INK).getCount(), 1,
+                    "Full bar must leave the second vial untouched");
+            helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 1,
+                    "Full bar must not create another bottle");
+            helper.succeed();
+        });
+    }
+
+    @GameTest(template = "empty")
+    public static void emptyDeskInkBarWaitsForBottleSpace(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(WritingDeskBlockEntity.RETURN, new ItemStack(Items.GLASS_BOTTLE, 64));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        helper.assertValueEqual(desk.inkRemaining(), 0, "Full bottle slot must block automatic refill");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).is(ModItems.INK_VIAL.get()),
+                "Blocked refill must preserve the vial");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 64,
+                "Blocked refill must preserve the bottle stack");
+        desk.removeItem(WritingDeskBlockEntity.RETURN, 1);
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Removing a bottle must immediately permit refill");
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(),
+                "Refill must consume the waiting vial");
+        helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.RETURN).getCount(), 64,
+                "Refill must return one glass bottle to the available space");
+        helper.succeed();
+    }
+
     @GameTest(template = "empty")
     public static void shiftClickCopiesOnlyWhenResourcesAndBottleSpaceExist(GameTestHelper helper) {
         BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
@@ -140,8 +184,8 @@ public final class WritingDeskGameTests {
         WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
         desk.setItem(0, PageItem.createLinkPanelPage());
         desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 2));
-        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
         desk.setItem(WritingDeskBlockEntity.RETURN, new ItemStack(Items.GLASS_BOTTLE, 64));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
         var player = helper.makeMockServerPlayerInLevel();
         player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
         WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
@@ -178,7 +222,7 @@ public final class WritingDeskGameTests {
         menu.broadcastChanges();
         helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().isEmpty(),
                 "An empty selected position must not create a copy");
-        helper.assertTrue(menu.clickMenuButton(player, 17), "Second page selection must be accepted");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.PAGE_BUTTON_BASE + 1), "Second page selection must be accepted");
         menu.broadcastChanges();
         helper.assertTrue(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem().is(ModItems.PAGE.get()),
                 "Selecting the populated page must show a copy");
@@ -228,8 +272,8 @@ public final class WritingDeskGameTests {
         var player = helper.makeMockServerPlayerInLevel();
         player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
         WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
-        helper.assertFalse(menu.clickMenuButton(player, 101), "Out-of-range catalog index must be rejected");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.CATALOG_BUTTON_BASE + 1), "Out-of-range catalog index must be rejected");
-        helper.assertTrue(menu.clickMenuButton(player, 100), "Known catalog symbol must be selectable");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.CATALOG_BUTTON_BASE), "Known catalog symbol must be selectable");
         desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
         desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
         menu.broadcastChanges();
@@ -260,9 +304,319 @@ public final class WritingDeskGameTests {
                 "Full inventory must reject shift-click copy");
         helper.assertValueEqual(desk.getItem(WritingDeskBlockEntity.PAPER).getCount(), 1,
                 "Rejected copy must preserve paper");
-        helper.assertValueEqual(desk.inkRemaining(), 0, "Rejected copy must preserve ink meter");
+        helper.assertValueEqual(desk.inkRemaining(), 16, "Rejected copy must preserve the filled ink meter");
-        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).is(ModItems.INK_VIAL.get()),
+        helper.assertTrue(desk.getItem(WritingDeskBlockEntity.INK).isEmpty(),
-                "Rejected copy must preserve ink vial");
+                "The vial should already have refilled the empty meter");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void twoBlockDeskSharesOneInventoryAndBreaksTogether(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var block = ModBlocks.WRITING_DESK.get();
+        var state = block.defaultBlockState().setValue(WritingDeskBlock.FACING, Direction.NORTH);
+        helper.getLevel().setBlock(pos, state, 3);
+        block.setPlacedBy(helper.getLevel(), pos, state, null, new ItemStack(block));
+        BlockPos extension = pos.relative(Direction.EAST);
+        helper.assertTrue(helper.getLevel().getBlockState(extension).is(block),
+                "Placing a desk must reserve the adjacent second block");
+        helper.assertTrue(helper.getLevel().getBlockState(extension).getValue(WritingDeskBlock.EXTENSION),
+                "Adjacent half must be marked as an extension");
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        helper.assertTrue(helper.getLevel().getBlockEntity(extension) == null,
+                "Extension must not duplicate the inventory");
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER, 7));
+        helper.getLevel().destroyBlock(extension, true);
+        helper.assertTrue(helper.getLevel().getBlockState(pos).isAir(),
+                "Breaking the extension must remove the controller");
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(3));
+        int desks = drops.stream().filter(e -> e.getItem().is(block.asItem()))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        int paper = drops.stream().filter(e -> e.getItem().is(Items.PAPER))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        helper.assertValueEqual(desks, 1, "Breaking either half must drop one desk");
+        helper.assertValueEqual(paper, 7, "Breaking either half must drop stored paper once");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void breakingControllerRemovesExtensionWithoutDuplicateDesk(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var block = ModBlocks.WRITING_DESK.get();
+        var state = block.defaultBlockState().setValue(WritingDeskBlock.FACING, Direction.NORTH);
+        helper.getLevel().setBlock(pos, state, 3);
+        block.setPlacedBy(helper.getLevel(), pos, state, null, new ItemStack(block));
+        BlockPos extension = pos.relative(Direction.EAST);
+        helper.getLevel().destroyBlock(pos, true);
+        helper.assertTrue(helper.getLevel().getBlockState(extension).isAir(),
+                "Breaking the controller must remove the extension");
+        var drops = helper.getLevel().getEntitiesOfClass(ItemEntity.class, new AABB(pos).inflate(3));
+        int desks = drops.stream().filter(e -> e.getItem().is(block.asItem()))
+                .mapToInt(e -> e.getItem().getCount()).sum();
+        helper.assertValueEqual(desks, 1, "Controller break must drop exactly one desk");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void openDeskDoesNotOccludeTerrain(GameTestHelper helper) {
+        helper.assertFalse(ModBlocks.WRITING_DESK.get().defaultBlockState().canOcclude(),
+                "Open shelves must not cull terrain behind the desk");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void allPagesSelectionUsesTheRequestedPhysicalTab(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        WritingDeskBlockEntity desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack first = PageItem.createLinkPanelPage();
+        ItemStack second = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        desk.setItem(0, first);
+        ItemStack notebook = new ItemStack(ModItems.NOTEBOOK.get());
+        notebook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(),
+                new NotebookContents(List.of(ItemStack.EMPTY, second)));
+        desk.setItem(1, notebook);
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        WritingDeskMenu menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + 2 * NotebookContents.MAX_PAGES),
+                "ALL view must reject empty cross-tab positions");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + NotebookContents.MAX_PAGES + 1),
+                "ALL view must accept the populated second tab page");
+        helper.assertTrue(ItemStack.matches(menu.getSlot(WritingDeskMenu.COPY_RESULT).getItem(), second),
+                "Copy preview must match the physical page selected from the other tab");
+        helper.assertValueEqual(desk.activeCollection(), 0,
+                "Selecting from ALL must not silently change the active tab");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void tabGroupsCycleByFourAndProtectHiddenSlots(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        var otherViewer = new WritingDeskMenu(2, player.getInventory(), desk);
+        menu.clickMenuButton(player, WritingDeskMenu.PREVIOUS_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 0, "Previous must stop at tabs 1-4");
+        menu.clickMenuButton(player, WritingDeskMenu.NEXT_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 4, "Next must show tabs 5-8");
+        helper.assertValueEqual(otherViewer.firstVisibleTab(), 0, "Cycling must not move another viewer's slots");
+        helper.assertFalse(menu.getSlot(0).isActive(), "Earlier tab slots must be hidden");
+        helper.assertTrue(menu.getSlot(4).isActive(), "New group's slots must be interactive");
+        desk.setItem(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        menu.clicked(0, 0, ClickType.PICKUP, player);
+        helper.assertTrue(menu.getCarried().isEmpty(), "Hidden slot clicks must not take items");
+        helper.assertTrue(menu.quickMoveStack(player, 0).isEmpty(), "Hidden shift-click must be rejected");
+        player.getInventory().setItem(9, new ItemStack(ModItems.NOTEBOOK.get()));
+        menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT + 1);
+        helper.assertTrue(desk.getItem(4).is(ModItems.NOTEBOOK.get()), "Shift-click must use the visible group");
+        for (int i = 0; i < 30; i++) menu.clickMenuButton(player, WritingDeskMenu.NEXT_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 84, "Last group must be tabs 85-88");
+        helper.assertTrue(menu.clickMenuButton(player, 87), "Tab 88 must be selectable without page-ID collisions");
+        helper.assertValueEqual(desk.activeCollection(), 87, "Tab 88 must become active");
+        helper.assertFalse(menu.clickMenuButton(player, 88), "Tab 89 must not exist");
+        desk.setItem(87, PageItem.createLinkPanelPage());
+        desk.setItem(WritingDeskBlockEntity.PAPER, new ItemStack(Items.PAPER));
+        desk.setItem(WritingDeskBlockEntity.INK, new ItemStack(ModItems.INK_VIAL.get()));
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.ALL_PAGE_BUTTON_BASE + 87 * NotebookContents.MAX_PAGES),
+                "ALL must select a physical page from tab 88");
+        helper.assertTrue(menu.quickMoveStack(player, WritingDeskMenu.COPY_RESULT).is(ModItems.PAGE.get()),
+                "Tab 88's page must be copyable");
+        menu.clickMenuButton(player, WritingDeskMenu.PREVIOUS_TABS);
+        helper.assertValueEqual(menu.firstVisibleTab(), 80, "Previous must move back four tabs");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void oldDeskInventoryMigratesAndAll88TabsPersist(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        var registries = helper.getLevel().registryAccess();
+        var oldItems = net.minecraft.core.NonNullList.withSize(8, ItemStack.EMPTY);
+        oldItems.set(0, new ItemStack(ModItems.NOTEBOOK.get()));
+        oldItems.set(3, PageItem.createLinkPanelPage());
+        oldItems.set(4, new ItemStack(ModItems.INK_VIAL.get(), 2));
+        oldItems.set(5, new ItemStack(Items.GLASS_BOTTLE, 3));
+        oldItems.set(6, new ItemStack(Items.PAPER, 12));
+        oldItems.set(7, PageItem.createLinkPanelPage());
+        var oldTag = new net.minecraft.nbt.CompoundTag();
+        net.minecraft.world.ContainerHelper.saveAllItems(oldTag, oldItems, registries);
+        oldTag.putInt("InkRemaining", 7);
+        oldTag.putInt("ActiveCollection", 3);
+        var desk = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        desk.loadWithComponents(oldTag, registries);
+        for (int i = 0; i < 4; i++) {
+            helper.assertTrue(ItemStack.matches(desk.getItem(i), oldItems.get(i)), "Original tab must survive migration");
+            helper.assertTrue(ItemStack.matches(desk.getItem(WritingDeskBlockEntity.INK + i), oldItems.get(4 + i)),
+                    "Original supplies and legacy output must survive migration");
+            helper.assertTrue(desk.getItem(4 + i).isEmpty(), "Supplies must not be duplicated into new tabs");
+        }
+        helper.assertValueEqual(desk.inkRemaining(), 7, "Migration must preserve ink meter");
+        helper.assertValueEqual(desk.activeCollection(), 3, "Migration must preserve active tab");
+        for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++) desk.setItem(i, PageItem.createLinkPanelPage());
+        desk.setActiveCollection(87);
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(desk.saveWithoutMetadata(registries), registries);
+        for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++)
+            helper.assertTrue(restored.getItem(i).is(ModItems.PAGE.get()), "All 88 tab contents must survive save/load");
+        helper.assertValueEqual(restored.activeCollection(), 87, "Tab 88 selection must survive save/load");
+        helper.assertValueEqual(restored.getItem(WritingDeskBlockEntity.PAPER).getCount(), 12, "Reload must not repeat migration");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void surfacePlacesCarriedPagesWithoutLossOrOverwrite(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        desk.setItem(87, new ItemStack(ModItems.NOTEBOOK.get()));
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        ItemStack held = PageItem.createLinkPanelPage().copyWithCount(3);
+        ItemStack expectedPage = held.copyWithCount(1);
+        player.getInventory().setItem(9, held);
+        menu.clicked(WritingDeskMenu.COPY_RESULT + 1, 0, ClickType.PICKUP, player);
+        int lastPosition = WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 87 * NotebookContents.MAX_PAGES + 26;
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition), "Surface must place into final notebook position");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Placing must consume exactly one held page");
+        var pages = desk.getItem(87).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertValueEqual(pages.size(), 27, "Placement must preserve addressed position");
+        helper.assertTrue(pages.get(0).isEmpty() && pages.get(25).isEmpty(), "Placement must preserve preceding gaps");
+        helper.assertTrue(ItemStack.matches(pages.get(26), expectedPage), "Stored page must preserve components");
+        helper.assertFalse(menu.clickMenuButton(player, lastPosition), "Occupied position must not be overwritten");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Rejected placement must preserve cursor");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 88 * NotebookContents.MAX_PAGES),
+                "Out-of-range placement must be rejected");
+        helper.assertValueEqual(menu.pageCapacity(87), NotebookContents.MAX_PAGES, "Notebook tab must expose normal notebook capacity");
+        helper.assertValueEqual(menu.pageCapacity(0), 0, "Empty tab has no page storage");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE), "Empty tab must require a collection first");
+        desk.setItem(0, PageItem.createLinkPanelPage());
+        helper.assertValueEqual(menu.pageCapacity(0), 1, "Loose page tab must expose exactly one position");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE), "Loose page must not be replaced");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.PLACE_PAGE_BUTTON_BASE + 1), "Loose page tab must not grow extra positions");
+        helper.assertValueEqual(menu.getCarried().getCount(), 2, "Rejected placements must preserve cursor");
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition - 1), "A second empty notebook position must accept a page");
+        helper.assertTrue(menu.clickMenuButton(player, lastPosition - 2), "A third empty notebook position must accept the last page");
+        helper.assertTrue(menu.getCarried().isEmpty(), "Final placement must clear cursor");
+        menu.setCarried(new ItemStack(Items.DIAMOND));
+        helper.assertFalse(menu.clickMenuButton(player, lastPosition - 3), "Non-page items must be rejected");
+        helper.assertTrue(menu.getCarried().is(Items.DIAMOND), "Rejected item must remain held");
+        var restored = new WritingDeskBlockEntity(pos, ModBlocks.WRITING_DESK.get().defaultBlockState());
+        restored.loadWithComponents(desk.saveWithoutMetadata(helper.getLevel().registryAccess()), helper.getLevel().registryAccess());
+        helper.assertValueEqual(restored.getItem(87).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 3,
+                "Placed pages must persist in the notebook");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void deskSurfaceDragMovesAndSwapsNotebookPages(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack linkPanel = PageItem.createLinkPanelPage();
+        ItemStack terrain = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        ItemStack firstBook = new ItemStack(ModItems.NOTEBOOK.get());
+        firstBook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(List.of(linkPanel, terrain)));
+        desk.setItem(0, firstBook);
+        desk.setItem(1, new ItemStack(ModItems.NOTEBOOK.get()));
+        desk.setItem(2, PageItem.createLinkPanelPage());
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        int moveToEmpty = WritingDeskMenu.movePageButtonId(0, 0, 0, 26);
+        helper.assertTrue(menu.clickMenuButton(player, moveToEmpty), "Drag must move to a distant empty notebook position");
+        var pages = desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(pages.get(0).isEmpty(), "Moving must clear the source position");
+        helper.assertTrue(ItemStack.matches(pages.get(26), linkPanel), "Moving must preserve page components");
+        helper.assertValueEqual(desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 2,
+                "Moving must preserve total page count");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 26, 0, 1)),
+                "Drag onto an occupied position must swap pages");
+        pages = desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(pages.get(1), linkPanel) && ItemStack.matches(pages.get(26), terrain),
+                "Swap must preserve both pages");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 1, 1, 5)),
+                "Drag into another notebook must work");
+        var otherPages = desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(otherPages.get(5), linkPanel)
+                && desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(1).isEmpty(),
+                "Cross notebook move must have one destination and no old source");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(0, 1, 1, 6)),
+                "Dragging an empty source must be rejected");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(2, 0, 1, 6)),
+                "A loose page should move into a notebook position");
+        helper.assertTrue(desk.getItem(2).isEmpty()
+                && desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(6).is(ModItems.PAGE.get()),
+                "Moving a loose page must empty its tab without losing the item");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(1, 5, 1, 5)),
+                "A no-op drag must be rejected");
+        menu.setCarried(new ItemStack(Items.DIAMOND));
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.movePageButtonId(1, 5, 1, 6)),
+                "Held inventory items must not be moved by a panel drag");
+        helper.assertTrue(ItemStack.matches(desk.getItem(1).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages().get(5), linkPanel),
+                "Rejected drags must leave notebook data intact");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void deskSurfaceDragExtractsPagesToInventoryAndTabs(GameTestHelper helper) {
+        BlockPos pos = helper.absolutePos(new BlockPos(1, 1, 1));
+        helper.getLevel().setBlock(pos, ModBlocks.WRITING_DESK.get().defaultBlockState(), 3);
+        var desk = (WritingDeskBlockEntity) helper.getLevel().getBlockEntity(pos);
+        ItemStack page = PageItem.createLinkPanelPage();
+        ItemStack source = new ItemStack(ModItems.NOTEBOOK.get());
+        source.set(ModDataComponents.NOTEBOOK_CONTENTS.get(),
+                new NotebookContents(List.of(page, page, page, page, page, page)));
+        desk.setItem(0, source);
+        ItemStack otherBook = new ItemStack(ModItems.NOTEBOOK.get());
+        ItemStack terrain = PageItem.createSymbolPage(new SymbolReference(
+                ResourceLocation.parse("rivencraft:terrain/standard")));
+        otherBook.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(List.of(terrain)));
+        desk.setItem(2, otherBook);
+        var player = helper.makeMockServerPlayerInLevel();
+        player.moveTo(pos.getX() + 0.5, pos.getY() + 0.5, pos.getZ() + 0.5);
+        player.getInventory().setItem(10, page.copyWithCount(2));
+        var menu = new WritingDeskMenu(1, player.getInventory(), desk);
+        int inventoryStart = WritingDeskMenu.COPY_RESULT + 1;
+
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 0, -1)),
+                "Dropping away from a slot must return the page to the cursor");
+        helper.assertTrue(ItemStack.matches(menu.getCarried(), page), "Cursor must hold the original page item");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 1, inventoryStart)),
+                "Extraction must not replace an occupied cursor");
+        menu.setCarried(ItemStack.EMPTY);
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 1, inventoryStart)),
+                "Dropping on player inventory must transfer a page");
+        helper.assertTrue(ItemStack.matches(player.getInventory().getItem(9), page),
+                "Transferred page must retain its components");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 2, 1)),
+                "Dropping on an empty tab must store a loose page");
+        helper.assertTrue(ItemStack.matches(desk.getItem(1), page), "Tab must hold the extracted page");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 3, 2)),
+                "Dropping on a notebook tab must insert the page");
+        var otherPages = desk.getItem(2).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pages();
+        helper.assertTrue(ItemStack.matches(otherPages.get(0), terrain)
+                && ItemStack.matches(otherPages.get(1), page), "Notebook drop must preserve existing pages");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 4, inventoryStart + 1)),
+                "Dropping on a matching inventory stack must merge one page");
+        helper.assertValueEqual(player.getInventory().getItem(10).getCount(), 3, "Merge must add exactly one page");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 5, 1)),
+                "Occupied loose-page tabs must reject a drop");
+        helper.assertFalse(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(0, 5, WritingDeskBlockEntity.INK)),
+                "Ink slot must not accept an extracted page");
+        helper.assertValueEqual(desk.getItem(0).get(ModDataComponents.NOTEBOOK_CONTENTS.get()).pageCount(), 1,
+                "Rejected drops must leave the remaining source page in the notebook");
+        helper.assertTrue(menu.clickMenuButton(player, WritingDeskMenu.extractPageButtonId(1, 0, -1)),
+                "A loose page shown on the panel must be draggable back to the cursor");
+        helper.assertTrue(desk.getItem(1).isEmpty() && ItemStack.matches(menu.getCarried(), page),
+                "Extracting a loose page must empty its tab and return the same item");
         helper.succeed();
     }
 }

src/main/java/net/dnorberg/rivencraft/menu/WritingDeskMenu.java

@@ -29,14 +29,27 @@ import net.minecraft.world.item.Items;
 
 public final class WritingDeskMenu extends AbstractContainerMenu {
     public static final int COPY_RESULT = WritingDeskBlockEntity.SIZE;
+    public static final int VISIBLE_TABS = 4;
+    public static final int PREVIOUS_TABS = 90;
+    public static final int NEXT_TABS = 91;
+    public static final int PAGE_BUTTON_BASE = 128;
+    public static final int CATALOG_BUTTON_BASE = 512;
+    public static final int ALL_PAGE_BUTTON_BASE = 32768;
+    public static final int PLACE_PAGE_BUTTON_BASE = 65536;
+    private static final int PAGE_ADDRESS_COUNT = WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES;
+    public static final int MOVE_PAGE_BUTTON_BASE = PLACE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT;
     private static final int PLAYER_START = COPY_RESULT + 1;
+    private static final int EXTRACT_TARGET_COUNT = PLAYER_START + 36 + 1;
+    public static final int EXTRACT_PAGE_BUTTON_BASE = MOVE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * PAGE_ADDRESS_COUNT;
     private final Container desk;
     private final WritingDeskBlockEntity blockEntity;
     private final SimpleContainer result = new SimpleContainer(1);
     private final boolean clientSide;
     private int syncedActiveCollection;
     private int syncedInkRemaining;
+    private int firstVisibleTab;
     private int selectedPage;
+    private int selectedCollection = -1;
     private ResourceLocation selectedSymbol;
     private List<SymbolDisplayMetadata> catalog = List.of();
     private final ServerPlayer serverViewer;
@@ -54,6 +67,11 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
         this.clientSide = inventory.player.level().isClientSide;
         this.serverViewer = inventory.player instanceof ServerPlayer serverPlayer ? serverPlayer : null;
         if (blockEntity != null && !clientSide) catalog = WritingDeskCatalog.available(blockEntity);
+        firstVisibleTab = blockEntity == null ? 0 : blockEntity.activeCollection() / VISIBLE_TABS * VISIBLE_TABS;
+        addDataSlot(new DataSlot() {
+            @Override public int get() { return firstVisibleTab; }
+            @Override public void set(int value) { firstVisibleTab = value; }
+        });
         addDataSlot(new DataSlot() {
             @Override public int get() { return WritingDeskMenu.this.blockEntity == null
                     ? syncedActiveCollection : WritingDeskMenu.this.blockEntity.activeCollection(); }
@@ -65,43 +83,94 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
             @Override public void set(int value) { syncedInkRemaining = value; }
         });
         for (int i = 0; i < WritingDeskBlockEntity.COLLECTIONS; i++) {
-            addSlot(new DeskSlot(desk, i, 12, 20 + i * 37, 1));
+            addSlot(new DeskSlot(desk, i, 37, 34 + (i % VISIBLE_TABS) * 37, 1));
         }
-        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.INK, 370, 20, 16));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.INK, 385, 28, 16));
-        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.RETURN, 370, 57, 64));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.RETURN, 385, 80, 64));
-        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.PAPER, 228, 20, 64));
+        addSlot(new DeskSlot(desk, WritingDeskBlockEntity.PAPER, 241, 28, 64));
         addSlot(new DeskSlot(desk, WritingDeskBlockEntity.LEGACY_OUTPUT, -1000, -1000, 64));
-        addSlot(new CopySlot(result, 0, 228, 57));
+        addSlot(new CopySlot(result, 0, 241, 80));
         for (int row = 0; row < 3; row++) {
             for (int column = 0; column < 9; column++) {
-                addSlot(new Slot(inventory, column + row * 9 + 9, 224 + column * 18, 91 + row * 18));
+                addSlot(new Slot(inventory, column + row * 9 + 9, 241 + column * 18, 104 + row * 18));
             }
         }
         for (int column = 0; column < 9; column++) {
-            addSlot(new Slot(inventory, column, 224 + column * 18, 149));
+            addSlot(new Slot(inventory, column, 241 + column * 18, 162));
         }
     }
 
     public int activeCollection() { return syncedActiveCollection; }
+    public int firstVisibleTab() { return firstVisibleTab; }
     public int inkRemaining() { return syncedInkRemaining; }
+    public int pageCapacity(int collectionIndex) {
+        if (collectionIndex < 0 || collectionIndex >= WritingDeskBlockEntity.COLLECTIONS) return 0;
+        ItemStack collection = desk.getItem(collectionIndex);
+        return collection.is(ModItems.NOTEBOOK.get()) ? NotebookContents.MAX_PAGES
+                : collection.is(ModItems.PAGE.get()) ? 1 : 0;
+    }
     public List<SymbolDisplayMetadata> catalog() { return catalog; }
     public void setCatalog(List<SymbolDisplayMetadata> symbols) { catalog = List.copyOf(symbols); }
 
+    public static int movePageButtonId(int sourceCollection, int sourcePage, int targetCollection, int targetPage) {
+        int source = sourceCollection * NotebookContents.MAX_PAGES + sourcePage;
+        int target = targetCollection * NotebookContents.MAX_PAGES + targetPage;
+        return MOVE_PAGE_BUTTON_BASE + source * PAGE_ADDRESS_COUNT + target;
+    }
+
+    /** targetSlot is -1 for the cursor, otherwise a visible player or desk-tab slot. */
+    public static int extractPageButtonId(int sourceCollection, int sourcePage, int targetSlot) {
+        int source = sourceCollection * NotebookContents.MAX_PAGES + sourcePage;
+        return EXTRACT_PAGE_BUTTON_BASE + source * EXTRACT_TARGET_COUNT + targetSlot + 1;
+    }
+
     @Override public boolean clickMenuButton(Player player, int id) {
         if (blockEntity == null || !stillValid(player)) return false;
-        if (id >= 0 && id < WritingDeskBlockEntity.COLLECTIONS) {
+        if (id == PREVIOUS_TABS || id == NEXT_TABS) {
+            firstVisibleTab = Math.clamp(firstVisibleTab + (id == NEXT_TABS ? VISIBLE_TABS : -VISIBLE_TABS),
+                    0, WritingDeskBlockEntity.COLLECTIONS - VISIBLE_TABS);
+            return true;
+        } else if (id >= 0 && id < WritingDeskBlockEntity.COLLECTIONS) {
+            if (id < firstVisibleTab || id >= firstVisibleTab + VISIBLE_TABS) return false;
             blockEntity.setActiveCollection(id);
             selectedPage = 0;
+            selectedCollection = -1;
             selectedSymbol = null;
-        } else if (id >= 16 && id < 16 + NotebookContents.MAX_PAGES) {
+        } else if (id >= EXTRACT_PAGE_BUTTON_BASE
-            selectedPage = id - 16;
+                && id < EXTRACT_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * EXTRACT_TARGET_COUNT) {
+            int offset = id - EXTRACT_PAGE_BUTTON_BASE;
+            int source = offset / EXTRACT_TARGET_COUNT;
+            int targetSlot = offset % EXTRACT_TARGET_COUNT - 1;
+            if (!extractPage(source / NotebookContents.MAX_PAGES, source % NotebookContents.MAX_PAGES,
+                    targetSlot)) return false;
+        } else if (id >= MOVE_PAGE_BUTTON_BASE && id < MOVE_PAGE_BUTTON_BASE + PAGE_ADDRESS_COUNT * PAGE_ADDRESS_COUNT) {
+            int offset = id - MOVE_PAGE_BUTTON_BASE;
+            int source = offset / PAGE_ADDRESS_COUNT;
+            int target = offset % PAGE_ADDRESS_COUNT;
+            if (!movePage(source / NotebookContents.MAX_PAGES, source % NotebookContents.MAX_PAGES,
+                    target / NotebookContents.MAX_PAGES, target % NotebookContents.MAX_PAGES)) return false;
+        } else if (id >= PLACE_PAGE_BUTTON_BASE
+                && id < PLACE_PAGE_BUTTON_BASE + WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES) {
+            int offset = id - PLACE_PAGE_BUTTON_BASE;
+            if (!placeCarriedPage(offset / NotebookContents.MAX_PAGES, offset % NotebookContents.MAX_PAGES)) return false;
+        } else if (id >= PAGE_BUTTON_BASE && id < PAGE_BUTTON_BASE + NotebookContents.MAX_PAGES) {
+            selectedPage = id - PAGE_BUTTON_BASE;
+            selectedCollection = -1;
             selectedSymbol = null;
-        } else if (id >= 100 && id < 100 + catalog.size()) {
+        } else if (id >= ALL_PAGE_BUTTON_BASE && id < ALL_PAGE_BUTTON_BASE + WritingDeskBlockEntity.COLLECTIONS * NotebookContents.MAX_PAGES) {
+            int offset = id - ALL_PAGE_BUTTON_BASE;
+            int collection = offset / NotebookContents.MAX_PAGES;
+            int page = offset % NotebookContents.MAX_PAGES;
+            if (pageAt(collection, page).isEmpty()) return false;
+            selectedCollection = collection;
+            selectedPage = page;
+            selectedSymbol = null;
+        } else if (id >= CATALOG_BUTTON_BASE && id < CATALOG_BUTTON_BASE + catalog.size()) {
             if (!catalog.equals(WritingDeskCatalog.available(blockEntity))) {
                 refreshCatalog();
                 return false;
             }
-            ResourceLocation requested = catalog.get(id - 100).id();
+            ResourceLocation requested = catalog.get(id - CATALOG_BUTTON_BASE).id();
             if (!WritingDeskCatalog.available(blockEntity).stream().anyMatch(entry -> entry.id().equals(requested))) {
                 return false;
             }
@@ -111,6 +180,129 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
         return true;
     }
 
+    private boolean placeCarriedPage(int collectionIndex, int pageIndex) {
+        // Resolve the actual storage position on the server, never a filtered list index.
+        ItemStack carried = getCarried();
+        if (clientSide || !carried.is(ModItems.PAGE.get())) return false;
+        ItemStack collection = desk.getItem(collectionIndex);
+        if (collection.is(ModItems.NOTEBOOK.get())) {
+            var pages = new java.util.ArrayList<>(collection.getOrDefault(
+                    ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages());
+            while (pages.size() <= pageIndex) pages.add(ItemStack.EMPTY);
+            if (!pages.get(pageIndex).isEmpty()) return false;
+            pages.set(pageIndex, carried.copyWithCount(1));
+            ItemStack updated = collection.copy();
+            updated.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(pages));
+            desk.setItem(collectionIndex, updated);
+        } else return false;
+        carried.shrink(1);
+        setCarried(carried.isEmpty() ? ItemStack.EMPTY : carried);
+        selectedCollection = collectionIndex;
+        selectedPage = pageIndex;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
+    private boolean movePage(int sourceCollection, int sourcePage, int targetCollection, int targetPage) {
+        if (!getCarried().isEmpty() || sourceCollection == targetCollection && sourcePage == targetPage) return false;
+        ItemStack sourceBook = desk.getItem(sourceCollection);
+        ItemStack targetBook = desk.getItem(targetCollection);
+        boolean sourceNotebook = sourceBook.is(ModItems.NOTEBOOK.get());
+        boolean targetNotebook = targetBook.is(ModItems.NOTEBOOK.get());
+        if ((!sourceNotebook && (!sourceBook.is(ModItems.PAGE.get()) || sourcePage != 0))
+                || (!targetNotebook && (!targetBook.is(ModItems.PAGE.get()) || targetPage != 0))) return false;
+        var sourcePages = sourceNotebook ? new java.util.ArrayList<>(sourceBook.getOrDefault(
+                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (sourceNotebook && (sourcePage >= sourcePages.size() || sourcePages.get(sourcePage).isEmpty())) return false;
+        ItemStack moving = sourceNotebook ? sourcePages.get(sourcePage) : sourceBook;
+        if (moving.getCount() != 1) return false;
+        if (!targetNotebook && targetBook.getCount() != 1) return false;
+        var targetPages = targetNotebook ? sourceCollection == targetCollection ? sourcePages
+                : new java.util.ArrayList<>(targetBook.getOrDefault(
+                        ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (targetNotebook) while (targetPages.size() <= targetPage) targetPages.add(ItemStack.EMPTY);
+        ItemStack displaced = targetNotebook ? targetPages.get(targetPage) : targetBook;
+        if (targetNotebook) targetPages.set(targetPage, moving);
+        if (sourceNotebook) {
+            sourcePages.set(sourcePage, displaced);
+            ItemStack updatedSource = sourceBook.copy();
+            updatedSource.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(sourcePages));
+            desk.setItem(sourceCollection, updatedSource);
+        } else desk.setItem(sourceCollection, displaced.isEmpty() ? ItemStack.EMPTY : displaced.copyWithCount(1));
+        if (targetNotebook && sourceCollection != targetCollection) {
+            ItemStack updatedTarget = targetBook.copy();
+            updatedTarget.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(targetPages));
+            desk.setItem(targetCollection, updatedTarget);
+        } else if (!targetNotebook) desk.setItem(targetCollection, moving.copyWithCount(1));
+        selectedCollection = targetCollection;
+        selectedPage = targetPage;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
+    private boolean extractPage(int sourceCollection, int sourcePage, int targetSlot) {
+        if (!getCarried().isEmpty() || targetSlot < -1 || targetSlot >= slots.size()) return false;
+        ItemStack sourceBook = desk.getItem(sourceCollection);
+        boolean sourceNotebook = sourceBook.is(ModItems.NOTEBOOK.get());
+        if (!sourceNotebook && (!sourceBook.is(ModItems.PAGE.get()) || sourcePage != 0)) return false;
+        var sourcePages = sourceNotebook ? new java.util.ArrayList<>(sourceBook.getOrDefault(
+                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages()) : null;
+        if (sourceNotebook && (sourcePage >= sourcePages.size() || sourcePages.get(sourcePage).isEmpty())) return false;
+        ItemStack moving = sourceNotebook ? sourcePages.get(sourcePage).copyWithCount(1) : sourceBook.copyWithCount(1);
+        if (!sourceNotebook && sourceBook.getCount() != 1) return false;
+
+        if (targetSlot == -1) {
+            setCarried(moving);
+        } else {
+            if (targetSlot >= WritingDeskBlockEntity.COLLECTIONS && targetSlot < PLAYER_START) return false;
+            Slot target = slots.get(targetSlot);
+            if (!target.isActive() || !target.mayPlace(moving)) return false;
+            ItemStack current = target.getItem();
+            if (targetSlot < WritingDeskBlockEntity.COLLECTIONS && current.is(ModItems.NOTEBOOK.get())) {
+                var targetPages = targetSlot == sourceCollection ? sourcePages
+                        : new java.util.ArrayList<>(current.getOrDefault(
+                                ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages());
+                int position = -1;
+                for (int i = 0; i < NotebookContents.MAX_PAGES; i++) {
+                    if (i >= targetPages.size() || targetPages.get(i).isEmpty()) {
+                        position = i;
+                        break;
+                    }
+                }
+                if (position < 0) return false;
+                while (targetPages.size() <= position) targetPages.add(ItemStack.EMPTY);
+                targetPages.set(position, moving);
+                if (targetSlot != sourceCollection) {
+                    ItemStack updatedTarget = current.copy();
+                    updatedTarget.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(targetPages));
+                    target.setByPlayer(updatedTarget);
+                }
+            } else if (current.isEmpty()) {
+                target.setByPlayer(moving);
+            } else if (targetSlot >= PLAYER_START && ItemStack.isSameItemSameComponents(current, moving)
+                    && current.getCount() < target.getMaxStackSize(moving)) {
+                target.setByPlayer(current.copyWithCount(current.getCount() + 1));
+            } else return false;
+        }
+
+        if (sourceNotebook) {
+            sourcePages.set(sourcePage, ItemStack.EMPTY);
+            ItemStack updatedSource = sourceBook.copy();
+            updatedSource.set(ModDataComponents.NOTEBOOK_CONTENTS.get(), new NotebookContents(sourcePages));
+            desk.setItem(sourceCollection, updatedSource);
+        } else desk.setItem(sourceCollection, ItemStack.EMPTY);
+        selectedCollection = sourceCollection;
+        selectedPage = sourcePage;
+        selectedSymbol = null;
+        refreshCatalog();
+        broadcastChanges();
+        return true;
+    }
+
     @Override public boolean stillValid(Player player) {
         return blockEntity != null && blockEntity.stillValid(player);
     }
@@ -130,6 +322,7 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
             return copy;
         }
         Slot slot = slots.get(index);
+        if (!slot.isActive()) return ItemStack.EMPTY;
         if (!slot.hasItem()) return ItemStack.EMPTY;
         ItemStack moving = slot.getItem();
         ItemStack original = moving.copy();
@@ -144,12 +337,13 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
     }
 
     private boolean moveIntoDesk(ItemStack moving) {
-        if (moving.is(ModItems.INK_VIAL.get())) return moveItemStackTo(moving, 4, 5, false);
+        if (moving.is(ModItems.INK_VIAL.get())) return moveItemStackTo(moving,
-        if (moving.is(ModItems.NOTEBOOK.get())) return moveItemStackTo(moving, 0, 4, false);
+                WritingDeskBlockEntity.INK, WritingDeskBlockEntity.INK + 1, false);
+        if (moving.is(ModItems.NOTEBOOK.get())) return moveItemStackTo(moving, firstVisibleTab, firstVisibleTab + VISIBLE_TABS, false);
         if (moving.is(Items.PAPER))
             return moveItemStackTo(moving, WritingDeskBlockEntity.PAPER,
                     WritingDeskBlockEntity.PAPER + 1, false);
-        if (moving.is(ModItems.PAGE.get())) return moveItemStackTo(moving, 0, 4, false);
+        if (moving.is(ModItems.PAGE.get())) return moveItemStackTo(moving, firstVisibleTab, firstVisibleTab + VISIBLE_TABS, false);
         return false;
     }
 
@@ -162,12 +356,20 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
                     .anyMatch(entry -> entry.id().equals(selectedSymbol))
                     ? PageItem.createSymbolPage(reference) : ItemStack.EMPTY;
         }
-        ItemStack collection = desk.getItem(blockEntity == null ? syncedActiveCollection : blockEntity.activeCollection());
+        int collectionIndex = selectedCollection >= 0 ? selectedCollection
-        if (collection.is(ModItems.PAGE.get())) return selectedPage == 0 ? collection : ItemStack.EMPTY;
+                : blockEntity == null ? syncedActiveCollection : blockEntity.activeCollection();
+        return pageAt(collectionIndex, selectedPage);
+    }
+
+    private ItemStack pageAt(int collectionIndex, int pageIndex) {
+        if (collectionIndex < 0 || collectionIndex >= WritingDeskBlockEntity.COLLECTIONS
+                || pageIndex < 0 || pageIndex >= NotebookContents.MAX_PAGES) return ItemStack.EMPTY;
+        ItemStack collection = desk.getItem(collectionIndex);
+        if (collection.is(ModItems.PAGE.get())) return pageIndex == 0 ? collection : ItemStack.EMPTY;
         if (collection.is(ModItems.NOTEBOOK.get())) {
             List<ItemStack> pages = collection.getOrDefault(
                     ModDataComponents.NOTEBOOK_CONTENTS.get(), NotebookContents.EMPTY).pages();
-            return selectedPage < pages.size() ? pages.get(selectedPage) : ItemStack.EMPTY;
+            return pageIndex < pages.size() ? pages.get(pageIndex) : ItemStack.EMPTY;
         }
         return ItemStack.EMPTY;
     }
@@ -181,6 +383,7 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
 
     private void refreshOutput() {
         if (clientSide) return;
+        if (blockEntity != null) blockEntity.setDisplayPage(selectedSource());
         ItemStack preview = canCopy() ? selectedSource().copyWithCount(1) : ItemStack.EMPTY;
         if (!ItemStack.matches(result.getItem(0), preview)) result.setItem(0, preview);
     }
@@ -210,6 +413,7 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
         }
         refreshCatalog();
         refreshOutput();
+        if (slotId >= 0 && slotId < slots.size() && !slots.get(slotId).isActive()) return;
         super.clicked(slotId, button, clickType, player);
     }
 
@@ -225,13 +429,19 @@ public final class WritingDeskMenu extends AbstractContainerMenu {
         }
     }
 
-    private static final class DeskSlot extends Slot {
+    private final class DeskSlot extends Slot {
         private final int limit;
         private DeskSlot(Container container, int index, int x, int y, int limit) {
             super(container, index, x, y);
             this.limit = limit;
         }
-        @Override public boolean mayPlace(ItemStack stack) { return container.canPlaceItem(getContainerSlot(), stack); }
+        @Override public boolean isActive() {
+            int slot = getContainerSlot();
+            return slot >= WritingDeskBlockEntity.COLLECTIONS
+                    || slot >= firstVisibleTab && slot < firstVisibleTab + VISIBLE_TABS;
+        }
+        @Override public boolean mayPickup(Player player) { return isActive(); }
+        @Override public boolean mayPlace(ItemStack stack) { return isActive() && container.canPlaceItem(getContainerSlot(), stack); }
         @Override public int getMaxStackSize() { return limit; }
     }
 }

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

@@ -49,7 +49,7 @@ public final class ModNetworking {
     }
 
     public static void register(RegisterPayloadHandlersEvent event) {
-        PayloadRegistrar registrar = event.registrar("10");
+        PayloadRegistrar registrar = event.registrar("11");
         registrar.playToServer(RequestDescriptiveBookScreenPayload.TYPE, RequestDescriptiveBookScreenPayload.STREAM_CODEC,
                 ModNetworking::requestDescriptiveBookScreen);
         registrar.playToClient(OpenDescriptiveBookScreenPayload.TYPE, OpenDescriptiveBookScreenPayload.STREAM_CODEC,

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

@@ -19,7 +19,7 @@ public final class ModBlocks {
     );
     public static final DeferredBlock<WritingDeskBlock> WRITING_DESK = BLOCKS.registerBlock(
             "writing_desk", WritingDeskBlock::new,
-            BlockBehaviour.Properties.ofFullCopy(Blocks.CRAFTING_TABLE)
+            BlockBehaviour.Properties.ofFullCopy(Blocks.CRAFTING_TABLE).noOcclusion()
     );
 
     private ModBlocks() {

src/main/resources/assets/rivencraft/blockstates/writing_desk.json

@@ -1,8 +1,12 @@
 {
   "variants": {
-    "facing=north": { "model": "rivencraft:block/writing_desk" },
+    "facing=north,extension=false": {"model":"rivencraft:block/writing_desk"},
-    "facing=east": { "model": "rivencraft:block/writing_desk", "y": 90 },
+    "facing=east,extension=false": {"model":"rivencraft:block/writing_desk","y":90},
-    "facing=south": { "model": "rivencraft:block/writing_desk", "y": 180 },
+    "facing=south,extension=false": {"model":"rivencraft:block/writing_desk","y":180},
-    "facing=west": { "model": "rivencraft:block/writing_desk", "y": 270 }
+    "facing=west,extension=false": {"model":"rivencraft:block/writing_desk","y":270},
+    "facing=north,extension=true": {"model":"rivencraft:block/writing_desk_extension"},
+    "facing=east,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":90},
+    "facing=south,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":180},
+    "facing=west,extension=true": {"model":"rivencraft:block/writing_desk_extension","y":270}
   }
 }

src/main/resources/assets/rivencraft/models/block/writing_desk.json

@@ -1,69 +1,62 @@
 {
-  "parent": "minecraft:block/block",
+	"format_version": "26.3",
-  "ambientocclusion": false,
+	"credit": "Made with Blockbench",
-  "textures": {
+	"parent": "minecraft:block/block",
-    "particle": "rivencraft:block/writing_desk",
+	"textures": {
-    "desk": "rivencraft:block/writing_desk"
+		"2": "rivencraft:block/writing_desk",
-  },
+		"particle": "rivencraft:block/writing_desk"
-  "elements": [
+	},
-    {
+	"elements": [
-      "from": [0, 8, 0], "to": [16, 9, 16],
+		{
-      "faces": {
+			"from": [0, 11, 0],
-        "up": {"uv": [1, 0, 3, 2], "texture": "#desk"},
+			"to": [16, 12, 16],
-        "down": {"uv": [1, 2, 3, 4], "texture": "#desk"},
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 3, 0]},
-        "north": {"uv": [1, 0, 3, 0.125], "texture": "#desk"},
+			"faces": {
-        "south": {"uv": [1, 0, 3, 0.125], "texture": "#desk"},
+				"north": {"uv": [1, 2, 2, 2.125], "texture": "#2"},
-        "east": {"uv": [1, 0, 3, 0.125], "texture": "#desk"},
+				"east": {"uv": [2.82031, 4.01563, 3.82031, 4.125], "texture": "#2"},
-        "west": {"uv": [1, 0, 3, 0.125], "texture": "#desk"}
+				"south": {"uv": [0, 2, 1, 2.125], "texture": "#2"},
-      }
+				"west": {"uv": [2.9375, 0.125, 3, 2.125], "rotation": 90, "texture": "#2"},
-    },
+				"up": {"uv": [1, 0, 2, 2], "texture": "#2"},
-    {
+				"down": {"uv": [3, 0, 3.9375, 2], "texture": "#2"}
-      "from": [0, 0, 1], "to": [2, 8, 15],
+			}
-      "faces": {
+		},
-        "north": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+		{
-        "south": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+			"from": [0, 0, 1],
-        "east": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+			"to": [1, 11, 15],
-        "west": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"}
+			"faces": {
-      }
+				"north": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
-    },
+				"east": {"uv": [7.6875, 2.625, 6.6875, 4], "texture": "#2"},
-    {
+				"south": {"uv": [1.42188, 10.78125, 2.4375, 11.85938], "texture": "#2"},
-      "from": [14, 0, 1], "to": [16, 8, 15],
+				"west": {"uv": [5.67969, 2.625, 6.6875, 4], "texture": "#2"},
-      "faces": {
+				"up": {"uv": [0.08594, 10.36719, 1.14063, 11.83594], "texture": "#2"},
-        "north": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+				"down": {"uv": [5.75, 5.25, 5.8125, 7.10938], "texture": "#2"}
-        "south": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+			}
-        "east": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"},
+		},
-        "west": {"uv": [5.625, 0.125, 5.875, 2], "texture": "#desk"}
+		{
-      }
+			"from": [1, 5, 1],
-    },
+			"to": [16, 6, 15],
-    {
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 2, 0]},
-      "from": [1, 3, 2], "to": [15, 4, 14],
+			"faces": {
-      "faces": {
+				"north": {"uv": [3, 2, 3.9375, 2.125], "texture": "#2"},
-        "up": {"uv": [0, 4.25, 3.75, 6.125], "texture": "#desk"},
+				"east": {"uv": [2.8125, 4, 3.75, 4.125], "texture": "#2"},
-        "down": {"uv": [0, 4.25, 3.75, 6.125], "texture": "#desk"},
+				"south": {"uv": [1.35938, 11.71875, 2.44531, 12.71875], "texture": "#2"},
-        "north": {"uv": [0, 4.25, 3.75, 4.5], "texture": "#desk"},
+				"west": {"uv": [0.03125, 11.66406, 0.99219, 12.66406], "texture": "#2"},
-        "south": {"uv": [0, 4.25, 3.75, 4.5], "texture": "#desk"},
+				"up": {"uv": [1.875, 4, 2.8125, 2.125], "texture": "#2"},
-        "east": {"uv": [0, 4.25, 3.75, 4.5], "texture": "#desk"},
+				"down": {"uv": [0.9375, 2.125, 1.875, 4], "texture": "#2"}
-        "west": {"uv": [0, 4.25, 3.75, 4.5], "texture": "#desk"}
+			}
-      }
+		},
-    },
+		{
-    {
+			"from": [0, 0, 15],
-      "from": [1, 9, 14], "to": [15, 15, 16],
+			"to": [16, 11, 16],
-      "faces": {
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, -9, 0]},
-        "north": {"uv": [8, 0, 11.75, 2], "texture": "#desk"},
+			"faces": {
-        "south": {"uv": [8, 0, 11.75, 2], "texture": "#desk"},
+				"north": {"uv": [8.0625, 0, 9.0625, 1.375], "texture": "#2"},
-        "east": {"uv": [8, 0, 8.25, 2], "texture": "#desk"},
+				"east": {"uv": [6.625, 0.125, 6.6875, 1.5], "texture": "#2"},
-        "west": {"uv": [8, 0, 8.25, 2], "texture": "#desk"},
+				"south": {"uv": [5.625, 2.625, 6.625, 4], "texture": "#2"},
-        "up": {"uv": [8, 0, 11.75, 0.25], "texture": "#desk"}
+				"west": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
-      }
+				"up": {"uv": [0, 15, 16, 16], "texture": "#2"},
-    },
+				"down": {"uv": [0, 9.17969, 16, 10.17969], "texture": "#2"}
-    {
+			}
-      "from": [1, 12, 9], "to": [15, 13, 15],
+		}
-      "faces": {
+	]
-        "up": {"uv": [8, 3.625, 11.75, 4.375], "texture": "#desk"},
-        "down": {"uv": [8, 3.625, 11.75, 4.375], "texture": "#desk"},
-        "north": {"uv": [8, 3.625, 11.75, 3.75], "texture": "#desk"},
-        "south": {"uv": [8, 3.625, 11.75, 3.75], "texture": "#desk"}
-      }
-    }
-  ]
 }

src/main/resources/assets/rivencraft/models/block/writing_desk_extension.json

@@ -0,0 +1,88 @@
+{
+	"format_version": "26.3",
+	"credit": "Made with Blockbench",
+	"parent": "minecraft:block/block",
+	"textures": {
+		"2": "rivencraft:block/writing_desk",
+		"particle": "rivencraft:block/writing_desk"
+	},
+	"elements": [
+		{
+			"from": [1, 0, 1],
+			"to": [15, 1, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [1, 0, 0]},
+			"faces": {
+				"north": {"uv": [1.8125, 4.125, 2.8125, 4.25], "texture": "#2"},
+				"east": {"uv": [0.21875, 11.88281, 1.04688, 12.88281], "texture": "#2"},
+				"south": {"uv": [1.53906, 10.5625, 2.63281, 11.5625], "texture": "#2"},
+				"west": {"uv": [0.14063, 10.5625, 1.17969, 11.5625], "texture": "#2"},
+				"up": {"uv": [1.8125, 4.125, 2.8125, 2.125], "texture": "#2"},
+				"down": {"uv": [4, 0, 5, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 11, 0],
+			"to": [16, 12, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, 3, 0]},
+			"faces": {
+				"north": {"uv": [2, 2, 3, 2.125], "texture": "#2"},
+				"east": {"uv": [1, 0, 1.0625, 2], "rotation": 90, "texture": "#2"},
+				"south": {"uv": [3, 2, 4, 2.125], "texture": "#2"},
+				"west": {"uv": [2.8125, 4, 3.8125, 4.125], "texture": "#2"},
+				"up": {"uv": [2, 0, 3, 2], "texture": "#2"},
+				"down": {"uv": [9, 0, 10, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [15, 0, 1],
+			"to": [16, 11, 15],
+			"faces": {
+				"north": {"uv": [7.6875, 2.625, 7.75, 4], "texture": "#2"},
+				"east": {"uv": [10.00156, 0.625, 11.00156, 2], "texture": "#2"},
+				"south": {"uv": [1.99219, 10.77344, 2.99219, 12.02344], "texture": "#2"},
+				"west": {"uv": [6.6875, 2.625, 7.6875, 4], "texture": "#2"},
+				"up": {"uv": [0.49219, 10.96094, 1.49219, 12.08594], "texture": "#2"},
+				"down": {"uv": [5.75313, 5.36719, 5.8125, 7.125], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 1],
+			"to": [1, 11, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [-15, 0, 0]},
+			"faces": {
+				"north": {"uv": [7.68828, 2.625, 7.75078, 4], "texture": "#2"},
+				"east": {"uv": [7.6875, 2.62539, 6.6875, 4.00039], "texture": "#2"},
+				"south": {"uv": [0.05469, 12.22656, 1.05469, 13.32031], "texture": "#2"},
+				"west": {"uv": [3, 0, 4, 1.375], "texture": "#2"},
+				"up": {"uv": [0.15625, 10.83594, 1.15625, 11.97656], "texture": "#2"},
+				"down": {"uv": [7, 4.60156, 7.0625, 6.375], "texture": "#2"}
+			}
+		},
+		{
+			"from": [1, 5, 1],
+			"to": [15, 6, 15],
+			"rotation": {"angle": 0, "axis": "y", "origin": [1, 2, 0]},
+			"faces": {
+				"north": {"uv": [1.8125, 4.25, 2.8125, 4.125], "texture": "#2"},
+				"east": {"uv": [1.86719, 11.82813, 2.79688, 12.82813], "texture": "#2"},
+				"south": {"uv": [0.32813, 11.80469, 1.28906, 12.80469], "texture": "#2"},
+				"west": {"uv": [0.27344, 10.5625, 1.53125, 11.5625], "texture": "#2"},
+				"up": {"uv": [1.8125, 4.125, 2.8125, 2.125], "texture": "#2"},
+				"down": {"uv": [9, 0, 10, 2], "texture": "#2"}
+			}
+		},
+		{
+			"from": [0, 0, 15],
+			"to": [16, 11, 16],
+			"rotation": {"angle": 0, "axis": "y", "origin": [0, -9, 0]},
+			"faces": {
+				"north": {"uv": [9, 0.125, 10, 1.5], "texture": "#2"},
+				"east": {"uv": [10.8125, 0.625, 10.875, 2], "texture": "#2"},
+				"south": {"uv": [10.875, 0.625, 11.875, 2], "texture": "#2"},
+				"west": {"uv": [6.6875, 0.125, 6.75, 1.5], "texture": "#2"},
+				"up": {"uv": [0, 15, 16, 16], "texture": "#2"},
+				"down": {"uv": [2.8125, 4, 3.8125, 4.125], "texture": "#2"}
+			}
+		}
+	]
+}

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

@@ -1,3 +1,4 @@
 {
-  "parent": "rivencraft:block/writing_desk"
+  "parent": "minecraft:item/generated",
+  "textures": {"layer0": "rivencraft:item/writing_desk"}
 }