Changing Table

Changing Table

A placed 2-block furniture item. Players right-click the top to lie down in a sleeping pose (for a diaper change), right-click any side or bottom to open a small storage inventory, and recolor it by right-clicking with a carpet. Left-click (punch) to break it down.

Gated behind the Nursery_Items global flag — when off, the recipe doesn’t register, the listener no-ops, and /debug give errors gracefully.

Package layout

All in com.storynook.furniture.changingtable:

Class	Role
ChangingTable	Immutable record — one placed table. Anchor cell + yaw; foot cell is derived from yaw, never stored.
ChangingTableRegistry	Static color registry (16 colors → CMD) + per-world live-table index (byBarrierBlock, ward occupancy).
ChangingTablePdcKeys	NamespacedKey bundle for PDC + the accidentprone.changing_table scoreboard tag.
ChangingTableListener	All Bukkit event handlers — placement, right-click dispatch, break, explosion/chunk handling, lay-down seating, movement lock.
ChangingTablePlacementService	Pure-Java placement math: footOffset(yaw), the validation predicate.
ChangingTableItem	Builds the slime_ball CustomModelData item for a given color.
ChangingTableRecipes / ChangingTableRecipeMatrixValidator / ChangingTableCraftingListener	Crafting: one shaped recipe per color, validated by a matrix check.
ChangingTableInventoryManager	Per-table 9-slot inventory, YAML-persisted at <dataFolder>/ChangingTables/<tableUuid>.yml.
ChangingTableInventoryFilter	isStorable(ItemStack) — only clean changing supplies are accepted; dirty/worn items rejected.
LaydownPoseNpc	GSit-style packet-only NPC clone that renders the lying-down body. See below.

CMD allocation

CMD = 630100 + colorIndex. Range reserved: 630100–630199 (100 slots; 16 used). The item base material is SLIME_BALL — it needs a range_dispatch entry in the resource pack’s items/slime_ball.json or it renders as a plain slimeball.

Placement

Right-click the top face of a solid block while holding a changing-table item:

1. Yaw is snapped to the nearest cardinal (ChangingTablePlacementService.snapYaw). footOffset(yaw) gives the foot cell — it sits to the player’s left of the anchor cell.
2. Both cells above the clicked block must be air, the player must not be standing in them, and both base blocks must be solid (validate(...)).
3. A synthetic BlockPlaceEvent per cell lets protection plugins (WorldGuard etc.) veto — silent no-op on veto, item retained.
4. Two BARRIER blocks are placed (anchor cell + foot cell).
5. One ItemDisplay (the visible model) plus two Interaction entities (one per barrier cell) are spawned. All three are persistent and the interactions carry the full table PDC + scoreboard tag.

Display transform tuning

The visible model is an ItemDisplay in NONE transform mode. Its placement is driven by named constants at the top of ChangingTableListener — tune these, no model-file edit needed:

Constant	Purpose
SCALE_X / SCALE_Y / SCALE_Z	Per-axis scale. Non-uniform — stretches the model’s native 1.125 × 0.625 × 0.578 block bounds to a 2-wide × 1-tall × 1-deep table.
TABLE_Y_LIFT	Vertical offset in the display translation so the base sits on the ground.
TABLE_BACK_SHIFT / TABLE_RIGHT_SHIFT	Empirical world-space nudge (relative to placer facing) to seat the model on the barrier cells.

The model rotation is (180 - yaw) around +Y — correct for all four cardinal placements.

Right-click dispatch

onInteractEntity fires on a tagged Interaction. resolveClickedFace determines which of the 6 box faces was hit (the click lands exactly on one face plane — it does not use largest-axis-magnitude, which would misread the upper half of a side as the top):

• Carpet in hand → recolor (swap the ItemDisplay’s item, rewrite PDC on both interactions, return the old carpet). Same color = silent no-op.
• Top face, empty hand → self lay-down.
• Top face, carrying a ward → caregiver lay-down (the carried ward is laid; saddle returned to caregiver).
• Any other face → open the storage inventory.

Interaction hitbox

Bukkit’s Interaction hitbox is square (width × width × height), so a single entity can’t be 2×1. Instead two interactions are spawned, one centered on each barrier cell — together they mirror the two barrier blocks. Size is set by INTERACTION_WIDTH / INTERACTION_HEIGHT (1.1 — slightly over 1.0 so they’re easy to click).

Lay-down — LaydownPoseNpc

The lying body is not the real player and not a real bed. The real player is teleported onto the mat, made invisible + no-gravity + movement-locked, and a packet-only fake ServerPlayer clone is broadcast to nearby viewers in Pose.SLEEPING. This is the GSit /lay approach — see GSit’s mcv/v1_21_4/.../model/Pose.java.

Why a clone instead of posing the real player: setting Pose.SLEEPING on the real player either fights the server’s per-tick updatePlayerPose() (clip-in/out) or triggers the client-side “Leave Bed” overlay / day-skip. A separate packet NPC has none of those side effects — no chat, no screen darken, no phantom skip.

Key implementation details (all NMS via reflection, so the plugin still builds against the Bukkit API):

• Fake bed packet — a client-only ClientboundBlockUpdatePacket places a WHITE_BED at world-min under the mat, so the client’s sleeping-pose renderer has an orientation anchor.
• Triple teleport — ClientboundTeleportEntityPacket is sent in the spawn bundle and again at tick+1 and tick+2, to out-shout the client’s LivingEntity tick that re-snaps the entity to sleepingPos. Without this the body clips in and out.
• Per-tick maintenance (perTick(), driven by a 1-tick BukkitTask):
  • re-broadcasts an empty-equipment packet for the real (invisible) player so Paper’s auto-resync doesn’t make their gear reappear,
  • mirrors the real player’s live equipment onto the clone (broadcastNpcEquipment — all 6 slots; removing the ward’s leggings mid-laydown clears them from the clone within a tick),
  • re-asserts setInvisible(true) on the real player.
• Nameplate hide — the clone’s random profile name (ld_<uuid8>) is added to a packet-only NMS PlayerTeam with NameTagVisibility.NEVER, broadcast per-viewer in the spawn bundle. Bukkit’s main-scoreboard auto-sync proved unreliable for this.
• Body alignment — LAY_Y_OFFSET (vertical) and LAY_XZ_OFFSET (along the bed-facing axis) tune where the body lands on the mat.

Release is triggered by sneak, teleport, death, world-change, or quit. onJoinStuckLaydown defensively clears stuck invisible / no-gravity / sleep-ignored flags on join — and onQuit restores them before the NBT save so a disconnect mid-laydown doesn’t persist a broken state.

Storage inventory

9 slots (1 row), title “Changing Table”. ChangingTableInventoryFilter.isStorable rejects anything that isn’t a clean changing supply; a close-time sweep ejects violators back to the player. Persisted as YAML per table UUID; loadOrCreate guards slot < SLOTS, so a table whose YAML predates the 9-slot size silently drops the overflow slots.

Teardown

teardown(table) is idempotent and reached from several paths:

• Attack a tagged Interaction (onAttackInteraction) — the normal break path. The interactions cover the barrier cells, so a left-click raycast hits an interaction before the block; we treat that attack as the break request.
• onLeftClickBarrier — fallback LEFT_CLICK_BLOCK path (still reachable from some angles / for the explosion + WorldEdit cases).
• onBarrierBreak (MONITOR BlockBreakEvent), explosions, chunk load orphan-cleanup.

Teardown releases any ward on the table, drops + deletes the inventory YAML, removes the ItemDisplay and both Interaction entities (found by scanning the two barrier cells, since only one UUID is stored in the record), clears the barriers, and drops the table item.

Bug-prone areas

• Two interactions, one stored UUID. The record’s interactionUuid is just whichever one fromPdc happened to read. Anything that needs to mutate or remove the interactions (teardown, recolor) must use findInteractions(table) to get both.
• LaydownPoseNpc is reflection-heavy. If a Paper revision renames an NMS symbol, init() logs once and the helper becomes a silent no-op for the JVM lifetime — lay-down just won’t render.
• Build hygiene. Always mvn clean package -Dmaven.test.skip=true and verify the jar has no Unresolved compilation problem stubs before deploying — an IDE auto-build can poison target/classes.