World packets

Server-to-client records about blocks, chunks, light, the world border, time, weather, sounds, particles and explosions. Every one arrives through PacketReceiveEvent.packet(); positions are in blocks, chunk coordinates are blocks/16, rotations are degrees and ticks run 20 per second — threads, cancelling and what a decode drops are on Packets.

on<PacketReceiveEvent> { e ->
    val packet = e.packet()
    if (packet !is S2CBlockUpdatePacket) return@on

    // a block somewhere turned into air
    if (packet.block() == "minecraft:air") log("${packet.x()} ${packet.y()} ${packet.z()}")
}

#S2CBlockBreakingProgressPacket

Break-progress overlay for a block another entity is mining.

#S2CBlockEntityUpdatePacket

Block entity data for one position.

#S2CBlockEventPacket

Block action — note block ping, chest lid, piston push, bell ring.

#S2CBlockUpdatePacket

Single block change; only the block id survives, not the state properties.

#S2CBlockValueDebugPacket

Debug block-value push; the value payload is not exposed.

#S2CChunkBiomeDataPacket

Biome-only chunk resend; no components.

#S2CChunkDataPacket

Full chunk send; sections, block entities, heightmaps and light are not exposed.

#S2CChunkDeltaUpdatePacket

Several block changes inside one 16x16x16 chunk section.

#S2CChunkDeltaUpdatePacket.BlockChange

One block change inside a chunk-delta update.

#S2CChunkLoadDistancePacket

Server-side view distance change.

#S2CChunkRenderDistanceCenterPacket

New center chunk for chunk loading.

#S2CChunkSentPacket

End of a chunk batch; answered with C2SAcknowledgeChunksPacket.

#S2CChunkValueDebugPacket

Debug chunk-value push; the value payload is not exposed.

#S2CDifficultyPacket

World difficulty sync.

#S2CExplosionPacket

Explosion effect; particle type, sound and the destroyed-block list are not exposed.

#S2CGameJoinPacket

Initial join info for the play phase.

#S2CGameStateChangePacket

Game-state change value; the reason is not exposed, so the value alone is ambiguous.

#S2CGameTestHighlightPosPacket

Game-test debug position highlight.

#S2CLightUpdatePacket

Chunk light data; the light arrays are not exposed.

#S2CMapUpdatePacket

Filled-map update; pixel colors, icons and the updated rectangle are not exposed.

#S2CParticlePacket

Particle spawn request; the particle type and its parameters are not exposed.

#S2CPlaySoundFromEntityPacket

Sound anchored to an entity.

#S2CPlaySoundPacket

Positional sound.

#S2CSimulationDistancePacket

Server simulation distance change.

#S2CStartChunkSendPacket

Start of a chunk batch; no components.

#S2CStopSoundPacket

Stops playing sounds.

#S2CTestInstanceBlockStatusPacket

Test instance block status report.

#S2CTickStepPacket

How many ticks to step while the world is frozen.

#S2CUnloadChunkPacket

Chunk removed from the client world.

#S2CUpdateTickRatePacket

Server tick rate and freeze state.

#S2CWaypointPacket

Locator-bar waypoint change; the waypoint id and its data are not exposed.

#S2CWorldBorderCenterChangedPacket

World border center moved.

#S2CWorldBorderInitializePacket

Full world border state, sent on join.

#S2CWorldBorderInterpolateSizePacket

World border starts resizing over time.

#S2CWorldBorderSizeChangedPacket

World border resized instantly.

#S2CWorldBorderWarningBlocksChangedPacket

World border warning distance changed.

#S2CWorldBorderWarningTimeChangedPacket

World border warning lead time changed.

#S2CWorldEventPacket

World event — block break sound and particles, door, portal, dispenser.

#S2CWorldTimeUpdatePacket

World time sync.