Difference between revisions of "Pre-release protocol"

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This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently [[Protocol version numbers|1.8.8, protocol 47]]) to the current pre-release (currently [[Protocol version numbers|15w31c, protocol 51]]). Note that this page contains bleeding-edge information that may not be completely or correctly documented.
+
This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently [[Protocol version numbers|1.14.4, protocol 498]]) to the current pre-release (currently [[Protocol version numbers|1.15.2, protocol 578]]). Note that this page contains bleeding-edge information that may not be completely or correctly documented.
  
 
One who wishes to commandeer the merging of this into [[Protocol]] when an update is made must be sure to respect any changes that may have occurred to the respective packets there.
 
One who wishes to commandeer the merging of this into [[Protocol]] when an update is made must be sure to respect any changes that may have occurred to the respective packets there.
  
== Protocol history ==
+
== Contents ==
  
None so far.
+
<div style="float:right;">__TOC__</div>
  
== New/modified data types ==
+
=== Data types ===
 +
 
 +
No changes so far.
  
None so far.
+
=== Packets ===
  
== Handshaking ==
+
{| class="wikitable"
 +
! ID
 +
! Packet name
 +
!colspan="2"| Documentation
 +
|-
 +
!colspan="4"| Handshaking serverbound
 +
{{PacketList|0x00|Handshake}}
 +
|-
 +
!colspan="4"| Play clientbound
 +
{{PacketList|0x03|Spawn Mob}}
 +
{{PacketList|0x05|Spawn Player}}
 +
{{PacketList|{{change|0x5C|0x08}}|Acknowledge Player Digging|pre=unchanged}}
 +
{{PacketList|{{change|0x08|0x09}}|Block Break Animation|pre=unchanged}}
 +
{{PacketList|{{change|0x09|0x0A}}|Update Block Entity}}
 +
{{PacketList|{{change|0x0A|0x0B}}|Block Action|pre=unchanged}}
 +
{{PacketList|{{change|0x0B|0x0C}}|Block Change|pre=unchanged}}
 +
{{PacketList|{{change|0x0C|0x0D}}|Boss Bar|pre=unchanged}}
 +
{{PacketList|{{change|0x0D|0x0E}}|Server Difficulty|pre=unchanged}}
 +
{{PacketList|{{change|0x0E|0x0F}}|Chat Message (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x0F|0x10}}|Multi Block Change|pre=unchanged}}
 +
{{PacketList|{{change|0x10|0x11}}|Tab-Complete (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x11|0x12}}|Declare Commands|pre=unchanged}}
 +
{{PacketList|{{change|0x12|0x13}}|Confirm Transaction (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x13|0x14}}|Close Window (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x14|0x15}}|Window Items|pre=unchanged}}
 +
{{PacketList|{{change|0x15|0x16}}|Window Property|pre=unchanged}}
 +
{{PacketList|{{change|0x16|0x17}}|Set Slot|pre=unchanged}}
 +
{{PacketList|{{change|0x17|0x18}}|Set Cooldown|pre=unchanged}}
 +
{{PacketList|{{change|0x18|0x19}}|Plugin Message (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x19|0x1A}}|Named Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x1A|0x1B}}|Disconnect (play)|pre=unchanged}}
 +
{{PacketList|{{change|0x1B|0x1C}}|Entity Status|pre=unchanged}}
 +
{{PacketList|{{change|0x1C|0x1D}}|Explosion|pre=unchanged}}
 +
{{PacketList|{{change|0x1D|0x1E}}|Unload Chunk|pre=unchanged}}
 +
{{PacketList|{{change|0x1E|0x1F}}|Change Game State}}
 +
{{PacketList|{{change|0x1F|0x20}}|Open Horse Window|pre=unchanged}}
 +
{{PacketList|{{change|0x20|0x21}}|Keep Alive (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x21|0x22}}|Chunk Data}}
 +
{{PacketList|{{change|0x22|0x23}}|Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x23|0x24}}|Particle}}
 +
{{PacketList|{{change|0x24|0x25}}|Update Light|pre=unchanged}}
 +
{{PacketList|{{change|0x25|0x26}}|Join Game}}
 +
{{PacketList|{{change|0x26|0x27}}|Map Data|pre=unchanged}}
 +
{{PacketList|{{change|0x27|0x28}}|Trade List|pre=unchanged}}
 +
{{PacketList|{{change|0x28|0x29}}|Entity Relative Move|pre=unchanged}}
 +
{{PacketList|{{change|0x29|0x2A}}|Entity Look And Relative Move|pre=unchanged}}
 +
{{PacketList|{{change|0x2A|0x2B}}|Entity Look|pre=unchanged}}
 +
{{PacketList|{{change|0x2B|0x2C}}|Entity|pre=unchanged}}
 +
{{PacketList|{{change|0x2C|0x2D}}|Vehicle Move (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x2D|0x2E}}|Open Book|pre=unchanged}}
 +
{{PacketList|{{change|0x2E|0x2F}}|Open Window|pre=unchanged}}
 +
{{PacketList|{{change|0x2F|0x30}}|Open Sign Editor|pre=unchanged}}
 +
{{PacketList|{{change|0x30|0x31}}|Craft Recipe Response|pre=unchanged}}
 +
{{PacketList|{{change|0x31|0x32}}|Player Abilities (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x32|0x33}}|Combat Event|pre=unchanged}}
 +
{{PacketList|{{change|0x33|0x34}}|Player Info|pre=unchanged}}
 +
{{PacketList|{{change|0x34|0x35}}|Face Player|pre=unchanged}}
 +
{{PacketList|{{change|0x35|0x36}}|Player Position And Look (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x36|0x37}}|Unlock Recipes|pre=unchanged}}
 +
{{PacketList|{{change|0x37|0x38}}|Destroy Entities|pre=unchanged}}
 +
{{PacketList|{{change|0x38|0x39}}|Remove Entity Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x39|0x3A}}|Resource Pack Send|pre=unchanged}}
 +
{{PacketList|{{change|0x3A|0x3B}}|Respawn}}
 +
{{PacketList|{{change|0x3B|0x3C}}|Entity Head Look|pre=unchanged}}
 +
{{PacketList|{{change|0x3C|0x3D}}|Select Advancement Tab|pre=unchanged}}
 +
{{PacketList|{{change|0x3D|0x3E}}|World Border|pre=unchanged}}
 +
{{PacketList|{{change|0x3E|0x3F}}|Camera|pre=unchanged}}
 +
{{PacketList|{{change|0x3F|0x40}}|Held Item Change (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x40|0x41}}|Update View Position|pre=unchanged}}
 +
{{PacketList|{{change|0x41|0x42}}|Update View Distance|pre=unchanged}}
 +
{{PacketList|{{change|0x42|0x43}}|Display Scoreboard|pre=unchanged}}
 +
{{PacketList|{{change|0x43|0x44}}|Entity Metadata|pre=unchanged}}
 +
{{PacketList|{{change|0x44|0x45}}|Attach Entity|pre=unchanged}}
 +
{{PacketList|{{change|0x45|0x46}}|Entity Velocity|pre=unchanged}}
 +
{{PacketList|{{change|0x46|0x47}}|Entity Equipment|pre=unchanged}}
 +
{{PacketList|{{change|0x47|0x48}}|Set Experience|pre=unchanged}}
 +
{{PacketList|{{change|0x48|0x49}}|Update Health|pre=unchanged}}
 +
{{PacketList|{{change|0x49|0x4A}}|Scoreboard Objective|pre=unchanged}}
 +
{{PacketList|{{change|0x4A|0x4B}}|Set Passengers|pre=unchanged}}
 +
{{PacketList|{{change|0x4B|0x4C}}|Teams|pre=unchanged}}
 +
{{PacketList|{{change|0x4C|0x4D}}|Update Score|pre=unchanged}}
 +
{{PacketList|{{change|0x4D|0x4E}}|Spawn Position|pre=unchanged}}
 +
{{PacketList|{{change|0x4E|0x4F}}|Time Update|pre=unchanged}}
 +
{{PacketList|{{change|0x4F|0x50}}|Title|pre=unchanged}}
 +
{{PacketList|{{change|0x50|0x51}}|Entity Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x51|0x52}}|Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x52|0x53}}|Stop Sound|pre=unchanged}}
 +
{{PacketList|{{change|0x53|0x54}}|Player List Header And Footer|pre=unchanged}}
 +
{{PacketList|{{change|0x54|0x55}}|NBT Query Response|pre=unchanged}}
 +
{{PacketList|{{change|0x55|0x56}}|Collect Item|pre=unchanged}}
 +
{{PacketList|{{change|0x56|0x57}}|Entity Teleport|pre=unchanged}}
 +
{{PacketList|{{change|0x57|0x58}}|Advancements|pre=unchanged}}
 +
{{PacketList|{{change|0x58|0x59}}|Entity Properties|pre=unchanged}}
 +
{{PacketList|{{change|0x59|0x5A}}|Entity Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x5A|0x5B}}|Declare Recipes|pre=unchanged}}
 +
{{PacketList|{{change|0x5B|0x5C}}|Tags|pre=unchanged}}
 +
|}
  
=== Clientbound ===
+
== New/modified data types ==
  
 
No changes so far.
 
No changes so far.
  
=== Serverbound ===
+
== Entity Metadata ==
 +
 
 +
{{#vardefine:meta_prerelease|1}}{{warning2|Lots of shifts, of course}}
  
==== Handshake ====
+
=== Living ===
  
This causes the server to switch into the target state.
+
{{Metadata inherit|Living|inherits=Entity|start_at=7}}
  
 
{| class="wikitable"
 
{| class="wikitable"
  ! Packet ID
+
  ! Index
  ! State
+
  ! Type
  ! Bound To
+
  !style="width: 250px;" colspan="2"| Meaning
  ! Field Name
+
  ! Default
  ! Field Type
+
|-
  ! Notes
+
|rowspan="5"| {{Metadata id|}}
 +
|rowspan="5"| Byte
 +
|colspan="2"| Hand states, used to trigger blocking/eating/drinking animation.
 +
|rowspan="5"| 0
 +
|-
 +
  ! Bit mask
 +
  ! Meaning
 +
|-
 +
| 0x01
 +
| Is hand active
 +
|-
 +
| 0x02
 +
| Active hand (0 = main hand, 1 = offhand)
 +
|-
 +
| 0x04
 +
| In riptide spin attack
 +
|-
 +
| {{Metadata id|}}
 +
| Float
 +
|colspan="2"| Health
 +
| 1.0
 
  |-
 
  |-
  |rowspan="4"| 0x00
+
  | {{Metadata id|}}
|rowspan="4"| Handshaking
 
|rowspan="4"| Server
 
| Protocol Version
 
 
  | VarInt
 
  | VarInt
  | See [[protocol version numbers]] (currently {{Change|47|50}})
+
  |colspan="2"| Potion effect color (or 0 if there is no effect)
 +
| 0
 
  |-
 
  |-
  | Server Address
+
  | {{Metadata id|}}
| String
+
  | Boolean
  | hostname or IP, e.g. localhost or 127.0.0.1<!-- does this support IPv6? -->
+
  |colspan="2"| Is potion effect ambient: reduces the number of particles generated by potions to 1/5 the normal amount
  |-
+
  | false
| Server Port
 
| Unsigned Short
 
  | default is 25565
 
 
  |-
 
  |-
  | Next State
+
  | {{Metadata id|}}
 +
| VarInt
 +
|colspan="2"| Number of arrows in entity
 +
| 0
 +
|- {{Added}}
 +
| {{Metadata id|added}}
 
  | VarInt
 
  | VarInt
  | 1 for [[#Status|status]], 2 for [[#Login|login]]
+
  |colspan="2"| Health added by absorption (based on the AbsorptionAmount tag)
 +
| 0
 +
|-
 +
| {{Metadata id|}}
 +
| OptBlockPos
 +
|colspan="2"| Sleeping location (from SleepingX, SleepingY, SleepingZ tags)
 +
| Absent
 
  |}
 
  |}
  
== Play ==
+
=== Bee ===
  
=== Clientbound ===
+
{{Metadata inherit|Bee|inherits=Insentient|start_at=16}}
  
==== Entity Equipment ====
+
{| class="wikitable" {{added}}
 
+
  ! Index
{| class="wikitable"
+
  ! Type
  ! Packet ID
+
  !style="width: 250px;" colspan="2"| Meaning
  ! State
+
  ! Default
  ! Bound To
+
  |-
  ! Field Name
+
|rowspan="5"| {{Metadata id|}}
  ! Field Type
+
|rowspan="5"| Byte
  ! Notes
+
|colspan="2"| Flags
 +
|rowspan="5"| 0
 +
|-
 +
| 0x01 || ''Unused''
 +
|-
 +
  | 0x02 || Is angry
 
  |-
 
  |-
  |rowspan="3"| 0x04
+
  | 0x04 || Has stung
|rowspan="3"| Play
 
|rowspan="3"| Client
 
| Entity ID
 
| VarInt
 
| Entity's EID
 
 
  |-
 
  |-
  | Slot
+
  | 0x08 || Has nectar
| {{Change|Short|VarInt}}
 
| Equipment slot. 0: main hand, {{Change||1: off hand}}, {{Change|1–4|2–5}}: armor slot (2: boots, 3: leggings, 4: chestplate, 5: helmet)
 
 
  |-
 
  |-
  | Item
+
  | {{Metadata id|}}
  | [[Slot Data|Slot]]
+
| VarInt
  | Item in slot format
+
  | colspan="2"| Anger time in ticks
 +
  | 0 (Not angry)
 
  |}
 
  |}
  
==== Spawn Player ====
+
=== Wolf ===
  
This packet is sent by the server when a player comes into visible range, ''not'' when a player joins.
+
{{Metadata inherit|Wolf|inherits=TameableAnimal|start_at=17|pre_start_at=18}}
  
This packet must be sent after the [[#Player List Item|Player List Item]] ([[#Play|Play]], 0x38, clientbound) packet that adds the player data for the client to use when spawning a player. The tab includes skin/cape data.
+
{| class="wikitable"
 +
! Index
 +
! Type
 +
!style="width: 250px;" colspan="2"| Meaning
 +
! Default
 +
|- {{removed}}
 +
| {{Metadata id|removed}}
 +
| Float
 +
|colspan="2"| Damage taken (used for tail rotation)
 +
| Value of health field (1.0)
 +
|-
 +
| {{Metadata id|}}
 +
| Boolean
 +
|colspan="2"| Is begging
 +
| false
 +
|-
 +
| {{Metadata id|}}
 +
| VarInt
 +
|colspan="2"| Collar color (values are those {{Minecraft Wiki|Data_values#Dyes|used with dyes}})
 +
| 14 (Red)
 +
|}
  
Servers can, however, safely spawn player entities for players not in visible range. The client appears to handle it correctly.
+
=== Enderman ===
  
When in online-mode the UUIDs must be valid and have valid skin blobs, in offline-mode UUID v3 is used.
+
{{Metadata inherit|Wolf|inherits=Monster|start_at=14|pre_start_at=15}}
  
For NPCs UUID v2 should be used. Note:
+
{| class="wikitable"
 +
! Index
 +
! Type
 +
!style="width: 250px;" colspan="2"| Meaning
 +
! Default
 +
|-
 +
| {{Metadata id|}}
 +
| Opt BlockID
 +
|colspan="2"| Carried block
 +
| Absent
 +
|-
 +
| {{Metadata id|}}
 +
| Boolean
 +
|colspan="2"| Is screaming
 +
| false
 +
|- {{added}}
 +
| {{Metadata id|added}}
 +
| Boolean
 +
|colspan="2"| Is stared at
 +
| false
 +
|}
  
<+Grum> i will never confirm this as a feature you know that :)
+
=== Trident ===
  
In an example UUID, <code>xxxxxxxx-xxxx-Yxxx-xxxx-xxxxxxxxxxxx</code>, the UUID version is specified by <code>Y</code>. So, for UUID v3, <code>Y</code> will always be <code>3</code>, and for UUID v2, <code>Y</code> will always be <code>2</code>.
+
{{Metadata inherit|Wolf|inherits=TameableAnimal|start_at=10}}
  
 
{| class="wikitable"
 
{| class="wikitable"
  ! Packet ID
+
  ! Index
  ! State
+
  ! Type
! Bound To
+
  !style="width: 250px;" colspan="2"| Meaning
! Field Name
+
  ! Default
  ! Field Type
 
  ! Notes
 
 
  |-
 
  |-
  |rowspan="9"| 0x0C
+
  | {{Metadata id|}}
|rowspan="9"| Play
 
|rowspan="9"| Client
 
| Entity ID
 
 
  | VarInt
 
  | VarInt
  | Player's EID
+
  |colspan="2"| Loyalty level (enchantment)
|-
+
  | 0
| Player UUID
+
  |- {{Added}}
| UUID
+
  | {{Metadata id|}}
  |  
+
  | Boolean
  |-
+
  |colspan="2"| Has enchantment glint
  | X
+
  | False
| Int
 
| Player X as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
| Y
 
| Int
 
| Player Y as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
  | Z
 
  | Int
 
| Player Z as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
| Yaw
 
| Angle
 
|
 
|-
 
| Pitch
 
| Angle
 
|
 
|- style="background-color: #f4cccc"
 
| Current Item
 
| Short
 
| The item the player is currently holding. Note that this should be 0 for “no item”, unlike -1 used in other packets.
 
|-
 
| Metadata
 
| [[Entities#Entity Metadata Format|Metadata]]
 
  |  
 
 
  |}
 
  |}
  
{{Warning|A negative Current Item crashes clients}}
+
== Block Actions ==
 +
 
 +
No changes so far.
  
{{Warning|The client will crash if no Metadata is sent}}
+
== Inventories ==
  
 +
No changes so far.
  
==== Spawn Object ====
+
== Plugin Channels ==
  
Sent by the server when an object/vehicle is created.
+
No changes so far.
  
{| class="wikitable"
+
== Play ==
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="13"| 0x0E
 
|rowspan="13"| Play
 
|rowspan="13"| Client
 
| Entity ID
 
| VarInt
 
| EID of the object
 
|- style="background-color: #d9ead3;"
 
| Object UUID
 
| UUID
 
|
 
|-
 
| Type
 
| Byte
 
| The type of object (See [[Entities#Objects]])
 
|-
 
| X
 
| Int
 
| X position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
| Y
 
| Int
 
| Y position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
| Z
 
| Int
 
| Z position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
 
|-
 
| Pitch
 
| Angle
 
|
 
|-
 
| Yaw
 
| Angle
 
|
 
|- style="background-color: #f4cccc"
 
| Data
 
| [[Object Data]]
 
|
 
|-  style="background-color: #d9ead3;"
 
| Info
 
| Int
 
| Depends on object [[Object Data]]
 
|-  style="background-color: #d9ead3;"
 
| Velocity X
 
| Short
 
|
 
|-  style="background-color: #d9ead3;"
 
| Velocity Y
 
| Short
 
|
 
|-  style="background-color: #d9ead3;"
 
| Velocity Z
 
| Short
 
 
|}
 
  
 +
=== Clientbound ===
 
==== Spawn Mob ====
 
==== Spawn Mob ====
  
Line 230: Line 306:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="13"| 0x0F
+
  |rowspan="13"| 0x03
 
  |rowspan="13"| Play
 
  |rowspan="13"| Play
 
  |rowspan="13"| Client
 
  |rowspan="13"| Client
Line 236: Line 312:
 
  | VarInt
 
  | VarInt
 
  |  
 
  |  
  |- style="background-color: #d9ead3;"
+
  |-
 
  | Entity UUID
 
  | Entity UUID
 
  | UUID
 
  | UUID
Line 242: Line 318:
 
  |-
 
  |-
 
  | Type
 
  | Type
  | Unsigned Byte
+
  | VarInt
 
  | The type of mob. See [[Entities#Mobs]]
 
  | The type of mob. See [[Entities#Mobs]]
 
  |-
 
  |-
 
  | X
 
  | X
  | Int
+
  | Double
  | X position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
+
  |  
 
  |-
 
  |-
 
  | Y
 
  | Y
  | Int
+
  | Double
  | Y position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
+
  |  
 
  |-
 
  |-
 
  | Z
 
  | Z
  | Int
+
  | Double
  | Z position as a [[Data Types#Fixed-point numbers|Fixed-Point number]]
+
  |  
 
  |-
 
  |-
 
  | Yaw
 
  | Yaw
Line 271: Line 347:
 
  | Velocity X
 
  | Velocity X
 
  | Short
 
  | Short
  | Same units as [[Protocol#Entity Velocity|Entity Velocity]]
+
  | Same units as [[#Entity Velocity|Entity Velocity]]
 
  |-
 
  |-
 
  | Velocity Y
 
  | Velocity Y
 
  | Short
 
  | Short
  | Same units as [[Protocol#Entity Velocity|Entity Velocity]]
+
  | Same units as [[#Entity Velocity|Entity Velocity]]
 
  |-
 
  |-
 
  | Velocity Z
 
  | Velocity Z
 
  | Short
 
  | Short
  | Same units as [[Protocol#Entity Velocity|Entity Velocity]]
+
  | Same units as [[#Entity Velocity|Entity Velocity]]
  |-
+
  |- {{removed}}
 
  | Metadata
 
  | Metadata
  | [[Entities#Entity Metadata Format|Metadata]]
+
  | [[Entities#Entity Metadata Format|Entity Metadata]]
 
  |  
 
  |  
 
  |}
 
  |}
  
==== Combat Event ====
+
==== Spawn Player ====
 +
 
 +
This packet is sent by the server when a player comes into visible range, ''not'' when a player joins.
 +
 
 +
This packet must be sent after the [[#Player Info|Player Info]] packet that adds the player data for the client to use when spawning a player. If the Player Info for the player spawned by this packet is not present when this packet arrives, Notchian clients will not spawn the player entity. The Player Info packet includes skin/cape data.
 +
 
 +
Servers can, however, safely spawn player entities for players not in visible range. The client appears to handle it correctly.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 296: Line 378:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="6"| 0x42
+
  |rowspan="8"| 0x05
  |rowspan="6"| Play
+
  |rowspan="8"| Play
  |rowspan="6"| Client
+
  |rowspan="8"| Client
  | Event
+
  | Entity ID
 
  | VarInt
 
  | VarInt
  | 0: enter combat, 1: end combat, 2: entity dead
+
  | Player's EID
 
  |-
 
  |-
| Duration
+
  | Player UUID
| Optional VarInt
 
| Only for end combat
 
|-
 
  | Player ID
 
| Optional VarInt
 
| Only for entity dead
 
|-
 
| Entity ID
 
| Optional Int
 
| Only for end combat and entity dead
 
|-
 
| Message
 
| {{Change|String|[[Chat]]}}
 
| Only for entity dead
 
|}
 
 
 
==== Boss Bar ====
 
This packet replaces Update Entity NBT packet which has been removed.
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
!colspan="2"| Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="15"| 0x49
 
|rowspan="15"| Play
 
|rowspan="15"| Client
 
|colspan="2"| UUID
 
 
  | UUID
 
  | UUID
  | Unique ID for this bar
+
  | See below for notes on {{Minecraft Wiki|Server.properties#online-mode|offline mode}} and NPCs
 
  |-
 
  |-
  |colspan="2"| Action
+
  | X
  | VarInt
+
  | Double
 
  |  
 
  |  
 
  |-
 
  |-
! Action
+
  | Y
! Field Name
+
  | Double
!
 
!
 
|-
 
|rowspan="5"| 0: add
 
  | Title
 
  | [[Chat]]
 
 
  |  
 
  |  
 
  |-
 
  |-
  | Health
+
  | Z
  | Float
+
  | Double
 
  |  
 
  |  
 
  |-
 
  |-
  | Color
+
  | Yaw
  | VarInt
+
  | Angle
| Color ID (see below)
 
|-
 
| Dividers
 
| VarInt
 
 
  |  
 
  |  
 
  |-
 
  |-
  | Flags
+
  | Pitch
  | Unsigned Byte
+
  | Angle
| Bit mask: 0x1 should darken sky, 0x2: is dragon bar
 
|-
 
| 1: remove
 
| ''no fields''
 
| ''no fields''
 
| Removes this boss bar
 
|-
 
| 2: update health
 
| Health
 
| Float
 
 
  |  
 
  |  
  |-
+
  |- {{removed}}
  | 3: update title
+
  | Metadata
| Title
+
  | [[Entities#Entity Metadata Format|Entity Metadata]]
  | [[Chat]]
 
 
  |  
 
  |  
|-
 
|rowspan="2"| 4: update style
 
| Color
 
| VarInt
 
|
 
|-
 
| Dividers
 
| VarInt
 
|
 
|-
 
| 5: update flags
 
| Flags
 
| Unsigned Byte
 
|
 
|-
 
|}
 
 
{| class="wikitable"
 
! ID
 
! Color
 
|-
 
| 0
 
| Pink(ish)
 
|-
 
| 1
 
| Cyan
 
|-
 
| 2
 
| Red
 
|-
 
| 3
 
| Lime
 
|-
 
| 4
 
| Yellow
 
|-
 
| 5
 
| Purple
 
|-
 
| 6
 
| White
 
 
  |}
 
  |}
  
=== Serverbound ===
+
When in {{Minecraft Wiki|Server.properties#online-mode|online mode}}, the UUIDs must be valid and have valid skin blobs.
  
==== Use Entity ====
+
In offline mode, [[Wikipedia:Universally unique identifier#Versions 3 and 5 (namespace name-based)|UUID v3]] is used with the String <code>OfflinePlayer:&lt;player name&gt;</code>, encoded in UTF-8 (and case-sensitive).
  
This packet is sent from the client to the server when the client attacks or right-clicks another entity (a player, minecart, etc).
+
For NPCs UUID v2 should be used. Note:
  
A Notchian server only accepts this packet if the entity being attacked/used is visible without obstruction and within a 4-unit radius of the player's position.
+
<+Grum> i will never confirm this as a feature you know that :)
  
Note that middle-click in creative mode is interpreted by the client and sent as a [[#Creative Inventory Action|Creative Inventory Action]] packet instead.
+
In an example UUID, <code>xxxxxxxx-xxxx-Yxxx-xxxx-xxxxxxxxxxxx</code>, the UUID version is specified by <code>Y</code>. So, for UUID v3, <code>Y</code> will always be <code>3</code>, and for UUID v2, <code>Y</code> will always be <code>2</code>.
  
{| class="wikitable"
+
==== Update Block Entity ====
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="6"| 0x02
 
|rowspan="6"| Play
 
|rowspan="6"| Server
 
| Target
 
| VarInt
 
|
 
|-
 
| Type
 
| VarInt
 
| 0: interact, 1: attack, 2: interact at
 
|-
 
| Target X
 
| Optional Float
 
| Only if Type is interact at
 
|-
 
| Target Y
 
| Optional Float
 
| Only if Type is interact at
 
|-
 
| Target Z
 
| Optional Float
 
| Only if Type is interact at
 
|- style="background-color: #d9ead3;"
 
| Hand
 
| Optional Byte
 
| Only if Type is interact or interact at; 0: main hand, 1: off hand
 
|}
 
 
 
==== Player Digging ====
 
  
Sent when the player mines a block. A Notchian server only accepts digging packets with coordinates within a 6-unit radius of the player's position.
+
Sets the block entity associated with the block at the given location.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 482: Line 436:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="3"| 0x07
+
  |rowspan="3"| {{change|0x09|0x0A}}
 
  |rowspan="3"| Play
 
  |rowspan="3"| Play
  |rowspan="3"| Server
+
  |rowspan="3"| Client
| Status
 
| Byte
 
| The action the player is taking against the block (see below)
 
|-
 
| Location
 
| Position
 
| Block position
 
|-
 
| Face
 
| Byte
 
| The face being hit (see below)
 
|}
 
 
 
Status can be one of seven values:
 
 
 
{| class="wikitable"
 
! Meaning
 
! Value
 
|-
 
| Started digging
 
| <code>0</code>
 
|-
 
| Cancelled digging
 
| <code>1</code>
 
|-
 
| Finished digging
 
| <code>2</code>
 
|-
 
| Drop item stack
 
| <code>3</code>
 
|-
 
| Drop item
 
| <code>4</code>
 
|-
 
| Shoot arrow / finish eating
 
| <code>5</code>
 
|- style="background-color: #d9ead3;"
 
| Swap item in Hand
 
| <code>6</code>
 
|}
 
 
 
Notchian clients send a 0 (started digging) when they start digging and a 2 (finished digging) once they think they are finished. If digging is aborted, the client simply sends a 1 (cancel digging).
 
 
 
Status code 4 (drop item) is a special case. In-game, when you use the Drop Item command (keypress 'q'), a dig packet with a status of 4, Location set to 0/0/0, and Face set to 0, is sent from client to server. Status code 3 is similar, but drops the entire stack.
 
 
 
Status code 5 (shoot arrow / finish eating) is also a special case. Location is set to 0/0/0 like above, but the face field is set to 255.
 
 
 
Status code 6 is another special case. Used to swap or assign an item to the second hand. Location is set to 0/0/0 and Face is set to 0.
 
 
 
The Face field can be one of six values, representing the face being hit:
 
 
 
{| class="wikitable"
 
|-
 
! Value
 
| 0
 
| 1
 
| 2
 
| 3
 
| 4
 
| 5
 
|-
 
! Offset
 
| -Y
 
| +Y
 
| -Z
 
| +Z
 
| -X
 
| +X
 
|}
 
 
 
==== {{Change||Use Item}} ====
 
 
 
Sent when pressing the Use Item key (default: right click) with an item in hand.
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="1"| 0x08
 
|rowspan="1"| Play
 
|rowspan="1"| Server
 
| Hand
 
| Byte
 
| Hand used for the animation
 
|}
 
 
 
==== Player Block Placement ====
 
 
 
{| class="wikitable"
 
|-
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="6"| {{Change|0x08|0x09}}
 
|rowspan="6"| Play
 
|rowspan="6"| Server
 
 
  | Location
 
  | Location
 
  | Position
 
  | Position
| Block position
 
|-
 
| Face
 
| {{Change|Byte|VarInt}}
 
| The face on which the block is placed (see above)
 
|-
 
| {{Change|Held Item|Hand}}
 
| {{Change|[[Slot Data|Slot]]|VarInt}}
 
| The hand from which the block is placed; 0: main hand, 1: off hand
 
|-
 
| Cursor Position X
 
| Byte
 
| The position of the crosshair on the block
 
|-
 
| Cursor Position Y
 
| Byte
 
 
  |  
 
  |  
 
  |-
 
  |-
  | Cursor Position Z
+
  | Action
  | Byte
+
  | Unsigned Byte
  |  
+
  | The type of update to perform, see below
|}
 
 
 
In normal operation (i.e. placing a block), this packet is sent once, with the values set normally.
 
 
 
This packet has a special case where X, Y, Z, and Direction are all -1. (Note that Y is unsigned so set to 255.) This special packet indicates that the currently held item for the player should have its state updated such as eating food, pulling back bows, using buckets, etc.
 
 
 
Special note on using buckets: When using buckets, the Notchian client might send two packets: first a normal and then a special case. The first normal packet is sent when you're looking at a block (e.g. the water you want to scoop up). This normal packet does not appear to do anything with a Notchian server. The second, special case packet appears to perform the action — based on current position/orientation and with a distance check — it appears that buckets can only be used within a radius of 6 units.
 
 
 
==== Held Item Change ====
 
 
 
Sent when the player changes the slot selection.
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
  |rowspan="1"| {{Change|0x09|0x0A}}
+
  | NBT Data
  |rowspan="1"| Play
+
  | [[NBT|NBT Tag]]
  |rowspan="1"| Server
+
  | Data to set. May be a TAG_END (0), in which case the block entity at the given location is removed (though this is not required since the client will remove the block entity automatically on chunk unload or block removal)
  | Slot
 
| Short
 
| The slot which the player has selected (0–8)
 
 
  |}
 
  |}
  
==== Animation ====
+
''Action'' field:
  
Sent when the player's arm swings
+
* '''1''': Set data of a mob spawner (everything except for SpawnPotentials: current delay, min/max delay, mob to be spawned, spawn count, spawn range, etc.)
 +
* '''2''': Set command block text (command and last execution status)
 +
* '''3''': Set the level, primary, and secondary powers of a beacon
 +
* '''4''': Set rotation and skin of mob head
 +
* '''5''': Declare a conduit
 +
* '''6''': Set base color and patterns on a banner
 +
* '''7''': Set the data for a Structure tile entity
 +
* '''8''': Set the destination for a end gateway
 +
* '''9''': Set the text on a sign
 +
* '''10''': Unused
 +
* '''11''': Declare a bed
 +
* '''12''': Set data of a jigsaw block
 +
* '''13''': Set items in a campfire
 +
* {{change||'''14''': Beehive information}}
  
{| class="wikitable"
+
==== Change Game State ====
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="1"| {{Change|0x0A|0x0B}}
 
|rowspan="1"| Play
 
|rowspan="1"| Server
 
|style="background-color: #d9ead3;"| Hand
 
|style="background-color: #d9ead3;"| Byte
 
|style="background-color: #d9ead3;"| Hand used for the animation
 
|}
 
  
==== Entity Action ====
+
Used for a wide variety of game state things, from whether to bed use to gamemode to demo messages.
 
 
Sent at least when crouching, leaving a bed, or sprinting. To send action animation to client use 0x28. The client will send this with Action ID = 3 when “Leave Bed” is clicked.
 
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 672: Line 481:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="3"| {{Change|0x0B|0x0C}}
+
  |rowspan="2"| 0x1F
  |rowspan="3"| Play
+
  |rowspan="2"| Play
  |rowspan="3"| Server
+
  |rowspan="2"| Client
  | Entity ID
+
  | Reason
  | VarInt
+
  | Unsigned Byte
  | Player ID
+
  | See below
 
  |-
 
  |-
  | Action ID
+
  | Value
  | VarInt
+
  | Float
  | The ID of the action, see below
+
  | Depends on Reason
|-
 
| Jump Boost
 
| VarInt
 
| Horse jump boost. Ranged from 0 -> 100.
 
 
  |}
 
  |}
  
Action ID can be one of the following values:
+
''Reason codes'':
  
 
{| class="wikitable"
 
{| class="wikitable"
  ! ID
+
  ! Reason
  ! Action
+
  ! Effect
 +
! Value
 
  |-
 
  |-
 
  | 0
 
  | 0
  | Crouch
+
  | Invalid Bed
 +
| Would be used to switch between messages, but the only used message is 0 for invalid bed
 
  |-
 
  |-
 
  | 1
 
  | 1
  | Uncrouch
+
  | End raining
 +
|
 
  |-
 
  |-
 
  | 2
 
  | 2
  | Leave bed
+
  | Begin raining
 +
|
 
  |-
 
  |-
 
  | 3
 
  | 3
  | Start sprinting
+
  | Change gamemode
 +
| 0: Survival, 1: Creative, 2: Adventure, 3: Spectator
 
  |-
 
  |-
 
  | 4
 
  | 4
  | Stop sprinting
+
  | Exit end
 +
| 0: Immediately send Client Status of respawn without showing end credits; 1: Show end credits and respawn at the end (or when esc is pressed).  1 is sent if the player has not yet received the "The end?" advancement, while if they do have it 0 is used.
 
  |-
 
  |-
 
  | 5
 
  | 5
  | Jump with horse
+
  | Demo message
  |- style="background-color: #f4cccc; text-decoration: line-through;"
+
  | 0: Show welcome to demo screen, 101: Tell movement controls, 102: Tell jump control, 103: Tell inventory control
 +
|-  
 
  | 6
 
  | 6
  | Open inventory
+
  | Arrow hitting player
  |}
+
  | Appears to be played when an arrow strikes another player in Multiplayer
 
+
|-
==== Steer Vehicle ====
+
  | 7
 
+
  | Fade value
{| class="wikitable"
+
  | The current darkness value. 1 = Dark, 0 = Bright, Setting the value higher causes the game to change color and freeze
  ! Packet ID
 
  ! State
 
  ! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
  |rowspan="3"| {{Change|0x0C|0x0D}}
+
  | 8
  |rowspan="3"| Play
+
  | Fade time
  |rowspan="3"| Server
+
  | Time in ticks for the sky to fade
| Sideways
 
| Float
 
| Positive to the left of the player
 
 
  |-
 
  |-
  | Forward
+
  | 9
  | Float
+
  | Play pufferfish sting sound
| Positive forward
 
 
  |-
 
  |-
  | Flags
+
  | 10
  | Unsigned Byte
+
  | Play elder guardian mob appearance (effect and sound)
  | Bit mask. 0x1: jump, 0x2: unmount
+
  |- {{Added}}
 +
| 11
 +
| Enable respawn screen
 +
| 0: Enable respawn screen, 1: Immediately respawn (sent when the doImmediateRespawn gamerule changes)
 
  |}
 
  |}
  
==== Close Window ====
+
==== Chunk Data ====
 +
{{Main|Chunk Format}}
 +
{{See also|#Unload Chunk}}
  
This packet is sent by the client when closing a window.
+
{{Need Info|How do biomes work now?  The biome change happened at the same time as the seed change, but it's not clear how/if biomes could be computed given that it's not the actual seed...  ([https://www.reddit.com/r/Mojira/comments/e5at6i/a_discussion_for_the_changes_to_how_biomes_are/ /r/mojira discussion] which notes that it seems to be some kind of interpolation, and 3D biomes are only used in the nether)}}
  
Note, Notchian clients send a close window message with Window ID 0 to close their inventory even though there is never an Open Window message for the inventory.
+
The server only sends skylight information for chunk pillars in the {{Minecraft Wiki|Overworld}}, it's up to the client to know in which dimenison the player is currently located. You can also infer this information from the primary bitmask and the amount of uncompressed bytes sent.  This packet also sends all block entities in the chunk (though sending them is not required; it is still legal to send them with [[#Update Block Entity|Update Block Entity]] later).
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 756: Line 563:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  | {{Change|0x0D|0x0E}}
+
  |rowspan="10"| {{change|0x21|0x22}}
  |rowspan="1"| Play
+
  |rowspan="10"| Play
  |rowspan="1"| Server
+
  |rowspan="10"| Client
  | Window ID
+
  | Chunk X
  | Unsigned Byte
+
  | Int
  | This is the ID of the window that was closed. 0 for inventory.
+
  | Chunk coordinate (block coordinate divided by 16, rounded down)
|}
 
 
 
==== Click Window ====
 
 
 
This packet is sent by the player when it clicks on a slot in a window.
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
  |rowspan="6"| {{Change|0x0E|0x0F}}
+
  | Chunk Z
|rowspan="6"| Play
+
  | Int
|rowspan="6"| Server
+
  | Chunk coordinate (block coordinate divided by 16, rounded down)
| Window ID
 
  | Unsigned Byte
 
  | The ID of the window which was clicked. 0 for player inventory.
 
 
  |-
 
  |-
  | Slot
+
  | Full chunk
  | Short
+
  | Boolean
  | The clicked slot number, see below
+
  | See [[Chunk Format#Full chunk|Chunk Format]]
 
  |-
 
  |-
  | Button
+
  | Primary Bit Mask
  | Byte
+
  | VarInt
  | The button used in the click, see below
+
  | Bitmask with bits set to 1 for every 16×16×16 chunk section whose data is included in Data. The least significant bit represents the chunk section at the bottom of the chunk column (from y=0 to y=15).
 
  |-
 
  |-
  | Action Number
+
  | Heightmaps
  | Short
+
  | [[NBT]]
  | A unique number for the action, implemented by Notchian as a counter, starting at 1. Used by the server to send back a [[Protocol#Confirm Transaction|Confirm Transaction]].
+
  | Compound containing one long array named <code>MOTION_BLOCKING</code>, which is a heightmap for the highest solid block at each position in the chunk (as a compacted long array with 256 entries at 9 bits per entry totaling 36 longs). The Notchian server also adds a <code>WORLD_SURFACE</code> long array, the purpose of which is unknown, but it's not required for the chunk to be accepted.
 +
|- {{Added}}
 +
| Biomes
 +
| Optional array of Integer
 +
| 1024 biome IDs, ordered by x then z then y, in 4&times;4&times;4 blocks.  Not present if full chunk is false.
 
  |-
 
  |-
  | Mode
+
  | Size
  | Byte
+
  | VarInt
  | Inventory operation mode, see below
+
  | Size of Data in bytes
 
  |-
 
  |-
  | Clicked item
+
  | Data
| [[Slot Data|Slot]]
+
  | Byte array
  | The clicked slot. Has to be empty (item ID = -1) for drop mode.
+
  | See [[Chunk Format#Data structure|data structure]] in Chunk Format
  |}
 
 
 
See [[Inventory#Windows]] for further information about how slots are indexed.
 
 
 
When right-clicking on a stack of items, half the stack will be picked up and half left in the slot. If the stack is an odd number, the half left in the slot will be smaller of the amounts.
 
 
 
The distinct type of click performed by the client is determined by the combination of the Mode and Button fields.
 
 
 
{| class="wikitable"
 
! Mode
 
! Button
 
! Slot
 
! Trigger
 
 
  |-
 
  |-
!rowspan="2"| 0
+
  | Number of block entities
| 0
+
  | VarInt
| Normal
+
  | Number of elements in the following array
| Left mouse click
 
|-
 
| 1
 
| Normal
 
| Right mouse click
 
|-
 
!rowspan="2"| 1
 
| 0
 
| Normal
 
| Shift + left mouse click
 
|-
 
| 1
 
| Normal
 
| Shift + right mouse click ''(identical behavior)''
 
|-
 
!rowspan="5"| 2
 
| 0
 
| Normal
 
  | Number key 1
 
|-
 
| 1
 
| Normal
 
| Number key 2
 
|-
 
| 2
 
  | Normal
 
  | Number key 3
 
|-
 
| ⋮
 
| ⋮
 
| ⋮
 
|-
 
| 8
 
| Normal
 
| Number key 9
 
|-
 
!rowspan="1"| 3
 
| 2
 
| Normal
 
| Middle click
 
|-
 
!rowspan="4"| 4
 
| 0
 
| Normal*
 
| Drop key (Q) (* Clicked item is different, see above)
 
|-
 
| 1
 
| Normal*
 
| Ctrl + Drop key (Ctrl-Q) ''(drops full stack)''
 
|-
 
| 0
 
| -999
 
| Left click outside inventory holding nothing ''(no-op)''
 
|-
 
| 1
 
| -999
 
| Right click outside inventory holding nothing ''(no-op)''
 
|-
 
!rowspan="6"| 5
 
| 0
 
| -999
 
| Starting left mouse drag ''(or middle mouse)''
 
|-
 
| 4
 
| -999
 
| Starting right mouse drag
 
|-
 
| 1
 
| Normal
 
| Add slot for left-mouse drag
 
|-
 
| 5
 
| Normal
 
| Add slot for right-mouse drag
 
|-
 
| 2
 
| -999
 
| Ending left mouse drag
 
|-
 
| 6
 
| -999
 
| Ending right mouse drag
 
|-
 
! 6
 
| 0
 
| Normal
 
| Double click
 
|}
 
 
 
Starting from version 1.5, “painting mode” is available for use in inventory windows. It is done by picking up stack of something (more than 1 item), then holding mouse button (left, right or middle) and dragging held stack over empty (or same type in case of right button) slots. In that case client sends the following to server after mouse button release (omitting first pickup packet which is sent as usual):
 
 
 
# packet with mode 5, slot -999, button (0 for left | 4 for right);
 
# packet for every slot painted on, mode is still 5, button (1 | 5);
 
# packet with mode 5, slot -999, button (2 | 6);
 
 
 
If any of the painting packets other than the “progress” ones are sent out of order (for example, a start, some slots, then another start; or a left-click in the middle) the painting status will be reset.
 
 
 
The server will send back a [[#Confirm Transaction|Confirm Transaction]]<!-- note that the anchor should be changed to #Confirm Transaction 2 when merging with [[Protocol]] --> packet. If the click was not accepted, the client must reflect that packet before sending more [[#Click Window|Click Window]] packets, otherwise the server will reject them silently. The Notchian server also sends a [[Protocol#Window Items|Window Items]] packet for the open window and [[Protocol#Set Slot|Set Slot]] packets for the clicked and cursor slot, but only when the click was not accepted, probably to resynchronize client and server.
 
 
 
==== Confirm Transaction ====
 
 
 
<SpaceManiac> noooo idea why the serverbound confirm transaction packet exists
 
<SpaceManiac> I think it's sent as a response to the clientbound confirm transaction in some situations, but it's fuzzy
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="3"| {{Change|0x0F|0x10}}
 
|rowspan="3"| Play
 
|rowspan="3"| Server
 
| Window ID
 
| Byte
 
| The ID of the window that the action occurred in
 
 
  |-
 
  |-
  | Action Number
+
  | Block entities
  | Short
+
  | Array of [[NBT|NBT Tag]]
  | Every action that is to be accepted has a unique number. This field corresponds to that number.
+
  | All block entities in the chunk. Use the x, y, and z tags in the NBT to determine their positions.
|-
 
| Accepted
 
| Boolean
 
| Whether the action was accepted
 
 
  |}
 
  |}
  
==== Creative Inventory Action ====
+
Note that the Notchian client requires an [[#Update View Position|Update View Position]] packet when it crosses a chunk border, otherwise it'll only display render distance + 2 chunks around the chunk it spawned in.
  
While the user is in the standard inventory (i.e., not a crafting bench) in Creative mode, the player will send this packet.
+
{{Change||To get the biome at a coordinate, use <code>biomes[((y >> 2) & 63) << 4 {{!}} ((z >> 2) & 3) << 2 {{!}} ((x >> 2) & 3)]</code>}}
  
Clicking in the creative inventory menu is quite different from non-creative inventory management. Picking up an item with the mouse actually deletes the item from the server, and placing an item into a slot or dropping it out of the inventory actually tells the server to create the item from scratch. (This can be verified by clicking an item that you don't mind deleting, then severing the connection to the server; the item will be nowhere to be found when you log back in.) As a result of this implementation strategy, the "Destroy Item" slot is just a client-side implementation detail that means "I don't intend to recreate this item.". Additionally, the long listings of items (by category, etc.) are a client-side interface for choosing which item to create. Picking up an item from such listings sends no packets to the server; only when you put it somewhere does it tell the server to create the item in that location.
+
===== Data structure =====
  
This action can be described as “set inventory slot”. Picking up an item sets the slot to item ID -1. Placing an item into an inventory slot sets the slot to the specified item. Dropping an item (by clicking outside the window) effectively sets slot -1 to the specified item, which causes the server to spawn the item entity, etc.. All other inventory slots are numbered the same as the non-creative inventory (including slots for the 2×2 crafting menu, even though they aren't visible in the vanilla client).
+
The data section of the packet contains most of the useful data for the chunk.
  
 
{| class="wikitable"
 
{| class="wikitable"
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
|rowspan="2"| {{Change|0x10|0x11}}
 
|rowspan="2"| Play
 
|rowspan="2"| Server
 
| Slot
 
| Short
 
| Inventory slot
 
|-
 
| Clicked Item
 
| [[Slot Data|Slot]]
 
|
 
|}
 
 
==== Enchant Item ====
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
 
  ! Field Name
 
  ! Field Name
 
  ! Field Type
 
  ! Field Type
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="2"| {{Change|0x11|0x12}}
+
  | Data
  |rowspan="2"| Play
+
  | Array of [[Chunk Format#Chunk Section structure|Chunk Section]]
|rowspan="2"| Server
+
  | The number of elements in the array is equal to the number of bits set in Primary Bit Mask. Sections are sent bottom-to-top, i.e. the first section, if sent, extends from Y=0 to Y=15.
| Window ID
+
  |- {{removed}}
| Byte
+
  | Biomes
  | The ID of the enchantment table window sent by [[Protocol#Open Window|Open Window]]
+
  | Optional Int Array
  |-
+
  | Only sent if full chunk is true; 256 entries if present
  | Enchantment
 
  | Byte
 
  | The position of the enchantment on the enchantment table window, starting with 0 as the topmost one
 
 
  |}
 
  |}
  
==== Update Sign ====
+
==== Particle ====
  
This message is sent from the client to the server when the “Done” button is pushed after placing a sign.
+
Displays the named particle.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 1,009: Line 642:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="5"| {{Change|0x12|0x13}}
+
  |rowspan="11"| {{Change|0x23|0x24}}
  |rowspan="5"| Play
+
  |rowspan="11"| Play
  |rowspan="5"| Server
+
  |rowspan="11"| Client
  | Location
+
  | Particle ID
  | Position
+
  | Int
  | Block Coordinates
+
  | The particle ID listed in [[#Particle|the particle data type]].
 
  |-
 
  |-
  | Line 1
+
  | Long Distance
  | [[Chat]]
+
  | Boolean
  | First line of text in the sign
+
  | If true, particle distance increases from 256 to 65536
 
  |-
 
  |-
  | Line 2
+
  | X
  | [[Chat]]
+
  | {{Change|Float|Double}}
  | Second line of text in the sign
+
  | X position of the particle
 
  |-
 
  |-
  | Line 3
+
  | Y
  | [[Chat]]
+
  | {{Change|Float|Double}}
  | Third line of text in the sign
+
  | Y position of the particle
 
  |-
 
  |-
  | Line 4
+
  | Z
  | [[Chat]]
+
  | {{Change|Float|Double}}
| Fourth line of text in the sign
+
  | Z position of the particle
  |}
 
 
 
==== Player Abilities ====
 
 
 
The latter 2 bytes are used to indicate the walking and flying speeds respectively, while the first byte is used to determine the value of 4 booleans.
 
 
 
The vanilla client sends this packet when the player starts/stops flying with the second parameter changed accordingly. All other parameters are ignored by the vanilla server.
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
  |rowspan="3"| {{Change|0x13|0x14}}
+
  | Offset X
  |rowspan="3"| Play
+
  | Float
  |rowspan="3"| Server
+
  | This is added to the X position after being multiplied by random.nextGaussian()
| Flags
 
| Byte
 
| Bit mask. 0x08: damage disabled (god mode), 0x04: can fly, 0x02: is flying, 0x01: is Creative
 
 
  |-
 
  |-
  | Flying Speed
+
  | Offset Y
 
  | Float
 
  | Float
  |  
+
  | This is added to the Y position after being multiplied by random.nextGaussian()
 
  |-
 
  |-
  | Walking Speed
+
  | Offset Z
 
  | Float
 
  | Float
  |  
+
  | This is added to the Z position after being multiplied by random.nextGaussian()
|}
 
 
 
==== Tab-Complete ====
 
 
 
Sent when the user presses ''tab'' while writing text.
 
 
 
{| class="wikitable"
 
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
 
  |-
 
  |-
  |rowspan="3"| {{Change|0x14|0x15}}
+
  | Particle Data
|rowspan="3"| Play
+
  | Float
|rowspan="3"| Server
+
  | The data of each particle
| Text
 
  | String
 
  | All text behind the cursor
 
 
  |-
 
  |-
  | Has Position
+
  | Particle Count
  | Boolean
+
  | Int
  |  
+
  | The number of particles to create
 
  |-
 
  |-
  | Looked At Block
+
  | Data
  | Optional Position
+
  | Varies
  | The position of the block being looked at. Only sent if Has Position is true
+
  | The variable data listed in [[#Particle|the particle data type]].
 
  |}
 
  |}
  
==== Client Settings ====
+
==== Join Game ====
  
Sent when the player connects, or when settings are changed.
+
See [[Protocol Encryption]] for information on logging in.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 1,103: Line 702:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="6"| {{Change|0x15|0x16}}
+
  |rowspan="9"| {{change|0x25|0x26}}
  |rowspan="6"| Play
+
  |rowspan="9"| Play
  |rowspan="6"| Server
+
  |rowspan="9"| Client
  | Locale
+
  | Entity ID
  | String
+
  | Int
  | e.g. en_GB
+
  | The player's Entity ID (EID)
 +
|-
 +
| Gamemode
 +
| Unsigned Byte
 +
| 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. Bit 3 (0x8) is the hardcore flag.
 
  |-
 
  |-
  | View Distance
+
  | Dimension
  | Byte
+
  | Int Enum
  | Client-side render distance, in chunks
+
  | -1: Nether, 0: Overworld, 1: End; also, note that this is not a VarInt but instead a regular int.
 +
|- {{Added}}
 +
| Hashed seed
 +
| Long
 +
| First 8 bytes of the SHA-256 hash of the world's seed.
 
  |-
 
  |-
  | Chat Mode
+
  | Max Players
  | {{Change|Byte|VarInt}}
+
  | Unsigned Byte
  | 0: enabled, 1: commands only, 2: hidden
+
  | Was once used by the client to draw the player list, but now is ignored
 
  |-
 
  |-
  | Chat Colors
+
  | Level Type
  | Boolean
+
  | String Enum (16)
  | “Colors” multiplayer setting
+
  | default, flat, largeBiomes, amplified, customized, buffet, default_1_1
 
  |-
 
  |-
  | Displayed Skin Parts
+
  | View Distance
| Unsigned Byte
 
| Skin parts, see note below
 
|- style="background-color: #d9ead3;"
 
| Main Hand
 
 
  | VarInt
 
  | VarInt
  | 0: Left, 1: Right
+
  | Render distance (2-32)
 +
|-
 +
| Reduced Debug Info
 +
| Boolean
 +
| If true, a Notchian client shows reduced information on the {{Minecraft Wiki|debug screen}}.  For servers in development, this should almost always be false.
 +
|- {{Added}}
 +
| Enable respawn screen
 +
| Boolean
 +
| Set to false when the doImmediateRespawn gamerule is true
 
  |}
 
  |}
  
''Displayed Skin Parts'' flags:
+
==== Respawn ====
 
 
* Bit 0 (0x01): Cape enabled
 
* Bit 1 (0x02): Jacket enabled
 
* Bit 2 (0x04): Left Sleeve enabled
 
* Bit 3 (0x08): Right Sleeve enabled
 
* Bit 4 (0x10): Left Pants Leg enabled
 
* Bit 5 (0x20): Right Pants Leg enabled
 
* Bit 6 (0x40): Hat enabled
 
 
 
The most significant bit (bit 7, 0x80) appears to be unused.
 
 
 
==== Client Status ====
 
  
Sent when the client is ready to complete login and when the client is ready to respawn after death.
+
To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 1,155: Line 754:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="1"| {{Change|0x16|0x17}}
+
  |rowspan="4"| {{change|0x3A|0x3B}}
  |rowspan="1"| Play
+
  |rowspan="4"| Play
  |rowspan="1"| Server
+
  |rowspan="4"| Client
  | Action ID
+
| Dimension
  | VarInt
+
| Int Enum
  | See below
+
| -1: The Nether, 0: The Overworld, 1: The End
 +
|- {{Added}}
 +
| Hashed seed
 +
| Long
 +
| First 8 bytes of the SHA-256 hash of the world's seed.
 +
|-
 +
| Gamemode
 +
| Unsigned Byte
 +
| 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included
 +
|-
 +
  | Level Type
 +
  | String (16)
 +
  | Same as [[#Join Game|Join Game]]
 
  |}
 
  |}
  
''Action ID'' values:
+
{{Warning2|Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).
  
{| class="wikitable"
+
If you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.}}
|-
 
! Action ID
 
! Action
 
|-
 
| 0
 
| Perform respawn
 
|-
 
| 1
 
| Request stats
 
|-
 
| 2
 
| {{Change|''Taking Inventory'' achievement|Open Inventory}}
 
|}
 
  
==== Plugin Message ====
+
=== Serverbound ===
  
Mods and plugins can use this to send their data. Minecraft itself uses a number of [[plugin channel]]s. These internal channels are prefixed with <code>MC|</code>.
+
No changes so far.
  
More documentation on this: [http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/ http://dinnerbone.com/blog/2012/01/13/minecraft-plugin-channels-messaging/]
+
== Handshaking ==
  
Note that the data length is known from the packet length, so there is no need for a length member being sent.
+
=== Clientbound ===
  
{| class="wikitable"
+
There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.  
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="2"| {{Change|0x17|0x18}}
 
|rowspan="2"| Play
 
|rowspan="2"| Server
 
| Channel
 
| String
 
| Name of the [[plugin channel]] used to send the data
 
|-
 
| Data
 
| Byte Array
 
| Any data, depending on the channel. <code><nowiki>MC|</nowiki></code> channels are documented [[plugin channel|here]].
 
|}
 
  
==== Spectate ====
+
=== Serverbound ===
  
{| class="wikitable"
+
==== Handshake ====
! Packet ID
 
! State
 
! Bound To
 
! Field Name
 
! Field Type
 
! Notes
 
|-
 
|rowspan="1"| {{Change|0x18|0x19}}
 
|rowspan="1"| Play
 
|rowspan="1"| Server
 
| Target Player
 
| UUID
 
|
 
|}
 
  
==== Resource Pack Status ====
+
This causes the server to switch into the target state.
  
 
{| class="wikitable"
 
{| class="wikitable"
Line 1,236: Line 802:
 
  ! Notes
 
  ! Notes
 
  |-
 
  |-
  |rowspan="2"| {{Change|0x19|0x1A}}
+
  |rowspan="4"| 0x00
  |rowspan="2"| Play
+
  |rowspan="4"| Handshaking
  |rowspan="2"| Server
+
  |rowspan="4"| Server
  | Hash
+
  | Protocol Version
 +
| VarInt
 +
| See [[protocol version numbers]] (currently {{change|498|578}})
 +
|-
 +
| Server Address
 
  | String
 
  | String
  | The hash sent in the [[Protocol#Resource Pack Send|Resource Pack Send]] packet.
+
  | Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a complete redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide mc.example.org as server address in addition to connecting to it.
 +
|-
 +
| Server Port
 +
| Unsigned Short
 +
| Default is 25565.  The Notchian server does not use this information.
 
  |-
 
  |-
  | Result
+
  | Next State
  | VarInt
+
  | VarInt Enum
  | 0: successfully loaded, 1: declined, 2: failed download, 3: accepted
+
  | 1 for [[#Status|status]], 2 for [[#Login|login]]
 
  |}
 
  |}
  
Line 1,267: Line 841:
  
 
No changes so far.
 
No changes so far.
 +
 +
 +
[[Category:Minecraft Modern]]

Latest revision as of 18:36, 22 January 2020

This page documents the changes from the last stable Minecraft release (currently 1.14.4, protocol 498) to the current pre-release (currently 1.15.2, protocol 578). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

One who wishes to commandeer the merging of this into Protocol when an update is made must be sure to respect any changes that may have occurred to the respective packets there.

Contents

Data types

No changes so far.

Packets

ID Packet name Documentation
Handshaking serverbound
0x00 Handshake Current Pre
Play clientbound
0x03 Spawn Mob Current Pre
0x05 Spawn Player Current Pre
0x5C 0x08 Acknowledge Player Digging Current (unchanged)
0x08 0x09 Block Break Animation Current (unchanged)
0x09 0x0A Update Block Entity Current Pre
0x0A 0x0B Block Action Current (unchanged)
0x0B 0x0C Block Change Current (unchanged)
0x0C 0x0D Boss Bar Current (unchanged)
0x0D 0x0E Server Difficulty Current (unchanged)
0x0E 0x0F Chat Message (clientbound) Current (unchanged)
0x0F 0x10 Multi Block Change Current (unchanged)
0x10 0x11 Tab-Complete (clientbound) Current (unchanged)
0x11 0x12 Declare Commands Current (unchanged)
0x12 0x13 Confirm Transaction (clientbound) Current (unchanged)
0x13 0x14 Close Window (clientbound) Current (unchanged)
0x14 0x15 Window Items Current (unchanged)
0x15 0x16 Window Property Current (unchanged)
0x16 0x17 Set Slot Current (unchanged)
0x17 0x18 Set Cooldown Current (unchanged)
0x18 0x19 Plugin Message (clientbound) Current (unchanged)
0x19 0x1A Named Sound Effect Current (unchanged)
0x1A 0x1B Disconnect (play) Current (unchanged)
0x1B 0x1C Entity Status Current (unchanged)
0x1C 0x1D Explosion Current (unchanged)
0x1D 0x1E Unload Chunk Current (unchanged)
0x1E 0x1F Change Game State Current Pre
0x1F 0x20 Open Horse Window Current (unchanged)
0x20 0x21 Keep Alive (clientbound) Current (unchanged)
0x21 0x22 Chunk Data Current Pre
0x22 0x23 Effect Current (unchanged)
0x23 0x24 Particle Current Pre
0x24 0x25 Update Light Current (unchanged)
0x25 0x26 Join Game Current Pre
0x26 0x27 Map Data Current (unchanged)
0x27 0x28 Trade List Current (unchanged)
0x28 0x29 Entity Relative Move Current (unchanged)
0x29 0x2A Entity Look And Relative Move Current (unchanged)
0x2A 0x2B Entity Look Current (unchanged)
0x2B 0x2C Entity Current (unchanged)
0x2C 0x2D Vehicle Move (clientbound) Current (unchanged)
0x2D 0x2E Open Book Current (unchanged)
0x2E 0x2F Open Window Current (unchanged)
0x2F 0x30 Open Sign Editor Current (unchanged)
0x30 0x31 Craft Recipe Response Current (unchanged)
0x31 0x32 Player Abilities (clientbound) Current (unchanged)
0x32 0x33 Combat Event Current (unchanged)
0x33 0x34 Player Info Current (unchanged)
0x34 0x35 Face Player Current (unchanged)
0x35 0x36 Player Position And Look (clientbound) Current (unchanged)
0x36 0x37 Unlock Recipes Current (unchanged)
0x37 0x38 Destroy Entities Current (unchanged)
0x38 0x39 Remove Entity Effect Current (unchanged)
0x39 0x3A Resource Pack Send Current (unchanged)
0x3A 0x3B Respawn Current Pre
0x3B 0x3C Entity Head Look Current (unchanged)
0x3C 0x3D Select Advancement Tab Current (unchanged)
0x3D 0x3E World Border Current (unchanged)
0x3E 0x3F Camera Current (unchanged)
0x3F 0x40 Held Item Change (clientbound) Current (unchanged)
0x40 0x41 Update View Position Current (unchanged)
0x41 0x42 Update View Distance Current (unchanged)
0x42 0x43 Display Scoreboard Current (unchanged)
0x43 0x44 Entity Metadata Current (unchanged)
0x44 0x45 Attach Entity Current (unchanged)
0x45 0x46 Entity Velocity Current (unchanged)
0x46 0x47 Entity Equipment Current (unchanged)
0x47 0x48 Set Experience Current (unchanged)
0x48 0x49 Update Health Current (unchanged)
0x49 0x4A Scoreboard Objective Current (unchanged)
0x4A 0x4B Set Passengers Current (unchanged)
0x4B 0x4C Teams Current (unchanged)
0x4C 0x4D Update Score Current (unchanged)
0x4D 0x4E Spawn Position Current (unchanged)
0x4E 0x4F Time Update Current (unchanged)
0x4F 0x50 Title Current (unchanged)
0x50 0x51 Entity Sound Effect Current (unchanged)
0x51 0x52 Sound Effect Current (unchanged)
0x52 0x53 Stop Sound Current (unchanged)
0x53 0x54 Player List Header And Footer Current (unchanged)
0x54 0x55 NBT Query Response Current (unchanged)
0x55 0x56 Collect Item Current (unchanged)
0x56 0x57 Entity Teleport Current (unchanged)
0x57 0x58 Advancements Current (unchanged)
0x58 0x59 Entity Properties Current (unchanged)
0x59 0x5A Entity Effect Current (unchanged)
0x5A 0x5B Declare Recipes Current (unchanged)
0x5B 0x5C Tags Current (unchanged)

New/modified data types

No changes so far.

Entity Metadata

Warning.png Lots of shifts, of course

Living

Extends Entity.

Index Type Meaning Default
7 Byte Hand states, used to trigger blocking/eating/drinking animation. 0
Bit mask Meaning
0x01 Is hand active
0x02 Active hand (0 = main hand, 1 = offhand)
0x04 In riptide spin attack
8 Float Health 1.0
9 VarInt Potion effect color (or 0 if there is no effect) 0
10 Boolean Is potion effect ambient: reduces the number of particles generated by potions to 1/5 the normal amount false
11 VarInt Number of arrows in entity 0
12 VarInt Health added by absorption (based on the AbsorptionAmount tag) 0
12 13 OptBlockPos Sleeping location (from SleepingX, SleepingY, SleepingZ tags) Absent

Bee

Extends Insentient.

Index Type Meaning Default
16 Byte Flags 0
0x01 Unused
0x02 Is angry
0x04 Has stung
0x08 Has nectar
17 VarInt Anger time in ticks 0 (Not angry)

Wolf

Extends TameableAnimal.

Index Type Meaning Default
17 Float Damage taken (used for tail rotation) Value of health field (1.0)
18 Boolean Is begging false
19 VarInt Collar color (values are those used with dyes) 14 (Red)

Enderman

Extends Monster.

Index Type Meaning Default
14 15 Opt BlockID Carried block Absent
15 16 Boolean Is screaming false
17 Boolean Is stared at false

Trident

Extends TameableAnimal.

Index Type Meaning Default
10 VarInt Loyalty level (enchantment) 0
11 Boolean Has enchantment glint False

Block Actions

No changes so far.

Inventories

No changes so far.

Plugin Channels

No changes so far.

Play

Clientbound

Spawn Mob

Sent by the server when a mob entity is spawned.

Packet ID State Bound To Field Name Field Type Notes
0x03 Play Client Entity ID VarInt
Entity UUID UUID
Type VarInt The type of mob. See Entities#Mobs
X Double
Y Double
Z Double
Yaw Angle
Pitch Angle
Head Pitch Angle
Velocity X Short Same units as Entity Velocity
Velocity Y Short Same units as Entity Velocity
Velocity Z Short Same units as Entity Velocity
Metadata Entity Metadata

Spawn Player

This packet is sent by the server when a player comes into visible range, not when a player joins.

This packet must be sent after the Player Info packet that adds the player data for the client to use when spawning a player. If the Player Info for the player spawned by this packet is not present when this packet arrives, Notchian clients will not spawn the player entity. The Player Info packet includes skin/cape data.

Servers can, however, safely spawn player entities for players not in visible range. The client appears to handle it correctly.

Packet ID State Bound To Field Name Field Type Notes
0x05 Play Client Entity ID VarInt Player's EID
Player UUID UUID See below for notes on offline mode and NPCs
X Double
Y Double
Z Double
Yaw Angle
Pitch Angle
Metadata Entity Metadata

When in online mode, the UUIDs must be valid and have valid skin blobs.

In offline mode, UUID v3 is used with the String OfflinePlayer:<player name>, encoded in UTF-8 (and case-sensitive).

For NPCs UUID v2 should be used. Note:

<+Grum> i will never confirm this as a feature you know that :)

In an example UUID, xxxxxxxx-xxxx-Yxxx-xxxx-xxxxxxxxxxxx, the UUID version is specified by Y. So, for UUID v3, Y will always be 3, and for UUID v2, Y will always be 2.

Update Block Entity

Sets the block entity associated with the block at the given location.

Packet ID State Bound To Field Name Field Type Notes
0x09 0x0A Play Client Location Position
Action Unsigned Byte The type of update to perform, see below
NBT Data NBT Tag Data to set. May be a TAG_END (0), in which case the block entity at the given location is removed (though this is not required since the client will remove the block entity automatically on chunk unload or block removal)

Action field:

  • 1: Set data of a mob spawner (everything except for SpawnPotentials: current delay, min/max delay, mob to be spawned, spawn count, spawn range, etc.)
  • 2: Set command block text (command and last execution status)
  • 3: Set the level, primary, and secondary powers of a beacon
  • 4: Set rotation and skin of mob head
  • 5: Declare a conduit
  • 6: Set base color and patterns on a banner
  • 7: Set the data for a Structure tile entity
  • 8: Set the destination for a end gateway
  • 9: Set the text on a sign
  • 10: Unused
  • 11: Declare a bed
  • 12: Set data of a jigsaw block
  • 13: Set items in a campfire
  • 14: Beehive information

Change Game State

Used for a wide variety of game state things, from whether to bed use to gamemode to demo messages.

Packet ID State Bound To Field Name Field Type Notes
0x1F Play Client Reason Unsigned Byte See below
Value Float Depends on Reason

Reason codes:

Reason Effect Value
0 Invalid Bed Would be used to switch between messages, but the only used message is 0 for invalid bed
1 End raining
2 Begin raining
3 Change gamemode 0: Survival, 1: Creative, 2: Adventure, 3: Spectator
4 Exit end 0: Immediately send Client Status of respawn without showing end credits; 1: Show end credits and respawn at the end (or when esc is pressed). 1 is sent if the player has not yet received the "The end?" advancement, while if they do have it 0 is used.
5 Demo message 0: Show welcome to demo screen, 101: Tell movement controls, 102: Tell jump control, 103: Tell inventory control
6 Arrow hitting player Appears to be played when an arrow strikes another player in Multiplayer
7 Fade value The current darkness value. 1 = Dark, 0 = Bright, Setting the value higher causes the game to change color and freeze
8 Fade time Time in ticks for the sky to fade
9 Play pufferfish sting sound
10 Play elder guardian mob appearance (effect and sound)
11 Enable respawn screen 0: Enable respawn screen, 1: Immediately respawn (sent when the doImmediateRespawn gamerule changes)

Chunk Data

Main article: Chunk Format
See also: #Unload Chunk
Huh.png The following information needs to be added to this page:
How do biomes work now? The biome change happened at the same time as the seed change, but it's not clear how/if biomes could be computed given that it's not the actual seed... (/r/mojira discussion which notes that it seems to be some kind of interpolation, and 3D biomes are only used in the nether)

The server only sends skylight information for chunk pillars in the Overworld, it's up to the client to know in which dimenison the player is currently located. You can also infer this information from the primary bitmask and the amount of uncompressed bytes sent. This packet also sends all block entities in the chunk (though sending them is not required; it is still legal to send them with Update Block Entity later).

Packet ID State Bound To Field Name Field Type Notes
0x21 0x22 Play Client Chunk X Int Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z Int Chunk coordinate (block coordinate divided by 16, rounded down)
Full chunk Boolean See Chunk Format
Primary Bit Mask VarInt Bitmask with bits set to 1 for every 16×16×16 chunk section whose data is included in Data. The least significant bit represents the chunk section at the bottom of the chunk column (from y=0 to y=15).
Heightmaps NBT Compound containing one long array named MOTION_BLOCKING, which is a heightmap for the highest solid block at each position in the chunk (as a compacted long array with 256 entries at 9 bits per entry totaling 36 longs). The Notchian server also adds a WORLD_SURFACE long array, the purpose of which is unknown, but it's not required for the chunk to be accepted.
Biomes Optional array of Integer 1024 biome IDs, ordered by x then z then y, in 4×4×4 blocks. Not present if full chunk is false.
Size VarInt Size of Data in bytes
Data Byte array See data structure in Chunk Format
Number of block entities VarInt Number of elements in the following array
Block entities Array of NBT Tag All block entities in the chunk. Use the x, y, and z tags in the NBT to determine their positions.

Note that the Notchian client requires an Update View Position packet when it crosses a chunk border, otherwise it'll only display render distance + 2 chunks around the chunk it spawned in.

To get the biome at a coordinate, use biomes[((y >> 2) & 63) << 4 | ((z >> 2) & 3) << 2 | ((x >> 2) & 3)]

Data structure

The data section of the packet contains most of the useful data for the chunk.

Field Name Field Type Notes
Data Array of Chunk Section The number of elements in the array is equal to the number of bits set in Primary Bit Mask. Sections are sent bottom-to-top, i.e. the first section, if sent, extends from Y=0 to Y=15.
Biomes Optional Int Array Only sent if full chunk is true; 256 entries if present

Particle

Displays the named particle.

Packet ID State Bound To Field Name Field Type Notes
0x23 0x24 Play Client Particle ID Int The particle ID listed in the particle data type.
Long Distance Boolean If true, particle distance increases from 256 to 65536
X Float Double X position of the particle
Y Float Double Y position of the particle
Z Float Double Z position of the particle
Offset X Float This is added to the X position after being multiplied by random.nextGaussian()
Offset Y Float This is added to the Y position after being multiplied by random.nextGaussian()
Offset Z Float This is added to the Z position after being multiplied by random.nextGaussian()
Particle Data Float The data of each particle
Particle Count Int The number of particles to create
Data Varies The variable data listed in the particle data type.

Join Game

See Protocol Encryption for information on logging in.

Packet ID State Bound To Field Name Field Type Notes
0x25 0x26 Play Client Entity ID Int The player's Entity ID (EID)
Gamemode Unsigned Byte 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. Bit 3 (0x8) is the hardcore flag.
Dimension Int Enum -1: Nether, 0: Overworld, 1: End; also, note that this is not a VarInt but instead a regular int.
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed.
Max Players Unsigned Byte Was once used by the client to draw the player list, but now is ignored
Level Type String Enum (16) default, flat, largeBiomes, amplified, customized, buffet, default_1_1
View Distance VarInt Render distance (2-32)
Reduced Debug Info Boolean If true, a Notchian client shows reduced information on the debug screen. For servers in development, this should almost always be false.
Enable respawn screen Boolean Set to false when the doImmediateRespawn gamerule is true

Respawn

To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.

Packet ID State Bound To Field Name Field Type Notes
0x3A 0x3B Play Client Dimension Int Enum -1: The Nether, 0: The Overworld, 1: The End
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed.
Gamemode Unsigned Byte 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included
Level Type String (16) Same as Join Game

Warning.png Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).

If you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.

Serverbound

No changes so far.

Handshaking

Clientbound

There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.

Serverbound

Handshake

This causes the server to switch into the target state.

Packet ID State Bound To Field Name Field Type Notes
0x00 Handshaking Server Protocol Version VarInt See protocol version numbers (currently 498 578)
Server Address String Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a complete redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide mc.example.org as server address in addition to connecting to it.
Server Port Unsigned Short Default is 25565. The Notchian server does not use this information.
Next State VarInt Enum 1 for status, 2 for login

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

No changes so far.

Serverbound

No changes so far.