Difference between revisions of "Pre-release protocol"

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This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently 1.3.1) to the current pre-release (or weekly release).
+
This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently [[Protocol version numbers|1.16.5, protocol 754]]) to the current pre-release (currently [[Protocol version numbers|1.17-rc2, protocol {{Snapshot PVN|1073741859}}]]). Note that this page contains bleeding-edge information that may not be completely or correctly documented.
  
== New packets ==
+
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.
  
-None-
+
== Contents ==
  
== Changed packets ==
+
<div style="float:right;">__TOC__</div>
  
{{anchor|0x4}}
+
=== Data types ===
=== Time Update (0x4) ===
 
  
''Server to Client''
+
No changes so far.
  
 +
=== Packets ===
  
Time is based on ticks, where 20 ticks happen every second. There are 24000 ticks in a day, making Minecraft days exactly 20 minutes long.  
+
{| class="wikitable"
 +
! ID
 +
! Packet name
 +
!colspan="2"| Documentation
 +
|-
 +
!colspan="4"| Play clientbound
 +
{{PacketList|0x05|Sculk Vibration Signal|rel=added}}
 +
{{PacketList|{{change|0x05|0x06}}|Entity Animation (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x06|0x07}}|Statistics|pre=unchanged}}
 +
{{PacketList|{{change|0x07|0x08}}|Acknowledge Player Digging|pre=unchanged}}
 +
{{PacketList|{{change|0x08|0x09}}|Block Break Animation|pre=unchanged}}
 +
{{PacketList|{{change|0x09|0x0A}}|Block Entity Data|pre=unchanged}}
 +
{{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|0x10|Clear Titles|rel=added}}
 +
{{PacketList|{{change|0x0F|0x11}}|Tab-Complete (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x10|0x12}}|Declare Commands|pre=unchanged}}
 +
{{PacketList|0x11|Window Confirmation (clientbound)|pre=removed}}
 +
{{PacketList|{{change|0x12|0x13}}|Close Window (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x13|0x14}}|Window Items|pre=unchanged}}
 +
{{PacketList|{{change|0x14|0x15}}|Window Property|pre=unchanged}}
 +
{{PacketList|{{change|0x15|0x16}}|Set Slot|pre=unchanged}}
 +
{{PacketList|{{change|0x16|0x17}}|Set Cooldown|pre=unchanged}}
 +
{{PacketList|{{change|0x17|0x18}}|Plugin Message (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x18|0x19}}|Named Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x19|0x1A}}|Disconnect (play)|pre=unchanged}}
 +
{{PacketList|{{change|0x1A|0x1B}}|Entity Status|pre=unchanged}}
 +
{{PacketList|{{change|0x1B|0x1C}}|Explosion}}
 +
{{PacketList|{{change|0x1C|0x1D}}|Unload Chunk|pre=unchanged}}
 +
{{PacketList|{{change|0x1D|0x1E}}|Change Game State|pre=unchanged}}
 +
{{PacketList|{{change|0x1E|0x1F}}|Open Horse Window|pre=unchanged}}
 +
{{PacketList|0x20|Initialize World Border|rel=added}}
 +
{{PacketList|{{change|0x1F|0x21}}|Keep Alive (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x20|0x22}}|Chunk Data}}
 +
{{PacketList|{{change|0x21|0x23}}|Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x22|0x24}}|Particle|pre=unchanged}}
 +
{{PacketList|{{change|0x23|0x25}}|Update Light}}
 +
{{PacketList|{{change|0x24|0x26}}|Join Game}}
 +
{{PacketList|{{change|0x25|0x27}}|Map Data}}
 +
{{PacketList|{{change|0x26|0x28}}|Trade List|pre=unchanged}}
 +
{{PacketList|{{change|0x27|0x29}}|Entity Position|pre=unchanged}}
 +
{{PacketList|{{change|0x28|0x2A}}|Entity Position and Rotation|pre=unchanged}}
 +
{{PacketList|{{change|0x29|0x2B}}|Entity Rotation|pre=unchanged}}
 +
{{PacketList|0x2A|Entity Movement|pre=removed}}
 +
{{PacketList|{{change|0x2B|0x2C}}|Vehicle Move (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x2C|0x2D}}|Open Book|pre=unchanged}}
 +
{{PacketList|{{change|0x2D|0x2E}}|Open Window|pre=unchanged}}
 +
{{PacketList|{{change|0x2E|0x2F}}|Open Sign Editor|pre=unchanged}}
 +
{{PacketList|0x30|Ping|rel=added}}
 +
{{PacketList|{{change|0x2F|0x31}}|Craft Recipe Response|pre=unchanged}}
 +
{{PacketList|{{change|0x30|0x32}}|Player Abilities (clientbound)|pre=unchanged}}
 +
{{PacketList|0x31|Combat Event|pre=removed}}
 +
{{PacketList|0x33|End Combat Event|rel=added}}
 +
{{PacketList|0x34|Enter Combat Event|rel=added}}
 +
{{PacketList|0x35|Death Combat Event|rel=added}}
 +
{{PacketList|{{change|0x32|0x36}}|Player Info|pre=unchanged}}
 +
{{PacketList|{{change|0x33|0x37}}|Face Player|pre=unchanged}}
 +
{{PacketList|0x36|Destroy Entities|pre=removed}}
 +
{{PacketList|{{change|0x34|0x38}}|Player Position And Look (clientbound)}}
 +
{{PacketList|{{change|0x35|0x39}}|Unlock Recipes|pre=unchanged}}
 +
{{PacketList|0x3A|Destroy Entity|rel=added}}
 +
{{PacketList|{{change|0x37|0x3B}}|Remove Entity Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x38|0x3C}}|Resource Pack Send}}
 +
{{PacketList|{{change|0x39|0x3D}}|Respawn|pre=unchanged}}
 +
{{PacketList|{{change|0x3A|0x3E}}|Entity Head Look|pre=unchanged}}
 +
{{PacketList|{{change|0x3B|0x3F}}|Multi Block Change|pre=unchanged}}
 +
{{PacketList|{{change|0x3C|0x40}}|Select Advancement Tab|pre=unchanged}}
 +
{{PacketList|0x41|Action Bar|rel=added}}
 +
{{PacketList|0x42|World Border Center|rel=added}}
 +
{{PacketList|0x43|World Border Lerp Size|rel=added}}
 +
{{PacketList|0x44|World Border Size |rel=added}}
 +
{{PacketList|0x45|World Border Warning Delay|rel=added}}
 +
{{PacketList|0x46|World Border Warning Reach|rel=added}}
 +
{{PacketList|{{change|0x3E|0x47}}|Camera|pre=unchanged}}
 +
{{PacketList|{{change|0x3F|0x48}}|Held Item Change (clientbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x40|0x49}}|Update View Position|pre=unchanged}}
 +
{{PacketList|{{change|0x41|0x4A}}|Update View Distance|pre=unchanged}}
 +
{{PacketList|{{change|0x42|0x4B}}|Spawn Position}}
 +
{{PacketList|{{change|0x43|0x4C}}|Display Scoreboard|pre=unchanged}}
 +
{{PacketList|{{change|0x44|0x4D}}|Entity Metadata|pre=unchanged}}
 +
{{PacketList|{{change|0x45|0x4E}}|Attach Entity|pre=unchanged}}
 +
{{PacketList|{{change|0x46|0x4F}}|Entity Velocity|pre=unchanged}}
 +
{{PacketList|{{change|0x47|0x50}}|Entity Equipment|pre=unchanged}}
 +
{{PacketList|0x4F|Title|pre=removed}}
 +
{{PacketList|{{change|0x48|0x51}}|Set Experience|pre=unchanged}}
 +
{{PacketList|{{change|0x49|0x52}}|Update Health|pre=unchanged}}
 +
{{PacketList|{{change|0x4A|0x53}}|Scoreboard Objective|pre=unchanged}}
 +
{{PacketList|{{change|0x4B|0x54}}|Set Passengers|pre=unchanged}}
 +
{{PacketList|{{change|0x4C|0x55}}|Teams|pre=unchanged}}
 +
{{PacketList|{{change|0x4D|0x56}}|Update Score|pre=unchanged}}
 +
{{PacketList|0x57|Set Title SubTitle|rel=added}}
 +
{{PacketList|{{change|0x4E|0x58}}|Time Update|pre=unchanged}}
 +
{{PacketList|0x59|Set Title Text|rel=added}}
 +
{{PacketList|0x5A|Set Title Time|rel=added}}
 +
{{PacketList|{{change|0x50|0x5B}}|Entity Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x51|0x5C}}|Sound Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x52|0x5D}}|Stop Sound|pre=unchanged}}
 +
{{PacketList|{{change|0x53|0x5E}}|Player List Header And Footer|pre=unchanged}}
 +
{{PacketList|{{change|0x54|0x5F}}|NBT Query Response|pre=unchanged}}
 +
{{PacketList|{{change|0x55|0x60}}|Collect Item|pre=unchanged}}
 +
{{PacketList|{{change|0x56|0x61}}|Entity Teleport|pre=unchanged}}
 +
{{PacketList|{{change|0x57|0x62}}|Advancements|pre=unchanged}}
 +
{{PacketList|{{change|0x58|0x63}}|Entity Properties}}
 +
{{PacketList|{{change|0x59|0x64}}|Entity Effect|pre=unchanged}}
 +
{{PacketList|{{change|0x5A|0x65}}|Declare Recipes|pre=unchanged}}
 +
{{PacketList|{{change|0x5B|0x66}}|Tags}}
 +
|-
 +
!colspan="4"| Play serverbound
 +
{{PacketList|0x05|Client Settings}}
 +
{{PacketList|0x07|Window Confirmation (serverbound)|pre=removed}}
 +
{{PacketList|{{change|0x08|0x07}}|Click Window Button|pre=unchanged}}
 +
{{PacketList|{{change|0x09|0x08}}|Click Window}}
 +
{{PacketList|{{change|0x0A|0x09}}|Close Window (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x0B|0x0A}}|Plugin Message (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x0C|0x0B}}|Edit Book|pre=unchanged}}
 +
{{PacketList|{{change|0x0D|0x0C}}|Query Entity NBT|pre=unchanged}}
 +
{{PacketList|{{change|0x0E|0x0D}}|Interact Entity|pre=unchanged}}
 +
{{PacketList|{{change|0x0F|0x0E}}|Generate Structure|pre=unchanged}}
 +
{{PacketList|{{change|0x10|0x0F}}|Keep Alive (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x11|0x10}}|Lock Difficulty|pre=unchanged}}
 +
{{PacketList|{{change|0x12|0x11}}|Player Position|pre=unchanged}}
 +
{{PacketList|{{change|0x13|0x12}}|Player Position And Rotation (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x14|0x13}}|Player Rotation|pre=unchanged}}
 +
{{PacketList|{{change|0x15|0x14}}|Player Movement|pre=unchanged}}
 +
{{PacketList|{{change|0x16|0x15}}|Vehicle Move (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x17|0x16}}|Steer Boat|pre=unchanged}}
 +
{{PacketList|{{change|0x18|0x17}}|Pick Item|pre=unchanged}}
 +
{{PacketList|{{change|0x19|0x18}}|Craft Recipe Request|pre=unchanged}}
 +
{{PacketList|{{change|0x1A|0x19}}|Player Abilities (serverbound)|pre=unchanged}}
 +
{{PacketList|{{change|0x1B|0x1A}}|Player Digging|pre=unchanged}}
 +
{{PacketList|{{change|0x1C|0x1B}}|Entity Action|pre=unchanged}}
 +
{{PacketList|{{change|0x1D|0x1C}}|Steer Vehicle|pre=unchanged}}
 +
{{PacketList|0x1D|Pong|rel=added}}
 +
|-
 +
!colspan="4"| Handshaking serverbound
 +
{{PacketList|0x00|Handshake}}
 +
|}
 +
 
 +
== New/modified data types ==
 +
 
 +
No changes so far.
 +
 
 +
== Entity Metadata ==
 +
 
 +
{{#vardefine:meta_prerelease|1}}
 +
 
 +
{{Warning2|Note that other entities have had metadata shifts due to these changes, not shown here.}}
 +
 
 +
=== Entity ===
 +
 
 +
{{metadata inherit|Entity}}
 +
 
 +
{| class="wikitable"
 +
! Index
 +
! Type
 +
!style="width: 250px;" colspan="2"| Meaning
 +
! Default
 +
|-
 +
|rowspan="9"| {{Metadata id|}}
 +
|rowspan="9"| Byte
 +
! Bit mask
 +
! Meaning
 +
|rowspan="9"| 0
 +
|-
 +
| 0x01
 +
| Is on fire
 +
|-
 +
| 0x02
 +
| Is crouching
 +
|-
 +
| 0x04
 +
| Unused (previously riding)
 +
|-
 +
| 0x08
 +
| Is sprinting
 +
|-
 +
| 0x10
 +
| Is swimming
 +
|-
 +
| 0x20
 +
| Is invisible
 +
|-
 +
| 0x40
 +
| has glowing effect
 +
|-
 +
| 0x80
 +
| Is flying with an {{Minecraft Wiki|elytra}}
 +
|-
 +
| {{Metadata id|}}
 +
| VarInt
 +
|colspan="2"| Air ticks
 +
| 300
 +
|-
 +
| {{Metadata id|}}
 +
| OptChat
 +
|colspan="2"| Custom name
 +
| empty
 +
|-
 +
| {{Metadata id|}}
 +
| Boolean
 +
|colspan="2"| Is custom name visible
 +
| false
 +
|-
 +
| {{Metadata id|}}
 +
| Boolean
 +
|colspan="2"| Is silent
 +
| false
 +
|-
 +
| {{Metadata id|}}
 +
| Boolean
 +
|colspan="2"| Has no gravity
 +
| false
 +
|-
 +
| {{Metadata id|}}
 +
| Pose
 +
|colspan="2"| Pose
 +
| STANDING
 +
|- {{added}}
 +
| {{Metadata id|added}}
 +
| VarInt
 +
|colspan="2"| Ticks frozen in powdered snow
 +
| 0
 +
|}
 +
 
 +
== Block Actions ==
 +
 
 +
No changes so far.
 +
 
 +
== Inventories ==
 +
 
 +
No changes so far.
 +
 
 +
== Plugin Channels ==
 +
 
 +
No changes so far.
 +
 
 +
== Play ==
 +
 
 +
=== Clientbound ===
 +
 
 +
==== Sculk Vibration Signal ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| 0x05
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| Source Position
 +
| Position
 +
| Source position for the vibration.
 +
|-
 +
| Destination Identifier
 +
| Identifier
 +
| Identifier of the destination codec type.
 +
|-
 +
| Destination
 +
| Varies
 +
| Vanilla default destinations are a block position encoded as a [https://wiki.vg/Protocol#Data_types Position] for "block" or an entity id encoded as a VarInt for "entity".
 +
|-
 +
| Arrival Ticks
 +
| VarInt
 +
| Ticks for the signal to arrive at the destination.
 +
|}
 +
This packet shows a permanent particle.
 +
 
 +
==== Clear Titles====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Added }}
 +
|rowspan="4"| 0x10
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
|- {{ Added }}
 +
| Reset
 +
| Boolean
 +
|
 +
|-
 +
|}
 +
 
 +
==== Explosion ====
 +
 
 +
Sent when an explosion occurs (creepers, TNT, and ghast fireballs).
 +
 
 +
Each block in Records is set to air. Coordinates for each axis in record is int(X) + record.x
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="9"| 0x1B
 +
|rowspan="9"| Play
 +
|rowspan="9"| Client
 +
| X
 +
| Float
 +
|
 +
|-
 +
| Y
 +
| Float
 +
|
 +
|-
 +
| Z
 +
| Float
 +
|
 +
|-
 +
| Strength
 +
| Float
 +
| A strength greater than or equal to 2.0 spawns a <code>minecraft:explosion_emitter</code> particle, while a lesser strength spawns a <code>minecraft:explosion</code> particle.
 +
|-
 +
| Record Count
 +
| {{change|Int|VarInt}}
 +
| Number of elements in the following array.
 +
|-
 +
| Records
 +
| Array of (Byte, Byte, Byte)
 +
| Each record is 3 signed bytes long; the 3 bytes are the XYZ (respectively) signed offsets of affected blocks.
 +
|-
 +
| Player Motion X
 +
| Float
 +
| X velocity of the player being pushed by the explosion.
 +
|-
 +
| Player Motion Y
 +
| Float
 +
| Y velocity of the player being pushed by the explosion.
 +
|-
 +
| Player Motion Z
 +
| Float
 +
| Z velocity of the player being pushed by the explosion.
 +
|}
 +
 
 +
==== Initialize World Border ====
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Added }}
 +
|rowspan="8"| 0x20
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
| X
 +
| Double
 +
|
 +
|- {{ Added }}
 +
| Z
 +
| Double
 +
|
 +
|- {{ Added }}
 +
| Old Diameter
 +
| Double
 +
| Current length of a single side of the world border, in meters.
 +
|- {{ Added }}
 +
| New Diameter
 +
| Double
 +
| Target length of a single side of the world border, in meters.
 +
|- {{ Added }}
 +
| Speed
 +
| VarLong
 +
| Number of real-time ''milli''seconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
 +
|- {{ Added }}
 +
| Portal Teleport Boundary
 +
| VarInt
 +
| Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
 +
|- {{ Added }}
 +
| Warning Blocks
 +
| VarInt
 +
| In meters.
 +
|- {{ Added }}
 +
| Warning Time
 +
| VarInt
 +
| In seconds as set by <code>/worldborder warning time</code>.
 +
|- {{ Added }}
 +
|}
 +
 
 +
The Notchian client determines how solid to display the warning by comparing to whichever is higher, the warning distance or whichever is lower, the distance from the current diameter to the target diameter or the place the border will be after warningTime seconds. In pseudocode:
 +
 
 +
<syntaxhighlight lang="java">
 +
distance = max(min(resizeSpeed * 1000 * warningTime, abs(targetDiameter - currentDiameter)), warningDistance);
 +
if (playerDistance < distance) {
 +
    warning = 1.0 - playerDistance / distance;
 +
} else {
 +
    warning = 0.0;
 +
}
 +
</syntaxhighlight>
 +
 
 +
==== Chunk Data ====
 +
{{Main|Chunk Format}}
 +
{{See also|#Unload Chunk}}
 +
 
 +
{{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)}}
 +
 
 +
The server only sends skylight information for chunk pillars in the {{Minecraft Wiki|Overworld}}, it's up to the client to know in which dimension 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"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="13"| {{change|0x20|0x22}}
 +
|rowspan="13"| Play
 +
|rowspan="13"| 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)
 +
|- {{removed}}
 +
| Full chunk
 +
| Boolean
 +
| See [[Chunk Format#Full chunk|Chunk Format]]
 +
|- {{removed}}
 +
| 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).
 +
|- {{added}}
 +
| Bit Mask Length
 +
| VarInt
 +
| Length of the following array
 +
|- {{added}}
 +
| Primary Bit Mask
 +
| Array of Long
 +
| BitSet with bits (world height in blocks / 16) 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 the lowest y to 15 blocks above).
 +
|-
 +
| Heightmaps
 +
| [[NBT]]
 +
| 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.
 +
|-
 +
| Biomes length
 +
| {{change|Optional|}} VarInt
 +
| Size of the following array; should always be 1024.  {{change|Not present if full chunk is false.|}}
 +
|-
 +
| Biomes
 +
| {{change|Optional|}} Array of VarInt
 +
| 1024 biome IDs, ordered by x then z then y, in 4&times;4&times;4 blocks.  {{change|Not present if full chunk is false.|}}  See [[Chunk Format#Biomes|Chunk Format § Biomes]].
 +
|-
 +
| Size
 +
| VarInt
 +
| Size of Data in bytes
 +
|-
 +
| Data
 +
| Byte array
 +
| See [[Chunk Format#Data structure|data structure]] in Chunk Format
 +
|-
 +
| Number of block entities
 +
| VarInt
 +
| Number of elements in the following array
 +
|-
 +
| Block entities
 +
| Array of [[NBT|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|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.
 +
 
 +
The compacted array format has been adjusted so that individual entries no longer span across multiple longs, affecting the main data array and heightmaps.
 +
 
 +
New format, 5 bits per block, containing the following references to blocks in a palette (not shown): <span style="border: solid 2px hsl(0, 90%, 60%)">1</span><span style="border: solid 2px hsl(30, 90%, 60%)">2</span><span style="border: solid 2px hsl(60, 90%, 60%)">2</span><span style="border: solid 2px hsl(90, 90%, 60%)">3</span><span style="border: solid 2px hsl(120, 90%, 60%)">4</span><span style="border: solid 2px hsl(150, 90%, 60%)">4</span><span style="border: solid 2px hsl(180, 90%, 60%)">5</span><span style="border: solid 2px hsl(210, 90%, 60%)">6</span><span style="border: solid 2px hsl(240, 90%, 60%)">6</span><span style="border: solid 2px hsl(270, 90%, 60%)">4</span><span style="border: solid 2px hsl(300, 90%, 60%)">8</span><span style="border: solid 2px hsl(330, 90%, 60%)">0</span><span style="border: solid 2px hsl(0, 90%, 30%)">7</span><span style="border: solid 2px hsl(30, 90%, 30%)">4</span><span style="border: solid 2px hsl(60, 90%, 30%)">3</span><span style="border: solid 2px hsl(90, 90%, 30%)">13</span><span style="border: solid 2px hsl(120, 90%, 30%)">15</span><span style="border: solid 2px hsl(150, 90%, 30%)">16</span><span style="border: solid 2px hsl(180, 90%, 30%)">9</span><span style="border: solid 2px hsl(210, 90%, 30%)">14</span><span style="border: solid 2px hsl(240, 90%, 30%)">10</span><span style="border: solid 2px hsl(270, 90%, 30%)">12</span><span style="border: solid 2px hsl(300, 90%, 30%)">0</span><span style="border: solid 2px hsl(330, 90%, 30%)">2</span>
 +
 
 +
<code>0020863148418841</code> <code><span style="outline: dashed 2px black">0000</span><span style="outline: solid 2px hsl(330, 90%, 60%)">00000</span><span style="outline: solid 2px hsl(300, 90%, 60%)">01000</span><span style="outline: solid 2px hsl(270, 90%, 60%)">00100</span><span style="outline: solid 2px hsl(240, 90%, 60%)">00110</span><span style="outline: solid 2px hsl(210, 90%, 60%)">00110</span><span style="outline: solid 2px hsl(180, 90%, 60%)">00101</span><span style="outline: solid 2px hsl(150, 90%, 60%)">00100</span><span style="outline: solid 2px hsl(120, 90%, 60%)">00100</span><span style="outline: solid 2px hsl(90, 90%, 60%)">00011</span><span style="outline: solid 2px hsl(60, 90%, 60%)">00010</span><span style="outline: solid 2px hsl(30, 90%, 60%)">00010</span><span style="outline: solid 2px hsl(0, 90%, 60%)">00001</span></code><br>
 +
<code>01018A7260F68C87</code> <code><span style="outline: dashed 2px black">0000</span><span style="outline: solid 2px hsl(330, 90%, 30%)">00010</span><span style="outline: solid 2px hsl(300, 90%, 30%)">00000</span><span style="outline: solid 2px hsl(270, 90%, 30%)">01100</span><span style="outline: solid 2px hsl(240, 90%, 30%)">01010</span><span style="outline: solid 2px hsl(210, 90%, 30%)">01110</span><span style="outline: solid 2px hsl(180, 90%, 30%)">01001</span><span style="outline: solid 2px hsl(150, 90%, 30%)">10000</span><span style="outline: solid 2px hsl(120, 90%, 30%)">01111</span><span style="outline: solid 2px hsl(90, 90%, 30%)">01101</span><span style="outline: solid 2px hsl(60, 90%, 30%)">00011</span><span style="outline: solid 2px hsl(30, 90%, 30%)">00100</span><span style="outline: solid 2px hsl(0, 90%, 30%)">00111</span></code>
 +
 
 +
==== Entity Movement ====
 +
 
 +
This packet may be used to initialize an entity.
 +
 
 +
For player entities, either this packet or any move/look packet is sent every game tick. So the meaning of this packet is basically that the entity did not move/look since the last such packet.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{removed}}
 +
| 0x2A
 +
| Play
 +
| Client
 +
| Entity ID
 +
| VarInt
 +
|
 +
|}
 +
 
 +
==== Ping ====
 +
 
 +
Unknown what this packet does just yet, not used by the Notchian server or client.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{added}}
 +
| 0x30
 +
| Play
 +
| Client
 +
| ID
 +
| Int
 +
|
 +
|}
 +
 
 +
==== Update Light ====
 +
 
 +
Updates light levels for a chunk.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
!colspan="2"| Field Type
 +
! Notes
 +
|-
 +
|rowspan="21"| {{change|0x23|0x25}}
 +
|rowspan="21"| Play
 +
|rowspan="21"| Client
 +
|colspan="2"| Chunk X
 +
|colspan="2"| VarInt
 +
| Chunk coordinate (block coordinate divided by 16, rounded down)
 +
|-
 +
|colspan="2"| Chunk Z
 +
|colspan="2"| VarInt
 +
| Chunk coordinate (block coordinate divided by 16, rounded down)
 +
|-
 +
|colspan="2"| Trust Edges
 +
|colspan="2"| Boolean
 +
| If edges should be trusted for light updates.
 +
|- {{removed}}
 +
|colspan="2"| Sky Light Mask
 +
|colspan="2"| VarInt
 +
| Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
 +
|- {{removed}}
 +
|colspan="2"| Block Light Mask
 +
|colspan="2"| VarInt
 +
| Mask containing 18 bits, with the same order as sky light
 +
|- {{removed}}
 +
|colspan="2"| Empty Sky Light Mask
 +
|colspan="2"| VarInt
 +
| Mask containing 18 bits, which indicates sections that have 0 for all their sky light values.  If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks).  If it is only set in this mask, it is not included in the sky light arrays.
 +
|- {{removed}}
 +
|colspan="2"| Empty Block Light Mask
 +
|colspan="2"| VarInt
 +
| Mask containing 18 bits, which indicates sections that have 0 for all their block light values.  If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks).  If it is only set in this mask, it is not included in the block light arrays.
 +
|- {{Added}}
 +
|colspan="2"| Length 1
 +
|colspan="2"| VarInt
 +
| Length of the following array
 +
|- {{Added}}
 +
|colspan="2"| Sky Light Mask
 +
|colspan="2"| Array of Long
 +
| BitSet containing bits for each sections in the world + 2 (lowest bit 16-1 blocks below min world height, highest 1-16 above max world height)
 +
|- {{Added}}
 +
|colspan="2"| Length 2
 +
|colspan="2"| VarInt
 +
| Length of the following array
 +
|- {{Added}}
 +
|colspan="2"| Block Light Mask
 +
|colspan="2"| Array of Long
 +
| BitSet containing bits for each sections in the world + 2, same order as sky light
 +
|- {{Added}}
 +
|colspan="2"| Length 3
 +
|colspan="2"| VarInt
 +
| Length of the following array
 +
|- {{Added}}
 +
|colspan="2"| Empty Sky Light Mask
 +
|colspan="2"| Array of Long
 +
| BitSet containing a variable amount of bits (see sky/block light) which indicates sections that have 0 for all their sky light values
 +
|- {{Added}}
 +
|colspan="2"| Length 4
 +
|colspan="2"| VarInt
 +
| Length of the following array
 +
|- {{Added}}
 +
|colspan="2"| Empty Block Light Mask
 +
|colspan="2"| Array of Long
 +
| BitSet containing a variable amount of bits (see sky/block light) which indicates sections that have 0 for all their block light values
 +
|- {{added}}
 +
|colspan="2"| Sky Light array count
 +
|colspan="2"| VarInt
 +
| Number of entries in the following array
 +
|-
 +
|rowspan="2"| Sky Light arrays
 +
| Length
 +
|rowspan="2"| Array
 +
| VarInt
 +
| Length of the following array in bytes (always 2048)
 +
|-
 +
| Sky Light array
 +
| Array of 2048 bytes
 +
| There is 1 array for each bit set to true in the sky light mask, starting with the lowest value.  Half a byte per light value.
 +
|- {{added}}
 +
|colspan="2"| Block Light array count
 +
|colspan="2"| VarInt
 +
| Number of entries in the following array
 +
|-
 +
|rowspan="2"| Block Light arrays
 +
| Length
 +
|rowspan="2"| Array
 +
| VarInt
 +
| Length of the following array in bytes (always 2048)
 +
|-
 +
| Block Light array
 +
| Array of 2048 bytes
 +
| There is 1 array for each bit set to true in the block light mask, starting with the lowest value.  Half a byte per light value.
 +
|}
 +
 
 +
==== Join Game ====
 +
 
 +
See [[Protocol Encryption]] for information on logging in.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="16"| 0x24
 +
|rowspan="16"| Play
 +
|rowspan="16"| Client
 +
| Entity ID
 +
| Int
 +
| The player's Entity ID (EID).
 +
|-
 +
| Is hardcore
 +
| Boolean
 +
|
 +
|-
 +
| Gamemode
 +
| Unsigned Byte
 +
| 0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
 +
|-
 +
| Previous Gamemode
 +
| Byte
 +
| 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included. The previous gamemode. Defaults to -1 if there is no previous gamemode. (More information needed)
 +
|-
 +
| World Count
 +
| VarInt
 +
| Size of the following array.
 +
|-
 +
| World Names
 +
| Array of Identifier
 +
| Identifiers for all worlds on the server.
 +
|-
 +
| Dimension Codec
 +
| [[NBT|NBT Tag Compound]]
 +
| The full extent of these is still unknown, but the tag represents a dimension and biome registry. See below for the vanilla default.
 +
|-
 +
| Dimension
 +
| [[NBT|NBT Tag Compound]]
 +
| Valid dimensions are defined per dimension registry sent before this. The structure of this tag is a dimension type (see below).
 +
|-
 +
| World Name
 +
| Identifier
 +
| Name of the world being spawned into.
 +
|-
 +
| Hashed seed
 +
| Long
 +
| First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
 +
|-
 +
| Max Players
 +
| VarInt
 +
| Was once used by the client to draw the player list, but now is ignored.
 +
|-
 +
| View Distance
 +
| VarInt
 +
| 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.
 +
|-
 +
| Enable respawn screen
 +
| Boolean
 +
| Set to false when the doImmediateRespawn gamerule is true.
 +
|-
 +
| Is Debug
 +
| Boolean
 +
| True if the world is a {{Minecraft Wiki|debug mode}} world; debug mode worlds cannot be modified and have predefined blocks.
 +
|-
 +
| Is Flat
 +
| Boolean
 +
| True if the world is a {{Minecraft Wiki|superflat}} world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
 +
|}
 +
 
 +
 
 +
The '''Dimension Codec''' NBT Tag Compound ([https://gist.githubusercontent.com/BomBardyGamer/c075a7a34b51f2df9d5aabdd2a762f4f/raw/c7352784dfadbca00d2282aeca04ed80081bfb09/dimension_codec.snbt Default value in SNBT]) includes two registries: "minecraft:dimension_type" and "minecraft:worldgen/biome".
 +
 
 +
{| class="wikitable"
 +
!Name
 +
!Type
 +
!style="width: 250px;" colspan="2"| Notes
 +
|-
 +
| minecraft:dimension_type
 +
| TAG_Compound
 +
| The dimension type registry (see below).
 +
|-
 +
| minecraft:worldgen/biome
 +
| TAG_Compound
 +
| The biome registry (see below).
 +
|}
 +
 
 +
Dimension type registry:
 +
 
 +
{| class="wikitable"
 +
!Name
 +
!Type
 +
!style="width: 250px;" colspan="2"| Notes
 +
|-
 +
| type
 +
| TAG_String
 +
| The name of the registry. Always "minecraft:dimension_type".
 +
|-
 +
| value
 +
| TAG_List
 +
| List of dimension types registry entries (see below).
 +
|}
 +
 
 +
Dimension type registry entry:
 +
 
 +
{| class="wikitable"
 +
!Name
 +
!Type
 +
!style="width: 250px;" colspan="2"| Notes
 +
|-
 +
| name
 +
| TAG_String
 +
| The name of the dimension type (for example, "minecraft:overworld").
 +
|-
 +
| id
 +
| TAG_Int
 +
| The protocol ID of the dimension (matches the index of the element in the registry list).
 +
|-
 +
| element
 +
| TAG_Compound
 +
| The dimension type (see below).
 +
|}
 +
 
 +
Dimension type:
 +
 
 +
{| class="wikitable"
 +
! Name
 +
! Type
 +
!style="width: 250px;" colspan="2"| Meaning
 +
! Values
 +
|-
 +
| piglin_safe
 +
| TAG_Byte
 +
|colspan="2"| Whether piglins shake and transform to zombified piglins.
 +
| 1: true, 0: false.
 +
|-
 +
| natural
 +
| TAG_Byte
 +
|colspan="2"| When false, compasses spin randomly. When true, nether portals can spawn zombified piglins.
 +
| 1: true, 0: false.
 +
|-
 +
| ambient_light
 +
| TAG_Float
 +
|colspan="2"| How much light the dimension has.
 +
| 0.0 to 1.0.
 +
|-
 +
| fixed_time
 +
| Optional TAG_Long
 +
|colspan="2"| If set, the time of the day is the specified value.
 +
| If set, 0 to 24000.
 +
|-
 +
| infiniburn
 +
| TAG_String
 +
|colspan="2"| A resource location defining what block tag to use for infiniburn.
 +
| "" or minecraft resource "minecraft:...".
 +
|-
 +
| respawn_anchor_works
 +
| TAG_Byte
 +
|colspan="2"| Whether players can charge and use respawn anchors.
 +
| 1: true, 0: false.
 +
|-
 +
| has_skylight
 +
| TAG_Byte
 +
|colspan="2"| Whether the dimension has skylight access or not.
 +
| 1: true, 0: false.
 +
|-
 +
| bed_works
 +
| TAG_Byte
 +
|colspan="2"| Whether players can use a bed to sleep.
 +
| 1: true, 0: false.
 +
|-
 +
| effects
 +
| TAG_String
 +
|colspan="2"| ?
 +
| "minecraft:overworld", "minecraft:the_nether", "minecraft:the_end" or something else.
 +
|-
 +
| has_raids
 +
| TAG_Byte
 +
|colspan="2"| Whether players with the Bad Omen effect can cause a raid.
 +
| 1: true, 0: false.
 +
|- {{added}}
 +
| min_y
 +
| TAG_Int
 +
|colspan="2"| The minimum Y level.
 +
|
 +
|- {{added}}
 +
| height
 +
| TAG_Int
 +
|colspan="2"| The maximum height.
 +
|
 +
|-
 +
| logical_height
 +
| TAG_Int
 +
|colspan="2"| The maximum height to which chorus fruits and nether portals can bring players within this dimension.
 +
| 0-256.
 +
|-
 +
| coordinate_scale
 +
| TAG_Float
 +
|colspan="2"| The multiplier applied to coordinates when traveling to the dimension.
 +
| 1: true, 0: false.
 +
|-
 +
| ultrawarm
 +
| TAG_Byte
 +
|colspan="2"| Whether the dimensions behaves like the nether (water evaporates and sponges dry) or not. Also causes lava to spread thinner.
 +
| 1: true, 0: false.
 +
|-
 +
| has_ceiling
 +
| TAG_Byte
 +
|colspan="2"| Whether the dimension has a bedrock ceiling or not. When true, causes lava to spread faster.
 +
| 1: true, 0: false.
 +
|}
 +
 
 +
Biome registry:
 +
 
 +
{| class="wikitable"
 +
!Name
 +
!Type
 +
!style="width: 250px;" colspan="2"| Notes
 +
|-
 +
| type
 +
| TAG_String
 +
| The name of the registry. Always "minecraft:worldgen/biome".
 +
|-
 +
| value
 +
| TAG_List
 +
| List of biome registry entries (see below).
 +
|}
 +
 
 +
Biome registry entry:
 +
 
 +
{| class="wikitable"
 +
!Name
 +
!Type
 +
!style="width: 250px;" colspan="2"| Notes
 +
|-
 +
| name
 +
| TAG_String
 +
| The name of the biome (for example, "minecraft:ocean").
 +
|-
 +
| id
 +
| TAG_Int
 +
| The protocol ID of the biome (matches the index of the element in the registry list).
 +
|-
 +
| element
 +
| TAG_Compound
 +
| The biome properties (see below).
 +
|}
 +
 
 +
Biome properties:
 +
 
 +
{| class="wikitable"
 +
!colspan="2"|Name
 +
!colspan="2"|Type
 +
!style="width: 250px;" colspan="2"| Meaning
 +
!colspan="2"|Values
 +
|-
 +
|colspan="2"|precipitation
 +
|colspan="2"|TAG_String
 +
|colspan="2"| The type of precipitation in the biome.
 +
|colspan="2"|"rain", "snow", or "none".
 +
|-
 +
|colspan="2"| depth
 +
|colspan="2"| TAG_Float
 +
|colspan="2"| The depth factor of the biome.
 +
|colspan="2"| The default values vary between 1.5 and -1.8.
 +
|-
 +
|colspan="2"| temperature
 +
|colspan="2"| TAG_Float
 +
|colspan="2"| The temperature factor of the biome.
 +
|colspan="2"| The default values vary between 2.0 and -0.5.
 +
|-
 +
|colspan="2"| scale
 +
|colspan="2"| TAG_Float
 +
|colspan="2"| ?
 +
|colspan="2"| The default values vary between 1.225 and 0.0.
 +
|-
 +
|colspan="2"| downfall
 +
|colspan="2"| TAG_Float
 +
|colspan="2"| ?
 +
|colspan="2"| The default values vary between 1.0 and 0.0.
 +
|-
 +
|colspan="2"| category
 +
|colspan="2"| TAG_String
 +
|colspan="2"| The category of the biome.
 +
|colspan="2"| Known values are "ocean", "plains", "desert", "forest", "extreme_hills", "taiga", "swamp", "river", "nether", "the_end", "icy", "mushroom", "beach", "jungle", "mesa", "savanna", and "none".
 +
|-
 +
|colspan="2"| temperature_modifier
 +
|colspan="2"| Optional TAG_String
 +
|colspan="2"| ?
 +
|colspan="2"| The only known value is "frozen".
 +
|-
 +
|rowspan="11"| effects
 +
| sky_color
 +
|rowspan="11"| TAG_Compound
 +
| TAG_Int
 +
|colspan="2"| The color of the sky.
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| water_fog_color
 +
| TAG_Int
 +
|colspan="2"| Possibly the tint color when swimming.
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| fog_color
 +
| TAG_Int
 +
|colspan="2"| Possibly the color of the fog effect when looking past the view distance.
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| water_color
 +
| TAG_Int
 +
|colspan="2"| The tint color of the water blocks.
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| foliage_color
 +
| Optional TAG_Int
 +
|colspan="2"| The tint color of the grass.
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| grass_color
 +
| Optional TAG_Int
 +
| colspan="2"| ?
 +
| Example: 8364543, which is #7FA1FF in RGB.
 +
|-
 +
| grass_color_modifier
 +
| Optional TAG_String
 +
|colspan="2"| Unknown, likely affects foliage color.
 +
| If set, known values are "swamp" and "dark_forest".
 +
|-
 +
| music
 +
| Optional TAG_Compound
 +
|colspan="2"| Music properties for the biome.
 +
| If present, contains the fields: replace_current_music (TAG_Byte), sound (TAG_String), max_delay (TAG_Int), min_delay (TAG_Int).
 +
|-
 +
| ambient_sound
 +
| Optional TAG_String
 +
|colspan="2"| Ambient soundtrack.
 +
| If present, the ID of a soundtrack. Example: "minecraft:ambient.basalt_deltas.loop".
 +
|-
 +
| additions_sound
 +
| Optional TAG_Compound
 +
|colspan="2"| Additional ambient sound that plays randomly.
 +
| If present, contains the fields: sound (TAG_String), tick_chance (TAG_Double).
 +
|-
 +
| mood_sound
 +
| Optional TAG_Compound
 +
|colspan="2"| Additional ambient sound that plays at an interval.
 +
| If present, contains the fields: sound (TAG_String), tick_delay (TAG_Int), offset (TAG_Double), block_search_extent (TAG_Int).
 +
|-
 +
| particle
 +
| Optional TAG_Compound
 +
|colspan="2"| Particles that appear randomly in the biome.
 +
| If present, contains the fields: probability (TAG_Float), options (TAG_Compound). The "options" compound contains the field "type" (TAG_String), which identifies the particle type.
 +
|}
 +
 
 +
==== Map Data ====
 +
 
 +
Updates a rectangular area on a {{Minecraft Wiki|map}} item.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
!colspan="2"| Field Type
 +
! Notes
 +
|-
 +
|rowspan="18"| {{change|0x25|0x27}}
 +
|rowspan="18"| Play
 +
|rowspan="18"| Client
 +
|colspan="2"| Map ID
 +
|colspan="2"| VarInt
 +
| Map ID of the map being modified
 +
|-
 +
|colspan="2"| Scale
 +
|colspan="2"| Byte
 +
| From 0 for a fully zoomed-in map (1 block per pixel) to 4 for a fully zoomed-out map (16 blocks per pixel)
 +
|- {{removed}}
 +
|colspan="2"| Tracking Position
 +
|colspan="2"| Boolean
 +
| Specifies whether player and item frame icons are shown
 +
|-
 +
|colspan="2"| Locked
 +
|colspan="2"| Boolean
 +
| True if the map has been locked in a cartography table
 +
|-
 +
|- {{added}}
 +
|colspan="2"| Tracking Position
 +
|colspan="2"| Boolean
 +
| Specifies whether player and item frame icons are shown
 +
|-
 +
|colspan="2"| Icon Count
 +
|colspan="2"| VarInt
 +
| Number of elements in the following array. {{change||Only present if "Tracking Position" is true.}}
 +
|-
 +
|rowspan="6"| Icon
 +
| Type
 +
|rowspan="6"| Array
 +
| VarInt enum
 +
| See below
 +
|-
 +
| X
 +
| Byte
 +
| Map coordinates: -128 for furthest left, +127 for furthest right
 +
|-
 +
| Z
 +
| Byte
 +
| Map coordinates: -128 for highest, +127 for lowest
 +
|-
 +
| Direction
 +
| Byte
 +
| 0-15
 +
|-
 +
| Has Display Name
 +
| Boolean
 +
|
 +
|-
 +
| Display Name
 +
| Optional [[Chat]]
 +
| Only present if previous Boolean is true
 +
|-
 +
|colspan="2"| Columns
 +
|colspan="2"| Unsigned Byte
 +
| Number of columns updated
 +
|-
 +
|colspan="2"| Rows
 +
|colspan="2"| Optional Byte
 +
| Only if Columns is more than 0; number of rows updated
 +
|-
 +
|colspan="2"| X
 +
|colspan="2"| Optional Byte
 +
| Only if Columns is more than 0; x offset of the westernmost column
 +
|-
 +
|colspan="2"| Z
 +
|colspan="2"| Optional Byte
 +
| Only if Columns is more than 0; z offset of the northernmost row
 +
|-
 +
|colspan="2"| Length
 +
|colspan="2"| Optional VarInt
 +
| Only if Columns is more than 0; length of the following array
 +
|-
 +
|colspan="2"| Data
 +
|colspan="2"| Optional Array of Unsigned Byte
 +
| Only if Columns is more than 0; see {{Minecraft Wiki|Map item format}}
 +
|}
 +
 
 +
For icons, a direction of 0 is a vertical icon and increments by 22.5&deg; (360/16).
 +
 
 +
Types are based off of rows and columns in <code>map_icons.png</code>:
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Icon type
 +
! Result
 +
|-
 +
| 0
 +
| White arrow (players)
 +
|-
 +
| 1
 +
| Green arrow (item frames)
 +
|-
 +
| 2
 +
| Red arrow
 +
|-
 +
| 3
 +
| Blue arrow
 +
|-
 +
| 4
 +
| White cross
 +
|-
 +
| 5
 +
| Red pointer
 +
|-
 +
| 6
 +
| White circle (off-map players)
 +
|-
 +
| 7
 +
| Small white circle (far-off-map players)
 +
|-
 +
| 8
 +
| Mansion
 +
|-
 +
| 9
 +
| Temple
 +
|-
 +
| 10
 +
| White Banner
 +
|-
 +
| 11
 +
| Orange Banner
 +
|-
 +
| 12
 +
| Magenta Banner
 +
|-
 +
| 13
 +
| Light Blue Banner
 +
|-
 +
| 14
 +
| Yellow Banner
 +
|-
 +
| 15
 +
| Lime Banner
 +
|-
 +
| 16
 +
| Pink Banner
 +
|-
 +
| 17
 +
| Gray Banner
 +
|-
 +
| 18
 +
| Light Gray Banner
 +
|-
 +
| 19
 +
| Cyan Banner
 +
|-
 +
| 20
 +
| Purple Banner
 +
|-
 +
| 21
 +
| Blue Banner
 +
|-
 +
| 22
 +
| Brown Banner
 +
|-
 +
| 23
 +
| Green Banner
 +
|-
 +
| 24
 +
| Red Banner
 +
|-
 +
| 25
 +
| Black Banner
 +
|-
 +
| 26
 +
| Treasure marker
 +
|}
 +
 
 +
==== Combat Event ====
 +
 
 +
Originally used for metadata for twitch streaming circa 1.8.  Now only used to display the game over screen (with enter combat and end combat completely ignored by the Notchain client)
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
! Field Type
 +
! Notes
 +
|- {{Removed}}
 +
|rowspan="8"| 0x31
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
|colspan="2"| Event
 +
| VarInt Enum
 +
| Determines the layout of the remaining packet.
 +
|- {{Removed}}
 +
! Event
 +
! Field Name
 +
!
 +
!
 +
|- {{Removed}}
 +
| 0: enter combat
 +
| ''no fields''
 +
| ''no fields''
 +
|
 +
|- {{Removed}}
 +
|rowspan="2"| 1: end combat
 +
| Duration
 +
| VarInt
 +
| Length of the combat in ticks.
 +
|- {{Removed}}
 +
| Entity ID
 +
| Int
 +
| ID of the primary opponent of the ended combat, or -1 if there is no obvious primary opponent.
 +
|- {{Removed}}
 +
|rowspan="3"| 2: entity dead
 +
| Player ID
 +
| VarInt
 +
| Entity ID of the player that died (should match the client's entity ID).
 +
|- {{Removed}}
 +
| Entity ID
 +
| Int
 +
| The killing entity's ID, or -1 if there is no obvious killer.
 +
|- {{Removed}}
 +
| Message
 +
| [[Chat]]
 +
| The death message.
 +
|}
 +
 
 +
==== End Combat Event ====
 +
 
 +
Unused by the Notchain client.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
! Field Type
 +
! Notes
 +
|- {{Added}}
 +
|rowspan="8"| 0x32
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
| Duration
 +
| VarInt
 +
| Length of the combat in ticks.
 +
|- {{Added}}
 +
| Entity ID
 +
| Int
 +
| ID of the primary opponent of the ended combat, or -1 if there is no obvious primary opponent.
 +
|- {{Added}}
 +
|}
 +
 
 +
==== Enter Combat Event ====
 +
 
 +
Unused by the Notchain client.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
! Field Type
 +
! Notes
 +
|- {{Added}}
 +
|rowspan="8"| 0x33
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
|}
 +
 
 +
 
 +
==== Death Combat Event ====
 +
 
 +
Used to send a respawn screen.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
! Field Type
 +
! Notes
 +
|- {{Added}}
 +
|rowspan="8"| 0x34
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
| Player ID
 +
| VarInt
 +
| Entity ID of the player that died (should match the client's entity ID).
 +
|- {{Added}}
 +
| Entity ID
 +
| Int
 +
| The killing entity's ID, or -1 if there is no obvious killer.
 +
|- {{Added}}
 +
| Message
 +
| [[Chat]]
 +
| The death message.
 +
|}
 +
 
 +
==== Player Position And Look (clientbound) ====
 +
 
 +
Updates the player's position on the server. This packet will also close the “Downloading Terrain” screen when joining/respawning.
 +
 
 +
If the distance between the last known position of the player on the server and the new position set by this packet is greater than 100 meters, the client will be kicked for “You moved too quickly :( (Hacking?)”.
 +
 
 +
Also if the fixed-point number of X or Z is set greater than <code>3.2E7D</code> the client will be kicked for “Illegal position”.
 +
 
 +
Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the XZ-plane starts at (0, 1) and turns counterclockwise, with 90 at (-1, 0), 180 at (0, -1) and 270 at (1, 0). Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360.
 +
 
 +
Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="8"| {{change|0x34|0x38}}
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
| X
 +
| Double
 +
| Absolute or relative position, depending on Flags.
 +
|-
 +
| Y
 +
| Double
 +
| Absolute or relative position, depending on Flags.
 +
|-
 +
| Z
 +
| Double
 +
| Absolute or relative position, depending on Flags.
 +
|-
 +
| Yaw
 +
| Float
 +
| Absolute or relative rotation on the X axis, in degrees.
 +
|-
 +
| Pitch
 +
| Float
 +
| Absolute or relative rotation on the Y axis, in degrees.
 +
|-
 +
| Flags
 +
| Byte
 +
| Bit field, see below.
 +
|-
 +
| Teleport ID
 +
| VarInt
 +
| Client should confirm this packet with [[#Teleport Confirm|Teleport Confirm]] containing the same Teleport ID.
 +
|- {{added}}
 +
| Dismount Vehicle
 +
| Boolean
 +
| True if the player should dismount their vehicle.
 +
|}
 +
 
 +
About the Flags field:
 +
 
 +
<Dinnerbone> It's a bitfield, X/Y/Z/Y_ROT/X_ROT. If X is set, the x value is relative and not absolute.
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Field
 +
! Bit
 +
|-
 +
| X
 +
| 0x01
 +
|-
 +
| Y
 +
| 0x02
 +
|-
 +
| Z
 +
| 0x04
 +
|-
 +
| Y_ROT
 +
| 0x08
 +
|-
 +
| X_ROT
 +
| 0x10
 +
|}
 +
 
 +
==== Destroy Entity ====
 +
 
 +
Sent by the server when {{change|a list of entities|an entity}} is to be destroyed on the client.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| 0x36
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
|- {{removed}}
 +
| Count
 +
| VarInt
 +
| Number of elements in the following array.
 +
|- {{Removed}}
 +
| Array of VarInt
 +
| The list of entities of destroy.
 +
|- {{Added}}
 +
| Entity ID
 +
| VarInt
 +
|}
 +
 
 +
==== Resource Pack Send ====
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| {{change|0x38|0x3B}}
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| URL
 +
| String (32767)
 +
| The URL to the resource pack.
 +
|-
 +
| Hash
 +
| String (40)
 +
| A 40 character hexadecimal and lowercase [[wikipedia:SHA-1|SHA-1]] hash of the resource pack file. (must be lower case in order to work)<br />If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth — but it will still treat it as a unique id
 +
|- {{Added}}
 +
| Forced
 +
| Boolean
 +
| The notchian client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
 +
|- {{Added}}
 +
| Forced Message
 +
| [[Chat]]
 +
| This is sent with the force resourcepack popup.
 +
|}
 +
==== Title ====
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Removed }}
 +
|rowspan="10"| 0x4F
 +
|rowspan="10"| Play
 +
|rowspan="10"| Client
 +
|colspan="2"| Action
 +
| VarInt Enum
 +
|
 +
|- {{ Removed }}
 +
! Action
 +
! Field Name
 +
!
 +
!
 +
|- {{ Removed }}
 +
| 0: set title
 +
| Title Text
 +
| [[Chat]]
 +
|
 +
|- {{ Removed }}
 +
| 1: set subtitle
 +
| Subtitle Text
 +
| [[Chat]]
 +
|
 +
|- {{ Removed }}
 +
| 2: set action bar
 +
| Action bar text
 +
| [[Chat]]
 +
| Displays a message above the hotbar (the same as position 2 in [[#Chat Message (clientbound)|Chat Message (clientbound)]].
 +
|- {{ Removed }}
 +
|rowspan="3"| 3: set times and display
 +
| Fade In
 +
| Int
 +
| Ticks to spend fading in.
 +
|- {{ Removed }}
 +
| Stay
 +
| Int
 +
| Ticks to keep the title displayed.
 +
|- {{ Removed }}
 +
| Fade Out
 +
| Int
 +
| Ticks to spend out, not when to start fading out.
 +
|- {{ Removed }}
 +
| 4: hide
 +
| ''no fields''
 +
| ''no fields''
 +
|
 +
|- {{ Removed }}
 +
| 5: reset
 +
| ''no fields''
 +
| ''no fields''
 +
|
 +
|}
 +
 
 +
“Hide” makes the title disappear, but if you run times again the same title will appear. “Reset” erases the text.
 +
 
 +
The title is visible on screen for Fade In + Stay + Fade Out ticks.
 +
 
 +
==== Action Bar ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="1"| 0x41
 +
|rowspan="1"| Play
 +
|rowspan="1"| Client
 +
| Action bar text
 +
| [[Chat]]
 +
| Displays a message above the hotbar (the same as position 2 in [[#Chat Message (clientbound)|Chat Message (clientbound)]].
 +
|}
 +
==== World Border Center ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="2"| 0x42
 +
|rowspan="2"| Play
 +
|rowspan="2"| Client
 +
| X
 +
| Double
 +
|
 +
|-
 +
| Z
 +
| Double
 +
|
 +
|}
 +
==== World Border Lerp Size ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="3"| 0x43
 +
|rowspan="3"| Play
 +
|rowspan="3"| Client
 +
| Old Diameter
 +
| Double
 +
| Current length of a single side of the world border, in meters.
 +
|-
 +
| New Diameter
 +
| Double
 +
| Target length of a single side of the world border, in meters.
 +
|-
 +
| Speed
 +
| VarLong
 +
| Number of real-time ''milli''seconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
 +
|}
 +
==== World Border Size ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="1"| 0x44
 +
|rowspan="1"| Play
 +
|rowspan="1"| Client
 +
| Diameter
 +
| Double
 +
| Length of a single side of the world border, in meters.
 +
|}
 +
 
 +
==== World Border Warning Delay ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="1"| 0x45
 +
|rowspan="1"| Play
 +
|rowspan="1"| Client
 +
| Warning Time
 +
| VarInt
 +
| In seconds as set by <code>/worldborder warning time</code>.
 +
|}
 +
 
 +
==== World Border Warning Reach ====
 +
 
 +
{| class="wikitable" {{Added}}
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="1"| 0x46
 +
|rowspan="1"| Play
 +
|rowspan="1"| Client
 +
| Warning Blocks
 +
| VarInt
 +
| In meters.
 +
|}
 +
 
 +
==== Spawn Position ====
 +
 
 +
Sent by the server after login to specify the coordinates of the spawn point (the point at which players spawn at, and which the compass points to). It can be sent at any time to update the point compasses point at.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| {{change|0x42|0x4B}}
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| Location
 +
| Position
 +
| Spawn location.
 +
|- {{added}}
 +
| Angle
 +
| Float
 +
|
 +
|}
 +
 
 +
==== Set Title SubTitle ====
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Added }}
 +
|rowspan="4"| 0x56
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| Subtitle Text
 +
| [[Chat]]
 +
|- {{ Added }}
 +
|}
  
The time of day is based on the timestamp modulo 24000. 0 is sunrise, 6000 is noon, 12000 is sunset, and 18000 is midnight.
 
  
The default SMP server increments both by 20 every second.
+
==== Set Title Text ====
  
The &#39;Time&#39; is the Age of the world. It is not changing on server commands and will increased by 20 every second.
+
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Added }}
 +
|rowspan="4"| 0x58
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| Title Text
 +
| [[Chat]]
 +
|- {{ Added }}
 +
|}
  
 +
==== Set Title Time====
  
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Added }}
 +
|rowspan="4"| 0x59
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
| Fade In
 +
| Int
 +
| Ticks to spend fading in.
 +
|- {{ Added }}
 +
| Stay
 +
| Int
 +
| Ticks to keep the title displayed.
 +
|- {{ Added }}
 +
| Fade Out
 +
| Int
 +
| Ticks to spend out, not when to start fading out.
 +
|}
  
 +
 +
==== Entity Properties ====
 +
 +
Sets {{Minecraft Wiki|Attribute|attributes}} on the given entity.
  
 
{| class="wikitable"
 
{| class="wikitable"
|- class="row0"
+
! Packet ID
! class="col0" | Packet ID
+
! State
! class="col1" | Field Name
+
! Bound To
! class="col2" | Field Type
+
!colspan="2"| Field Name
! class="col3" | Example
+
!colspan="2"| Field Type
! class="col4" | Notes
+
! Notes
|- class="row1"
+
|-
| class="col0 centeralign" rowspan="2" | 0x4
+
|rowspan="6"| {{change|0x58|0x63}}
| class="col1 centeralign" | Time
+
|rowspan="6"| Play
| class="col2 centeralign" | long
+
|rowspan="6"| Client
| class="col3 centeralign" | 45464654
+
|colspan="2"| Entity ID
| class="col4" | The &#39;Age of the world&#39;, in ticks
+
|colspan="2"| VarInt
 +
|
 +
|-
 +
|colspan="2"| Number Of Properties
 +
|colspan="2"| {{change|Int|VarInt}}
 +
| Number of elements in the following array.
 +
|-
 +
|rowspan="4"| Property
 +
| Key
 +
|rowspan="4"| Array
 +
| Identifier
 +
| See below.
 +
|-
 +
| Value
 +
| Double
 +
| See below.
 +
|-
 +
| Number Of Modifiers
 +
| VarInt
 +
| Number of elements in the following array.
 +
|-
 +
| Modifiers
 +
| Array of Modifier Data
 +
| See {{Minecraft Wiki|Attribute#Modifiers}}. Modifier Data defined below.
 +
|}
 +
 
 +
Known Key values (see also {{Minecraft Wiki|Attribute#Modifiers}}):
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Key
 +
! Default
 +
! Min
 +
! Max
 +
! Label
 +
|-
 +
| generic.max_health
 +
| 20.0
 +
| 0.0
 +
| 1024.0
 +
| Max Health.
 +
|-
 +
| generic.follow_range
 +
| 32.0
 +
| 0.0
 +
| 2048.0
 +
| Follow Range.
 +
|-
 +
| generic.knockback_resistance
 +
| 0.0
 +
| 0.0
 +
| 1.0
 +
| Knockback Resistance.
 +
|-
 +
| generic.movement_speed
 +
| 0.7
 +
| 0.0
 +
| 1024.0
 +
| Movement Speed.
 +
|-
 +
| generic.attack_damage
 +
| 2.0
 +
| 0.0
 +
| 2048.0
 +
| Attack Damage.
 +
|-
 +
| generic.attack_speed
 +
| 4.0
 +
| 0.0
 +
| 1024.0
 +
| Attack Speed.
 +
|-
 +
| generic.flying_speed
 +
| 0.4
 +
| 0.0
 +
| 1024.0
 +
| Flying Speed.
 +
|-
 +
| generic.armor
 +
| 0.0
 +
| 0.0
 +
| 30.0
 +
| Armor.
 +
|-
 +
| generic.armor_toughness
 +
| 0.0
 +
| 0.0
 +
| 20.0
 +
| Armor Toughness.
 +
|-
 +
| generic.attack_knockback
 +
| 0.0
 +
| 0.0
 +
| 5.0
 +
| &mdash;
 +
|-
 +
| generic.luck
 +
| 0.0
 +
| -1024.0
 +
| 1024.0
 +
| Luck.
 +
|-
 +
| horse.jump_strength
 +
| 0.7
 +
| 0.0
 +
| 2.0
 +
| Jump Strength.
 +
|-
 +
| zombie.spawn_reinforcements
 +
| 0.0
 +
| 0.0
 +
| 1.0
 +
| Spawn Reinforcements Chance.
 +
|-
 +
| generic.reachDistance
 +
| 5.0
 +
| 0.0
 +
| 1024.0
 +
| Player Reach Distance (Forge only).
 +
|-
 +
| forge.swimSpeed
 +
| 1.0
 +
| 0.0
 +
| 1024.0
 +
| Swimming Speed (Forge only).
 +
|}
 +
 
 +
Unknown attributes will cause a game crash ([https://bugs.mojang.com/browse/MC-150405 MC-150405]) due to the default minimum being larger than the default value.
 +
 
 +
''Modifier Data'' structure:
 +
 
 +
{| class="wikitable"
 +
|-
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
| UUID
 +
| UUID
 +
|
 +
|-
 +
| Amount
 +
| Double
 +
| May be positive or negative.
 +
|-
 +
| Operation
 +
| Byte
 +
| See below.
 +
|}
 +
 
 +
The operation controls how the base value of the modifier is changed.
 +
 
 +
* 0: Add/subtract amount
 +
* 1: Add/subtract amount percent of the current value
 +
* 2: Multiply by amount percent
 +
 
 +
All of the 0's are applied first, and then the 1's, and then the 2's.
 +
 
 +
==== Tags ====
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
!colspan="2"| Field Type
 +
! Notes
 +
|-
 +
|rowspan="8"| {{change|0x5B|0x65}}
 +
|rowspan="8"| Play
 +
|rowspan="8"| Client
 +
|- {{removed}}
 +
| colspan="2"| Block Tags
 +
| colspan="2"| (See below)
 +
| IDs are block IDs
 +
|- {{removed}}
 +
| colspan="2"| Item Tags
 +
| colspan="2"| (See below)
 +
| IDs are item IDs
 +
|- {{removed}}
 +
| colspan="2"| Fluid Tags
 +
| colspan="2"| (See below)
 +
| IDs are fluid IDs
 +
|- {{removed}}
 +
| colspan="2"| Entity Tags
 +
| colspan="2"| (See below)
 +
| IDs are entity IDs
 +
|- {{added}}
 +
| colspan="2"| Length of the array
 +
| colspan="2"| VarInt
 +
|
 +
|- {{added}}
 +
|rowspan="2"| Array of tags
 +
| Tag type
 +
|rowspan="2"| Array
 +
| Identifier
 +
| Tag identifier (Vanilla required tags are <code>minecraft:block</code>, <code>minecraft:item</code>, <code>minecraft:fluid</code>, <code>minecraft:entity_type</code>, and <code>minecraft:game_event</code>)
 +
|-
 +
| Array of Tag
 +
| (See below)
 +
|
 +
|}
 +
 
 +
Tags look like:
 +
 
 +
{| class="wikitable"
 +
!colspan="2"| Field Name
 +
!colspan="2"| Field Type
 +
! Notes
 +
|-
 +
|colspan="2"| Length
 +
|colspan="2"| VarInt
 +
| Number of elements in the following array
 +
|-
 +
|rowspan="3"| Tags
 +
| Tag name
 +
|rowspan="3"| Array
 +
| Identifier
 +
|
 +
|-
 +
| Count
 +
| VarInt
 +
| Number of elements in the following array
 +
|-
 +
| Entries
 +
| Array of VarInt
 +
| Numeric ID of the given type (block, item, etc.).
 +
|}
 +
 
 +
 
 +
=== Serverbound ===
 +
 
 +
==== Client Settings ====
 +
 
 +
Sent when the player connects, or when settings are changed.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="7"| 0x05
 +
|rowspan="7"| Play
 +
|rowspan="7"| Server
 +
| Locale
 +
| String (16)
 +
| e.g. <code>en_GB</code>.
 +
|-
 +
| View Distance
 +
| Byte
 +
| Client-side render distance, in chunks.
 +
|-
 +
| Chat Mode
 +
| VarInt Enum
 +
| 0: enabled, 1: commands only, 2: hidden.  See [[Chat#Processing chat|processing chat]] for more information.
 +
|-
 +
| Chat Colors
 +
| Boolean
 +
| “Colors” multiplayer setting.
 +
|-
 +
| Displayed Skin Parts
 +
| Unsigned Byte
 +
| Bit mask, see below.
 +
|-
 +
| Main Hand
 +
| VarInt Enum
 +
| 0: Left, 1: Right.
 +
|- {{Added}}
 +
| Disable text filtering
 +
| Boolean
 +
| Disables filtering of text on signs and written book titles.  Currently always true (i.e. the filtering is disabled)
 +
|}
 +
 
 +
''Displayed Skin Parts'' flags:
 +
 
 +
* 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.
 +
 
 +
 
 +
==== Window Confirmation (serverbound) ====
 +
 
 +
If a confirmation sent by the client was not accepted, the server will reply with a [[#Window Confirmation (clientbound)|Window Confirmation (clientbound)]] packet with the Accepted field set to false. When this happens, the client must send this packet to apologize (as with movement), otherwise the server ignores any successive confirmations.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{ Removed }}
 +
|rowspan="3"| 0x07
 +
|rowspan="3"| Play
 +
|rowspan="3"| Server
 +
| Window ID
 +
| Byte
 +
| The ID of the window that the action occurred in.
 +
|- {{ Removed }}
 +
| Action Number
 +
| Short
 +
| Every action that is to be accepted has a unique number. This number is an incrementing integer (starting at 1) with separate counts for each window ID.
 +
|- {{ Removed }}
 +
| Accepted
 +
| Boolean
 +
| Whether the action was accepted.
 +
|}
 +
 
 +
==== Click Window ====
 +
 
 +
This packet is sent by the client when the player clicks on a slot in a window.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2" | Field Name
 +
!colspan="2" | Field Type
 +
! Notes
 +
|-
 +
|rowspan="9"| 0x09
 +
|rowspan="9"| Play
 +
|rowspan="9"| Server
 +
|colspan="2" | Window ID
 +
|colspan="2" | Unsigned Byte
 +
|colspan="2" | The ID of the window which was clicked. 0 for player inventory.
 +
|-
 +
|colspan="2" | Slot
 +
|colspan="2" | Short
 +
|colspan="2" | The clicked slot number, see below.
 +
|-
 +
|colspan="2" | Button
 +
|colspan="2" | Byte
 +
|colspan="2" | The button used in the click, see below.
 +
|- {{ Removed }}
 +
|colspan="2" | Action Number
 +
|colspan="2" | Short
 +
|colspan="2" | A unique number for the action, implemented by Notchian as a counter, starting at 1 (different counter for every window ID). Used by the server to send back a [[#Window Confirmation (clientbound)|Window Confirmation (clientbound)]].
 +
|-
 +
|colspan="2" | Mode
 +
|colspan="2" | VarInt Enum
 +
|colspan="2" | Inventory operation mode, see below.
 +
|- {{ Added }}
 +
| colspan="2"| Length of the array
 +
| colspan="2"| VarInt
 +
|
 +
|- {{ Added }}
 +
|rowspan="2"| Array of slots
 +
| Slot number
 +
|rowspan="2"| Array
 +
| Short
 +
|
 +
|-
 +
| Slot data
 +
| Slot
 +
| New data for this slot
 +
|-
 +
|colspan="2" | Clicked item
 +
|colspan="2" | [[Slot Data|Slot]]
 +
|colspan="2" | The clicked slot. Has to be empty (item ID = -1) for drop mode. Is always empty for mode 2 and mode 5 packets.
 +
|}
 +
 
 +
See [[Inventory]] 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="4"| 0
 +
| 0
 +
| Normal
 +
| Left mouse click
 +
|-
 +
| 1
 +
| Normal
 +
| Right mouse click
 +
|-
 +
| 0
 +
| -999
 +
| Left click outside inventory (drop cursor stack)
 +
|-
 +
| 1
 +
| -999
 +
| Right click outside inventory (drop cursor single item)
 +
|-
 +
!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
 +
|-
 +
! 3
 +
| 2
 +
| Normal
 +
| Middle click, only defined for creative players in non-player inventories.
 +
|-
 +
!rowspan="1"| 4
 +
| 0
 +
| Normal*
 +
| Drop key (Q) (* Clicked item is always empty)
 +
|-
 +
!rowspan="9"| 5
 +
| 0
 +
| -999
 +
| Starting left mouse drag
 +
|-
 +
| 4
 +
| -999
 +
| Starting right mouse drag
 +
|-
 +
| 8
 +
| -999
 +
| Starting middle mouse drag, only defined for creative players in non-player inventories.  (Note: the vanilla client will still incorrectly send this for non-creative players - see [https://bugs.mojang.com/browse/MC-46584 MC-46584])
 +
|-
 +
| 1
 +
| Normal
 +
| Add slot for left-mouse drag
 +
|-
 +
| 5
 +
| Normal
 +
| Add slot for right-mouse drag
 +
|-
 +
| 9
 +
| Normal
 +
| Add slot for middle-mouse drag, only defined for creative players in non-player inventories.  (Note: the vanilla client will still incorrectly send this for non-creative players - see [https://bugs.mojang.com/browse/MC-46584 MC-46584])
 +
|-
 +
| 2
 +
| -999
 +
| Ending left mouse drag
 +
|-
 +
| 6
 +
| -999
 +
| Ending right mouse drag
 +
|-
 +
| 10
 +
| -999
 +
| Ending middle mouse drag, only defined for creative players in non-player inventories.  (Note: the vanilla client will still incorrectly send this for non-creative players - see [https://bugs.mojang.com/browse/MC-46584 MC-46584])
 +
|-
 +
! 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 [[#Window Confirmation (clientbound)|Window Confirmation]] packet. If the click was not accepted, the client must send a matching [[#Window Confirmation (serverbound)|serverbound window confirmation]] packet before sending more [[#Click Window|Click Window]] packets, otherwise the server will reject them silently. The Notchian server also sends a [[#Window Items|Window Items]] packet for the open window and [[#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.
 +
 
 +
==== Pong ====
 +
 
 +
A response to the ping packet. Unknown what this is used for, this is ignored by the Notchian client and server.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|- {{added}}
 +
| 0x1D
 +
| Play
 +
| Server
 +
| ID
 +
| Int
 +
|
 +
|}
 +
 
 +
== 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.
 +
 
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
! Field Name
 +
! Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| 0x00
 +
|rowspan="4"| Handshaking
 +
|rowspan="4"| Server
 +
| Protocol Version
 +
| VarInt
 +
| See [[protocol version numbers]] (currently {{change|754|{{Snapshot PVN|1073741839}}}})
 +
|-
 +
| 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 {{change|complete|simple}} redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide {{change|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|status]], 2 for [[#Login|login]]
 +
|}
 +
 
 +
== Status ==
 +
 
 +
=== Clientbound ===
 +
 
 +
No changes so far.
  
|- class="row2"
+
=== Serverbound ===
| class="col0 centeralign" | Day Time
 
| class="col1 centeralign" | long
 
| class="col2 centeralign" | 21321
 
| class="col3" | The world (or region) time, in ticks
 
|- class="row3"
 
! class="col0" | Total Size:
 
| class="col1 rightalign" colspan="4" | 1 Byte
 
|}
 
  
 +
No changes so far.
  
== Changed Data Type ==
+
== Login ==
  
-None-
+
=== Clientbound ===
  
== Removed packets ==
+
No changes so far.
  
-None-
+
=== Serverbound ===
  
== Protocol History ==
+
No changes so far.
  
=== 2012-08-09 ===
 
* 12w32a
 
* Protocol version is now 40
 
  
* Changed Time Update packet
+
[[Category:Minecraft Modern]]

Latest revision as of 18:04, 13 June 2021

This page documents the changes from the last stable Minecraft release (currently 1.16.5, protocol 754) to the current pre-release (currently 1.17-rc2, protocol Snapshot 35). 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
Play clientbound
0x05 Sculk Vibration Signal Pre
0x05 0x06 Entity Animation (clientbound) Current (unchanged)
0x06 0x07 Statistics Current (unchanged)
0x07 0x08 Acknowledge Player Digging Current (unchanged)
0x08 0x09 Block Break Animation Current (unchanged)
0x09 0x0A Block Entity Data Current (unchanged)
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)
0x10 Clear Titles Pre
0x0F 0x11 Tab-Complete (clientbound) Current (unchanged)
0x10 0x12 Declare Commands Current (unchanged)
0x11 Window Confirmation (clientbound) Current
0x12 0x13 Close Window (clientbound) Current (unchanged)
0x13 0x14 Window Items Current (unchanged)
0x14 0x15 Window Property Current (unchanged)
0x15 0x16 Set Slot Current (unchanged)
0x16 0x17 Set Cooldown Current (unchanged)
0x17 0x18 Plugin Message (clientbound) Current (unchanged)
0x18 0x19 Named Sound Effect Current (unchanged)
0x19 0x1A Disconnect (play) Current (unchanged)
0x1A 0x1B Entity Status Current (unchanged)
0x1B 0x1C Explosion Current Pre
0x1C 0x1D Unload Chunk Current (unchanged)
0x1D 0x1E Change Game State Current (unchanged)
0x1E 0x1F Open Horse Window Current (unchanged)
0x20 Initialize World Border Pre
0x1F 0x21 Keep Alive (clientbound) Current (unchanged)
0x20 0x22 Chunk Data Current Pre
0x21 0x23 Effect Current (unchanged)
0x22 0x24 Particle Current (unchanged)
0x23 0x25 Update Light Current Pre
0x24 0x26 Join Game Current Pre
0x25 0x27 Map Data Current Pre
0x26 0x28 Trade List Current (unchanged)
0x27 0x29 Entity Position Current (unchanged)
0x28 0x2A Entity Position and Rotation Current (unchanged)
0x29 0x2B Entity Rotation Current (unchanged)
0x2A Entity Movement Current
0x2B 0x2C Vehicle Move (clientbound) Current (unchanged)
0x2C 0x2D Open Book Current (unchanged)
0x2D 0x2E Open Window Current (unchanged)
0x2E 0x2F Open Sign Editor Current (unchanged)
0x30 Ping Pre
0x2F 0x31 Craft Recipe Response Current (unchanged)
0x30 0x32 Player Abilities (clientbound) Current (unchanged)
0x31 Combat Event Current
0x33 End Combat Event Pre
0x34 Enter Combat Event Pre
0x35 Death Combat Event Pre
0x32 0x36 Player Info Current (unchanged)
0x33 0x37 Face Player Current (unchanged)
0x36 Destroy Entities Current
0x34 0x38 Player Position And Look (clientbound) Current Pre
0x35 0x39 Unlock Recipes Current (unchanged)
0x3A Destroy Entity Pre
0x37 0x3B Remove Entity Effect Current (unchanged)
0x38 0x3C Resource Pack Send Current Pre
0x39 0x3D Respawn Current (unchanged)
0x3A 0x3E Entity Head Look Current (unchanged)
0x3B 0x3F Multi Block Change Current (unchanged)
0x3C 0x40 Select Advancement Tab Current (unchanged)
0x41 Action Bar Pre
0x42 World Border Center Pre
0x43 World Border Lerp Size Pre
0x44 World Border Size Pre
0x45 World Border Warning Delay Pre
0x46 World Border Warning Reach Pre
0x3E 0x47 Camera Current (unchanged)
0x3F 0x48 Held Item Change (clientbound) Current (unchanged)
0x40 0x49 Update View Position Current (unchanged)
0x41 0x4A Update View Distance Current (unchanged)
0x42 0x4B Spawn Position Current Pre
0x43 0x4C Display Scoreboard Current (unchanged)
0x44 0x4D Entity Metadata Current (unchanged)
0x45 0x4E Attach Entity Current (unchanged)
0x46 0x4F Entity Velocity Current (unchanged)
0x47 0x50 Entity Equipment Current (unchanged)
0x4F Title Current
0x48 0x51 Set Experience Current (unchanged)
0x49 0x52 Update Health Current (unchanged)
0x4A 0x53 Scoreboard Objective Current (unchanged)
0x4B 0x54 Set Passengers Current (unchanged)
0x4C 0x55 Teams Current (unchanged)
0x4D 0x56 Update Score Current (unchanged)
0x57 Set Title SubTitle Pre
0x4E 0x58 Time Update Current (unchanged)
0x59 Set Title Text Pre
0x5A Set Title Time Pre
0x50 0x5B Entity Sound Effect Current (unchanged)
0x51 0x5C Sound Effect Current (unchanged)
0x52 0x5D Stop Sound Current (unchanged)
0x53 0x5E Player List Header And Footer Current (unchanged)
0x54 0x5F NBT Query Response Current (unchanged)
0x55 0x60 Collect Item Current (unchanged)
0x56 0x61 Entity Teleport Current (unchanged)
0x57 0x62 Advancements Current (unchanged)
0x58 0x63 Entity Properties Current Pre
0x59 0x64 Entity Effect Current (unchanged)
0x5A 0x65 Declare Recipes Current (unchanged)
0x5B 0x66 Tags Current Pre
Play serverbound
0x05 Client Settings Current Pre
0x07 Window Confirmation (serverbound) Current
0x08 0x07 Click Window Button Current (unchanged)
0x09 0x08 Click Window Current Pre
0x0A 0x09 Close Window (serverbound) Current (unchanged)
0x0B 0x0A Plugin Message (serverbound) Current (unchanged)
0x0C 0x0B Edit Book Current (unchanged)
0x0D 0x0C Query Entity NBT Current (unchanged)
0x0E 0x0D Interact Entity Current (unchanged)
0x0F 0x0E Generate Structure Current (unchanged)
0x10 0x0F Keep Alive (serverbound) Current (unchanged)
0x11 0x10 Lock Difficulty Current (unchanged)
0x12 0x11 Player Position Current (unchanged)
0x13 0x12 Player Position And Rotation (serverbound) Current (unchanged)
0x14 0x13 Player Rotation Current (unchanged)
0x15 0x14 Player Movement Current (unchanged)
0x16 0x15 Vehicle Move (serverbound) Current (unchanged)
0x17 0x16 Steer Boat Current (unchanged)
0x18 0x17 Pick Item Current (unchanged)
0x19 0x18 Craft Recipe Request Current (unchanged)
0x1A 0x19 Player Abilities (serverbound) Current (unchanged)
0x1B 0x1A Player Digging Current (unchanged)
0x1C 0x1B Entity Action Current (unchanged)
0x1D 0x1C Steer Vehicle Current (unchanged)
0x1D Pong Pre
Handshaking serverbound
0x00 Handshake Current Pre

New/modified data types

No changes so far.

Entity Metadata

Warning.png Note that other entities have had metadata shifts due to these changes, not shown here.

Entity

The base class.

Index Type Meaning Default
0 Byte Bit mask Meaning 0
0x01 Is on fire
0x02 Is crouching
0x04 Unused (previously riding)
0x08 Is sprinting
0x10 Is swimming
0x20 Is invisible
0x40 has glowing effect
0x80 Is flying with an elytra
1 VarInt Air ticks 300
2 OptChat Custom name empty
3 Boolean Is custom name visible false
4 Boolean Is silent false
5 Boolean Has no gravity false
6 Pose Pose STANDING
7 VarInt Ticks frozen in powdered snow 0

Block Actions

No changes so far.

Inventories

No changes so far.

Plugin Channels

No changes so far.

Play

Clientbound

Sculk Vibration Signal

Packet ID State Bound To Field Name Field Type Notes
0x05 Play Client Source Position Position Source position for the vibration.
Destination Identifier Identifier Identifier of the destination codec type.
Destination Varies Vanilla default destinations are a block position encoded as a Position for "block" or an entity id encoded as a VarInt for "entity".
Arrival Ticks VarInt Ticks for the signal to arrive at the destination.

This packet shows a permanent particle.

Clear Titles

Packet ID State Bound To Field Name Field Type Notes
0x10 Play Client
Reset Boolean

Explosion

Sent when an explosion occurs (creepers, TNT, and ghast fireballs).

Each block in Records is set to air. Coordinates for each axis in record is int(X) + record.x

Packet ID State Bound To Field Name Field Type Notes
0x1B Play Client X Float
Y Float
Z Float
Strength Float A strength greater than or equal to 2.0 spawns a minecraft:explosion_emitter particle, while a lesser strength spawns a minecraft:explosion particle.
Record Count Int VarInt Number of elements in the following array.
Records Array of (Byte, Byte, Byte) Each record is 3 signed bytes long; the 3 bytes are the XYZ (respectively) signed offsets of affected blocks.
Player Motion X Float X velocity of the player being pushed by the explosion.
Player Motion Y Float Y velocity of the player being pushed by the explosion.
Player Motion Z Float Z velocity of the player being pushed by the explosion.

Initialize World Border

Packet ID State Bound To Field Name Field Type Notes
0x20 Play Client X Double
Z Double
Old Diameter Double Current length of a single side of the world border, in meters.
New Diameter Double Target length of a single side of the world border, in meters.
Speed VarLong Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.
Portal Teleport Boundary VarInt Resulting coordinates from a portal teleport are limited to ±value. Usually 29999984.
Warning Blocks VarInt In meters.
Warning Time VarInt In seconds as set by /worldborder warning time.

The Notchian client determines how solid to display the warning by comparing to whichever is higher, the warning distance or whichever is lower, the distance from the current diameter to the target diameter or the place the border will be after warningTime seconds. In pseudocode:

distance = max(min(resizeSpeed * 1000 * warningTime, abs(targetDiameter - currentDiameter)), warningDistance);
if (playerDistance < distance) {
    warning = 1.0 - playerDistance / distance;
} else {
    warning = 0.0;
}

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 dimension 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
0x20 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).
Bit Mask Length VarInt Length of the following array
Primary Bit Mask Array of Long BitSet with bits (world height in blocks / 16) 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 the lowest y to 15 blocks above).
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 length Optional VarInt Size of the following array; should always be 1024. Not present if full chunk is false.
Biomes Optional Array of VarInt 1024 biome IDs, ordered by x then z then y, in 4×4×4 blocks. Not present if full chunk is false. See Chunk Format § Biomes.
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.

The compacted array format has been adjusted so that individual entries no longer span across multiple longs, affecting the main data array and heightmaps.

New format, 5 bits per block, containing the following references to blocks in a palette (not shown): 122344566480743131516914101202

0020863148418841 0000000000100000100001100011000101001000010000011000100001000001
01018A7260F68C87 0000000100000001100010100111001001100000111101101000110010000111

Entity Movement

This packet may be used to initialize an entity.

For player entities, either this packet or any move/look packet is sent every game tick. So the meaning of this packet is basically that the entity did not move/look since the last such packet.

Packet ID State Bound To Field Name Field Type Notes
0x2A Play Client Entity ID VarInt

Ping

Unknown what this packet does just yet, not used by the Notchian server or client.

Packet ID State Bound To Field Name Field Type Notes
0x30 Play Client ID Int

Update Light

Updates light levels for a chunk.

Packet ID State Bound To Field Name Field Type Notes
0x23 0x25 Play Client Chunk X VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Trust Edges Boolean If edges should be trusted for light updates.
Sky Light Mask VarInt Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
Block Light Mask VarInt Mask containing 18 bits, with the same order as sky light
Empty Sky Light Mask VarInt Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
Empty Block Light Mask VarInt Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
Length 1 VarInt Length of the following array
Sky Light Mask Array of Long BitSet containing bits for each sections in the world + 2 (lowest bit 16-1 blocks below min world height, highest 1-16 above max world height)
Length 2 VarInt Length of the following array
Block Light Mask Array of Long BitSet containing bits for each sections in the world + 2, same order as sky light
Length 3 VarInt Length of the following array
Empty Sky Light Mask Array of Long BitSet containing a variable amount of bits (see sky/block light) which indicates sections that have 0 for all their sky light values
Length 4 VarInt Length of the following array
Empty Block Light Mask Array of Long BitSet containing a variable amount of bits (see sky/block light) which indicates sections that have 0 for all their block light values
Sky Light array count VarInt Number of entries in the following array
Sky Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Sky Light array Array of 2048 bytes There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
Block Light array count VarInt Number of entries in the following array
Block Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Block Light array Array of 2048 bytes There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.

Join Game

See Protocol Encryption for information on logging in.

Packet ID State Bound To Field Name Field Type Notes
0x24 Play Client Entity ID Int The player's Entity ID (EID).
Is hardcore Boolean
Gamemode Unsigned Byte 0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
Previous Gamemode Byte 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included. The previous gamemode. Defaults to -1 if there is no previous gamemode. (More information needed)
World Count VarInt Size of the following array.
World Names Array of Identifier Identifiers for all worlds on the server.
Dimension Codec NBT Tag Compound The full extent of these is still unknown, but the tag represents a dimension and biome registry. See below for the vanilla default.
Dimension NBT Tag Compound Valid dimensions are defined per dimension registry sent before this. The structure of this tag is a dimension type (see below).
World Name Identifier Name of the world being spawned into.
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
Max Players VarInt Was once used by the client to draw the player list, but now is ignored.
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.
Is Debug Boolean True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
Is Flat Boolean True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.


The Dimension Codec NBT Tag Compound (Default value in SNBT) includes two registries: "minecraft:dimension_type" and "minecraft:worldgen/biome".

Name Type Notes
minecraft:dimension_type TAG_Compound The dimension type registry (see below).
minecraft:worldgen/biome TAG_Compound The biome registry (see below).

Dimension type registry:

Name Type Notes
type TAG_String The name of the registry. Always "minecraft:dimension_type".
value TAG_List List of dimension types registry entries (see below).

Dimension type registry entry:

Name Type Notes
name TAG_String The name of the dimension type (for example, "minecraft:overworld").
id TAG_Int The protocol ID of the dimension (matches the index of the element in the registry list).
element TAG_Compound The dimension type (see below).

Dimension type:

Name Type Meaning Values
piglin_safe TAG_Byte Whether piglins shake and transform to zombified piglins. 1: true, 0: false.
natural TAG_Byte When false, compasses spin randomly. When true, nether portals can spawn zombified piglins. 1: true, 0: false.
ambient_light TAG_Float How much light the dimension has. 0.0 to 1.0.
fixed_time Optional TAG_Long If set, the time of the day is the specified value. If set, 0 to 24000.
infiniburn TAG_String A resource location defining what block tag to use for infiniburn. "" or minecraft resource "minecraft:...".
respawn_anchor_works TAG_Byte Whether players can charge and use respawn anchors. 1: true, 0: false.
has_skylight TAG_Byte Whether the dimension has skylight access or not. 1: true, 0: false.
bed_works TAG_Byte Whether players can use a bed to sleep. 1: true, 0: false.
effects TAG_String ? "minecraft:overworld", "minecraft:the_nether", "minecraft:the_end" or something else.
has_raids TAG_Byte Whether players with the Bad Omen effect can cause a raid. 1: true, 0: false.
min_y TAG_Int The minimum Y level.
height TAG_Int The maximum height.
logical_height TAG_Int The maximum height to which chorus fruits and nether portals can bring players within this dimension. 0-256.
coordinate_scale TAG_Float The multiplier applied to coordinates when traveling to the dimension. 1: true, 0: false.
ultrawarm TAG_Byte Whether the dimensions behaves like the nether (water evaporates and sponges dry) or not. Also causes lava to spread thinner. 1: true, 0: false.
has_ceiling TAG_Byte Whether the dimension has a bedrock ceiling or not. When true, causes lava to spread faster. 1: true, 0: false.

Biome registry:

Name Type Notes
type TAG_String The name of the registry. Always "minecraft:worldgen/biome".
value TAG_List List of biome registry entries (see below).

Biome registry entry:

Name Type Notes
name TAG_String The name of the biome (for example, "minecraft:ocean").
id TAG_Int The protocol ID of the biome (matches the index of the element in the registry list).
element TAG_Compound The biome properties (see below).

Biome properties:

Name Type Meaning Values
precipitation TAG_String The type of precipitation in the biome. "rain", "snow", or "none".
depth TAG_Float The depth factor of the biome. The default values vary between 1.5 and -1.8.
temperature TAG_Float The temperature factor of the biome. The default values vary between 2.0 and -0.5.
scale TAG_Float ? The default values vary between 1.225 and 0.0.
downfall TAG_Float ? The default values vary between 1.0 and 0.0.
category TAG_String The category of the biome. Known values are "ocean", "plains", "desert", "forest", "extreme_hills", "taiga", "swamp", "river", "nether", "the_end", "icy", "mushroom", "beach", "jungle", "mesa", "savanna", and "none".
temperature_modifier Optional TAG_String ? The only known value is "frozen".
effects sky_color TAG_Compound TAG_Int The color of the sky. Example: 8364543, which is #7FA1FF in RGB.
water_fog_color TAG_Int Possibly the tint color when swimming. Example: 8364543, which is #7FA1FF in RGB.
fog_color TAG_Int Possibly the color of the fog effect when looking past the view distance. Example: 8364543, which is #7FA1FF in RGB.
water_color TAG_Int The tint color of the water blocks. Example: 8364543, which is #7FA1FF in RGB.
foliage_color Optional TAG_Int The tint color of the grass. Example: 8364543, which is #7FA1FF in RGB.
grass_color Optional TAG_Int ? Example: 8364543, which is #7FA1FF in RGB.
grass_color_modifier Optional TAG_String Unknown, likely affects foliage color. If set, known values are "swamp" and "dark_forest".
music Optional TAG_Compound Music properties for the biome. If present, contains the fields: replace_current_music (TAG_Byte), sound (TAG_String), max_delay (TAG_Int), min_delay (TAG_Int).
ambient_sound Optional TAG_String Ambient soundtrack. If present, the ID of a soundtrack. Example: "minecraft:ambient.basalt_deltas.loop".
additions_sound Optional TAG_Compound Additional ambient sound that plays randomly. If present, contains the fields: sound (TAG_String), tick_chance (TAG_Double).
mood_sound Optional TAG_Compound Additional ambient sound that plays at an interval. If present, contains the fields: sound (TAG_String), tick_delay (TAG_Int), offset (TAG_Double), block_search_extent (TAG_Int).
particle Optional TAG_Compound Particles that appear randomly in the biome. If present, contains the fields: probability (TAG_Float), options (TAG_Compound). The "options" compound contains the field "type" (TAG_String), which identifies the particle type.

Map Data

Updates a rectangular area on a map item.

Packet ID State Bound To Field Name Field Type Notes
0x25 0x27 Play Client Map ID VarInt Map ID of the map being modified
Scale Byte From 0 for a fully zoomed-in map (1 block per pixel) to 4 for a fully zoomed-out map (16 blocks per pixel)
Tracking Position Boolean Specifies whether player and item frame icons are shown
Locked Boolean True if the map has been locked in a cartography table
Tracking Position Boolean Specifies whether player and item frame icons are shown
Icon Count VarInt Number of elements in the following array. Only present if "Tracking Position" is true.
Icon Type Array VarInt enum See below
X Byte Map coordinates: -128 for furthest left, +127 for furthest right
Z Byte Map coordinates: -128 for highest, +127 for lowest
Direction Byte 0-15
Has Display Name Boolean
Display Name Optional Chat Only present if previous Boolean is true
Columns Unsigned Byte Number of columns updated
Rows Optional Byte Only if Columns is more than 0; number of rows updated
X Optional Byte Only if Columns is more than 0; x offset of the westernmost column
Z Optional Byte Only if Columns is more than 0; z offset of the northernmost row
Length Optional VarInt Only if Columns is more than 0; length of the following array
Data Optional Array of Unsigned Byte Only if Columns is more than 0; see Map item format

For icons, a direction of 0 is a vertical icon and increments by 22.5° (360/16).

Types are based off of rows and columns in map_icons.png:

Icon type Result
0 White arrow (players)
1 Green arrow (item frames)
2 Red arrow
3 Blue arrow
4 White cross
5 Red pointer
6 White circle (off-map players)
7 Small white circle (far-off-map players)
8 Mansion
9 Temple
10 White Banner
11 Orange Banner
12 Magenta Banner
13 Light Blue Banner
14 Yellow Banner
15 Lime Banner
16 Pink Banner
17 Gray Banner
18 Light Gray Banner
19 Cyan Banner
20 Purple Banner
21 Blue Banner
22 Brown Banner
23 Green Banner
24 Red Banner
25 Black Banner
26 Treasure marker

Combat Event

Originally used for metadata for twitch streaming circa 1.8. Now only used to display the game over screen (with enter combat and end combat completely ignored by the Notchain client)

Packet ID State Bound To Field Name Field Type Notes
0x31 Play Client Event VarInt Enum Determines the layout of the remaining packet.
Event Field Name
0: enter combat no fields no fields
1: end combat Duration VarInt Length of the combat in ticks.
Entity ID Int ID of the primary opponent of the ended combat, or -1 if there is no obvious primary opponent.
2: entity dead Player ID VarInt Entity ID of the player that died (should match the client's entity ID).
Entity ID Int The killing entity's ID, or -1 if there is no obvious killer.
Message Chat The death message.

End Combat Event

Unused by the Notchain client.

Packet ID State Bound To Field Name Field Type Notes
0x32 Play Client Duration VarInt Length of the combat in ticks.
Entity ID Int ID of the primary opponent of the ended combat, or -1 if there is no obvious primary opponent.

Enter Combat Event

Unused by the Notchain client.

Packet ID State Bound To Field Name Field Type Notes
0x33 Play Client


Death Combat Event

Used to send a respawn screen.

Packet ID State Bound To Field Name Field Type Notes
0x34 Play Client Player ID VarInt Entity ID of the player that died (should match the client's entity ID).
Entity ID Int The killing entity's ID, or -1 if there is no obvious killer.
Message Chat The death message.

Player Position And Look (clientbound)

Updates the player's position on the server. This packet will also close the “Downloading Terrain” screen when joining/respawning.

If the distance between the last known position of the player on the server and the new position set by this packet is greater than 100 meters, the client will be kicked for “You moved too quickly :( (Hacking?)”.

Also if the fixed-point number of X or Z is set greater than 3.2E7D the client will be kicked for “Illegal position”.

Yaw is measured in degrees, and does not follow classical trigonometry rules. The unit circle of yaw on the XZ-plane starts at (0, 1) and turns counterclockwise, with 90 at (-1, 0), 180 at (0, -1) and 270 at (1, 0). Additionally, yaw is not clamped to between 0 and 360 degrees; any number is valid, including negative numbers and numbers greater than 360.

Pitch is measured in degrees, where 0 is looking straight ahead, -90 is looking straight up, and 90 is looking straight down.

Packet ID State Bound To Field Name Field Type Notes
0x34 0x38 Play Client X Double Absolute or relative position, depending on Flags.
Y Double Absolute or relative position, depending on Flags.
Z Double Absolute or relative position, depending on Flags.
Yaw Float Absolute or relative rotation on the X axis, in degrees.
Pitch Float Absolute or relative rotation on the Y axis, in degrees.
Flags Byte Bit field, see below.
Teleport ID VarInt Client should confirm this packet with Teleport Confirm containing the same Teleport ID.
Dismount Vehicle Boolean True if the player should dismount their vehicle.

About the Flags field:

<Dinnerbone> It's a bitfield, X/Y/Z/Y_ROT/X_ROT. If X is set, the x value is relative and not absolute.
Field Bit
X 0x01
Y 0x02
Z 0x04
Y_ROT 0x08
X_ROT 0x10

Destroy Entity

Sent by the server when a list of entities an entity is to be destroyed on the client.

Packet ID State Bound To Field Name Field Type Notes
0x36 Play Client
Count VarInt Number of elements in the following array.
Array of VarInt The list of entities of destroy.
Entity ID VarInt

Resource Pack Send

Packet ID State Bound To Field Name Field Type Notes
0x38 0x3B Play Client URL String (32767) The URL to the resource pack.
Hash String (40) A 40 character hexadecimal and lowercase SHA-1 hash of the resource pack file. (must be lower case in order to work)
If it's not a 40 character hexadecimal string, the client will not use it for hash verification and likely waste bandwidth — but it will still treat it as a unique id
Forced Boolean The notchian client will be forced to use the resource pack from the server. If they decline they will be kicked from the server.
Forced Message Chat This is sent with the force resourcepack popup.

Title

Packet ID State Bound To Field Name Field Type Notes
0x4F Play Client Action VarInt Enum
Action Field Name
0: set title Title Text Chat
1: set subtitle Subtitle Text Chat
2: set action bar Action bar text Chat Displays a message above the hotbar (the same as position 2 in Chat Message (clientbound).
3: set times and display Fade In Int Ticks to spend fading in.
Stay Int Ticks to keep the title displayed.
Fade Out Int Ticks to spend out, not when to start fading out.
4: hide no fields no fields
5: reset no fields no fields

“Hide” makes the title disappear, but if you run times again the same title will appear. “Reset” erases the text.

The title is visible on screen for Fade In + Stay + Fade Out ticks.

Action Bar

Packet ID State Bound To Field Name Field Type Notes
0x41 Play Client Action bar text Chat Displays a message above the hotbar (the same as position 2 in Chat Message (clientbound).

World Border Center

Packet ID State Bound To Field Name Field Type Notes
0x42 Play Client X Double
Z Double

World Border Lerp Size

Packet ID State Bound To Field Name Field Type Notes
0x43 Play Client Old Diameter Double Current length of a single side of the world border, in meters.
New Diameter Double Target length of a single side of the world border, in meters.
Speed VarLong Number of real-time milliseconds until New Diameter is reached. It appears that Notchian server does not sync world border speed to game ticks, so it gets out of sync with server lag. If the world border is not moving, this is set to 0.

World Border Size

Packet ID State Bound To Field Name Field Type Notes
0x44 Play Client Diameter Double Length of a single side of the world border, in meters.

World Border Warning Delay

Packet ID State Bound To Field Name Field Type Notes
0x45 Play Client Warning Time VarInt In seconds as set by /worldborder warning time.

World Border Warning Reach

Packet ID State Bound To Field Name Field Type Notes
0x46 Play Client Warning Blocks VarInt In meters.

Spawn Position

Sent by the server after login to specify the coordinates of the spawn point (the point at which players spawn at, and which the compass points to). It can be sent at any time to update the point compasses point at.

Packet ID State Bound To Field Name Field Type Notes
0x42 0x4B Play Client Location Position Spawn location.
Angle Float

Set Title SubTitle

Packet ID State Bound To Field Name Field Type Notes
0x56 Play Client Subtitle Text Chat


Set Title Text

Packet ID State Bound To Field Name Field Type Notes
0x58 Play Client Title Text Chat

Set Title Time

Packet ID State Bound To Field Name Field Type Notes
0x59 Play Client Fade In Int Ticks to spend fading in.
Stay Int Ticks to keep the title displayed.
Fade Out Int Ticks to spend out, not when to start fading out.


Entity Properties

Sets attributes on the given entity.

Packet ID State Bound To Field Name Field Type Notes
0x58 0x63 Play Client Entity ID VarInt
Number Of Properties Int VarInt Number of elements in the following array.
Property Key Array Identifier See below.
Value Double See below.
Number Of Modifiers VarInt Number of elements in the following array.
Modifiers Array of Modifier Data See Attribute#Modifiers. Modifier Data defined below.

Known Key values (see also Attribute#Modifiers):

Key Default Min Max Label
generic.max_health 20.0 0.0 1024.0 Max Health.
generic.follow_range 32.0 0.0 2048.0 Follow Range.
generic.knockback_resistance 0.0 0.0 1.0 Knockback Resistance.
generic.movement_speed 0.7 0.0 1024.0 Movement Speed.
generic.attack_damage 2.0 0.0 2048.0 Attack Damage.
generic.attack_speed 4.0 0.0 1024.0 Attack Speed.
generic.flying_speed 0.4 0.0 1024.0 Flying Speed.
generic.armor 0.0 0.0 30.0 Armor.
generic.armor_toughness 0.0 0.0 20.0 Armor Toughness.
generic.attack_knockback 0.0 0.0 5.0
generic.luck 0.0 -1024.0 1024.0 Luck.
horse.jump_strength 0.7 0.0 2.0 Jump Strength.
zombie.spawn_reinforcements 0.0 0.0 1.0 Spawn Reinforcements Chance.
generic.reachDistance 5.0 0.0 1024.0 Player Reach Distance (Forge only).
forge.swimSpeed 1.0 0.0 1024.0 Swimming Speed (Forge only).

Unknown attributes will cause a game crash (MC-150405) due to the default minimum being larger than the default value.

Modifier Data structure:

Field Name Field Type Notes
UUID UUID
Amount Double May be positive or negative.
Operation Byte See below.

The operation controls how the base value of the modifier is changed.

  • 0: Add/subtract amount
  • 1: Add/subtract amount percent of the current value
  • 2: Multiply by amount percent

All of the 0's are applied first, and then the 1's, and then the 2's.

Tags

Packet ID State Bound To Field Name Field Type Notes
0x5B 0x65 Play Client
Block Tags (See below) IDs are block IDs
Item Tags (See below) IDs are item IDs
Fluid Tags (See below) IDs are fluid IDs
Entity Tags (See below) IDs are entity IDs
Length of the array VarInt
Array of tags Tag type Array Identifier Tag identifier (Vanilla required tags are minecraft:block, minecraft:item, minecraft:fluid, minecraft:entity_type, and minecraft:game_event)
Array of Tag (See below)

Tags look like:

Field Name Field Type Notes
Length VarInt Number of elements in the following array
Tags Tag name Array Identifier
Count VarInt Number of elements in the following array
Entries Array of VarInt Numeric ID of the given type (block, item, etc.).


Serverbound

Client Settings

Sent when the player connects, or when settings are changed.

Packet ID State Bound To Field Name Field Type Notes
0x05 Play Server Locale String (16) e.g. en_GB.
View Distance Byte Client-side render distance, in chunks.
Chat Mode VarInt Enum 0: enabled, 1: commands only, 2: hidden. See processing chat for more information.
Chat Colors Boolean “Colors” multiplayer setting.
Displayed Skin Parts Unsigned Byte Bit mask, see below.
Main Hand VarInt Enum 0: Left, 1: Right.
Disable text filtering Boolean Disables filtering of text on signs and written book titles. Currently always true (i.e. the filtering is disabled)

Displayed Skin Parts flags:

  • 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.


Window Confirmation (serverbound)

If a confirmation sent by the client was not accepted, the server will reply with a Window Confirmation (clientbound) packet with the Accepted field set to false. When this happens, the client must send this packet to apologize (as with movement), otherwise the server ignores any successive confirmations.

Packet ID State Bound To Field Name Field Type Notes
0x07 Play Server Window ID Byte The ID of the window that the action occurred in.
Action Number Short Every action that is to be accepted has a unique number. This number is an incrementing integer (starting at 1) with separate counts for each window ID.
Accepted Boolean Whether the action was accepted.

Click Window

This packet is sent by the client when the player clicks on a slot in a window.

Packet ID State Bound To Field Name Field Type Notes
0x09 Play Server Window ID Unsigned Byte The ID of the window which was clicked. 0 for player inventory.
Slot Short The clicked slot number, see below.
Button Byte The button used in the click, see below.
Action Number Short A unique number for the action, implemented by Notchian as a counter, starting at 1 (different counter for every window ID). Used by the server to send back a Window Confirmation (clientbound).
Mode VarInt Enum Inventory operation mode, see below.
Length of the array VarInt
Array of slots Slot number Array Short
Slot data Slot New data for this slot
Clicked item Slot The clicked slot. Has to be empty (item ID = -1) for drop mode. Is always empty for mode 2 and mode 5 packets.

See Inventory 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.

Mode Button Slot Trigger
0 0 Normal Left mouse click
1 Normal Right mouse click
0 -999 Left click outside inventory (drop cursor stack)
1 -999 Right click outside inventory (drop cursor single item)
1 0 Normal Shift + left mouse click
1 Normal Shift + right mouse click (identical behavior)
2 0 Normal Number key 1
1 Normal Number key 2
2 Normal Number key 3
8 Normal Number key 9
3 2 Normal Middle click, only defined for creative players in non-player inventories.
4 0 Normal* Drop key (Q) (* Clicked item is always empty)
5 0 -999 Starting left mouse drag
4 -999 Starting right mouse drag
8 -999 Starting middle mouse drag, only defined for creative players in non-player inventories. (Note: the vanilla client will still incorrectly send this for non-creative players - see MC-46584)
1 Normal Add slot for left-mouse drag
5 Normal Add slot for right-mouse drag
9 Normal Add slot for middle-mouse drag, only defined for creative players in non-player inventories. (Note: the vanilla client will still incorrectly send this for non-creative players - see MC-46584)
2 -999 Ending left mouse drag
6 -999 Ending right mouse drag
10 -999 Ending middle mouse drag, only defined for creative players in non-player inventories. (Note: the vanilla client will still incorrectly send this for non-creative players - see MC-46584)
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):

  1. packet with mode 5, slot -999, button (0 for left | 4 for right);
  2. packet for every slot painted on, mode is still 5, button (1 | 5);
  3. 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 Window Confirmation packet. If the click was not accepted, the client must send a matching serverbound window confirmation packet before sending more Click Window packets, otherwise the server will reject them silently. The Notchian server also sends a Window Items packet for the open window and Set Slot packets for the clicked and cursor slot, but only when the click was not accepted, probably to resynchronize client and server.

Pong

A response to the ping packet. Unknown what this is used for, this is ignored by the Notchian client and server.

Packet ID State Bound To Field Name Field Type Notes
0x1D Play Server ID Int

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 754 Snapshot 15)
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 simple 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.