Difference between revisions of "Pre-release protocol"
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− | This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently [[Protocol version numbers|1.15.2, protocol 578]]) to the current pre-release (currently [[Protocol version numbers| | + | This page documents the changes from the [[Protocol|last stable Minecraft release]] (currently [[Protocol version numbers|1.15.2, protocol 578]]) to the current pre-release (currently [[Protocol version numbers|20w19a, protocol 715]]). Note that this page contains bleeding-edge information that may not be completely or correctly documented. |
One who wishes to commandeer the merging of this into [[Protocol]] when an update is made must be sure to respect any changes that may have occurred to the respective packets there. | One who wishes to commandeer the merging of this into [[Protocol]] when an update is made must be sure to respect any changes that may have occurred to the respective packets there. |
Revision as of 21:23, 6 May 2020
This page documents the changes from the last stable Minecraft release (currently 1.15.2, protocol 578) to the current pre-release (currently 20w19a, protocol 715). 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
The UUID type is now also sometimes encoded by the Notchian server as an array of four 32-bit integers, from most significant to least significant (matching the new format used on entity NBT). This representation is identical to using 16 bytes, two 64-bit integers, or one 128-bit integers.
Packets
ID | Packet name | Documentation | |
---|---|---|---|
Handshaking serverbound | |||
0x00 | Handshake | Current | Pre |
Play clientbound | |||
0x22 | Chunk Data | Current | Pre |
0x3B | Respawn | Current | Pre |
Spawn Position | Current | (unchanged) | |
Display Scoreboard | Current | (unchanged) | |
Entity Metadata | Current | (unchanged) | |
Attach Entity | Current | (unchanged) | |
Entity Velocity | Current | (unchanged) | |
Entity Equipment | Current | (unchanged) | |
Set Experience | Current | (unchanged) | |
Update Health | Current | (unchanged) | |
Scoreboard Objective | Current | (unchanged) | |
Set Passengers | Current | (unchanged) | |
Teams | Current | (unchanged) | |
Update Score | Current | (unchanged) | |
0x59 | Entity Properties | Current | Pre |
Play serverbound | |||
0x0F | Generate Structure | Pre | |
Keep Alive (serverbound) | Current | (unchanged) | |
Lock Difficulty | Current | (unchanged) | |
Player Position | Current | (unchanged) | |
Player Position And Rotation (serverbound) | Current | (unchanged) | |
Player Rotation | Current | (unchanged) | |
Player Movement | Current | (unchanged) | |
Vehicle Move (serverbound) | Current | (unchanged) | |
Steer Boat | Current | (unchanged) | |
Pick Item | Current | (unchanged) | |
Craft Recipe Request | Current | (unchanged) | |
Player Abilities (serverbound) | Current | (unchanged) | |
Player Digging | Current | (unchanged) | |
Entity Action | Current | (unchanged) | |
Steer Vehicle | Current | (unchanged) | |
Recipe Book Data | Current | (unchanged) | |
Name Item | Current | (unchanged) | |
Resource Pack Status | Current | (unchanged) | |
Advancement Tab | Current | (unchanged) | |
Select Trade | Current | (unchanged) | |
Set Beacon Effect | Current | (unchanged) | |
Held Item Change (serverbound) | Current | (unchanged) | |
Update Command Block | Current | (unchanged) | |
Update Command Block Minecart | Current | (unchanged) | |
Creative Inventory Action | Current | (unchanged) | |
Update Jigsaw Block | Current | Pre | |
Update Structure Block | Current | (unchanged) | |
Update Sign | Current | (unchanged) | |
Animation (serverbound) | Current | (unchanged) | |
Spectate | Current | (unchanged) | |
Player Block Placement | Current | (unchanged) | |
Use Item | Current | (unchanged) | |
Login clientbound | |||
0x02 | Login Success | Current | Pre |
New/modified data types
No changes so far.
Entity Metadata
FishingHook
Extends Entity.
Index | Type | Meaning | Default | |
---|---|---|---|---|
7 | VarInt | Hooked entity id + 1, or 0 if there is no hooked entity | 0 | |
8 | Boolean | Is catchable | False |
Abstract Arrow
Extends Entity.
Abstract base class for Tipped Arrow (which is used for regular arrows as well as tipped ones) and Spectral Arrow.
Index | Type | Meaning | Default | |
---|---|---|---|---|
7 | Byte | Bit mask | Meaning | 0 |
0x01 | Is critical | |||
0x02 | Is noclip (used by loyalty tridents when returning) | |||
OptUUID | Unused | Empty | ||
Byte | Peircing level | 0 |
Tipped Arrow
Extends Abstract Arrow.
Used for both tipped and regular arrows. If not tipped, then color is set to -1 and no tipped arrow particles are used.
Index | Type | Meaning | Default | |
---|---|---|---|---|
VarInt | Color (-1 for no particles) | -1 |
Spectral Arrow
Extends Abstract Arrow.
No additional metadata.
Trident
Extends Abstract Arrow.
Index | Type | Meaning | Default | |
---|---|---|---|---|
VarInt | Loyalty level (enchantment) | 0 | ||
Boolean | Has enchantment glint | False |
Strider
Extends Animal.
Index | Type | Meaning | Default | |
---|---|---|---|---|
16 | VarInt | Total time to "boost" with warped fungus on a stick for | 0 | |
17 | Boolean | Should display name tag (true unless riding a vehicle or on or in a block tagged with strider_warm_blocks (default: lava)) | false | |
18 | Boolean | Has saddle | false |
Hoglin
Extends Animal.
Index | Type | Meaning | Default | |
---|---|---|---|---|
16 | Boolean | Is immune to zombification | false |
Zoglin
Extends Monster.
Index | Type | Meaning | Default | |
---|---|---|---|---|
15 | Boolean | Is baby | false |
Piglin
Extends Monster.
Index | Type | Meaning | Default | |
---|---|---|---|---|
15 | Boolean | Is baby | false | |
16 | Boolean | Is immune to zombification | false | |
17 | Boolean | Is charging crossbow | false |
Zombie Pigman Zombified Piglin
Extends Zombie.
No additional metadata.
Block Actions
No changes so far.
Inventories
No changes so far.
Plugin Channels
No changes so far.
Play
Clientbound
Chunk Data
- Main article: Chunk Format
- See also: #Unload Chunk
The following information needs to be added to this page: | |
How do biomes work now? The biome change happened at the same time as the seed change, but it's not clear how/if biomes could be computed given that it's not the actual seed... (/r/mojira discussion which notes that it seems to be some kind of interpolation, and 3D biomes are only used in the nether) |
The server only sends skylight information for chunk pillars in the Overworld, it's up to the client to know in which dimenison the player is currently located. You can also infer this information from the primary bitmask and the amount of uncompressed bytes sent. This packet also sends all block entities in the chunk (though sending them is not required; it is still legal to send them with Update Block Entity later).
Packet ID | State | Bound To | Field Name | Field Type | Notes |
---|---|---|---|---|---|
0x22 | Play | Client | Chunk X | Int | Chunk coordinate (block coordinate divided by 16, rounded down) |
Chunk Z | Int | Chunk coordinate (block coordinate divided by 16, rounded down) | |||
Full chunk | Boolean | See Chunk Format | |||
Primary Bit Mask | VarInt | Bitmask with bits set to 1 for every 16×16×16 chunk section whose data is included in Data. The least significant bit represents the chunk section at the bottom of the chunk column (from y=0 to y=15). | |||
Heightmaps | NBT | Compound containing one long array named MOTION_BLOCKING , which is a heightmap for the highest solid block at each position in the chunk (as a compacted long array with 256 entries at 9 bits per entry totaling 36 longs). The Notchian server also adds a WORLD_SURFACE long array, the purpose of which is unknown, but it's not required for the chunk to be accepted.
| |||
Biomes | Optional array of Integer | 1024 biome IDs, ordered by x then z then y, in 4×4×4 blocks. Not present if full chunk is false. | |||
Size | VarInt | Size of Data in bytes | |||
Data | Byte array | See data structure in Chunk Format | |||
Number of block entities | VarInt | Number of elements in the following array | |||
Block entities | Array of NBT Tag | All block entities in the chunk. Use the x, y, and z tags in the NBT to determine their positions. |
Note that the Notchian client requires an Update View Position packet when it crosses a chunk border, otherwise it'll only display render distance + 2 chunks around the chunk it spawned in.
The compacted array format has been adjusted so that individual entries no longer span across multiple longs, affecting the main data array and heightmaps.
Respawn
To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.
Packet ID | State | Bound To | Field Name | Field Type | Notes |
---|---|---|---|---|---|
0x3B | Play | Client | Dimension | Int Enum | -1: The Nether, 0: The Overworld, 1: The End |
Hashed seed | Long | First 8 bytes of the SHA-256 hash of the world's seed. | |||
Gamemode | Unsigned Byte | 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included | |||
Level Type | String (16) | Same as Join Game | |||
Copy metadata | Boolean | If false, metadata is reset on the respawned player entity. Set to true for dimension changes (including the dimension change triggered by sending client status perform respawn to exit the end poem/credits), and false for normal respawns. |
Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).
If you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.
Entity Properties
Sets attributes on the given entity.
Packet ID | State | Bound To | Field Name | Field Type | Notes | ||
---|---|---|---|---|---|---|---|
0x59 | Play | Client | Entity ID | VarInt | |||
Number Of Properties | Int | Number of elements in the following array | |||||
Property | Key | Array | 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 |
---|---|---|---|---|
20.0 | 0.0 | 1024.0 | Max Health | |
32.0 | 0.0 | 2048.0 | Follow Range | |
0.0 | 0.0 | 1.0 | Knockback Resistance | |
0.7 | 0.0 | 1024.0 | Movement Speed | |
2.0 | 0.0 | 2048.0 | Attack Damage | |
4.0 | 0.0 | 1024.0 | Attack Speed | |
0.4 | 0.0 | 1024.0 | Flying Speed | |
generic.armor | 0.0 | 0.0 | 30.0 | Armor |
0.0 | 0.0 | 20.0 | Armor Toughness | |
0.0 | 0.0 | 5.0 | — | |
generic.luck | 0.0 | -1024.0 | 1024.0 | Luck |
0.7 | 0.0 | 2.0 | Jump Strength | |
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.
Serverbound
Generate Structure
Sent when Generate is pressed on the Jigsaw Block interface.
Packet ID | State | Bound To | Field Name | Field Type | Notes |
---|---|---|---|---|---|
0x0F | Play | Server | Location | Position | Block entity location |
Levels | VarInt | Value of the levels slider/max depth to generate |
Update Jigsaw Block
Sent when Done is pressed on the Jigsaw Block interface.
Packet ID | State | Bound To | Field Name | Field Type | Notes |
---|---|---|---|---|---|
Play | Server | Location | Position | Block entity location | |
Attachment type | Identifier | ||||
Name | Identifier | ||||
Target | Identifier | ||||
Identifier | |||||
Final state | String | "Turns into" on the GUI, final_state in NBT
| |||
Joint type | String | rollable if the attached piece can be rotated, else aligned
|
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 |
Server Address | String | Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a complete redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide mc.example.org as server address in addition to connecting to it. | |||
Server Port | Unsigned Short | Default is 25565. The Notchian server does not use this information. | |||
Next State | VarInt Enum | 1 for status, 2 for login |
Status
Clientbound
No changes so far.
Serverbound
No changes so far.
Login
Clientbound
Login Success
Packet ID | State | Bound To | Field Name | Field Type | Notes |
---|---|---|---|---|---|
0x02 | Login | Client | UUID | ||
Username | String (16) |
This packet switches the connection state to play.
Serverbound
No changes so far.