Block Action

Packet ID	Direction
0x36	Clientbound

Clientbound

This packet is sent to inform the client when a block has perfored an action. There are only two blocks that make use this packet, Noteblocks and Pistons.

Noteblock

Noteblocks use the Packet to indicate they’ve played a tone. They use the two bytes the packet offers for Instrument and Pitch information.

Field	Type	Description
X	Integer	The X position of where the block is.
Y	Short	The Y position of where the block is.
Z	Integer	The Z position of where the block is.
Instrument	Byte	The instrument type.
Pitch	Byte	The pitch of the note.

Value	Instrument
0	Harp
1	Bass
2	Snare Drum
3	Hi-hat
4	Bass Drum

Piston

Pistons use it to indicate whether they’re extended or not and what direction they face. This also plays the piston push or retract sound as needed.*

Field	Type	Description
X	Integer	The X position of where the block is
Y	Short	The Y position of where the block is
Z	Integer	The Z position of where the block is
State	Byte	false for extending, true for retracting
Direction	Byte	The direction the piston extends/retracts to

The direction matches the lower 3-Bits of the metadata values that’re used for pistons as described on the Blocks page.

Value	Direction
0	Down
1	Up
2	East
3	West
4	North
5	South

A lot of this still needs to be tested. I’m unsure if this just plays the sound or if this is also responsible for playing the piston extend/retract animations!

Example Packet

TODO: Capture or at least write example packet data