Changes

== Creating a <code>BlockEntity</code> ==

== Creating a <code>BlockEntity</code> ==

You can also use a <code>DeferredRegister</code> instead.

You can also use a <code>DeferredRegister</code> instead.

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<syntaxhighlight lang="java">

== Attaching a <code>BlockEntity</code> to a <code>Block</code> ==

== Attaching a <code>BlockEntity</code> to a <code>Block</code> ==

To attach your new <code>BlockEntity</code> to a <code>Block</code>, the <code>EntityBlock</code> interface must be implemented on your <code>Block</code> subclass. The method <code>EntityBlock#newBlockEntity(BlockPos, BlockState)</code> must be implemented and return a new isntance of your <code>BlockEntity</code>.

To attach your new <code>BlockEntity</code> to a <code>Block</code>, the <code>EntityBlock</code> interface must be implemented on your <code>Block</code> subclass. The method <code>EntityBlock#newBlockEntity(BlockPos, BlockState)</code> must be implemented and return a new instance of your <code>BlockEntity</code>.

== Storing Data within your <code>BlockEntity</code> ==

== Storing Data within your <code>BlockEntity</code> ==

In order to save data, override the following two methods  

In order to save data, override the following two methods  

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<syntaxhighlight lang="java">

BlockEntity#save(CompoundTag tag)

BlockEntity#saveAdditional(CompoundTag tag)

BlockEntity#load(CompoundTag tag)

BlockEntity#load(CompoundTag tag)

=== Synchronizing on block update  ===

=== Synchronizing on block update  ===

This method is a bit more complicated, but again you just need to override 2 methods. Here is a tiny example implementation of it:

This method is a bit more complicated, but again you just need to override 2 or 3 methods. Here is a tiny example implementation of it:

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<syntaxhighlight lang="java">

@Override

@Override

public ClientboundBlockEntityDataPacket getUpdatePacket(){

public CompoundTag getUpdateTag() {

    CompoundTag tag = new CompoundTag();

  CompoundTag tag = new CompoundTag();

    //Write your data into the tag

  //Write your data into the tag

    return new ClientboundBlockEntityDataPacket(getBlockPos(), -1, tag);

  return tag;

}

}

@Override

@Override

public void onDataPacket(Connection connection, ClientboundBlockEntityDataPacket pkt){

public Packet<ClientGamePacketListener> getUpdatePacket() {

    CompoundTag tag = pkt.getTag();

  // Will get tag from #getUpdateTag

  return ClientboundBlockEntityDataPacket.create(this);

}

}

</syntaxhighlight>

</syntaxhighlight>

The Constructor of <code>ClientboundBlockEntityDataPacket</code> takes:

The static constructors <code>ClientboundBlockEntityDataPacket#create</code> takes:

* The position of your <code>BlockEntity</code>.

* The <code>BlockEntity</code>.

* An ID, though it isn’t really used besides by Vanilla, therefore you can just put a -1 in there.

* An optional function to get the <code>CompoundTag</code> from the <code>BlockEntity</code>. By default, this uses <code>BlockEntity#getUpdateTag</code>.

* A <code>CompoundTag</code> which should contain your data.

Now, to send the packet, an update notification must be given on the server.  

Now, to send the packet, an update notification must be given on the server.  

Level#sendBlockUpdated(BlockPos pos, BlockState oldState, BlockState newState, int flags)

Level#sendBlockUpdated(BlockPos pos, BlockState oldState, BlockState newState, int flags)

</code>

</code>

The <code>pos</code> should be your <code>BlockEntity</code>’s position. For <code>oldState</code> and <code>newState</code> you can pass the current <code>BlockState</code> at that position. The <code>flags</code> are a bitmask and should contain <code>2</code>, which will sync the changes to the client. See <code>Constants$BlockFlags</code> for more info as well as the rest of the flags. The flag <code>2</code> is equivalent to <code><nowiki>Constants$BlockFlags#BLOCK_UPDATE</nowiki></code>.

The <code>pos</code> should be your <code>BlockEntity</code>’s position. For <code>oldState</code> and <code>newState</code> you can pass the current <code>BlockState</code> at that position. The <code>flags</code> are a bitmask and should contain <code>2</code>, which will sync the changes to the client. See <code>Block</code> for more info as well as the rest of the flags. The flag <code>2</code> is equivalent to <code><nowiki>Block#UPDATE_CLIENTS</nowiki></code>.

=== Synchronizing using a custom network message ===

=== Synchronizing using a custom network message ===