[1.10] Custom Hanging Entity Issues

[Draco18s]

I've created a custom hanging entity that I want to use to replace the ItemFrame so that I can supply some additional logic.

 

However, I have a couple issues.

If I don't register the mod entity, then the entity shows up and behaves normally, except that it doesn't save (this makes sense: there's no entity ID mapping for it).  However, if I add the registerModEntity line for it, then it doesn't show up in-game at all () but does save (as well as popping off if the block it's attached to is broken).

 

Main mod class:

			itemFrameReplacement = new ItemItemFrame();
	itemFrameReplacement.setRegistryName(new ResourceLocation("minecraft","item_frame"));
	itemFrameReplacement.setUnlocalizedName("frame");
	try {
		GameRegistry.addSubstitutionAlias("minecraft:item_frame", Type.ITEM, itemFrameReplacement);
	} catch (ExistingSubstitutionException e) {
		e.printStackTrace();
	}
	//commenting this line changes behavior:
	EntityRegistry.registerModEntity(EntityItemFrameReplacement.class, "item_frame_rep", 0, this, 48, 10, false);

[Draco18s]

If you look at

EntityTrackerEntry::createSpawnPacket

you will see that item frames use a specialized spawn packet, which uses a special constructor to set the positional data. FMLs spawn mechanic doesn't do this and you have to emulate it using

IEntityAdditionalSpawnData

.

 

Ahh. I wouldn't have even thought to look there.

Thanks.

[Draco18s]

As there are very few posts about IEntityAdditionalSpawnData...

(Not that it was hard, but having the reference is nice!)

 

Make the custom entity implement it and then write this:

 

	@Override
public void writeSpawnData(ByteBuf buffer) {
	BlockPos p = getHangingPosition();
	buffer.writeInt(p.getX());
	buffer.writeInt(p.getY());
	buffer.writeInt(p.getZ());
	buffer.writeInt(this.getHorizontalFacing().getIndex());
}

@Override
public void readSpawnData(ByteBuf buffer) {
	BlockPos p = new BlockPos(buffer.readInt(),buffer.readInt(),buffer.readInt());
	this.hangingPosition = p;
	int f = buffer.readInt();
	updateFacingWithBoundingBox(EnumFacing.values()[f]);
}

[Draco18s]

Just as a note, you can encode a

BlockPos

more easily and efficiently using either the method in

PacketBuffer

or

BlockPos::toLong

resp.

BlockPos.fromLong

.

If you use

PacketBuffer

that also has methods

readEnumValue

and

writeEnumValue

for maximum convenience

 

I wondered about that with the BlockPos, I hadn't seen anywhere a good way to encode it in packets (and vanilla decomposes it, or at least does for SPacketSpawnObject packet; see line 58).  Also, good to know about the read/write enum values.  Much handy.

 

Makes things

	@Override
public void writeSpawnData(ByteBuf buffer) {
	PacketBuffer pack = new PacketBuffer(buffer);
	pack.writeBlockPos(getHangingPosition());
	pack.writeEnumValue(this.getHorizontalFacing());
}

@Override
public void readSpawnData(ByteBuf buffer) {
	PacketBuffer pack = new PacketBuffer(buffer);
	hangingPosition = pack.readBlockPos();
	updateFacingWithBoundingBox(pack.readEnumValue(EnumFacing.class));
}

[Draco18s]

PacketBuffer

also has

readBlockPos

/

writeBlockPos

 

Oh, you put "or" and I read it as "and."  Thanks diesieben07.