Help on understanding CompoundTag and Tag class for structure .nbt file

[tios]

Hello,

I want to create a mod where player create a village to gain ressources and more functions. (mod version is 1.18.1)

To start, i want player to right click on a block and spawn the structure like a miner house or the chef house.

I use the function NBT to see what is inside the CompoundTag and understand it. The problem is that I can get data from the Compound only with the compound.get() even if I get Type of the tag, i can't get ListTag even for blocks in the nbt file.

All method to get data from CompoundTag or Tag doesn't work.

Could someone explain or link a solution, a path to understand ?

This is the Structure class that I have created :

package com.tios.villageum.world.structure;

import com.tios.villageum.Villageum;
import net.minecraft.core.BlockPos;
import net.minecraft.nbt.*;
import net.minecraft.network.chat.NbtComponent;
import net.minecraft.resources.ResourceLocation;
import net.minecraft.server.packs.resources.Resource;
import net.minecraft.server.packs.resources.ResourceManager;
import net.minecraft.world.level.Level;
import net.minecraft.world.level.block.Block;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.levelgen.structure.templatesystem.StructureManager;
import net.minecraft.world.level.levelgen.structure.templatesystem.StructureTemplate;

import java.io.*;
import java.util.List;
import java.util.zip.GZIPInputStream;

public class Structure {

    public int length;  // X
    public int height;  // Y
    public int width;   // Z

    protected String fileName;
    protected InputStream fileStream;
    private BlockState[][][] blocks;
    private int[][][] blockData;
    private CompoundTag[] entities;
    private CompoundTag[] tileEntities;

    public Structure(String filename){
        this.fileName = filename;
        this.fileStream = Structure.class.getResourceAsStream("/assets/"+Villageum.MOD_ID+"/structs/" + filename + ".nbt");
    }


    public void createStructure(Level level, BlockPos pos){
    }

    public boolean emptyInSizedSpace(Level level, BlockPos pos) {
        return level.getChunkAt(pos).isEmpty();
    }


    public void readFromFile()
    {
        CompoundTag nbtTagCompound = null;
        DataInputStream dataInputStream;
        try
        {
            dataInputStream = new DataInputStream(new GZIPInputStream(this.fileStream));
            nbtTagCompound = NbtIo.read(dataInputStream);
            dataInputStream.close();
        }
        catch (Exception e)
        {
            System.err.println("Villageum Mod: Error loading structure '" + this.fileName + "'");
            return;
        }

        var keys = nbtTagCompound.getAllKeys();

        var size1 = nbtTagCompound.get("size").getAsString().replace("[","").replace("]","").split(",");
        // In schematics, length is z and width is x. Here it is reversed.
        this.length = Integer.parseInt(size1[0]);
        this.height = Integer.parseInt(size1[1]);
        this.width = Integer.parseInt(size1[2]);

        int size = this.length * this.width * this.height;


        blocks = new BlockState[this.height][this.width][this.length];
        blockData = new int[this.height][this.width][this.length];
        NBT(nbtTagCompound, "blocks");
        var tag = nbtTagCompound.get("blocks");
        byte[] blockIdsByte = nbtTagCompound.getByteArray("blocks");
        byte[] blockDataByte = nbtTagCompound.getByteArray("palette");
        int x = 1, y = 1, z = 1;
        for (int i = 0; i < blockIdsByte.length; i++)
        {
            int blockId = (short) (blockIdsByte[i] & 0xFF);
            blocks[y - 1][z - 1][x - 1] = Block.stateById(blockId);
            blockData[y - 1][z - 1][x - 1] = blockDataByte[i];
            x++;
            if (x > this.length)
            {
                x = 1;
                z++;
            }
            if (z > this.width)
            {
                z = 1;
                y++;
            }
        }

        ListTag entityList = nbtTagCompound.getList("Entities", 10);
        entities = new CompoundTag[entityList.size()];
        for (int i = 0; i < entityList.size(); i++)
            entities[i] = entityList.getCompound(i);

        /*
        ListTag tileEntityList = nbtTagCompound.getList("TileEntities", 10);
        tileEntities = new CompoundTag[tileEntityList.size()];
        for (int i = 0; i < tileEntityList.size(); i++)
            tileEntities[i] = tileEntityList.getCompound(i);*/
    }


    private void NBT(CompoundTag compoundTag,String key){
        var id = compoundTag.getId();
        var keys = compoundTag.getAllKeys();
        var contain = compoundTag.contains(key);
        var tag = compoundTag.get(key);
        var type = tag.getType();
        var astring =tag.getAsString();
    }
}

[warjort]

I am guessing from the import that this is related to StructureTemplates?

Look at the value for StructureTemplate.ENTITIES_TAG and you will see it is all lower case. i.e. you need to change Entities -> entities

 

If that's not the problem, use NBTUtils.prettyPrint() to show the structure of what you are parsing.