[Solved][1.16.1] One time initializing for entities

[DavidQF555]

I was told that the onInitialSpawn() method was for one time initializing for things like armor, but I also thought that was a good place to initialize many lists and maps that are my own fields for my own custom entity. However, I'm getting loads of nullpointerexceptions because apparently it initializes the fields after ticks and goals are run. I don't want to put it in the constructor because then the lists will be constantly cleared. Is there a way to initialize them once before the ticks and goals run? I really don't want to put null checkers in every tick method. 

Edited August 15, 2020 by DavidQF555

[DavidQF555]

4 hours ago, diesieben07 said:

The constructor should be fine. What do you mean by "constantly cleared"? show your code.

Someone told me that the constructor runs every time an entity spawns, so I should use onInitialSpawn for 1 time events. So if I did list = new ArrayList<>() in the construtor, wouldn't it just reset every time an entity spawns? Is that not how the constructor runs?

[DavidQF555]

15 minutes ago, diesieben07 said:

The constructor runs whenever a new instance of your entity is created.

This happens when it spawns, but also when it is loaded from disk (e.g. when the chunk got unloaded). It also happens when your entity is created on the client, that is when a player is in or comes into range.

onInitialSpawn fires only when the entity is first spawned, not when it is e.g. loaded from disk.

 

As for your list: you need to of course create it in the constructor, that is how objects work (basic Java knowledge is needed, read up on how objects work if you don't know this stuff).

Then you can use onInitialSpawn to set the intial data of your entity. You then need to use the NBT read and write function to actually make your data persist.

for reading and writing NBT for entities, do you use the read/write additional methods?

[DavidQF555]

@Override
    public void readAdditional(@Nonnull CompoundNBT nbt) {
        super.readAdditional(nbt);
        System.out.println("run");
        if (nbt.contains("testmod.customentity")) {
            System.out.println("has nbt");
            CompoundNBT reg = (CompoundNBT) nbt.get("testmod.customentity");
            personality = Personality.get(reg.getString("personality"));
            level = nbt.getInt("level");
        }
    }

    @Override
    public void writeAdditional(@Nonnull CompoundNBT nbt) {
        super.writeAdditional(nbt);
        CompoundNBT reg = new CompoundNBT();
        reg.putString("personality", personality.name());
        reg.putInt("level", level);
        nbt.put("testmod.customentity", reg);
    }

It seems like some of my fields were just left as null because the nbt apparently doesn't have "testmod.customentity". Did I do something wrong? "has nbt" does not appear, but "run" does.

[Draco18s]

If you had entities in the world already that were saved before you added that code, of course they won't have it.

[DavidQF555]

I'm confused as to the order that the constructor runs. I set a default value in the constructor and had it randomized to the actual value in the onInitalSpawn method. It keeps on changing back to the default value though. 

public CustomEntity(World worldIn, int level) {
        super(RegistryHandler.CUSTOM_ENTITY.get(), worldIn);
        this.level = level;
        personality = Personality.NEUTRAL;
        System.out.println("constructor");
    }

public ILivingEntityData onInitialSpawn(IWorld worldIn, DifficultyInstance difficultyIn, SpawnReason reason, ILivingEntityData spawnDataIn, CompoundNBT dataTag) {
  		Personality[] personalities = Personality.values();
        personality = personalities[(int) (Math.random() * personalities.length)];
    }

I checked the personality value by printing in livingTick() and also because the entity is rendered with a texture based on personality. In livingTick(), the personality constantly switches between NEUTRAL and another value. The rendered texture is always just the default one. 

[Draco18s]

22 minutes ago, DavidQF555 said:

constantly switches between NEUTRAL and another value.

See also: Threads.

$100 says that the client thread (which doesn't matter) prints NEUTRAL while the server thread prints the randomized value.

[DavidQF555]

1 hour ago, Draco18s said:

See also: Threads.

$100 says that the client thread (which doesn't matter) prints NEUTRAL while the server thread prints the randomized value.

How would I retrieve the server side version of Personality for rendering then? Or how would I make it so that I only retrieve the server side version? 

Edited August 13, 2020 by DavidQF555

[Draco18s]

Usually packets.

There's also a way to specify entity data values (eg. things that don't change, or change rarely), I'm drawing a blank on what they're called at the moment.

Edited August 13, 2020 by Draco18s

[DavidQF555]

On 8/13/2020 at 9:13 AM, diesieben07 said:

For your own entities you can use EntityDataManager (look at vanilla for examples) for data that can change or IEntityAdditionalSpawnData for data that never changes.

I was able to use data parameters to sync client and server data