[1.12.2] Trying to make item scan entire world for a specific entity and make it teleport to the player.

[NovaViper]

So far, I have adapted the ItemWhistle code from Sophisticated Wolves (and given them proper credit of it) to make the whistle in Doggy Talents function, however I want to take the item to a whole new level. Basically, the entire purpose of the whistle is to recall all of the dogs that you have tamed to you in case you lost them somewhere. What I intend to do is take that furthur by allowing the item to call the dogs back from any distance, basically anywhere in the dimension. While the basic code is working, I can't figure out how to make the item scan the entire world for all entities that use the class EntityDog, select them and then make them teleport to the player. Here's what I have so far: https://hastebin.com/agodoqihix.swift

[jabelar]

Why would you have to scan for this? Why not have player simply have extended data that keeps track of all dogs that the player has trained?

[NovaViper]

I thought it would be easiest to scan the world for the entities. I was not aware of this other alternative method of achieving the same thing

[Draco18s]

What if the dog is an unloaded chunk?

What if the dog is in a different dimension?

[NovaViper]

1 minute ago, Draco18s said:

What if the dog is an unloaded chunk?

What if the dog is in a different dimension?

I noticed when the chunks ended up being unloaded, the dog wouldn't come to me anymore. And as for the different dimension, the item wouldn't be meant to call them from different dimensions, but rather within the same one

[Draco18s]

8 minutes ago, NovaViper said:

I noticed when the chunks ended up being unloaded, the dog wouldn't come to me anymore.

Yes, because it literally ceased to exist.

[NovaViper]

1 minute ago, Draco18s said:

Yes, because it literally ceased to exist.

Oh.. that would make a whole lot of sense. I haven't experimented with chunks (really, this is my first time actually dealing with that sector of Minecraft)

[jabelar]

27 minutes ago, Draco18s said:

Yes, because it literally ceased to exist.

This brings up another issue of entity persistence as well. In regular Minecraft, entities can literally "despawn" if they are far away for long enough and I think that is probably forced during chunk unloads. This works okay for general animals (who really cares if a sheep is still there later) but for some things like structure-generated mobs (like in mansions) and maybe things like tamed animals you might want to make sure they are persistent.

 

I prefer the idea of using a list to keep track of your tamed animals, rather than scanning all entities in the world to see if they are the right type and then further checking to see if they are tamed, because that is very inefficient -- less than 0.1% of entities in the world are likely to be tamed at any given time. However, you can do it by scanning if you want as the world has a list of loaded entities which you can loop through (or use contains() type methods if the data structure is amenable).

[NovaViper]

10 hours ago, jabelar said:

This brings up another issue of entity persistence as well. In regular Minecraft, entities can literally "despawn" if they are far away for long enough and I think that is probably forced during chunk unloads. This works okay for general animals (who really cares if a sheep is still there later) but for some things like structure-generated mobs (like in mansions) and maybe things like tamed animals you might want to make sure they are persistent.

 

I prefer the idea of using a list to keep track of your tamed animals, rather than scanning all entities in the world to see if they are the right type and then further checking to see if they are tamed, because that is very inefficient -- less than 0.1% of entities in the world are likely to be tamed at any given time. However, you can do it by scanning if you want as the world has a list of loaded entities which you can loop through (or use contains() type methods if the data structure is amenable).

Well, which ever method is easiest is the one I want to go with.. However.. I've haven't done this sort before (as in actually put in code). I don't want a direct copy-paste of code, rather I want to learn it so next time I would be able to apply this skill in any other part of the code with no problem.

[jabelar]

Here's how I suggest going about it. This is how I figure things out.

 

So your original question was how to "scan" the entities in the world. So I would go to the World class and look at what fields and methods are available, literally scroll through them to see if anything looks interesting. In Eclipse you can use the Type Hierarchy for the World class (and generally a good idea to enable all inherited stuff with little button at top of the list of methods).

 

If you scroll through that you will see there is a field called loadedEntityList. If you right click and pick "Declaration" you can go to where it is declared in the code. There you will see that it is public scope meaning that it is available for you to use in your classes -- cool. Sometimes in modding the names of the fields and methods don't match what you expect, so it is a good idea to confirm this is what you want by looking at the Call Hierarchy for that field. If you do you'll see how it is used by Minecraft and in this case it looks like a useful thing.

 

Now the type of field is a simple Java List<Entity>. So basically you can do everything you would want to do with a List. If you don't know Java well you should look it up, but Lists can be iterated in a loop so you can just loop through and find all the entries that are instanceof EntityDog (or whatever you're looking for) and so on.

 

That is how you "scan the entire world for a specific entity"...

[NovaViper]

3 hours ago, jabelar said:

Here's how I suggest going about it. This is how I figure things out.

 

So your original question was how to "scan" the entities in the world. So I would go to the World class and look at what fields and methods are available, literally scroll through them to see if anything looks interesting. In Eclipse you can use the Type Hierarchy for the World class (and generally a good idea to enable all inherited stuff with little button at top of the list of methods).

 

If you scroll through that you will see there is a field called loadedEntityList. If you right click and pick "Declaration" you can go to where it is declared in the code. There you will see that it is public scope meaning that it is available for you to use in your classes -- cool. Sometimes in modding the names of the fields and methods don't match what you expect, so it is a good idea to confirm this is what you want by looking at the Call Hierarchy for that field. If you do you'll see how it is used by Minecraft and in this case it looks like a useful thing.

 

Now the type of field is a simple Java List<Entity>. So basically you can do everything you would want to do with a List. If you don't know Java well you should look it up, but Lists can be iterated in a loop so you can just loop through and find all the entries that are instanceof EntityDog (or whatever you're looking for) and so on.

 

That is how you "scan the entire world for a specific entity"...

That's actually the same method I was using before; but I burrowed some code from an experimental 1.12.2 branch of DragonMounts, it seemed to do the job but it would stop working if the dogs got unloaded.

 

I made a few changes to the code, but I haven't given it a test (yet) -- Gave it a test, still the same results as before

List<EntityDog> dogsList = world.getLoadedEntityList().stream().filter(dog -> dog instanceof EntityDog).map(dog -> (EntityDog) dog).collect(Collectors.toList());
			for(EntityDog dog : dogsList) {
				int xPos = MathHelper.floor(player.posX);
				int zPos = MathHelper.floor(player.posZ);
				int yPos = MathHelper.floor(player.getEntityBoundingBox().minY);
				
				if (dog.isTamed() && dog.isOwner(player) && (!dog.isSitting() || player.isSneaking())) {
					for (int x = -2; x <= 2; x++) {
						for (int z = -2; z <= 2; z++) {
							if(DogUtil.isTeleportFriendlyBlock(dog, world, xPos, zPos, yPos, x, z)) {
								dog.setSitting(false);
								dog.getAISit().setSitting(false);
								dog.setLocationAndAngles(xPos + x + 0.5, yPos, zPos + z + 0.5, dog.rotationYaw, dog.rotationPitch);
								dog.getNavigator().clearPath();
								dog.setAttackTarget(null);
							}
						}
					}
				}
			}

 

Edited April 6, 2018 by NovaViper

[jabelar]

What do you mean it "would stop working"? Is there an error?

 

If you mean that some of the dogs have disappeared due to being unloaded, that is a separate problem. As I already mentioned you need to set persistence on your tamed dogs if you want them to not be unloaded. 

[NovaViper]

4 minutes ago, jabelar said:

What do you mean it "would stop working"? Is there an error?

 

If you mean that some of the dogs have disappeared due to being unloaded, that is a separate problem. As I already mentioned you need to set persistence on your tamed dogs if you want them to not be unloaded. 

The dogs won't teleport to me anymore, there isn't any sort of error with it either

[jabelar]

Are the dogs in the list, or they are not even in the list? You should use print statements to print out the list to see what is in it.

 

[NovaViper]

25 minutes ago, jabelar said:

Are the dogs in the list, or they are not even in the list? You should use print statements to print out the list to see what is in it.

 

When I get too far away, they seem to not appear in the list. Seems that going outside of the 102.50 z range seems to cause it to no longer show up in the list

 

[19:35:02] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-259.50, y=66.00, z=83.50]]
[19:35:06] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:12] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:13] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:13] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:14] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:14] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:14] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:14] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:14] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:15] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:15] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:15] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:15] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:16] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:16] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:35:17] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/61, l='New World', x=-439.50, y=81.00, z=-102.50]]
[19:44:03] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: []
[19:44:04] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: []
[19:44:04] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: []
[19:46:10] [Server thread/INFO] [STDOUT]: [doggytalents.item.ItemWhistle:onItemRightClick:36]: [EntityDog['Dog'/11235, l='New World', x=-439.50, y=81.00, z=-102.50]]

 

[Draco18s]

Probably because it unloaded.

[NovaViper]

1 minute ago, Draco18s said:

Probably because it unloaded.

That seems to be the case.. and since that's an issue. How would I add the dogs to a "database" to keep track of them?

[Draco18s]

You can't "track" unloaded entities: they've been completely removed from RAM and only exist as serialized and compressed data on the hard drive.

[NovaViper]

I mean like what jabelar had suggested

20 hours ago, jabelar said:

I prefer the idea of using a list to keep track of your tamed animals, rather than scanning all entities in the world to see if they are the right type and then further checking to see if they are tamed, because that is very inefficient -- less than 0.1% of entities in the world are likely to be tamed at any given time. However, you can do it by scanning if you want as the world has a list of loaded entities which you can loop through (or use contains() type methods if the data structure is amenable).

 

[jabelar]

Did you try making the entities persistent with the setPersistent() method when they are tamed?

 

If you look at EntityLiving there are some related fields/methods:

- canDespawn() which defaults to true

- despawnEntity() which looks at a couple things including distance, the canDespawn() and also

- isPersistenceRequired which can be set with the enablePersistence() method, and this also is returned for the isNoDespawnRequired() method.

 

If you look at the despawnEntity() method and trace the logic, you'll see that simply setting the persistence with enablePersistence() method will prevent despawning.

 

That should help a fair bit because entities despawn even when chunks are loaded without persistence.

 

Now I don't think persistence really helps if the chunk is actually unloaded. But it might so maybe Draco18s or diesieben07 know more details about that. You could force the entities to stay loaded by handling the chunk unload event and directly manipulating the world unloadedEntitiesList, but I think that would be a problem to have entities loaded without the chunk. But again others might know better.

 

I would start by ensuring your entities are persistent. If there is still an issue, then what I would do is create a capability for the player that contains a List of the EntityDogs that have been tamed. I think you would actually just keep some information about the dogs and when you want to whistle them you would find the ones in the world and bring them, and then all the ones that are missing you'd have to re-construct. But I'm guessing at this point.

[NovaViper]

28 minutes ago, jabelar said:

Did you try making the entities persistent with the setPersistent() method when they are tamed?

 

If you look at EntityLiving there are some related fields/methods:

- canDespawn() which defaults to true

- despawnEntity() which looks at a couple things including distance, the canDespawn() and also

- isPersistenceRequired which can be set with the enablePersistence() method, and this also is returned for the isNoDespawnRequired() method.

 

If you look at the despawnEntity() method and trace the logic, you'll see that simply setting the persistence with enablePersistence() method will prevent despawning.

 

That should help a fair bit because entities despawn even when chunks are loaded without persistence.

 

Now I don't think persistence really helps if the chunk is actually unloaded. But it might so maybe Draco18s or diesieben07 know more details about that. You could force the entities to stay loaded by handling the chunk unload event and directly manipulating the world unloadedEntitiesList, but I think that would be a problem to have entities loaded without the chunk. But again others might know better.

 

I would start by ensuring your entities are persistent. If there is still an issue, then what I would do is create a capability for the player that contains a List of the EntityDogs that have been tamed. I think you would actually just keep some information about the dogs and when you want to whistle them you would find the ones in the world and bring them, and then all the ones that are missing you'd have to re-construct. But I'm guessing at this point.

Enabling that method seemed to do to the trick!  Hm.. how can I make that as soon as it is spawned? There are multiple ways the dogs can be spawned in the world and tamed (via giving a wolf a treat, spawning them directly with an item, retaming them after untaming them and so on). Would I put that within the entityInt() method to accomplish the same thing?

[jabelar]

10 hours ago, NovaViper said:

Enabling that method seemed to do to the trick!  Hm.. how can I make that as soon as it is spawned? There are multiple ways the dogs can be spawned in the world and tamed (via giving a wolf a treat, spawning them directly with an item, retaming them after untaming them and so on). Would I put that within the entityInt() method to accomplish the same thing?

It depends on what you want. If there are a lot of dogs in world you probably shouldn't make them all persistent. Rather only tamed one. So If you have a method for taming then I would set the persistence there. The persistenceRequired field is private and the enablePersistence() only sets it to true -- there is no way without Reflection to clear it again. But it is probably okay to leave dogs persistent if they've ever been tamed as that shouldn't be that many and certainly would be less than all the dogs in the world. But if you really wanted to clear it again you can use reflection or alternatively you can create your own field and override the despawn method to use that instead.

 

But I would start by just using enablePersistence() whenever you do the taming.

[NovaViper]

I added the enablePersistence() in the entityInt() since obtaining the dog is acutally done when you feed a tamed wolf dog treats, it automatically spawns a tamed dog with data from the wolf.

 

I do have one other question relating to this actually, but it relates to another piece of code I'm adding in (not relating to the topic). I'm going to create another topic about it to avoid confusion