[1.15.x] Problem With Spawning Entity

[Scaleios]

I've been digging around for a while, looking for a way to spawn items in the world. In essence, I have the player, I want to take an ItemStack from their inventory (so far so good), and drop it. Now I know that my question is about entity spawning, but this says dropping, but I couldn't get either to work. The first thing I did was try to use ClientPlayerEntity.dropItem, which did nothing, so I assumed that was because I used InvWrapper.extractItem beforehand. That is when I transitioned to spawning. I tried to create a new ItemEntity and use World.addEntity on it. I know I have a valid ItemEntity, and I saw some form of this idea used in other projects & minecraft code. When executing however, nothing happens. I also tried to add the ItemStack back to the inventory and drop it, but that did nothing either.

I am not sure where to go from here. Here is my code (Really starts at Functions.java):

 

Mod.java

@Mod("Mod")
public class Mod {
  MinecraftForge.EVENT_BUS.register(clientEventHandlers);
}

 

ClientEventHandlers.java

class ClientEventHandlers {
  @SubscribeEvent
  public void onKeyRelease(GuiScreenEvent.KeyboardKeyReleasedEvent.Post event) {
    if (true) { // Ignore what this says, this is just used for simplicity
      Functions.myFunction();
    }
  }
}

 

Functions.java

class Functions {
  static void myFunction(){
    ClientPlayerEntity player = Minecraft.getInstance().player;
    InvWrapper invWrapper = new InvWrapper(player.inventory);
    ArrayList<ItemStack> removed;
    removed.add(invWrapper.extractItems(my, logic, false); // Removing item from inventory, works as expected
    
    // Important Bit Starts here
    BlockPos pos = player.getPosition();
    for (ItemStack itemStack: removed){
      // Each of the following comment blocks is something I tried, all to the same end
      /*
      ItemEntity itemEntity = new ItemEntity(player.world, pos.getX(), pos.getY(), pos.getZ(), itemStack.getStack());
      player.world.addEntity(itemEntity); */
      
      /*
      ItemEntity itemEntity = new ItemEntity(player.world, pos.getX(), pos.getY(), pos.getZ(), itemStack.getStack());
      itemEntity.world.addEntity(itemEntity); */
      
      /*
      invWrapper.setStackInSlot(someSlot, itemStack);
      player.dropItem(itemStack, true, true); // I tried every combination of bools here */
    }
  }
}

 

(Player has to be correct because all other logic works as expected)

An example value of itemEntity: "ItemEntity['Spruce Wood'/4, l='MpServer', x=4.00, y=56.00, z=-7.00]"

[ChampionAsh5357]

You cannot spawn an entity on the client. If you want to execute a spawn, you have to send a packet to the server from the client and have that packet spawn the entity.

[DragonITA]

  On 3/22/2020 at 2:06 PM, Scaleios said:

I've been digging around for a while, looking for a way to spawn items in the world. In essence, I have the player, I want to take an ItemStack from their inventory (so far so good), and drop it. Now I know that my question is about entity spawning, but this says dropping, but I couldn't get either to work. The first thing I did was try to use ClientPlayerEntity.dropItem, which did nothing, so I assumed that was because I used InvWrapper.extractItem beforehand. That is when I transitioned to spawning. I tried to create a new ItemEntity and use World.addEntity on it. I know I have a valid ItemEntity, and I saw some form of this idea used in other projects & minecraft code. When executing however, nothing happens. I also tried to add the ItemStack back to the inventory and drop it, but that did nothing either.

I am not sure where to go from here. Here is my code (Really starts at Functions.java):

 

Mod.java

@Mod("Mod")
public class Mod {
  MinecraftForge.EVENT_BUS.register(clientEventHandlers);
}

 

ClientEventHandlers.java

class ClientEventHandlers {
  @SubscribeEvent
  public void onKeyRelease(GuiScreenEvent.KeyboardKeyReleasedEvent.Post event) {
    if (true) { // Ignore what this says, this is just used for simplicity
      Functions.myFunction();
    }
  }
}

 

Functions.java

class Functions {
  static void myFunction(){
    ClientPlayerEntity player = Minecraft.getInstance().player;
    InvWrapper invWrapper = new InvWrapper(player.inventory);
    ArrayList<ItemStack> removed;
    removed.add(invWrapper.extractItems(my, logic, false); // Removing item from inventory, works as expected
    
    // Important Bit Starts here
    BlockPos pos = player.getPosition();
    for (ItemStack itemStack: removed){
      // Each of the following comment blocks is something I tried, all to the same end
      /*
      ItemEntity itemEntity = new ItemEntity(player.world, pos.getX(), pos.getY(), pos.getZ(), itemStack.getStack());
      player.world.addEntity(itemEntity); */
      
      /*
      ItemEntity itemEntity = new ItemEntity(player.world, pos.getX(), pos.getY(), pos.getZ(), itemStack.getStack());
      itemEntity.world.addEntity(itemEntity); */
      
      /*
      invWrapper.setStackInSlot(someSlot, itemStack);
      player.dropItem(itemStack, true, true); // I tried every combination of bools here */
    }
  }
}

 

(Player has to be correct because all other logic works as expected)

An example value of itemEntity: "ItemEntity['Spruce Wood'/4, l='MpServer', x=4.00, y=56.00, z=-7.00]"

Expand  

Can you send us your crash.report if this still don‘t work?

[Scaleios]

  On 3/22/2020 at 2:11 PM, ChampionAsh5357 said:

You cannot spawn an entity on the client. If you want to execute a spawn, you have to send a packet to the server from the client and have that packet spawn the entity.

Expand  

That was it, thank you.

 

  On 3/22/2020 at 2:13 PM, DragonITA said:

Can you send us your crash.report if this still don‘t work?

Expand  

There isn't a crash, and nothing of note shows up in the logs. Thank you anyways.

 

  On 3/22/2020 at 2:14 PM, diesieben07 said:

Note that this requires careful checks on the server to prevent malicious clients spawning infinite entities.

Expand  

Noted, thank you.