[1.12.2 Eclipse] Making a player drop their armor when custom mob attacks them.

[BenjiBrat]

Hi. I'm currently teaching myself about modding through tutorials and looking at the Minecraft Source code. My problem is, I have a custom mob, and it's supposed to force the player to drop it's armor on attack.

Here's my code:

public boolean attackEntityAsMob(EntityPlayer player)
    {
        if (super.attackEntityAsMob(player))
        {
        	if (player instanceof EntityPlayer)
            {
        		
                int i = 0;
                if (this.world.getDifficulty() == EnumDifficulty.EASY)
                {
                    i = 3;
                }
                if (this.world.getDifficulty() == EnumDifficulty.NORMAL)
                {
                    i = 5;
                }
                else if (this.world.getDifficulty() == EnumDifficulty.HARD)
                {
                    i = 7;
                }

                if (i > 0)
                {
                	
                	ItemStack itemstack = this.getItemStackFromSlot(EntityEquipmentSlot.HEAD);
                	
                    if (!itemstack.isEmpty())
                    {
                    	
        				EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack);
        				entityitem.setPickupDelay(i);
        				player.world.spawnEntity(entityitem);
                    }
                }
            )
        }
    }

 

But when it hits me, I don't drop any of my armor. I've been trying to figure this out, and I can't seem to get this to work. Any help?

[Draco18s]

You haven't done anything to remove the item from the player's equipment slots.

[BenjiBrat]

2 minutes ago, Draco18s said:

You haven't done anything to remove the item from the player's equipment slots.

oh, shoot i haven't. Do you know what could do that?

[Draco18s]

Same way you make any inventory slot empty.

[BenjiBrat]

8 minutes ago, Draco18s said:

Same way you make any inventory slot empty.

adding player.setItemStackToSlot(EntityEquipmentSlot.HEAD, ItemStack.EMPTY);

doesn't do anything. is that what I', supposed to write?

[Draco18s]

Two things:

1) Are you sure that the item stack you're getting is not empty?

47 minutes ago, BenjiBrat said:

ItemStack itemstack = this.getItemStackFromSlot(EntityEquipmentSlot.HEAD);

2) That's not the only way to make an item slot empty

[BenjiBrat]

32 minutes ago, Draco18s said:

Two things:

1) Are you sure that the item stack you're getting is not empty?

2) That's not the only way to make an item slot empty

I'm sure it's not empty. I have a diamond helmet on, and when it hits me, I still have it on, and no diamond helmet spawns.

And how else can I remove items?

[Draco18s]

That's not what I asked.

 

This line:

1 hour ago, BenjiBrat said:

if (!itemstack.isEmpty())

 

Is this true when it executes?

[BenjiBrat]

5 minutes ago, Draco18s said:

That's not what I asked.

 

This line:

 

Is this true when it executes?

Strange, I just added a system.out.print to say if it gets activated, and it never gets called.

[BenjiBrat]

7 minutes ago, BenjiBrat said:

Strange, I just added a system.out.print to say if it gets activated, and it never gets called.

It's not even calling the public boolean attackEntityAsMob!

What is wrong with this! I copied this from EntityCaveSpider and just slightly tweaked it because the original layout didn't work either.

[BenjiBrat]

Ok, I now have it calling the boolean, and right above

if(!itemstack.IsEmpty())

I put

System.out.println(itemstack)

And it's giving me "0xtile.air@0" as the output? Please help, I am so confused.

[BenjiBrat]

1 hour ago, Draco18s said:

That's not what I asked.

 

This line:

 

Is this true when it executes?

From what I've learned, no this is somehow not true.

[BenjiBrat]

56 minutes ago, BenjiBrat said:

From what I've learned, no this is somehow not true.

Partial success! Changed

if(!itemstack.isEmpty())

to

if(itemstack != null)

works and removes the Diamond Helmet. Now I just need it to spawn the item itself...

[Draco18s]

59 minutes ago, BenjiBrat said:

Partial success! Changed

if(!itemstack.isEmpty())

to

if(itemstack != null)

works and removes the Diamond Helmet. Now I just need it to spawn the item itself...

Item stacks are never null:

2 hours ago, BenjiBrat said:

And it's giving me "0xtile.air@0" as the output

No idea why dropping a stack of air is causing your diamond helmet to pop off though.

[BenjiBrat]

Well, I have this for my code to remove the helmet and spawn it on the ground:

if(!this.world.isRemote) {
/* my other hit detect code*/
player.setItemStackToSlot(EntityEquipmentSlot.HEAD, ItemStack.EMPTY);
EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack);
entityitem.setPickupDelay(i);
this.world.spawnEntity(new EntityItem(player.world, player.posX, player.posY + (double)player.height, player.posZ,  itemstack));
}

It removes the helmet fine, but doesn't spawn it in the world.

The int (i) changes depending on the difficulty of the world.

 

[BenjiBrat]

bump. Still need help dropping item.

[jabelar]

Can you post more of your code? it is hard to check over if you have fields like itemstack which I can't see where they are coming from.

 

One obvious thing wrong with your code is you're creating two different EntityItem. You create one but then don't use it because you spawn another one.

 

Are you sure that the itemstack field has something in it at the time you create the EntityItem?

[BenjiBrat]

19 minutes ago, jabelar said:

Can you post more of your code? it is hard to check over if you have fields like itemstack which I can't see where they are coming from.

 

One obvious thing wrong with your code is you're creating two different EntityItem. You create one but then don't use it because you spawn another one.

 

Are you sure that the itemstack field has something in it at the time you create the EntityItem?

Ok, here's my full Entity code:

package com.benjibrat.minecraftplusmod.entity;

import java.util.Random;

import javax.annotation.Nullable;

import com.google.common.base.Function;
import com.google.common.base.Predicate;

import net.minecraft.entity.Entity;
import net.minecraft.entity.EntityLivingBase;
import net.minecraft.entity.SharedMonsterAttributes;
import net.minecraft.entity.ai.EntityAIAttackMelee;
import net.minecraft.entity.ai.EntityAIAvoidEntity;
import net.minecraft.entity.ai.EntityAIFollow;
import net.minecraft.entity.ai.EntityAIHurtByTarget;
import net.minecraft.entity.ai.EntityAILookIdle;
import net.minecraft.entity.ai.EntityAINearestAttackableTarget;
import net.minecraft.entity.ai.EntityAIWanderAvoidWater;
import net.minecraft.entity.ai.EntityAIWatchClosest;
import net.minecraft.entity.item.EntityItem;
import net.minecraft.entity.monster.EntityEnderman;
import net.minecraft.entity.monster.EntityMob;
import net.minecraft.entity.monster.EntityVindicator;
//import net.minecraft.entity.monster.EntityEnderman.AIFindPlayer;
import net.minecraft.entity.passive.EntityVillager;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.init.Blocks;
import net.minecraft.init.MobEffects;
import net.minecraft.inventory.EntityEquipmentSlot;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.pathfinding.PathNodeType;
import net.minecraft.potion.PotionEffect;
import net.minecraft.util.EnumParticleTypes;
import net.minecraft.util.math.Vec3d;
import net.minecraft.world.EnumDifficulty;
import net.minecraft.world.World;

public class EntityWatcher extends EntityMob{

	public EntityWatcher(World worldIn) {
		super(worldIn);
		this.setSize(0.6f, 1.9f);
		this.setPathPriority(PathNodeType.WATER, -1.0F);
		// TODO Auto-generated constructor stub
	}
	@Override
	protected void initEntityAI() {
		this.targetTasks.addTask(1, new EntityAIHurtByTarget(this, true, new Class[] {EntityWatcher.class}));
		this.tasks.addTask(2, new EntityAIAttackMelee(this, 1.0D, false));
		this.targetTasks.addTask(3, new EntityAINearestAttackableTarget(this, EntityPlayer.class, false));
        this.tasks.addTask(7, new EntityAIWanderAvoidWater(this, 1.0D, 0.0F));
        this.tasks.addTask(8, new EntityAIWatchClosest(this, EntityPlayer.class, 8.0F));
        this.tasks.addTask(8, new EntityAILookIdle(this));
        //this.tasks.addTask(9, new EntityAIAvoidEntity(this, EntityPlayer.class, 10.0f, 0.8D, 0.8D));
        //this.tasks.addTask(9, new EntityAIFollow(this, interpTargetPitch, maximumHomeDistance, maximumHomeDistance));
	}
	
	@Override
	protected void applyEntityAttributes()
    {
        super.applyEntityAttributes();
        this.getEntityAttribute(SharedMonsterAttributes.MAX_HEALTH).setBaseValue(30.0D);
        this.getEntityAttribute(SharedMonsterAttributes.MOVEMENT_SPEED).setBaseValue(0.31);
        this.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).setBaseValue(2.5D);
        this.getEntityAttribute(SharedMonsterAttributes.FOLLOW_RANGE).setBaseValue(64.0D);
    }
	
	protected void applyEntityAI() {
		
	}
	
	
	
	public float getEyeHeight()
    {
        return 1.55F;
    }

	public void onLivingUpdate()
    {
        if (this.world.isRemote)
        {
            for (int i = 0; i < 2; ++i)
            {
                this.world.spawnParticle(EnumParticleTypes.PORTAL, this.posX + (this.rand.nextDouble() - 0.5D) * (double)this.width, this.posY + this.rand.nextDouble() * (double)this.height - 0.25D, this.posZ + (this.rand.nextDouble() - 0.5D) * (double)this.width, (this.rand.nextDouble() - 0.5D) * 2.0D, -this.rand.nextDouble(), (this.rand.nextDouble() - 0.5D) * 2.0D);
            }
            
            
        }
        
        this.isJumping = false;
        super.onLivingUpdate();
    }
	public boolean attackEntityAsMob(Entity player)
    {
		if(!this.world.isRemote) {
		System.out.print("ATTACK BOOL");
        if (super.attackEntityAsMob(player))
        {
        	System.out.println("SUPER.ATTACK");
        	if (player instanceof EntityLivingBase)
            {
        		System.out.println("INSTANCEOF");
                int i = 1;
                if (this.world.getDifficulty() == EnumDifficulty.EASY)
                {
                    i = 3;
                }
                if (this.world.getDifficulty() == EnumDifficulty.NORMAL)
                {
                    i = 4;
                }
                else if (this.world.getDifficulty() == EnumDifficulty.HARD)
                {
                    i = 5;
                }

                if (i > 0)
                {
                	Random slotRandom = new Random();
                	int slotHigh = 3;
                	int slotLow = 0;
                	int randomSlotInt = slotRandom.nextInt(slotHigh) + slotLow;
                	Random chanceRandom = new Random();
                	int chanceHigh = 5;
                	int chanceLow = 1;
                	int randomInt = chanceRandom.nextInt(chanceHigh) + chanceLow;
                	/*Random r = new Random();
                	int i1 = r.nextInt(4 - 0) + 0;
                	int i2 = r.nextInt(101 - 1) + 1;*/
                	ItemStack itemstack = this.getItemStackFromSlot(EntityEquipmentSlot.HEAD);
                	System.out.println("int i > 0");
                	System.out.println(itemstack);
                	
                	if (randomInt == 1) {
	                    if (itemstack != null && randomSlotInt == 0 /*&& i2 < 20*/)
	                    {
	                    	System.out.println("HEAD IS COVERED");
	                    	player.setItemStackToSlot(EntityEquipmentSlot.HEAD, ItemStack.EMPTY);
	        				EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack);
	        				entityitem.setPickupDelay(i);
	        				this.world.spawnEntity(new EntityItem(player.world, player.posX, player.posY + (double)player.height, player.posZ,  itemstack));
	                    }
	                    
	                    ItemStack itemstack2 = this.getItemStackFromSlot(EntityEquipmentSlot.CHEST);
	                	
	                    if (itemstack2 != null && randomSlotInt == 1/*&& i2 < 20*/)
	                    {
	                    	player.setItemStackToSlot(EntityEquipmentSlot.CHEST, ItemStack.EMPTY);
	        				EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack2);
	        				entityitem.setPickupDelay(i);
	        				this.world.spawnEntity(new EntityItem(player.world, player.posX, player.posY + (double)player.height, player.posZ, itemstack2));
	                    }
	                    
	                    ItemStack itemstack3 = this.getItemStackFromSlot(EntityEquipmentSlot.LEGS);
	                	
	                    if (itemstack3 != null && randomSlotInt == 2/*&& i2 < 20*/)
	                    {
	                    	player.setItemStackToSlot(EntityEquipmentSlot.LEGS, ItemStack.EMPTY);
	        				EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack3);
	        				entityitem.setPickupDelay(i);
	        				this.world.spawnEntity(new EntityItem(player.world, player.posX, player.posY + (double)player.height, player.posZ,  itemstack3));
	                    }
	                	
	                    ItemStack itemstack4 = this.getItemStackFromSlot(EntityEquipmentSlot.FEET);
	                	
	                    if (itemstack4 != null && randomSlotInt == 3/*&& i2 < 20*/)
	                    {
	                    	player.setItemStackToSlot(EntityEquipmentSlot.FEET, ItemStack.EMPTY);
	        				EntityItem entityitem = new EntityItem(player.world, player.posX, player.posY+1, player.posZ, itemstack4);
	        				entityitem.setPickupDelay(i);
	        				this.world.spawnEntity(new EntityItem(player.world, player.posX, player.posY + (double)player.height, player.posZ,  itemstack4));
	                    }
                	
                	}
                	
                }
            }
        	}
            return true;
        }
        else
        {
            return false;
        }

 
		
	
    }
}

 

[loordgek]

54 minutes ago, BenjiBrat said:

(itemstack != null && randomSlotInt == 0 /*&& i2 < 20*/)

the stack is never null check for ItemStack.isEmpty

[BenjiBrat]

27 minutes ago, loordgek said:

the stack is never null check for ItemStack.isEmpty

If you read above, I already tried that. It doesn't work, at least not when I do:

if (!itemstack.isEmpty())

It never gets called.

[loordgek]

put a break point on it

[BenjiBrat]

Just now, loordgek said:

put a break point on it

I'm sorry, but what does that mean? I am a little new to java/eclipse.

[loordgek]

https://www.ibm.com/developerworks/library/os-ecbug/

[jabelar]

1 hour ago, BenjiBrat said:

If you read above, I already tried that. It doesn't work, at least not when I do:

if (!itemstack.isEmpty())

It never gets called.

But that's the problem. In Java an instance is null if it doesn't exist at all. But in Minecraft the ItemStack can exist but be empty (usually if the quantity is 0, but can be other conditions like an illegal value for the quantity).

 

So checking if Itemstack != null will always execute because it can't be null. So then if !itemstack.isEmpty() is never true then it means that your itemstack is empty. So you need to figure out why it is empty at that point. In other words, if a condition isn't true that doesn't mean the code was wrong, it can mean that the data isn't what you expect.

[BenjiBrat]

1 hour ago, loordgek said:

https://www.ibm.com/developerworks/library/os-ecbug/

ok thank you for that. I set a breakpoint, and after looking at the code, changed the if statement to:

if(player.inventory.armorInventory.contains(itemstack) && randomSlotInt == 0)

but now if I try and run debug mode again, it won't stop at the breakpoint, where as it did the first time. Please help, I have no idea why it's not stopping at the new breakpoint.