I am having trouble retrieving the attack damage of the held item:

 

FMLClientHandler.instance().getClient().thePlayer.getEntityAttribute(SharedMonsterAttributes.ATTACK_DAMAGE).getAttributeValue()

 

This always returns 1.0, no matter what is being held

That looks like it would return the damage of the PlayerEntity which fists are weak, and would assume 1.0f damage to be correct for a player to do.

 

Try getting

 

Player.Inventory.HeldItem();

 

and checking the damage of the ITEM rather the PLAYER however most "damage" comes from the material the ITEM is made from.

It doesn't seem like items carry a damage value.

It doesn't seem like items carry a damage value.

...however most "damage" comes from the material the ITEM is made from.

From ItemSword base class:

    public float getDamageVsEntity()
    {
        return this.material.getDamageVsEntity();
    }

How do I go about using that? I'm using this to test:

 

Items.DIAMOND_SWORD.getDamageVsEntity();

Not 100% sure if this will work, but here is something you could try:

 

double damage = 0;
for (AttributeModifier modifier : player.getHeldItemMainhand().getAttributeModifiers(EntityEquipmentSlot.MAINHAND).get(SharedMonsterAttributes.ATTACK_DAMAGE.getAttributeUnlocalizedName()))
{
damage += modifier.getAmount();
}

You are are a genius! thank you!

Not every

AttributeModifier

adds a flat amount to the attribute's value, so you can't just sum the value of each modifier to get the total attack damage. Operations 1 and 2 multiply the value by some amount rather than adding a flat value.

 

To calculate the actual attack damage provided by an item, use the attribute system:

• Create an

  AttributeMap

  
  

• Call

  AttributeMap#registerAttribute

  with

  SharedMonsterAttributes.ATTACK_DAMAGE

  
  

• Store the resulting

  IAttributeInstance

  and set its base value to 1.0 (the same base value used by players)

 

When you want to calculate the attack damage:

• Remove all existing modifiers from the attribute instance (

  IAttributeInstance#removeModifier

  )
  

• Apply the current item's modifiers (

  IAttributeInstance#applyModifier

  )
  

• Get the value (

  IAttributeInstance#getAttributeValue

  )

 

Since modifiers can be multiplicative, you may want to include the modifiers provided by the player's other items. A sword that adds 8 attack damage will be better than a sword that adds 50% attack damage if the player's other items add less than 16 attack damage or worse if the player's other items add more than 16 attack damage.

 

I have an example of a similar use of the attribute system here. I copy modifiers from an entity's

SharedMonsterAttributes.MAX_HEALTH

IAttributeInstance

to my own

IAttributeInstance

and adjust the value of a modifier to ensure the entity's max health is at least 2.0.

Not every

AttributeModifier

adds a flat amount to the attribute's value, so you can't just sum the value of each modifier to get the total attack damage. Operations 1 and 2 multiply the value by some amount rather than adding a flat value.

 

To calculate the actual attack damage provided by an item, use the attribute system:

• Create an

  AttributeMap

  
  

• Call

  AttributeMap#registerAttribute

  with

  SharedMonsterAttributes.ATTACK_DAMAGE

  
  

• Store the resulting

  IAttributeInstance

  and set its base value to 1.0 (the same base value used by players)

 

When you want to calculate the attack damage:

• Remove all existing modifiers from the attribute instance (

  IAttributeInstance#removeModifier

  )
  

• Apply the current item's modifiers (

  IAttributeInstance#applyModifier

  )
  

• Get the value (

  IAttributeInstance#getAttributeValue

  )

 

Since modifiers can be multiplicative, you may want to include the modifiers provided by the player's other items. A sword that adds 8 attack damage will be better than a sword that adds 50% attack damage if the player's other items add less than 16 attack damage or worse if the player's other items add more than 16 attack damage.

 

I have an example of a similar use of the attribute system here. I copy modifiers from an entity's

SharedMonsterAttributes.MAX_HEALTH

IAttributeInstance

to my own

IAttributeInstance

and adjust the value of a modifier to ensure the entity's max health is at least 2.0.

 

Does this look right:

 

IAttributeInstance damage = new AttributeMap().registerAttribute(SharedMonsterAttributes.ATTACK_DAMAGE);
if (itemStack != null)
for (AttributeModifier modifier : mc.thePlayer.getHeldItemMainhand().getAttributeModifiers(EntityEquipmentSlot.MAINHAND).get(SharedMonsterAttributes.ATTACK_DAMAGE.getAttributeUnlocalizedName()))
	damage.applyModifier(modifier);

Actually, that doesn't properly calculate bonus damage from things like bane of arthropods. I'm not exactly sure how to do this...

Does this look right:

 

IAttributeInstance damage = new AttributeMap().registerAttribute(SharedMonsterAttributes.ATTACK_DAMAGE);
if (itemStack != null)
for (AttributeModifier modifier : mc.thePlayer.getHeldItemMainhand().getAttributeModifiers(EntityEquipmentSlot.MAINHAND).get(SharedMonsterAttributes.ATTACK_DAMAGE.getAttributeUnlocalizedName()))
	damage.applyModifier(modifier);

 

That looks correct apart from the fact that you're using

Minecraft#thePlayer

.

Minecraft

is a client-only class and can't be used in common code.

 

If this code is meant to run on the server, you need to figure out which player you're running it for. If it's only meant to run on the client, using the client player is acceptable.

 

Actually, that doesn't properly calculate bonus damage from things like bane of arthropods. I'm not exactly sure how to do this...

Use

EnchantmentHelper.getModifierForCreature

to get the bonus damage against a specific

EnumCreatureAttribute

provided by the player's held item.