[1.8.9] Figuring out Capabilities.

[Ernio]

Hey again, some intro 1st:

 

After some updates, I am rewiewing my code regarding Skills/Effects.

 

Say we have 2 approaches of coding stuff in MC:

* Multiple description singletons + one universal holder - in MC this system is used by ItemStack + Item.

* Multiple classes using some hierarchy - here I am directly talking about Entities (each has own instance).

 

My Skill/Effect system is based on a bit of both - you mainly code stuff like you do Entities (where additionally you can use shitload of listener interfaces to track anything any entity does when it is using/casting/anything given skill/effect).

BUT - it also has simple wrapper that can be used toachieve Item/ItemStack -like system. This approach is nice when we are talking about writing Skills/Effects in Mod config where you can use other Entity-like coded skill as your base, but you can also hold additional data in ItemStack-like instance.

 

Now to main thing:

 

Since @Capability has been introduced I can't stop thinking about making my own Skill/Effect Capabilities attaching.

My question/s:

 

To this time when we wanted to have data in ItemStack we used NBT and manipulated it e.g: onUpdate() - that sadly was quite "slow" since if we would have tons of data in ItemStack, parsing it to "normal" values would take time (I am not talking about reading integer, I am talking about creating lots of objects from ItemStack NBT).

Do I understand correctly - using @Capability we can read that NBT ONCE and hold it in capability instance of ItemStack, and then save it back, right?

 

Okay - which classes/parts of code am I interested in if I wanted to make something similar for my Skills/Effects?

 

And since @Mod != Forge/Vanilla code, will this even work? (I have no idea how Forge injects Caps to objects, not that I don't understand, I just didn't look that much).

[captaincleric]

I'm not sure about the item/stack stuff, but I might be able to help with the entity capabilities, as I've added two of my own; mana, and spell research.

 

I'm not sure about the @Capability, either, unfortunately.

 

What I do know, is that I might be able to help you out with the entity capabilities. Here's the code for my mana stuff:

 

PlayerManaCapability

package com.nosrick.masterofmagic.capabilities;

import com.nosrick.masterofmagic.MoMMod;
import com.nosrick.masterofmagic.items.wands.ItemBaseWand;
import com.nosrick.masterofmagic.packets.PlayerManaChangePacket;
import com.nosrick.masterofmagic.utils.PlayerUtils;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.entity.player.EntityPlayerMP;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;

public class PlayerManaCapability implements IBaseManaCapability
{
protected int m_Mana = 0;

@Override
public int GetMana() 
{
	return m_Mana;
}

@Override
public void SetMana(int mana, EntityPlayer player) 
{
	ItemStack itemStack = PlayerUtils.FindWand(player);
	if(itemStack == null)
		return;

	ItemBaseWand wand = (ItemBaseWand)itemStack.getItem();

	m_Mana = Math.min(wand.GetMaxMana(), mana);
	MoMMod.s_NetworkChannel.sendTo(new PlayerManaChangePacket(Integer.toString(m_Mana)), (EntityPlayerMP)player);
}

@Override
public void SetManaNoUpdate(int mana) 
{
	m_Mana = mana;
}

@Override
public NBTTagCompound saveNBTData() 
{
	NBTTagCompound nbt = new NBTTagCompound();
	nbt.setInteger("mana", m_Mana);
	return nbt;
}

@Override
public void loadNBTData(NBTTagCompound compound) 
{
	m_Mana = compound.getInteger("mana");
}
}

 

PlayerManaCapabilityHandler

package com.nosrick.masterofmagic.capabilities;

import net.minecraft.nbt.NBTBase;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.EnumFacing;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.Capability.IStorage;
import net.minecraftforge.common.capabilities.CapabilityManager;

public class PlayerManaCapabilityHandler implements IStorage<IBaseManaCapability> 
{	
public static final PlayerManaCapabilityHandler s_ManaHandler = new PlayerManaCapabilityHandler();

@Override
public NBTBase writeNBT(Capability<IBaseManaCapability> capability, IBaseManaCapability instance,
		EnumFacing side) 
{
	return instance.saveNBTData();
}

@Override
public void readNBT(Capability<IBaseManaCapability> capability, IBaseManaCapability instance, EnumFacing side,
		NBTBase nbt) 
{
	instance.loadNBTData((NBTTagCompound) nbt);
}
}

 

PlayerManaFactory

package com.nosrick.masterofmagic.capabilities;

import java.util.concurrent.Callable;

import net.minecraft.util.EnumFacing;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.ICapabilityProvider;

public class PlayerManaFactory implements Callable<IBaseManaCapability> 
{
@Override
public PlayerManaCapability call() throws Exception 
{
	return new PlayerManaCapability();
}
}

 

And finally PlayerManaProvider

package com.nosrick.masterofmagic.capabilities;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.nbt.NBTBase;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.EnumFacing;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.CapabilityInject;
import net.minecraftforge.common.capabilities.ICapabilityProvider;
import net.minecraftforge.common.util.INBTSerializable;

public class PlayerManaProvider implements ICapabilityProvider, INBTSerializable
{
@CapabilityInject(IBaseManaCapability.class)
public static Capability<IBaseManaCapability> s_Mana = null;

protected IBaseManaCapability m_Mana = null;

public PlayerManaProvider(){
	m_Mana = new PlayerManaCapability();
}

public PlayerManaProvider(IBaseManaCapability mana){
	this.m_Mana = mana;
}

public static IBaseManaCapability Get(EntityPlayer player) 
{
	if(player.hasCapability(s_Mana, null))
	{
		return player.getCapability(s_Mana, null);
	}
	return null;
}

@Override
public boolean hasCapability(Capability<?> capability, EnumFacing facing) 
{
	return s_Mana != null && capability == s_Mana;
}

@Override
public <T> T getCapability(Capability<T> capability, EnumFacing facing) 
{
	if (s_Mana != null && capability == s_Mana) 
		return (T)m_Mana;

	return null;
}

@Override
public NBTBase serializeNBT() 
{
	return m_Mana.saveNBTData();
}

@Override
public void deserializeNBT(NBTBase nbt) 
{		
	m_Mana.loadNBTData((NBTTagCompound) nbt);
}

}

 

These four parts combine to make CAPTAIN PLANET! my mana system, which allows players to cast spells.

 

I'm not sure it'll help, but I hope it does!

[UberAffe]

Based on Log events that I have put into my save and load methods it seems like capabilities for entities only get loaded once and then the work the same way as the IEEP system did in that each entity instance works with its own capability object. Any functional code (the code that actually uses skills) you would use in your IEEP can be copy pasted into capability.

[Ernio]

No, no, no, no, no... (batman ;p)

I am not having problems with implementing actual caps, I am asking about adding my own handler.

 

Where MC has:

* Block + World (data)

* Item + ItemStack

* Entity

* TileEntity

I am adding:

* Skill (can be "cast" by entity (+npc, player), world, block, tile, chunk, biome).

* Effect (can be applied to entity (+player), world, block, tile, chunk, biome).

... which are totally new "kind" of data types.

 

I want myself and others to be able to add Capabilities to those data types, so e.g they can attach additional values and/or event-calls to alredy-created Skills/Effects. (E.g: one mod implements "Freeze" effect (using my API) and other one attaches capability to it that not only it will act like author made it - freeze action of given holder (holder can be like said before - entity, block, tile, chunk, etc...), but also invoke anything a capability author (second one) wants to).

[UberAffe]

Ah in that case I am at a loss, but if you figure it out let us know. I already have a capability in mind that I would like to add to vanilla blocks.

[BusyBeever]

Yes capabilites are created once. Yes they are safing tons of processing time bc reading from nbt is a bitch :b

If you want to know how it works just look at the AttachCapabilities event and F3(eclipse)  the addCap method. Helped me a lot

[gotet]

Can you add the source of IBaseManaCapability, please?

[Laike_Endaril]

Ernio hasn't posted anything since 2017 (and I have no idea whether the mod/api was released, or what its name was if so)