Custom Weapons With Abilities

[T05619]

Hello! I've recently started modding and i'm not amazing so i'm not too sure where to start with this if someone could help by replying with some good resources or something i can use to learn that would be amazing :)

[coalbricks]

What are you trying to do exactly? I have a half-finished mod that lets you bind commands to weapons/tools and run them when you right-click with the item. The commands can be triggered by clicking on a block or entity an arbitrary distance away. All of this info is stored in the itemstack's NBT, and the only way to create these custom tools is with /give + NBT. Is that the kind of thing you want to make?

[T05619]

I'm not sure if you have seen the custom weapons used in SpeedSilver's YouTube videos (Video i'm referencing: link) but something like that so when you kill with it, it increases in the level of sharpness by one or you gain a permanent heart or a staff that gives you a random amount of emeralds for each entity you kill.

[coalbricks]

Oh yeah, you would probably want to store some custom NBT data on itemstacks then. You can figure out exactly what you need to store on the item, but at the very least it sounds like you would want to:

1. Store a custom NBT tag - call it `onKill` or something - that maps to a string. See the `StringTag` class and places where it's used. This string would probably be some command that would be run when the item is used to kill something - look at the `ExecuteCommand` class to see how to run an arbitrary command manually

2. Listen to `LivingDeathEvent`

3. In your event listener, determine if the causing entity is holding an item, if the item was used to kill, and if the item has your `onKill` tag

3. If all of this is true, get the string out of the `onKill` key and run the command. You will need to create an instance of `CommandSourceStack` to run the command, and it sounds like you will need to figure out exactly what the command source should be (i.e., who is executing the command?). You may also need to worry about the permission level of the thing running the command - again, see `ExecuteCommand` for a reference.

4. Get this working, and then add specialized behavior to do specific things as needed - for example, if it would be nontrivial to "add 1 to the sharpness enchantment" via commands, consider making this a custom action that you check for in your `LivingDeathEvent` handler. You should find that most things can be accomplished with vanilla commands - although you may want to extend your `onKill` tag and use a ListTag or an ArrayTag instead, and run commands in sequence.

Hint: If you're doing this, you will want to learn about entity selectors, and if normal commands fail you, the /data command will usually save the day. You can do a whole lot with the data command.

Another tip: Use the data command when debugging; it can be used to display all the NBT data on an entity. It can also be used to add NBT data to most entities, but the /give command is probably more convenient for you. You may also want to make a custom command that accepts an entity, item id, and greedy string, and gives the entity the item with `onKill` set to the string. Again, look at existing commands, and look at implementations of `ArgumentType` to see all the different kinds of arguments your command can accept. Almost all of what you need to know can be learned by looking through Minecraft's code and seeing how they do things. The rest can be learned by trying it out and seeing what happens.

 

This is all very doable without any client-side modifications, which is great because it means more people will be able to use your cool mod on their servers.

Edited August 30, 2023 by coalbricks

[T05619]

Thanks for the help ill be sure to try

[andreybadrey]

1 use in yor weapons classes^

  @Override
    public ICapabilityProvider initCapabilities(ItemStack stack, @Nullable CompoundTag nbt) {
        return new ProviderItemStak();
    }

2 create provider class for capabilit itemstacks:

package com.bodryak.gmod.variables.server;

import net.minecraft.core.Direction;
import net.minecraft.nbt.CompoundTag;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.CapabilityManager;
import net.minecraftforge.common.capabilities.CapabilityToken;
import net.minecraftforge.common.capabilities.ICapabilityProvider;
import net.minecraftforge.common.util.INBTSerializable;
import net.minecraftforge.common.util.LazyOptional;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

public class ProviderItemStak implements ICapabilityProvider, INBTSerializable<CompoundTag> {
    public static Capability<IDS> ITEM_DATA = CapabilityManager.get(new CapabilityToken<IDS>() { });

    private IDS data = null;
    private final LazyOptional<IDS> optional = LazyOptional.of(this::createItemData);

    private IDS createItemData() {
        if (this.data == null) {
            this.data = new IDS();
        }
        return this.data;
    }



    @Override
    public @NotNull <T> LazyOptional<T> getCapability(@NotNull Capability<T> cap, @Nullable Direction side) {
        if(cap == ITEM_DATA) {
            return optional.cast();
        }

        return LazyOptional.empty();
    }

    @Override
    public CompoundTag serializeNBT() {
        CompoundTag nbt = new CompoundTag();
        createItemData().saveNBTData(nbt);
        return nbt;
    }

    @Override
    public void deserializeNBT(CompoundTag nbt) {
        createItemData().loadNBTData(nbt);
    }
}

package com.bodryak.gmod.variables.server;

import net.minecraft.nbt.CompoundTag;

public class IDS {
    private int damage = 1;

    public int getDamage() {
        return damage;
    }

    public void setDamage(int damage) {
        this.damage = damage;
    }

    public void saveNBTData(CompoundTag nbt) {
        nbt.putInt("damage", damage);
    }

    public void loadNBTData(CompoundTag nbt) {
        damage = nbt.getInt("damage");
    }

}