1.19.4 - How to create custom DamageSources

[UselessAccount]

In my mod, I need to make a special kind of damage.

I put the value of it into a custom DamageSource class that extends the original one, then I applied it on entities with LivingHurtEvent in an event handler.

In 1.19.3, the constructor of the DamageSource was simple. All you needed was a simple String. It worked pretty well.

But in 1.19.4, Mojang added something like tons of DamageTypes and Holders. I checked the source code of net.minecraft.world.damagesource.DamageSources, but I cannot understand it at all.

So my question is:  How can I create custom DamageSources in 1.19.4?

(I'm not a native English speaker, and I'm new to forge modding and this forum. If there are any mistakes, please correct me!)

Spoiler

Old code:

 

public class MyDamageSource extends DamageSource {

 

    public final int customDamage;

 

    public static final MyDamageSource SOMETHING = new MyDamageSource(/* ... */); // Just an instance I used

 

    public MyDamageSource(String name, int damage) {

           super(name); // ???

           this.customDamage= damage;

    }

 

}

 

Somewhere else:

 

@Mod.EventBusSubscriber(bus = Mod.EventBusSubscriber.Bus.FORGE)

public class DamageHandler {

   

    @SubscribeEvent

    public static void onDamage(LivingHurtEvent event) {

        if (event.getSource() instanceof MyDamageSource source) {

            // Do something...

        }

    }

 

}

 

 

[warjort]

The DamageSources are now made from DamageTypes that are part of datapacks

See "DAMAGE TYPES" here: https://www.minecraft.net/en-us/article/minecraft-java-edition-1-19-4

 

That means they can only be created when you are loaded into the world.

Because the game needs

MinecraftServer.registryAccess()

to lookup the DamageType from the data packs.

 

This is not something I have done myself.

But here's an example from BOP. With a its "bramble" DamageType

https://github.com/Glitchfiend/BiomesOPlenty/blob/BOP-1.19.4-17.3.x/src/generated/resources/data/biomesoplenty/damage_type/bramble.json

And here is where it applies the damage using the ResourceKey of that damage type:

https://github.com/Glitchfiend/BiomesOPlenty/blob/551bff467ade42cb2a0b23609f439137ca7fa60f/src/main/java/biomesoplenty/common/block/BrambleBlock.java#L67

 

[warjort]

To  check if it is your damage type you would probably use

damageSource.is(resourceKey)

where resourceKey is the ResourceKey to the damage type.

It looks like you can now also use tags to group and check damage types.

[UselessAccount]

10 minutes ago, warjort said:

The DamageSources are now made from DamageTypes that are part of datapacks

See "DAMAGE TYPES" here: https://www.minecraft.net/en-us/article/minecraft-java-edition-1-19-4

 

That means they can only be created when you are loaded into the world.

Because the game needs

MinecraftServer.registryAccess()

to lookup the DamageType from the data packs.

 

This is not something I have done myself.

But here's an example from BOP. With a its "bramble" DamageType

https://github.com/Glitchfiend/BiomesOPlenty/blob/BOP-1.19.4-17.3.x/src/generated/resources/data/biomesoplenty/damage_type/bramble.json

And here is where it applies the damage using the ResourceKey of that damage type:

https://github.com/Glitchfiend/BiomesOPlenty/blob/551bff467ade42cb2a0b23609f439137ca7fa60f/src/main/java/biomesoplenty/common/block/BrambleBlock.java#L67

 

Thank you so much! I'll try it later!

I'll always believe in the power of communities...

[JimiIT92]

I did it this way:

I have a class with all the Damage Types I need to declare and then in the bootstrap method I register them

public static final ResourceKey<DamageType> SPEAR = ResourceKey.create(Registries.DAMAGE_TYPE, new ResourceLocation("mod_id", "spear"));

public static void bootstrap(BootstapContext<DamageType> context) { context.register(SPEAR, new DamageType("spear", 0.1F)); }

Then, where I need to use that damage type, I can call it like this

DamageSource damagesource = new DamageSource(this.level.registryAccess().registryOrThrow(Registries.DAMAGE_TYPE).getHolderOrThrow(MyDamageTypes.SPEAR), this, entity1 == null ? this : entity1);

In this case I'm providing 2 more arguments to the constructor since I need them, but these depends on the type of damage. What I'm trying to mimic here is something similar to the trident damage, so that's why I need those parameters. Anyawy the key here is how you retrieve the DamageType

this.level.registryAccess().registryOrThrow(Registries.DAMAGE_TYPE).getHolderOrThrow(MyDamageTypes.SPEAR)

Essentially we get the RegistryAccess instance from a Level (world) instance (in this case the Level instance of the entity I'm calling this in). From here we get the Damage Type registry and from here we get the DamageType we want providing a Resouce Key (in this case we provide oure resource key).
This method is similar to how vanilla/forge implements it, you can see the vanilla game damage sources inside the DamageSources class

After all this you need the JSON files inside your mod's assets data folder.
Under <your_mod_id> you need to add a new folder called "damage_type". Inside you need to add a json file named like the damage type you're adding. In the example above I'm adding a "spear" damage type, so I create a "spear.json" file in which I specify the damage type properties

{
    "exhaustion": 0.1,
    "message_id": "spear",
    "scaling": "when_caused_by_living_non_player"
}

This may vary based on the damage type you're trying to add/mimic and of course on your needs.

You may also want to add your damage type to the minecraft tags, if there is one that fits your new damage type, under minecraft/tags/damage_type.
In my case my new damage is a projectile type one, so I added the "is_projectile.json" file

{
  "replace": false,
  "values": [
    "mod_id:spear"
  ]
}

 

[warjort]

Quote

DamageSource damagesource = new DamageSource(this.level.registryAccess().registryOrThrow(Registries.DAMAGE_TYPE).getHolderOrThrow(MyDamageTypes.SPEAR), this, entity1 == null ? this : entity1);

You don't need to do all that registry access yourself. You can just use the "smart constructor":

DamageSource damagesource = this.level.damageSources().source(MyDamageTypes.SPEAR, this, entity1 == null ? this : entity1);

If you look at the code for DamageSources.trident() that's pretty much what it does.

[JimiIT92]

27 minutes ago, warjort said:

You don't need to do all that registry access yourself. You can just use the "smart constructor":

DamageSource damagesource = this.level.damageSources().source(MyDamageTypes.SPEAR, this, entity1 == null ? this : entity1);

If you look at the code for DamageSources.trident() that's pretty much what it does.

Yeah, but the source method is private

[warjort]

Use an access transformer.

https://docs.minecraftforge.net/en/latest/advanced/accesstransformers/

 

Or even better submit a patch to forge so it does it for you.

[JimiIT92]

Yeah I know you can use an access transformer, and honestly I have no problem using that. However at the end of the day the source method is just calling that constructor accessing the registry, so I don't know what real advantages would give an access transformer.

[7194.f.null]

I did this on Forge 47.1.44

first, I made ModDamageTypes interface by copying net.minecraft.world.damagesource.DamageTypes

public interface ModDamageTypes {
    ResourceKey<DamageType> DEHYDRATION = ResourceKey.create(Registries.DAMAGE_TYPE,
            new ResourceLocation(MyModCommon.MODID, "dehydration")
    );
    ResourceKey<DamageType> BEACON_BEAM = ResourceKey.create(Registries.DAMAGE_TYPE,
            new ResourceLocation(MymodCommon.MODID, "beacon_beam")
    );
}

And then I made a ModDamageSources class by copying net.minecraft.world.damagesource.DamageSources

public class ModDamageSources {
    private final Registry<DamageType> damageTypes;

    private final DamageSource dehydration;
    private final DamageSource beaconBeam;


    public ModDamageSources(RegistryAccess pRegistry) {
        this.damageTypes = pRegistry.registryOrThrow(Registries.DAMAGE_TYPE);
        this.dehydration = this.source(ModDamageTypes.DEHYDRATION);
        this.beaconBeam = this.source(ModDamageTypes.BEACON_BEAM);
    }

    private DamageSource source(ResourceKey<DamageType> pDamageTypeKey) {
        return new DamageSource(this.damageTypes.getHolderOrThrow(pDamageTypeKey));
    }

    private DamageSource source(ResourceKey<DamageType> pDamageTypeKey, @Nullable Entity pEntity) {
        return new DamageSource(this.damageTypes.getHolderOrThrow(pDamageTypeKey), pEntity);
    }

    private DamageSource source(ResourceKey<DamageType> pDamageTypeKey, @Nullable Entity pCausingEntity, @Nullable Entity pDirectEntity) {
        return new DamageSource(this.damageTypes.getHolderOrThrow(pDamageTypeKey), pCausingEntity, pDirectEntity);
    }

    public DamageSource dehydration() {
        return this.dehydration;
    }

    public DamageSource beaconBeam() {
        return this.beaconBeam;
    }
}

In ModCommonEvents class

 @SubscribeEvent
    public static void onPlayerTick(TickEvent.PlayerTickEvent event) {
        if(event.side == LogicalSide.SERVER && !event.player.isCreative()) {
            event.player.getCapability(PlayerThirstProvider.PLAYER_THIRST)
                    .ifPresent(thirst -> {
                        if (thirst.getThirst() > 0 && event.player.getRandom().nextFloat() < 0.005f) {
                            thirst.subThirst(1);
                            ModNetworking.sendToPlayer(
                                    new ThirstDataSyncS2CPacket(thirst.getThirst()),
                                    () -> (ServerPlayer)event.player
                            );
                        }
                        if (thirst.getThirst() == 0 && event.player.getRandom().nextFloat() < 0.005f) {
                            DamageSource dehydration =
                                    new ModDamageSources(event.player.level().registryAccess()).dehydration();
                             event.player.hurt(dehydration, 2f);
                        }
                    });
        }
 }

Also, in src/main/resources/data/mymod/damage_type/

there needs to be dehydration.json and beacon_beam.json

{
  "exhaustion": 0.1,
  "message_id": "dehydration",
  "scaling": "never"
}

{
  "exhaustion": 0.1,
  "message_id": "beacon_beam",
  "scaling": "never"
}

And this will work in dev env

copying vanilla minecraft can always get me somewhere, but I am pretty sure this is not the proper way to do this.

 

 

Edited August 27, 2023 by 7194.f.null