Effect Classes

In this guide, you'll learn to make make custom class effect like RegenerationMobEffect.

Creating the Class

To start go to the effect folder in world, and create a class named TestMobEffect. First we need to have the class extend MobEffect:

public class TestMobEffect extends MobEffect

Now it'll start erroring, we'll need to have a constructor for it to stop being mad, if you're using IntelliJ you can hover over it and it'll do it for you, but you can manually add it:

protected TestMobEffect(MobEffectCategory p_19451_, int p_19452_) {
    super(p_19451_, p_19452_);
}

Nice! Now we can start adding the methods used for healing the player. First add:

public void applyEffectTick(LivingEntity p_301282_, int p_300945_) {
    super.applyEffectTick(p_301282_, p_300945_);
}

This is where the effect will tick its healing, to get started adding that start with:

public void applyEffectTick(LivingEntity p_301282_, int p_300945_) {
    super.applyEffectTick(p_301282_, p_300945_);
    if (p_301282_.getHealth() < p_301282_.getMaxHealth()) {

    }
}

This will prevent us from trying to heal at or above the entity's max health. Next we'll just need to add:

public void applyEffectTick(LivingEntity entity, int p_300945_) {
    super.applyEffectTick(p_301282_, p_300945_);
    if (p_301282_.getHealth() < p_301282_.getMaxHealth()) {
        p_301282_.heal(2.0F);
    }
}

And any entity with this effect will now health a full heart of health! But how fast will it do that? It'll do that every tick since we haven't add one thing yet, let's add that now:

public boolean shouldApplyEffectTickThisTick(int tickCount, int amplifier) {

}

This is what will determine if it should heal this tick or not. We can start by adding:

public boolean shouldApplyEffectTickThisTick(int tickCount, int amplifier) {
    int i = 35 >> amplifier;
}

This will determine the ticks inbetween the effect being applied. Now we add the conditional:

public boolean shouldApplyEffectTickThisTick(int tickCount, int amplifier) {
    int i = 35 >> amplifier;
    if (i > 0) {
        return tickCount % i == 0;
    } else {
        return true;
    }
}

Now that we have the effect class created, we can create an effect with it!

Creating the Effect

If you followed the Getting Started guide, you'll know how you created an effect in there, we'll just create a basic effect like:

public static final MobEffect NAME = register("name", (new MobEffect(MobEffectCategory.BENEFICIAL, 3402751)));

Now that we have this we'll want to change the (new MobEffect()) to (new TestMobEffect()) keeping all the values inside the same, so it should look like:

public static final MobEffect NAME = register("name", (new TestMobEffect(MobEffectCategory.BENEFICIAL, 3402751)));

You can now give yourself the effect and start healing!

Closing

Creating effect classes is very simple, later we'll take about how effects can mess with your vision and that kind of stuff.