[1.18.1] Implementing MobEffect with variable duration

[Adil Yilan]

Hi,

I have enchantment named "Stun" that can be applied to weapon and that has 3 levels:

• Level 1 - 10% chance to stun mob for 1 sec
• Level 2 - 20% chance to stun mob for 2 secs
• Level 3 - 30% chance to stun mob for 3 secs

Plan is to apply MobEffect named StunnedMobEffect on doPostAttack in enchantment.

StunnedMobEffect should have variable duration based on the level of enchantment that was applied on weapon.

I am trying to find an example on how to do the following:

• How can I set duration of effect dynamically?
• How can I track whether duration has expired?

I have found these two methods that can be overriden:
 

public void applyEffectTick(LivingEntity pLivingEntity, int pAmplifier) {

public boolean isDurationEffectTick(int pDuration, int pAmplifier) {

But looking at the source code of MobEffect class, I can't figure out what pAmplifier is?

Any hints / samples on this would be appreciated.

 

 

 

 

 

[poopoodice]

Amplifier is like the strength of the effect, for example movement speed boost with amplifier 0 will be Speed I, and 1 will be Speed II, 2 will be Speed III.

Effect is just an...effect type, EffectInstance contains all information for the actual effect being applied to the entity (duration, amplifier...etc).

For example there's only an effect type "Speed", but for an EffectInstance it could be:

"Level 2 Speed for 10 seconds"

"Level 4 Speed for 2 seconds"...

 

The first method applyEffectTick is called when a effect is impacting the entity, the first arg is the entity that has the effect/is affected by the effect, and amplifier is the strength of the effect.

The second method isDurationEFfectTick is to check whether the effect should impact/affect the entity this tick (the effects usually don't trigger every tick!), if true, then the first method is called.

 

Edited January 22, 2022 by poopoodice

[Adil Yilan]

@poopoodice Thanks!

So, assuming that I got your comment correctly, would this be a proper way to apply an effect:
 

@Override
    public void doPostAttack(LivingEntity pAttacker, Entity pTarget, int pLevel) {
        
        // IF: Code is executing on the client.
        if (pAttacker.level.isClientSide()) {
            return;
        }
        
        // IF: Entity is not living entity.
        if (!(pTarget instanceof LivingEntity)) {
            return;
        }

        // Cast entity to living entity.
        LivingEntity mob = (LivingEntity)pTarget;
        
        // IF: Player already has effect.
        if (mob.hasEffect(PlayerMobEffects.STUNNED.get())){
            return;
        }

        // Calculate hit chance.
        int hitChance = pLevel * 10;
        
        // Create random generator.
        Random random = new Random();
        
        // Get number between 0 and 99.
        int roll = random.nextInt(100);
        
        // IF: Apply on hit chance was missed.
        if (roll >= hitChance) {
            return;
        }
        
        // Calculate duration of the effect
        int duration = 20 * pLevel;

        // Create instance of effect.
        MobEffectInstance effect = new MobEffectInstance(PlayerMobEffects.STUNNED.get(), duration, pLevel);

        // Apply effect to mob.
        mob.addEffect(effect);
    }

 

I have tested the code and it works, although I am not sure if there is smarter way to apply effect.

Still need to figure out how to make mob die after it gets stunned.

 

[poopoodice]

Looked very nice 😀

Effect#removeAttributeModifiers gets called upon effect removal, you may find it useful in your case.