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[Version 1.18.2, SOLVED] Increased hitbox size only works for entity collision, but not for block collision


LeeCrafts
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Posted (edited)

Hello,

I was playing around with changing the size of the AABB and discovered something that stumped me. As seen in my previous posts, I have been able to increase the size of the player with a custom status effect. I have been trying to do the same for all living entities, not just the player. Therefore, I--ideally--would not have to change the AABB by hardcoded values, like below:

// overriding MobEffect::applyEffectTick in my custom effect class

pLivingEntity.setBoundingBox(new AABB(pLivingEntity.getX()+2.5, pLivingEntity.getY()+3.6, pLivingEntity.getZ()+2.5, pLivingEntity.getX()-2.5, pLivingEntity.getY(), pLivingEntity.getZ()-2.5));

Simply using something like "pLivingEntity.setBoundingBox(pLivingEntity.getBoundingBox().inflate(2.5, 1.8, 2.5))" would be dangerous because the entity's AABB would expand to astronomical proportions. So I tried using a capability that stores the "original" dimensions of the entity's AABB when that entity joins the world (e.g. EntityJoinWorldEvent). This is what it looked like:

// custom capability that stores the original AABB dimensions of the entity

pLivingEntity.getCapability(ModCapabilities.HITBOX_CAPABILITY).ifPresent(iHitbox -> {
    Hitbox hitbox = (Hitbox) iHitbox;
    pLivingEntity.setBoundingBox(new AABB(
            pLivingEntity.getX() + hitbox.originalXSize * 4.2,
            pLivingEntity.getY() + hitbox.originalYSize * 2,
            pLivingEntity.getZ() + hitbox.originalZSize * 4.2,
            pLivingEntity.getX() - hitbox.originalXSize * 4.2,
            pLivingEntity.getY(),
            pLivingEntity.getZ() - hitbox.originalZSize * 4.2)
    );
});

When I tested this, the changed hitbox collides with entities but not with blocks. I am quite confused because changing the AABB by hardcoded values worked for both entity and block collision. How?

 

Previous post for reference (where I set the bounding box): https://forums.minecraftforge.net/topic/111159-version-1182-solved-custom-status-effect-that-changes-the-players-size-part-ii/?do=findComment&comment=496252

 

Edited by LeeCrafts
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  • LeeCrafts changed the title to [Version 1.18.2] Increased hitbox size only works for entity collision, but not for block collision
Posted (edited)

Update: I realized I don't need capabilities. In fact, I don't need to override applyEffectTick at all. But it seems like I need reflections. The increased hitbox size now works for both entity and block collision--with a little drawback. This is what it looks like so far:

// this event handler checks every tick if the living entity has the "big" effect
@SubscribeEvent
public static void entitySizeChange(LivingEvent.LivingUpdateEvent event) {
    LivingEntity livingEntity = event.getEntityLiving();
    if (livingEntity.getActiveEffectsMap() != null && livingEntity.hasEffect(ModEffects.BIG.get())) {
        EntityDimensions newDims = livingEntity.getDimensions(livingEntity.getPose()).scale(8.0F, 2.0F);
        try {
            // using reflection
            Field field = Entity.class.getDeclaredField("dimensions");
            field.setAccessible(true);
            field.set(livingEntity, newDims); // setting the living entity's EntityDimensions
            EntityDimensions newEntityDimensions = (EntityDimensions) field.get(livingEntity);
            livingEntity.setBoundingBox(newEntityDimensions.makeBoundingBox( // setting the living entity's AABB
                    livingEntity.getX(),
                    livingEntity.getY(),
                    livingEntity.getZ()
            ));
        } catch (NoSuchFieldException | IllegalAccessException e) {
            e.printStackTrace();
        }
    }
}

 

The aforementioned drawback is that, when the effect wears off, the living entity still keeps its bigger hitbox until it changes pose (i.e. my player crouching). Given that the EntityEvent.Size event fires whenever an entity changes pose, should I manually fire it with EVENT_BUS::post when that entity's effect wears off? If so, where? I tried manually firing EntityEvent.Size on my overridden removeAttributeModifiers(), but to no avail. 

Edited by LeeCrafts
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14 hours ago, LeeCrafts said:
Field field = Entity.class.getDeclaredField("dimensions");
            field.setAccessible(true);

You should save this somewhere static, instead of computing it every time.

15 hours ago, LeeCrafts said:

I tried manually firing EntityEvent.Size on my overridden removeAttributeModifiers(), but to no avail.

That's not how forge events work. The event doesn't fire to set the size, it fires when the size is changed to allow mods to override it. It is called from the (mojmap) method `Entity#refreshDimensions`, so if you call that method you should restore the entity size. Alternatively, if you don't want to allow other mods to react to the change in size, just recompute the AABB as vanilla does (either setPos, or setBoundingBox(makeBoundingBox())), but I would strongly suggest using the first method.

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38 minutes ago, Alpvax said:

You should save this somewhere static, instead of computing it every time.

in addition you need to use ObfuscationReflectionHelper and
you need the SRG name of "dimensions" otherwiese it wont work outside of your IDE

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Posted (edited)

Solved and it works consistently. Calling Entity::refreshDimensions every tick would be problematic, so I called it only when I needed to. Thank you both for the help!

 

// edit: lol forgot to use SRG name
private static final Field dimensionsField = ObfuscationReflectionHelper.findField(Entity.class, "f_19815_");

public ModEvents() {
    dimensionsField.setAccessible(true);
}

// this event handler increases the living entity's hitbox size if it has the "big" effect
@SubscribeEvent
public static void entityHitboxSizeChange(LivingEvent.LivingUpdateEvent event) throws IllegalAccessException {
    LivingEntity livingEntity = event.getEntityLiving();
    if (livingEntity.getActiveEffectsMap() != null) {

        EntityDimensions entityDimensions = livingEntity.getDimensions(livingEntity.getPose());

        boolean isBig = livingEntity.hasEffect(ModEffects.BIG.get());

        // Refresh dimensions if the living entity does not have the "big" effect AND its AABB has not changed back to normal.
        double aabbWidth = roundDigits(livingEntity.getBoundingBox().getXsize(), 4);
        double bigWidth = roundDigits(8 * entityDimensions.width, 4);
        if (!isBig && aabbWidth == bigWidth) livingEntity.refreshDimensions();

        // change dimensions of living entity using reflections
        if (isBig) {
            dimensionsField.set(livingEntity, entityDimensions.scale(8.0F, 2.0F));
            EntityDimensions newEntityDimensions = (EntityDimensions) dimensionsField.get(livingEntity);
            livingEntity.setBoundingBox(newEntityDimensions.makeBoundingBox(
                    livingEntity.getX(),
                    livingEntity.getY(),
                    livingEntity.getZ()
            ));
        }

    }
}

// little helper function that rounds a double to n digits
private static double roundDigits(double num, int digits) {
    double tenPower = Math.pow(10, digits);
    return Math.round(num * tenPower) / tenPower;
}
Edited by LeeCrafts
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  • LeeCrafts changed the title to [Version 1.18.2, SOLVED] Increased hitbox size only works for entity collision, but not for block collision

EntityEvent.Size exists specifically for this purpose. You don't need to set the dimensions field using reflection. Your use of reflection will also crash outside of the development environment (you must use SRG names). Also not that you should put the Field instance in a static final field, this allows the JVM to more aggressively optimize it.

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Posted (edited)

(updated the code in my previous comment)

 

The reason why I have been reluctant to use EntityEvent.Size is because whenever I increase the hitbox size of the living entity via setNewSize(), the enlarged hitbox starts jittering whenever it touches a solid block. Would there be anything else I have to do besides call setNewSize()?

Edited by LeeCrafts
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When I tried using EntityEvent.Size, this is the code:

@SubscribeEvent
public static void entityHitboxSizeChange(EntityEvent.Size event) {
    if (event.getEntity() instanceof LivingEntity livingEntity && livingEntity.getActiveEffectsMap() != null) {
        EntityDimensions entityDimensions = livingEntity.getDimensions(livingEntity.getPose());
        if (livingEntity.hasEffect(ModEffects.BIG.get())) {
            event.setNewSize(entityDimensions.scale(8, 2));
        }
        else {
            event.setNewSize(entityDimensions);
        }
    }
}

 

// When I refreshDimensions in removeAttributeModifiers(), the size still does not revert immediately unless the pose changes (i.e. player crouching).
// This is under the assumption that refreshDimensions() always triggers an EntityEvent.Size event
@Override
public void addAttributeModifiers(@NotNull LivingEntity pLivingEntity, @NotNull AttributeMap pAttributeMap, int pAmplifier) {
    if (!pLivingEntity.level.isClientSide()) {
      
        // other stuff ...
      
        pLivingEntity.refreshDimensions();
    }
    super.addAttributeModifiers(pLivingEntity, pAttributeMap, pAmplifier);
}

@Override
public void removeAttributeModifiers(@NotNull LivingEntity pLivingEntity, @NotNull AttributeMap pAttributeMap, int pAmplifier) {
    if (!pLivingEntity.level.isClientSide()) {
      
        // other stuff ...
      
        pLivingEntity.refreshDimensions();
    }
    super.removeAttributeModifiers(pLivingEntity, pAttributeMap, pAmplifier);
}

 

 

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