[1.18.1] - Add custom goals to vanilla Entities

[Davide_24]

So I am making a catnip carpet type block, and I want to make cats go to it and lie on it. I have already made the code for the AI goal itself. Only issue is adding that AI goal to the cat. I couldn't find anything while searching and now I want to ask here. The only way that comes to my mind is changing the registerGoals() method in Cat.java, but that seems like a bad idea.

[diesieben07]

You can register new goals to entities in EntityJoinWorldEvent.

[Davide_24]

23 hours ago, diesieben07 said:

You can register new goals to entities in EntityJoinWorldEvent.

So I tried this and it won't work. This is the code: 

public class events {

    private static final Logger LOGGER = LogManager.getLogger();

    @SubscribeEvent
    public static void EntityJoined(EntityJoinWorldEvent event) {
        LOGGER.info("Entity Joined World!");
        Entity entity = event.getEntity();
        if (entity instanceof Cat) {
            Cat cat = (Cat) entity;
            ((Cat) event.getEntity()).goalSelector.addGoal(7, new CatLieOnCatnipGoal(cat, 1.1D, 8));
        }
    }
}

 

The event does fire which is confirmed by the logger.

 

EDIT: Sorry for the late reply!

Edited January 31, 2022 by Davide_24

[diesieben07]

Use the debugger - are the methods on your Goal called?

[Davide_24]

47 minutes ago, diesieben07 said:

Use the debugger - are the methods on your Goal called?

So the isValidTarget() Method is firing but nothing else. The cats won't move to the target block. (temporarily set to slab blocks). I found that the tick() method should also fire while doing some research but it doesn't.

public class CatLieOnCatnipGoal extends MoveToBlockGoal {
    private final Cat cat;

    private static final Logger LOGGER = LogManager.getLogger();

    public CatLieOnCatnipGoal(Cat cat, double p_25136_, int p_25137_) {
        super(cat, p_25136_, p_25137_, 6);
        this.cat = cat;
        this.verticalSearchStart = -2;
        this.setFlags(EnumSet.of(Goal.Flag.JUMP, Goal.Flag.MOVE));
    }

    @Override
    public boolean canUse() {
        return !this.cat.isOrderedToSit() && !this.cat.isLying() && super.canUse();
    }

    @Override
    public void start() {
        LOGGER.info("CAT LIE ON CATNIP GOAL STARTED");
        super.start();
        this.cat.setInSittingPose(false);
    }

    @Override
    protected int nextStartTick(PathfinderMob mob) {
        return 40;
    }

    @Override
    public void stop() {
        LOGGER.info("STOPPED");
        super.stop();
        this.cat.setLying(false);
    }

    @Override
    public void tick() {
        LOGGER.info("CAT LIE ON CATNIP GOAL TICK!");
        super.tick();
        this.cat.setInSittingPose(false);
        if (!this.isReachedTarget()) {
            this.cat.setLying(false);
        } else if (!this.cat.isLying()) {
            this.cat.setLying(true);
        }

    }

    @Override
    protected boolean isValidTarget(LevelReader levelReader, BlockPos pos) {
        LOGGER.info("CAT LIE ON CATNIP GOAL SETTING TARGET!");
        return levelReader.isEmptyBlock(pos.above()) && levelReader.getBlockState(pos).is(BlockTags.SLABS);
    }
}

 

Edited January 31, 2022 by Davide_24
Added more explanation

[diesieben07]

Does it return true or false?

[Davide_24]

So it does always return true! The weird part is that it is inconsisten in when it works. restarting without code changes just makes it randomly work (only rarely)????

[Theirown]

Old thread I know, but thought I would share the behavior that caused this since it is very interesting.

 

One problem I found in the code above is that in the CatLieOnCatnipGoal constructor, you have this line:

this.verticalSearchStart = -2;

While counter-intuitive and a bit obfuscated, the find nearest block uses this variable like so:

for(int k = this.verticalSearchStart; k <= j; k = k > 0 ? -k : 1 - k) {

This is a part of a series of for loops to search every block within the range. The line above will perform a search going away from a vertical start in a pseudo- absolute value fashion. Basically it alternates between going up then down. If the starting value is 0, the pattern is:

START k=0
EVALUATE k= k > 0 ? -k : 1 - k (FALSE, so evaluate right side of ":")
EVALUATE k=1-k (1-0)
END k=1 
(do stuff and loop again)
EVALUATE k= k > 0 ? -k : 1 - k (TRUE, so evaluate left side of ":")
EVALUATE k = -k (-1)
END k=-1
(skipping ahead)
k=2
k=-2
k=3
k=-3

By starting at -2, the search will never land on any blocks within 1 vertical block of your cats.