Detect all nearby entities to player and then shoot lightning at them

[Xile]

Hello everyone,

 

I'm new to modding and java in general, and I'm currently working on an RF powered armor set. The issue is I would like to make my armor detect nearby players and mobs within a configurable radius around the player and then constantly zap them with lightning at a configurable interval. If anyone could provide insight into how I would go about doing this I would be immensely grateful.

 

Thank you.

[Jwosty]

Do you mean like just vanilla lightning raining down from the sky, or zaps coming from the player to mobs? If the latter, you'll have to create your own entity.

[david476]

To get the players around you, entites have methods for finding other ones inside an AABB, just go through the list.

[Xile]

Do you mean like just vanilla lightning raining down from the sky, or zaps coming from the player to mobs? If the latter, you'll have to create your own entity.

 

Initially i was going to do my own zaps, but this is my first mod and im a noob so I just want to make vanilla lightning from sky hit them.

 

To get the players around you, entites have methods for finding other ones inside an AABB, just go through the list.

 

This is what I have tried so far. to no avail.

 

//Bounding Box Attempt

    public double minX;

    public double minY;

    public double minZ;

    public double maxX;

    public double maxY;

    public double maxZ;

    public AxisAlignedBB axisalignedbb = AxisAlignedBB.getBoundingBox(minX, minY, minZ, maxX, maxY, maxZ); {

        this.minX = 0;

        this.minY = 0;

        this.minZ = 0;

        this.maxX = 10;

        this.maxY = 10;

        this.maxZ = 10;

}

@Override

    public void onArmorTick(World world, EntityPlayer player, ItemStack armor) {

 

        List entities = world.getEntitiesWithinAABB(getClass(), axisalignedbb);

        System.out.println("These Entities Are within Range!" + entities + "");

 

 

        }

 

It doesn't detect any entities unfortunately

[jabelar]

I'm not sure, but I think the bounding box minX, maxX, etc. are absolute positions.  I mean you're looking between 0 and 10 but do you even know where that is in the world?  How are you sure there are even any entities there?  I think that might be way underground or something.

[Xile]

Yea that's the part i'm having trouble with how do make it follow the player around. If its even possible.

[hugo_the_dwarf]

List players = getWorldObj().getEntitiesWithinAABB(EntityPlayer.class,player.getBoundingBox().expand(3, 3, 3);

 

this will get all players around the player (and probably the origin player too) just change what class to find to something else or use the base class, I think EntityLiving? EntitiyLivingBase? then when spawning lightening just make sure you're not spawning one on whoever created the bounding box.

[Xile]

List players = getWorldObj().getEntitiesWithinAABB(EntityPlayer.class,player.getBoundingBox().expand(3, 3, 3);

 

this will get all players around the player (and probably the origin player too) just change what class to find to something else or use the base class, I think EntityLiving? EntitiyLivingBase? then when spawning lightening just make sure you're not spawning one on whoever created the bounding box.

 

Thank you very much! However getWorldObj() says that it cannot find that method. I forgot to mention this is on 1.7.10. That may be why?

[Eternaldoom]

Just use the worldObj field.

[Xile]

Ok this is what I tried.

 

List players = worldObj.getEntitiesWithinAABB(EntityLivingBase.class, player.getBoundingBox().expand(3, 3, 3));

        System.out.println("Nearby Entities" + players + "!");

 

Is this correct? apologies if this is a noob question. I've been able to figure out some stuff myself but this one has been stumping me.

[hugo_the_dwarf]

yeah I didn't want to give copy paste ready code (which i'm bad for) because I was hoping you'd see the error and go "maybe it just takes a world object/instance"

 

but the expand(3,3,3) can be any numbers you want it to be. I just used 3's as a placeholder to show you how to use it.

 

PreEdit:

you might want to use an Iterator and a while loop, or some kindof loop to go through the list for each entry. you can also refactor the "players" to something like "entities" or "targets" idk whatever you want to call it. I used it for a block that would store mana, and recharge nearby mages.

 

but yeah looks a bit better, altho since it's an "onArmorTick" it should have a world param that you can toss in.

like par2World.getEntitiesWithin.....

and if it doesn't it should at least reference the player or entity wearing it (since zombies and skeletons can wear armor) and you can get the world object from there too.

[Xile]

You guys have all been an immense help thus far!

 

This is what I currently have in the armortick

 

//Armor Effects

@Override

    public void onArmorTick(World world, EntityPlayer player, ItemStack armor) {

 

 

    EnergyStored = armor.stackTagCompound.getInteger("Energy");

    if (EnergyStored < 1) NoPower = true;

    if (KeyInputHandler.ArmorOn == true)

        if (NoPower != true)

            System.out.println("Tesla AOE Activated");

        else System.out.println("Tesla Ability Deactivated");

 

 

    //Just A Test For Charging Armor Without External Mods!

    if (KeyInputHandler.ArmorOn == false)

        armor.stackTagCompound.setInteger("Energy", (EnergyStored + 1000));

 

    //PotionEffects Not sure why they dont work when all armor equipped... is weird..

 

    if (player.inventory.armorItemInSlot(2) == ItemLoader.armorTeslaLegs) {

        if (NoPower != true)

            player.addPotionEffect(new PotionEffect(Potion.moveSpeed.id, 500, 4));

    }

 

 

    if (player.inventory.armorItemInSlot(3) == ItemLoader.armorTeslaBoots) {

        if (NoPower != true)

            player.addPotionEffect(new PotionEffect(Potion.jump.id, 500, 4));

    }

    while (KeyInputHandler.ArmorOn == true) {

        List players = world.getEntitiesWithinAABB(EntityLivingBase.class, player.getBoundingBox().expand(7, 7, 7));

        System.out.println("Nearby Entities" + players + "!");

    }

}

 

currently I'm just testing random things to find out how they work but the bounding box crashes the game when my world with me wearing my armor loads up with this crash.

 

http://pastebin.com/KgYbz6gh

 

I got this crash when i was previously messing with bounding boxes as well. I feel like its something obvious I'm missing here.

[Xile]

Disregard that!

 

After some searching I was able to get it working with this code:

 

List entities = player.worldObj.getEntitiesWithinAABB(EntityLivingBase.class, AxisAlignedBB.getBoundingBox(player.posX - 5, player.posY - 5, player.posZ - 5, player.posX + 7, player.posY + 7, player.posZ + 7)

 

This correctly prints out all nearby entities in the console as well

 

Thank you everyone!

[Xile]

Well, I'm once again stumped lol. How do I go about pulling the entities coordinates out of the list by using the Iterator? Any help or hints is much appreciated

[TheGreyGhost]

Hi

 

EntityPotion.onImpact() has a good example of this

 

entity.posX, .posY, .posZ contain the position.

 

-TGG

[DonKresenko]

Can you post the full source?

[larsgerrits]

No, they are vanilla files and you can look at them yourself (located at Referenced Libraries->forgeSrc.jar)

[Xile]

Edit: Nevermind I fixed it! Should I just use this code after the lightning spawn to make it only fire every half second?

try {

    TimeUnit.MILLISECONDS.sleep(500);

 

} catch (InterruptedException e) {

    //Handle exception

}

 

 

 

Working Code:

 

//Attempt at Entity scan and target

    if (KeyInputHandler.ArmorOn == true) {

        System.out.println("Scanner Activated");

        List entities = player.worldObj.getEntitiesWithinAABB(EntityLivingBase.class, AxisAlignedBB.getBoundingBox(player.posX - 5, player.posY - 5, player.posZ - 5, player.posX + 7, player.posY + 7, player.posZ + 7));

        if (entities != null && !entities.isEmpty()) {

            Iterator iterator = entities.iterator();

 

            double posX;

            double posY;

            double posZ;

            EntityLivingBase ent;

 

                while (iterator.hasNext())

                {

                ent = (EntityLivingBase) iterator.next();

                posX = ent.posX;

                posY = ent.posY;

                posZ = ent.posZ;

 

                EntityLightningBolt Lightning = new EntityLightningBolt(world, posX, posY, posZ);

 

                world.spawnEntityInWorld(Lightning);

            }

        }

    }

 

}

 

 

Pre Edit:

 

 

Ok, I feel like this should work. However as soon as I activate it my whole game just freezes with no errors

 

//Attempt at Entity scan and target

    if (KeyInputHandler.ArmorOn == true) {

        System.out.println("Scanner Activated");

        List entities = player.worldObj.getEntitiesWithinAABB(EntityLivingBase.class, AxisAlignedBB.getBoundingBox(player.posX - 5, player.posY - 5, player.posZ - 5, player.posX + 7, player.posY + 7, player.posZ + 7));

        Iterator iterator = entities.iterator();

        double posX;

        double posY;

        double posZ;

        EntityLivingBase ent;

        while (iterator.hasNext());

        ent = (EntityLivingBase)iterator.next();

        posX = ent.posX;

        posY = ent.posY;

        posZ = ent.posZ;

 

        EntityLightningBolt Lightning = new EntityLightningBolt(world, posX, posY, posZ);

 

        world.spawnEntityInWorld(Lightning);

 

[Xile]

Thank you very much! You have all been a great help. One thing that's been giving me issues is that for some reason the detection of the armor that is equipped doesnt work properly. Currently this is how I am detecting what armor is worn. It doesn't seem to work at all though. This is just a test.

 

public void onArmorTick(World world, EntityPlayer player, ItemStack armor) {

    //0 is Boots

    //1 is Legs

    //2 is Chest

    //3 is Helm

    ItemStack armorslot = player.inventory.armorItemInSlot(0);

    System.out.println(armorslot + " Is Equipped");

 

    if (player.inventory.armorItemInSlot(0) == ItemLoader.ArmorTeslaBoots) {

        System.out.println("Boots worn");

 

in console it prints:

 

1xitem.ArmorTeslaBoots@0 Is Equipped

 

however it does not print "Boots Worn" when equipped...

 

 

[hugo_the_dwarf]

the problem is "armorItemInSlot(0)" returns an ItemStack, you can't compare ItemStacks with Items you will always get a false. You want

armorItemInSlot(0).getItem()

.equals(item) or

== item,

or instanceof item

 

also you already have the itemstack from this line:

ItemStack armorslot = player.inventory.armorItemInSlot(0);

 

so just use

if (armorslot.getItem()  == ItemLoader.ArmorTeslaBoots)

{

//do stuff

}

[jeffryfisher]

You should take a look at the getEntitiesWithinAABB(...) method and the other methods around it in its class. By that I mean to select the method name in your code in Eclipse, then right-click on it, then use the popup menu to view the method's declaration. You'll learn much more that way much faster than coming here to ask others to go do that reading for you.

 

Once there, you will see several such methods. Look at their arguments. You can exclude an entity or include only a certain type of entity. I think you'll also see some calls to underlying methods in the chunk management class. Investigating those might give you more ideas how to refine your search to get exactly those entities you want to electrocute (i.e. you probably don't want lightning shooting at paintings and lead-knots).

 

Good Luck!