Wizards of Lua

The Art of Spell Crafting

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Entity - The Base Class of all Organic or Inorganic Entities

The Entity class is the base class of all entities that populate the world.

The Entity class is a subtype of the Object class and inherits all its properties and functions.

Here is an overview of the Entity properties:

Here is an overview of the Entity functions:

Properties

Below you find short descriptions about each of the properties and some examples about how to use them in your spells.

alive : boolean

This is true, if this entity is alive, false otherwise.

dimension : number (int)

The ‘dimension’ is a magic number that tells us something about the world where this entity currently is living in. 0 means the Overworld. -1 is the Nether, and 1 is the End.

entityType : string

The ‘entity type’ of this entity is something like ‘pig’ or ‘creeper’. For a player this is “player”. This is nil if the entity type isn’t known.

eyeHeight : number (float)

The ‘eyeHeight’ is the distance from this entity’s feet to its eyes in Y direction.

facing : string

The ‘facing’ is the compass direction this entity is facing. This is one of ‘north’, ‘east’, ‘south’, and ‘west’.

invisible : boolean

The ‘invisible’ property is true if this entity can not be seen by others.

lookVec : Vec3

The ‘lookVec’ is a 3-dimensional vector that points into the direction this entity is looking at, or nil, if it is not looking anywhere, for example, if it has no eyes.

Example

Letting the wizard spit 10 meters into the direction he is looking at.

local dir=spell.owner.lookVec
local s=spell.owner.pos+Vec3(0,spell.owner.eyeHeight,0)
for i=1,10,0.1 do
  spell.pos=s+dir*i
  spell:execute("particle droplet ~ ~ ~ 0 0 0 0")
end

Example

Moving the spell into the owners eye and pointing it into the owner’s look direction.

spell.pos = spell.owner.pos+Vec3(0,spell.owner.eyeHeight,0);
spell.lookVec = spell.owner.lookVec

motion : Vec3

The ‘motion’ is a 3-dimensional vector that represents the velocity of this entity when it is moved by some external force, e.g. when it is falling or when it is pushed by an explosion.

Example

Pushing the wizard up into the sky.

spell.owner.motion=Vec3(0,5,0)

name : string

The ‘name’ of this entity is unlike the UUID not unique in the world. For most entities it is just something like ‘Pig’ or ‘Zombie’. For player entities it is the nickkname of the character, like ‘mickkay’ or ‘bytemage’.

nbt : table

The ‘nbt’ value (short for Named Binary Tag) is a table of entity-specifc key-value pairs also called data tags.

The nbt property is readonly but gives you a modifiable copy of the internal value.

You can change the contents, but to activate them you have to assign the modified table to the entity by using the putNbt() function.

Example

Putting on a helmet on all zombies.

for _,zombie in pairs(Entities.find("@e[type=zombie]")) do
  local n=zombie.nbt
  n.ArmorItems[4]={Count=1,id="iron_helmet"}
  zombie:putNbt(n)
end

pos : Vec3

The ‘pos’ is short for ‘position’. It is a 3-dimensional vector containing the location of the entity inside the world it is living in.

rotationPitch : number (float)

The ‘rotationPitch’ is the rotation of this entity’s head around its X axis in degrees. A value of -90 means the entity is looking straight up. A value of 90 means it is looking straight down.

rotationYaw : number (float)

The ‘rotationYaw’ is the rotation of this entity around its Y axis in degrees. For example, a value of 0 means the entity is facing south. 90 corresponds to west, and 45 to south-west.

sneaking : boolean

This is true, if this entity is currently sneaking, false otherwise.

sprinting : boolean

The ‘sprinting’ property is true whenever this entity is running fast.

tags : table

The ‘tags’ value is a list of strings that have been assigned to this entity.

Example

Tagging the wizard as great and fearsome.

spell.owner.tags = {"great", "fearsome"}

Example

Printing the wizard’s tags.

print( str( spell.owner.tags))

uuid : string

The ‘uuid’ is a string of 36 characters forming an immutable universally unique identifier that identifies this entity inside the world. This means if entities have the same ID they are actually the same object.

world : World

The world the the space this entity is living in.

Functions

Below you find short descriptions about each of the functions and some examples about how to use them in your spells.

addTag (tag) -> boolean

The ‘addTag’ function adds the given tag to the set of tags of this entity. This function returns true if the tag was added successfully.

dropItem (item, offsetY) -> DroppedItem

The ‘dropItem’ function drops the given item at this entity’s position modified by the optionally given vertical offset.

Example

Dropping the block at the spell’s position as an item.

if spell.block.name ~= "air" then
  local item = spell.block:asItem()
  spell:dropItem( item)
  spell.block = Blocks.get("air")
end

kill () -> nil

The ‘kill’ function kills this entity during the next game tick.

Example

Killing all pigs that are swimming in liquid material.

local pigs = Entities.find("@e[type=pig]")
for _,pig in pairs(pigs) do
  spell.pos = pig.pos
  if spell.block.material.liquid then
    pig:kill()
  end
end

move (directionName, distance) -> nil

The ‘move’ function teleports this entity instantly to the position relative to its current position specified by the given direction and distance.

If no distance is specified, 1 meter is taken as default distance. Valid direction values are absolute directions (‘up’, ‘down’, ‘north’, ‘east’, ‘south’, and ‘west’), as well as relative directions (‘forward’, ‘back’, ‘left’, and ‘right’).

Relative directions are interpreted relative to the direction the entity is facing.

Example

Moving the spell’s owner for half a meter to the left.

spell.owner:move( "left", 0.5)

putNbt (nbt) -> nil

The ‘putNbt’ function inserts the given table entries into the nbt property of this entity.

Please note that this function is not supported for Player objects.

Example

Cutting the health of all bats to half.

local e = Entities.find("@e[type=bat]")
for _,bat in pairs(e) do
  local h = math.floor(bat.nbt.Health/2)
  bat:putNbt({Health=h})
  print(bat.nbt.Health)
end

Example

Finding all pigs and putting a saddle on each of them.

for _,pig in pairs(Entities.find("@e[type=pig]")) do
  pig:putNbt({Saddle=1})
end

removeTag (tag) -> boolean

The ‘removeTag’ function removes the given tag from the set of tags of this entity. This function returns true if the tag has been removed successfully, and false if there was no such tag.

scanView (distance) -> BlockHit

The ‘scanView’ function scans the view of this entity for the next (non-liquid) block.

On success it returns a BlockHit, otherwise nil. It scans the view with a line-of-sight-range of up to the given distance (meter).

Example

Prints the name of the block the spell’s owner is looking at (up to a maximum distance of 10 meters).

local maxDistance = 10
local hit = spell.owner:scanView( maxDistance)
if hit then
  spell.pos = hit.pos
  print(spell.owner.name.." is looking at "..spell.block.name)
end