Wizards of Lua

The Art of Spell Crafting

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VirtualEntity - The Base Class of all Virtual Entities

The VirtualEntity class is the base class of all virtual entities that populate the world. Virtual entities live on the server only and are never synced to the client.

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

Here is an overview of the VirtualEntity properties:

Here is an overview of the VirtualEntity 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.

facing : string

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

forceChunk : boolean

The ‘forceChunk’ property specifies whether the current world chunk that contains this entity should always stay loaded in the server’s memory even when there is no player close to it. Default is true.

Please note that Minecraft Forge has an upper limit for the number of ‘chunk loading tickets’ that can be requested per Minecraft mod. By default this value is set to 200, which means that effectively a maximum number of 200 spells can exist concurrently with ‘forceChunk’ set to true. However, this value can be configured by setting the attribute defaults.maximumTicketCount in the file config/forgeChunkLoading.cfg.

If ‘forceChunk’ is set to false and there is no player close to the current world chunk, then this chunk will become unloaded eventually and stored to the disk. This means that entities that are inside this chunk will not take part in the update cycle anymore and neither can be found with Entities.find(). Please also note that you can’t summon any entities inside an unloaded chunk.

However, even when the world chunk has been unloaded, this virtual entity itself will always stay active. It will always take part in the update cycle and handle events. Additionally, if this entity accesses a block of an unloaded chunk, that chunk will get loaded.

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

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.

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’. And for spells it is typically the spell’s id prefixed with “Spell-“.

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.

tags : table

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

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 is 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.

kill () -> nil

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

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 1 meter upwards.

spell.move( "up")

Example

Moving the spell 10 meters to the north.

spell.move( "north", 10)

Example

Building a huge circle of wool blocks.

wool=Blocks.get( "wool")
for i=1,360 do
  spell.block=wool
  spell.rotationYaw=spell.rotationYaw+1
  spell:move("forward")
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).

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