Virtual Entities

Let's start by creating a virtual entity for a given dimension. In order to create a virtual entity we need an VirtualEntityAttachment, we can create an attachment that attaches our virtual entities to a given dimension if we have a reference to a ServerLevel:

val level: ServerLevel = // ...
val attachment = level.createVirtualEntityAttachment(::SimpleVirtualEntityAttachment)

// later...
level.removeVirtualEntityAttachment(attachment)

We'll just use SimpleVirtualEntityAttachment for now, but we will later discuss implementing our own attachment implementation.

Once we have an attachment instance we can create a virtual entity, so let's create a virtual zombie entity:

val level: ServerLevel = // ...
val attachment = level.createVirtualEntityAttachment(::SimpleVirtualEntityAttachment)
val zombie = attachment.attach { SimpleVirtualEntity(EntityType.ZOMBIE, it) }

Again we're using a SimpleVirtualEntity for now, but we will discuss other virtual entity types later.

We can modify some of the basic data for this virtual entity:

zombie.position = VirtualPosition.Absolute(Vec3(0.0, 100.0, 0.0))
zombie.rotation = VirtualRotation.Absolute(Vec2(0.0F, 90.0F))

zombie.setOnFire(true)
zombie.setDataEntry(EntityDataAccessors.LivingEntity.ARROW_COUNT, 10)

val observer: ServerPlayer = // ...
zombie.setInvisibleFor(observer, true)

The position and rotation of the virtual entity can be absolute or relative. In this example it doesn't matter since the origin of the world is set to be (0, 0, 0) facing (0, 0), but if our attachment was a specific entity then we can make the position/rotation relative to that entity.

We can set specific entity data, SimpleVirtualEntity provides methods for entity data that is shared between all entity instances, e.g. setOnFire, but we can also set entity data as long as we have a reference to its accessor. Arcade provides EntityDataAccessors which ships with some of the entity data accessors, but you may need to mixin to access specific accessors. We can also set entity data on a per-player basis, as shown by the setInvisibleFor method.

Entity Attachments

Other than being able to attach your virtual entities to a dimension arcade also provides a way for you to attach virtual entities to real entities, it's exactly the same as you would with a dimension, except on an Entity instance:

val entity: Entity = // ...
val attachment = entity.createVirtualEntityAttachment(::SimpleVirtualEntityAttachment)