luanti/doc/builtin_entities.md

Builtin Entities

Minetest registers two entities by default: Falling nodes and dropped items. This document describes how they behave and what you can do with them.

Falling node (__builtin:falling_node)

This entity is created by minetest.check_for_falling in place of a node with the special group falling_node=1. Falling nodes can also be created artificially with minetest.spawn_falling_node.

Needs manual initialization when spawned using /spawnentity.

Default behavior:

• Falls down in a straight line (gravity = movement_gravity setting)
• Collides with walkable node
• Collides with all physical objects except players
• If the node group float=1 is set, it also collides with liquid nodes (nodes with liquidtype ~= "none")
• When it hits a solid (=walkable) node, it will try to place itself as a node, replacing the node above.
  • If the falling node cannot replace the destination node, it is dropped as an item.
  • If the destination node is a leveled node (paramtype2="leveled") of the same node name, the levels of both are summed.

Entity fields

• set_node(self, node[, meta])
  • Function to initialize the falling node
  • node and meta are explained below.
  • The meta argument is optional.
• node: Node table of the node (name, param1, param2) that this entity represents. Read-only.
• meta: Node metadata of the falling node. Will be used when the falling nodes tries to place itself as a node. Read-only.

Rendering / supported nodes

Falling nodes have visuals to look as close as possible to the original node. This works for most drawtypes, but there are limitations.

Supported drawtypes:

• normal
• signlike
• torchlike
• nodebox
• raillike
• glasslike
• glasslike_framed
• glasslike_framed_optional
• allfaces
• allfaces_optional
• firelike
• mesh
• fencelike
• liquid
• airlike (not pointable)

Other drawtypes still kinda work, but they might look weird. If the node uses a world-aligned texture with a scale greater than 1, the falling node will display the top-most, left-most portion of that texture.

Supported paramtype2 values:

• wallmounted
• facedir
• 4dir
• colorwallmounted
• colorfacedir
• color4dir
• color

Dropped item stack (__builtin:item)

This is an item stack in a collectable form.

Common cases that spawn a dropped item:

• Item dropped by player
• The root node of a node with the group attached_node=1 is removed
• minetest.add_item is called

Needs manual initialization when spawned using /spawnentity.

Behavior

• Players can collect it by punching
• Lifespan is defined by the setting item_entity_ttl
• Slides on slippery nodes
• Subject to gravity (uses movement_gravity setting)
• Collides with walkable nodes
• Does not collide physical objects
• When it's inside a solid (walkable=true) node, it tries to escape to a neighboring non-solid (walkable=false) node

Entity fields

• set_item(self, item):
  • Function to initialize the dropped item
  • item (type ItemStack) specifies the item to represent
• age: Age in seconds. Behavior according to the setting item_entity_ttl
• itemstring: Itemstring of the item that this item entity represents. Read-only.

Other fields are for internal use only.