minetest/builtin/game/item_entity.lua

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-- Minetest: builtin/item_entity.lua
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function core.spawn_item(pos, item)
-- Take item in any format
local stack = ItemStack(item)
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local obj = core.add_entity(pos, "__builtin:item")
-- Don't use obj if it couldn't be added to the map.
if obj then
obj:get_luaentity():set_item(stack:to_string())
end
return obj
end
-- If item_entity_ttl is not set, enity will have default life time
-- Setting it to -1 disables the feature
local time_to_live = tonumber(core.settings:get("item_entity_ttl")) or 900
local gravity = tonumber(core.settings:get("movement_gravity")) or 9.81
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core.register_entity(":__builtin:item", {
initial_properties = {
hp_max = 1,
physical = true,
collide_with_objects = false,
collisionbox = {-0.3, -0.3, -0.3, 0.3, 0.3, 0.3},
visual = "wielditem",
visual_size = {x = 0.4, y = 0.4},
textures = {""},
is_visible = false,
},
itemstring = "",
moving_state = true,
physical_state = true,
-- Item expiry
age = 0,
-- Pushing item out of solid nodes
force_out = nil,
force_out_start = nil,
set_item = function(self, item)
local stack = ItemStack(item or self.itemstring)
self.itemstring = stack:to_string()
if self.itemstring == "" then
-- item not yet known
return
end
-- Backwards compatibility: old clients use the texture
-- to get the type of the item
local itemname = stack:is_known() and stack:get_name() or "unknown"
local max_count = stack:get_stack_max()
local count = math.min(stack:get_count(), max_count)
local size = 0.2 + 0.1 * (count / max_count) ^ (1 / 3)
local def = core.registered_items[itemname]
local glow = def and def.light_source and
math.floor(def.light_source / 2 + 0.5)
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local size_bias = 1e-3 * math.random() -- small random bias to counter Z-fighting
local c = {-size, -size, -size, size, size, size}
self.object:set_properties({
is_visible = true,
visual = "wielditem",
textures = {itemname},
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visual_size = {x = size + size_bias, y = size + size_bias},
collisionbox = c,
automatic_rotate = math.pi * 0.5 * 0.2 / size,
wield_item = self.itemstring,
glow = glow,
infotext = stack:get_description(),
})
-- cache for usage in on_step
self._collisionbox = c
end,
get_staticdata = function(self)
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return core.serialize({
itemstring = self.itemstring,
age = self.age,
dropped_by = self.dropped_by
})
end,
on_activate = function(self, staticdata, dtime_s)
if string.sub(staticdata, 1, string.len("return")) == "return" then
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local data = core.deserialize(staticdata)
if data and type(data) == "table" then
self.itemstring = data.itemstring
self.age = (data.age or 0) + dtime_s
self.dropped_by = data.dropped_by
end
else
self.itemstring = staticdata
end
self.object:set_armor_groups({immortal = 1})
self.object:set_velocity({x = 0, y = 2, z = 0})
self.object:set_acceleration({x = 0, y = -gravity, z = 0})
self._collisionbox = self.initial_properties.collisionbox
self:set_item()
end,
try_merge_with = function(self, own_stack, object, entity)
if self.age == entity.age then
-- Cannot merge with itself
return false
end
local stack = ItemStack(entity.itemstring)
local name = stack:get_name()
if own_stack:get_name() ~= name or
own_stack:get_meta() ~= stack:get_meta() or
own_stack:get_wear() ~= stack:get_wear() or
own_stack:get_free_space() == 0 then
-- Cannot merge different or full stack
return false
end
local count = own_stack:get_count()
local total_count = stack:get_count() + count
local max_count = stack:get_stack_max()
if total_count > max_count then
return false
end
-- Merge the remote stack into this one
local pos = object:get_pos()
pos.y = pos.y + ((total_count - count) / max_count) * 0.15
self.object:move_to(pos)
self.age = 0 -- Handle as new entity
own_stack:set_count(total_count)
self:set_item(own_stack)
entity.itemstring = ""
object:remove()
return true
end,
enable_physics = function(self)
if not self.physical_state then
self.physical_state = true
self.object:set_properties({physical = true})
self.object:set_velocity({x=0, y=0, z=0})
self.object:set_acceleration({x=0, y=-gravity, z=0})
end
end,
disable_physics = function(self)
if self.physical_state then
self.physical_state = false
self.object:set_properties({physical = false})
self.object:set_velocity({x=0, y=0, z=0})
self.object:set_acceleration({x=0, y=0, z=0})
end
end,
on_step = function(self, dtime, moveresult)
self.age = self.age + dtime
if time_to_live > 0 and self.age > time_to_live then
self.itemstring = ""
self.object:remove()
return
end
local pos = self.object:get_pos()
local node = core.get_node_or_nil({
x = pos.x,
y = pos.y + self._collisionbox[2] - 0.05,
z = pos.z
})
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-- Delete in 'ignore' nodes
if node and node.name == "ignore" then
self.itemstring = ""
self.object:remove()
return
end
-- Prevent assert when item_entity is attached
if moveresult == nil and self.object:get_attach() then
return
end
if self.force_out then
-- This code runs after the entity got a push from the is_stuck code.
-- It makes sure the entity is entirely outside the solid node
local c = self._collisionbox
local s = self.force_out_start
local f = self.force_out
local ok = (f.x > 0 and pos.x + c[1] > s.x + 0.5) or
(f.y > 0 and pos.y + c[2] > s.y + 0.5) or
(f.z > 0 and pos.z + c[3] > s.z + 0.5) or
(f.x < 0 and pos.x + c[4] < s.x - 0.5) or
(f.z < 0 and pos.z + c[6] < s.z - 0.5)
if ok then
-- Item was successfully forced out
self.force_out = nil
self:enable_physics()
return
end
end
if not self.physical_state then
return -- Don't do anything
end
assert(moveresult,
"Collision info missing, this is caused by an out-of-date/buggy mod or game")
if not moveresult.collides then
-- future TODO: items should probably decelerate in air
return
end
-- Push item out when stuck inside solid node
local is_stuck = false
local snode = core.get_node_or_nil(pos)
if snode then
local sdef = core.registered_nodes[snode.name] or {}
is_stuck = (sdef.walkable == nil or sdef.walkable == true)
and (sdef.collision_box == nil or sdef.collision_box.type == "regular")
and (sdef.node_box == nil or sdef.node_box.type == "regular")
end
if is_stuck then
local shootdir
local order = {
{x=1, y=0, z=0}, {x=-1, y=0, z= 0},
{x=0, y=0, z=1}, {x= 0, y=0, z=-1},
}
-- Check which one of the 4 sides is free
for o = 1, #order do
local cnode = core.get_node(vector.add(pos, order[o])).name
local cdef = core.registered_nodes[cnode] or {}
if cnode ~= "ignore" and cdef.walkable == false then
shootdir = order[o]
break
end
end
-- If none of the 4 sides is free, check upwards
if not shootdir then
shootdir = {x=0, y=1, z=0}
local cnode = core.get_node(vector.add(pos, shootdir)).name
if cnode == "ignore" then
shootdir = nil -- Do not push into ignore
end
end
if shootdir then
-- Set new item moving speed accordingly
local newv = vector.multiply(shootdir, 3)
self:disable_physics()
self.object:set_velocity(newv)
self.force_out = newv
self.force_out_start = vector.round(pos)
return
end
end
node = nil -- ground node we're colliding with
if moveresult.touching_ground then
for _, info in ipairs(moveresult.collisions) do
if info.axis == "y" then
node = core.get_node(info.node_pos)
break
end
end
end
-- Slide on slippery nodes
local def = node and core.registered_nodes[node.name]
local keep_movement = false
if def then
local slippery = core.get_item_group(node.name, "slippery")
local vel = self.object:get_velocity()
if slippery ~= 0 and (math.abs(vel.x) > 0.1 or math.abs(vel.z) > 0.1) then
-- Horizontal deceleration
local factor = math.min(4 / (slippery + 4) * dtime, 1)
self.object:set_velocity({
x = vel.x * (1 - factor),
y = 0,
z = vel.z * (1 - factor)
})
keep_movement = true
end
end
if not keep_movement then
self.object:set_velocity({x=0, y=0, z=0})
end
if self.moving_state == keep_movement then
-- Do not update anything until the moving state changes
return
end
self.moving_state = keep_movement
-- Only collect items if not moving
if self.moving_state then
return
end
-- Collect the items around to merge with
local own_stack = ItemStack(self.itemstring)
if own_stack:get_free_space() == 0 then
return
end
local objects = core.get_objects_inside_radius(pos, 1.0)
for k, obj in pairs(objects) do
local entity = obj:get_luaentity()
if entity and entity.name == "__builtin:item" then
if self:try_merge_with(own_stack, obj, entity) then
own_stack = ItemStack(self.itemstring)
if own_stack:get_free_space() == 0 then
return
end
end
end
end
end,
on_punch = function(self, hitter, ...)
if self.itemstring == "" then
self.object:remove()
return
end
-- Call on_pickup callback in item definition.
local itemstack = ItemStack(self.itemstring)
local callback = itemstack:get_definition().on_pickup
local ret = callback(itemstack, hitter, {type = "object", ref = self.object}, ...)
if not ret then
-- Don't modify (and don't reset rotation)
return
end
itemstack = ItemStack(ret)
-- Handle the leftover itemstack
if itemstack:is_empty() then
self.itemstring = ""
self.object:remove()
else
self:set_item(itemstack)
end
end,
})