builtin/game/item_entity.lua

   1 -- Minetest: builtin/item_entity.lua
   2
   3 function core.spawn_item(pos, item)
   4         -- Take item in any format
   5         local stack = ItemStack(item)
   6         local obj = core.add_entity(pos, "__builtin:item")
   7         -- Don't use obj if it couldn't be added to the map.
   8         if obj then
   9                 obj:get_luaentity():set_item(stack:to_string())
  10         end
  11         return obj
  12 end
  13
  14 -- If item_entity_ttl is not set, enity will have default life time
  15 -- Setting it to -1 disables the feature
  16
  17 local time_to_live = tonumber(core.settings:get("item_entity_ttl")) or 900
  18 local gravity = tonumber(core.settings:get("movement_gravity")) or 9.81
  19
  20
  21 core.register_entity(":__builtin:item", {
  22         initial_properties = {
  23                 hp_max = 1,
  24                 physical = true,
  25                 collide_with_objects = false,
  26                 collisionbox = {-0.3, -0.3, -0.3, 0.3, 0.3, 0.3},
  27                 visual = "wielditem",
  28                 visual_size = {x = 0.4, y = 0.4},
  29                 textures = {""},
  30                 spritediv = {x = 1, y = 1},
  31                 initial_sprite_basepos = {x = 0, y = 0},
  32                 is_visible = false,
  33         },
  34
  35         itemstring = "",
  36         moving_state = true,
  37         slippery_state = false,
  38         physical_state = true,
  39         -- Item expiry
  40         age = 0,
  41         -- Pushing item out of solid nodes
  42         force_out = nil,
  43         force_out_start = nil,
  44
  45         set_item = function(self, item)
  46                 local stack = ItemStack(item or self.itemstring)
  47                 self.itemstring = stack:to_string()
  48                 if self.itemstring == "" then
  49                         -- item not yet known
  50                         return
  51                 end
  52
  53                 -- Backwards compatibility: old clients use the texture
  54                 -- to get the type of the item
  55                 local itemname = stack:is_known() and stack:get_name() or "unknown"
  56
  57                 local max_count = stack:get_stack_max()
  58                 local count = math.min(stack:get_count(), max_count)
  59                 local size = 0.2 + 0.1 * (count / max_count) ^ (1 / 3)
  60                 local coll_height = size * 0.75
  61
  62                 self.object:set_properties({
  63                         is_visible = true,
  64                         visual = "wielditem",
  65                         textures = {itemname},
  66                         visual_size = {x = size, y = size},
  67                         collisionbox = {-size, -coll_height, -size,
  68                                 size, coll_height, size},
  69                         selectionbox = {-size, -size, -size, size, size, size},
  70                         automatic_rotate = math.pi * 0.5 * 0.2 / size,
  71                         wield_item = self.itemstring,
  72                 })
  73
  74         end,
  75
  76         get_staticdata = function(self)
  77                 return core.serialize({
  78                         itemstring = self.itemstring,
  79                         age = self.age,
  80                         dropped_by = self.dropped_by
  81                 })
  82         end,
  83
  84         on_activate = function(self, staticdata, dtime_s)
  85                 if string.sub(staticdata, 1, string.len("return")) == "return" then
  86                         local data = core.deserialize(staticdata)
  87                         if data and type(data) == "table" then
  88                                 self.itemstring = data.itemstring
  89                                 self.age = (data.age or 0) + dtime_s
  90                                 self.dropped_by = data.dropped_by
  91                         end
  92                 else
  93                         self.itemstring = staticdata
  94                 end
  95                 self.object:set_armor_groups({immortal = 1})
  96                 self.object:set_velocity({x = 0, y = 2, z = 0})
  97                 self.object:set_acceleration({x = 0, y = -gravity, z = 0})
  98                 self:set_item()
  99         end,
 100
 101         try_merge_with = function(self, own_stack, object, entity)
 102                 if self.age == entity.age then
 103                         -- Can not merge with itself
 104                         return false
 105                 end
 106
 107                 local stack = ItemStack(entity.itemstring)
 108                 local name = stack:get_name()
 109                 if own_stack:get_name() ~= name or
 110                                 own_stack:get_meta() ~= stack:get_meta() or
 111                                 own_stack:get_wear() ~= stack:get_wear() or
 112                                 own_stack:get_free_space() == 0 then
 113                         -- Can not merge different or full stack
 114                         return false
 115                 end
 116
 117                 local count = own_stack:get_count()
 118                 local total_count = stack:get_count() + count
 119                 local max_count = stack:get_stack_max()
 120
 121                 if total_count > max_count then
 122                         return false
 123                 end
 124                 -- Merge the remote stack into this one
 125
 126                 local pos = object:get_pos()
 127                 pos.y = pos.y + ((total_count - count) / max_count) * 0.15
 128                 self.object:move_to(pos)
 129
 130                 self.age = 0 -- Handle as new entity
 131                 own_stack:set_count(total_count)
 132                 self:set_item(own_stack)
 133
 134                 entity.itemstring = ""
 135                 object:remove()
 136                 return true
 137         end,
 138
 139         enable_physics = function(self)
 140                 if not self.physical_state then
 141                         self.physical_state = true
 142                         self.object:set_properties({physical = true})
 143                         self.object:set_velocity({x=0, y=0, z=0})
 144                         self.object:set_acceleration({x=0, y=-gravity, z=0})
 145                 end
 146         end,
 147
 148         disable_physics = function(self)
 149                 if self.physical_state then
 150                         self.physical_state = false
 151                         self.object:set_properties({physical = false})
 152                         self.object:set_velocity({x=0, y=0, z=0})
 153                         self.object:set_acceleration({x=0, y=0, z=0})
 154                 end
 155         end,
 156
 157         on_step = function(self, dtime)
 158                 self.age = self.age + dtime
 159                 if time_to_live > 0 and self.age > time_to_live then
 160                         self.itemstring = ""
 161                         self.object:remove()
 162                         return
 163                 end
 164
 165                 local pos = self.object:get_pos()
 166                 local node = core.get_node_or_nil({
 167                         x = pos.x,
 168                         y = pos.y + self.object:get_properties().collisionbox[2] - 0.05,
 169                         z = pos.z
 170                 })
 171                 -- Delete in 'ignore' nodes
 172                 if node and node.name == "ignore" then
 173                         self.itemstring = ""
 174                         self.object:remove()
 175                         return
 176                 end
 177
 178                 local is_stuck = false
 179                 local snode = core.get_node_or_nil(pos)
 180                 if snode then
 181                         local sdef = core.registered_nodes[snode.name] or {}
 182                         is_stuck = (sdef.walkable == nil or sdef.walkable == true)
 183                                 and (sdef.collision_box == nil or sdef.collision_box.type == "regular")
 184                                 and (sdef.node_box == nil or sdef.node_box.type == "regular")
 185                 end
 186
 187                 -- Push item out when stuck inside solid node
 188                 if is_stuck then
 189                         local shootdir
 190                         local order = {
 191                                 {x=1, y=0, z=0}, {x=-1, y=0, z= 0},
 192                                 {x=0, y=0, z=1}, {x= 0, y=0, z=-1},
 193                         }
 194
 195                         -- Check which one of the 4 sides is free
 196                         for o = 1, #order do
 197                                 local cnode = core.get_node(vector.add(pos, order[o])).name
 198                                 local cdef = core.registered_nodes[cnode] or {}
 199                                 if cnode ~= "ignore" and cdef.walkable == false then
 200                                         shootdir = order[o]
 201                                         break
 202                                 end
 203                         end
 204                         -- If none of the 4 sides is free, check upwards
 205                         if not shootdir then
 206                                 shootdir = {x=0, y=1, z=0}
 207                                 local cnode = core.get_node(vector.add(pos, shootdir)).name
 208                                 if cnode == "ignore" then
 209                                         shootdir = nil -- Do not push into ignore
 210                                 end
 211                         end
 212
 213                         if shootdir then
 214                                 -- Set new item moving speed accordingly
 215                                 local newv = vector.multiply(shootdir, 3)
 216                                 self:disable_physics()
 217                                 self.object:set_velocity(newv)
 218
 219                                 self.force_out = newv
 220                                 self.force_out_start = vector.round(pos)
 221                                 return
 222                         end
 223                 elseif self.force_out then
 224                         -- This code runs after the entity got a push from the above code.
 225                         -- It makes sure the entity is entirely outside the solid node
 226                         local c = self.object:get_properties().collisionbox
 227                         local s = self.force_out_start
 228                         local f = self.force_out
 229                         local ok = (f.x > 0 and pos.x + c[1] > s.x + 0.5) or
 230                                 (f.y > 0 and pos.y + c[2] > s.y + 0.5) or
 231                                 (f.z > 0 and pos.z + c[3] > s.z + 0.5) or
 232                                 (f.x < 0 and pos.x + c[4] < s.x - 0.5) or
 233                                 (f.z < 0 and pos.z + c[6] < s.z - 0.5)
 234                         if ok then
 235                                 -- Item was successfully forced out
 236                                 self.force_out = nil
 237                                 self:enable_physics()
 238                         end
 239                 end
 240
 241                 if not self.physical_state then
 242                         return -- Don't do anything
 243                 end
 244
 245                 -- Slide on slippery nodes
 246                 local vel = self.object:get_velocity()
 247                 local def = node and core.registered_nodes[node.name]
 248                 local is_moving = (def and not def.walkable) or
 249                         vel.x ~= 0 or vel.y ~= 0 or vel.z ~= 0
 250                 local is_slippery = false
 251
 252                 if def and def.walkable then
 253                         local slippery = core.get_item_group(node.name, "slippery")
 254                         is_slippery = slippery ~= 0
 255                         if is_slippery and (math.abs(vel.x) > 0.2 or math.abs(vel.z) > 0.2) then
 256                                 -- Horizontal deceleration
 257                                 local slip_factor = 4.0 / (slippery + 4)
 258                                 self.object:set_acceleration({
 259                                         x = -vel.x * slip_factor,
 260                                         y = 0,
 261                                         z = -vel.z * slip_factor
 262                                 })
 263                         elseif vel.y == 0 then
 264                                 is_moving = false
 265                         end
 266                 end
 267
 268                 if self.moving_state == is_moving and
 269                                 self.slippery_state == is_slippery then
 270                         -- Do not update anything until the moving state changes
 271                         return
 272                 end
 273
 274                 self.moving_state = is_moving
 275                 self.slippery_state = is_slippery
 276
 277                 if is_moving then
 278                         self.object:set_acceleration({x = 0, y = -gravity, z = 0})
 279                 else
 280                         self.object:set_acceleration({x = 0, y = 0, z = 0})
 281                         self.object:set_velocity({x = 0, y = 0, z = 0})
 282                 end
 283
 284                 --Only collect items if not moving
 285                 if is_moving then
 286                         return
 287                 end
 288                 -- Collect the items around to merge with
 289                 local own_stack = ItemStack(self.itemstring)
 290                 if own_stack:get_free_space() == 0 then
 291                         return
 292                 end
 293                 local objects = core.get_objects_inside_radius(pos, 1.0)
 294                 for k, obj in pairs(objects) do
 295                         local entity = obj:get_luaentity()
 296                         if entity and entity.name == "__builtin:item" then
 297                                 if self:try_merge_with(own_stack, obj, entity) then
 298                                         own_stack = ItemStack(self.itemstring)
 299                                         if own_stack:get_free_space() == 0 then
 300                                                 return
 301                                         end
 302                                 end
 303                         end
 304                 end
 305         end,
 306
 307         on_punch = function(self, hitter)
 308                 local inv = hitter:get_inventory()
 309                 if inv and self.itemstring ~= "" then
 310                         local left = inv:add_item("main", self.itemstring)
 311                         if left and not left:is_empty() then
 312                                 self:set_item(left)
 313                                 return
 314                         end
 315                 end
 316                 self.itemstring = ""
 317                 self.object:remove()
 318         end,
 319 })