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                 is_visible = false,
  31         },
  32
  33         itemstring = "",
  34         moving_state = true,
  35         physical_state = true,
  36         -- Item expiry
  37         age = 0,
  38         -- Pushing item out of solid nodes
  39         force_out = nil,
  40         force_out_start = nil,
  41
  42         set_item = function(self, item)
  43                 local stack = ItemStack(item or self.itemstring)
  44                 self.itemstring = stack:to_string()
  45                 if self.itemstring == "" then
  46                         -- item not yet known
  47                         return
  48                 end
  49
  50                 -- Backwards compatibility: old clients use the texture
  51                 -- to get the type of the item
  52                 local itemname = stack:is_known() and stack:get_name() or "unknown"
  53
  54                 local max_count = stack:get_stack_max()
  55                 local count = math.min(stack:get_count(), max_count)
  56                 local size = 0.2 + 0.1 * (count / max_count) ^ (1 / 3)
  57                 local def = core.registered_nodes[itemname]
  58                 local glow = def and math.floor(def.light_source / 2 + 0.5)
  59
  60                 self.object:set_properties({
  61                         is_visible = true,
  62                         visual = "wielditem",
  63                         textures = {itemname},
  64                         visual_size = {x = size, y = size},
  65                         collisionbox = {-size, -size, -size, size, size, size},
  66                         automatic_rotate = math.pi * 0.5 * 0.2 / size,
  67                         wield_item = self.itemstring,
  68                         glow = glow,
  69                 })
  70
  71         end,
  72
  73         get_staticdata = function(self)
  74                 return core.serialize({
  75                         itemstring = self.itemstring,
  76                         age = self.age,
  77                         dropped_by = self.dropped_by
  78                 })
  79         end,
  80
  81         on_activate = function(self, staticdata, dtime_s)
  82                 if string.sub(staticdata, 1, string.len("return")) == "return" then
  83                         local data = core.deserialize(staticdata)
  84                         if data and type(data) == "table" then
  85                                 self.itemstring = data.itemstring
  86                                 self.age = (data.age or 0) + dtime_s
  87                                 self.dropped_by = data.dropped_by
  88                         end
  89                 else
  90                         self.itemstring = staticdata
  91                 end
  92                 self.object:set_armor_groups({immortal = 1})
  93                 self.object:set_velocity({x = 0, y = 2, z = 0})
  94                 self.object:set_acceleration({x = 0, y = -gravity, z = 0})
  95                 self:set_item()
  96         end,
  97
  98         try_merge_with = function(self, own_stack, object, entity)
  99                 if self.age == entity.age then
 100                         -- Can not merge with itself
 101                         return false
 102                 end
 103
 104                 local stack = ItemStack(entity.itemstring)
 105                 local name = stack:get_name()
 106                 if own_stack:get_name() ~= name or
 107                                 own_stack:get_meta() ~= stack:get_meta() or
 108                                 own_stack:get_wear() ~= stack:get_wear() or
 109                                 own_stack:get_free_space() == 0 then
 110                         -- Can not merge different or full stack
 111                         return false
 112                 end
 113
 114                 local count = own_stack:get_count()
 115                 local total_count = stack:get_count() + count
 116                 local max_count = stack:get_stack_max()
 117
 118                 if total_count > max_count then
 119                         return false
 120                 end
 121                 -- Merge the remote stack into this one
 122
 123                 local pos = object:get_pos()
 124                 pos.y = pos.y + ((total_count - count) / max_count) * 0.15
 125                 self.object:move_to(pos)
 126
 127                 self.age = 0 -- Handle as new entity
 128                 own_stack:set_count(total_count)
 129                 self:set_item(own_stack)
 130
 131                 entity.itemstring = ""
 132                 object:remove()
 133                 return true
 134         end,
 135
 136         enable_physics = function(self)
 137                 if not self.physical_state then
 138                         self.physical_state = true
 139                         self.object:set_properties({physical = true})
 140                         self.object:set_velocity({x=0, y=0, z=0})
 141                         self.object:set_acceleration({x=0, y=-gravity, z=0})
 142                 end
 143         end,
 144
 145         disable_physics = function(self)
 146                 if self.physical_state then
 147                         self.physical_state = false
 148                         self.object:set_properties({physical = false})
 149                         self.object:set_velocity({x=0, y=0, z=0})
 150                         self.object:set_acceleration({x=0, y=0, z=0})
 151                 end
 152         end,
 153
 154         on_step = function(self, dtime, moveresult)
 155                 self.age = self.age + dtime
 156                 if time_to_live > 0 and self.age > time_to_live then
 157                         self.itemstring = ""
 158                         self.object:remove()
 159                         return
 160                 end
 161
 162                 local pos = self.object:get_pos()
 163                 local node = core.get_node_or_nil({
 164                         x = pos.x,
 165                         y = pos.y + self.object:get_properties().collisionbox[2] - 0.05,
 166                         z = pos.z
 167                 })
 168                 -- Delete in 'ignore' nodes
 169                 if node and node.name == "ignore" then
 170                         self.itemstring = ""
 171                         self.object:remove()
 172                         return
 173                 end
 174
 175                 if self.force_out then
 176                         -- This code runs after the entity got a push from the is_stuck code.
 177                         -- It makes sure the entity is entirely outside the solid node
 178                         local c = self.object:get_properties().collisionbox
 179                         local s = self.force_out_start
 180                         local f = self.force_out
 181                         local ok = (f.x > 0 and pos.x + c[1] > s.x + 0.5) or
 182                                 (f.y > 0 and pos.y + c[2] > s.y + 0.5) or
 183                                 (f.z > 0 and pos.z + c[3] > s.z + 0.5) or
 184                                 (f.x < 0 and pos.x + c[4] < s.x - 0.5) or
 185                                 (f.z < 0 and pos.z + c[6] < s.z - 0.5)
 186                         if ok then
 187                                 -- Item was successfully forced out
 188                                 self.force_out = nil
 189                                 self:enable_physics()
 190                                 return
 191                         end
 192                 end
 193
 194                 if not self.physical_state then
 195                         return -- Don't do anything
 196                 end
 197
 198                 assert(moveresult,
 199                         "Collision info missing, this is caused by an out-of-date/buggy mod or game")
 200
 201                 if not moveresult.collides then
 202                         -- future TODO: items should probably decelerate in air
 203                         return
 204                 end
 205
 206                 -- Push item out when stuck inside solid node
 207                 local is_stuck = false
 208                 local snode = core.get_node_or_nil(pos)
 209                 if snode then
 210                         local sdef = core.registered_nodes[snode.name] or {}
 211                         is_stuck = (sdef.walkable == nil or sdef.walkable == true)
 212                                 and (sdef.collision_box == nil or sdef.collision_box.type == "regular")
 213                                 and (sdef.node_box == nil or sdef.node_box.type == "regular")
 214                 end
 215
 216                 if is_stuck then
 217                         local shootdir
 218                         local order = {
 219                                 {x=1, y=0, z=0}, {x=-1, y=0, z= 0},
 220                                 {x=0, y=0, z=1}, {x= 0, y=0, z=-1},
 221                         }
 222
 223                         -- Check which one of the 4 sides is free
 224                         for o = 1, #order do
 225                                 local cnode = core.get_node(vector.add(pos, order[o])).name
 226                                 local cdef = core.registered_nodes[cnode] or {}
 227                                 if cnode ~= "ignore" and cdef.walkable == false then
 228                                         shootdir = order[o]
 229                                         break
 230                                 end
 231                         end
 232                         -- If none of the 4 sides is free, check upwards
 233                         if not shootdir then
 234                                 shootdir = {x=0, y=1, z=0}
 235                                 local cnode = core.get_node(vector.add(pos, shootdir)).name
 236                                 if cnode == "ignore" then
 237                                         shootdir = nil -- Do not push into ignore
 238                                 end
 239                         end
 240
 241                         if shootdir then
 242                                 -- Set new item moving speed accordingly
 243                                 local newv = vector.multiply(shootdir, 3)
 244                                 self:disable_physics()
 245                                 self.object:set_velocity(newv)
 246
 247                                 self.force_out = newv
 248                                 self.force_out_start = vector.round(pos)
 249                                 return
 250                         end
 251                 end
 252
 253                 node = nil -- ground node we're colliding with
 254                 if moveresult.touching_ground then
 255                         for _, info in ipairs(moveresult.collisions) do
 256                                 if info.axis == "y" then
 257                                         node = core.get_node(info.node_pos)
 258                                         break
 259                                 end
 260                         end
 261                 end
 262
 263                 -- Slide on slippery nodes
 264                 local def = node and core.registered_nodes[node.name]
 265                 local keep_movement = false
 266
 267                 if def then
 268                         local slippery = core.get_item_group(node.name, "slippery")
 269                         local vel = self.object:get_velocity()
 270                         if slippery ~= 0 and (math.abs(vel.x) > 0.1 or math.abs(vel.z) > 0.1) then
 271                                 -- Horizontal deceleration
 272                                 local factor = math.min(4 / (slippery + 4) * dtime, 1)
 273                                 self.object:set_velocity({
 274                                         x = vel.x * (1 - factor),
 275                                         y = 0,
 276                                         z = vel.z * (1 - factor)
 277                                 })
 278                                 keep_movement = true
 279                         end
 280                 end
 281
 282                 if not keep_movement then
 283                         self.object:set_velocity({x=0, y=0, z=0})
 284                 end
 285
 286                 if self.moving_state == keep_movement then
 287                         -- Do not update anything until the moving state changes
 288                         return
 289                 end
 290                 self.moving_state = keep_movement
 291
 292                 -- Only collect items if not moving
 293                 if self.moving_state then
 294                         return
 295                 end
 296                 -- Collect the items around to merge with
 297                 local own_stack = ItemStack(self.itemstring)
 298                 if own_stack:get_free_space() == 0 then
 299                         return
 300                 end
 301                 local objects = core.get_objects_inside_radius(pos, 1.0)
 302                 for k, obj in pairs(objects) do
 303                         local entity = obj:get_luaentity()
 304                         if entity and entity.name == "__builtin:item" then
 305                                 if self:try_merge_with(own_stack, obj, entity) then
 306                                         own_stack = ItemStack(self.itemstring)
 307                                         if own_stack:get_free_space() == 0 then
 308                                                 return
 309                                         end
 310                                 end
 311                         end
 312                 end
 313         end,
 314
 315         on_punch = function(self, hitter)
 316                 local inv = hitter:get_inventory()
 317                 if inv and self.itemstring ~= "" then
 318                         local left = inv:add_item("main", self.itemstring)
 319                         if left and not left:is_empty() then
 320                                 self:set_item(left)
 321                                 return
 322                         end
 323                 end
 324                 self.itemstring = ""
 325                 self.object:remove()
 326         end,
 327 })