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         physical_state = true,
  38         -- Item expiry
  39         age = 0,
  40         -- Pushing item out of solid nodes
  41         force_out = nil,
  42         force_out_start = nil,
  43
  44         set_item = function(self, item)
  45                 local stack = ItemStack(item or self.itemstring)
  46                 self.itemstring = stack:to_string()
  47                 if self.itemstring == "" then
  48                         -- item not yet known
  49                         return
  50                 end
  51
  52                 -- Backwards compatibility: old clients use the texture
  53                 -- to get the type of the item
  54                 local itemname = stack:is_known() and stack:get_name() or "unknown"
  55
  56                 local max_count = stack:get_stack_max()
  57                 local count = math.min(stack:get_count(), max_count)
  58                 local size = 0.2 + 0.1 * (count / max_count) ^ (1 / 3)
  59                 local coll_height = size * 0.75
  60                 local def = core.registered_nodes[itemname]
  61                 local glow = def and math.floor(def.light_source / 2 + 0.5)
  62
  63                 self.object:set_properties({
  64                         is_visible = true,
  65                         visual = "wielditem",
  66                         textures = {itemname},
  67                         visual_size = {x = size, y = size},
  68                         collisionbox = {-size, -coll_height, -size,
  69                                 size, coll_height, size},
  70                         selectionbox = {-size, -size, -size, size, size, size},
  71                         automatic_rotate = math.pi * 0.5 * 0.2 / size,
  72                         wield_item = self.itemstring,
  73                         glow = glow,
  74                 })
  75
  76         end,
  77
  78         get_staticdata = function(self)
  79                 return core.serialize({
  80                         itemstring = self.itemstring,
  81                         age = self.age,
  82                         dropped_by = self.dropped_by
  83                 })
  84         end,
  85
  86         on_activate = function(self, staticdata, dtime_s)
  87                 if string.sub(staticdata, 1, string.len("return")) == "return" then
  88                         local data = core.deserialize(staticdata)
  89                         if data and type(data) == "table" then
  90                                 self.itemstring = data.itemstring
  91                                 self.age = (data.age or 0) + dtime_s
  92                                 self.dropped_by = data.dropped_by
  93                         end
  94                 else
  95                         self.itemstring = staticdata
  96                 end
  97                 self.object:set_armor_groups({immortal = 1})
  98                 self.object:set_velocity({x = 0, y = 2, z = 0})
  99                 self.object:set_acceleration({x = 0, y = -gravity, z = 0})
 100                 self:set_item()
 101         end,
 102
 103         try_merge_with = function(self, own_stack, object, entity)
 104                 if self.age == entity.age then
 105                         -- Can not merge with itself
 106                         return false
 107                 end
 108
 109                 local stack = ItemStack(entity.itemstring)
 110                 local name = stack:get_name()
 111                 if own_stack:get_name() ~= name or
 112                                 own_stack:get_meta() ~= stack:get_meta() or
 113                                 own_stack:get_wear() ~= stack:get_wear() or
 114                                 own_stack:get_free_space() == 0 then
 115                         -- Can not merge different or full stack
 116                         return false
 117                 end
 118
 119                 local count = own_stack:get_count()
 120                 local total_count = stack:get_count() + count
 121                 local max_count = stack:get_stack_max()
 122
 123                 if total_count > max_count then
 124                         return false
 125                 end
 126                 -- Merge the remote stack into this one
 127
 128                 local pos = object:get_pos()
 129                 pos.y = pos.y + ((total_count - count) / max_count) * 0.15
 130                 self.object:move_to(pos)
 131
 132                 self.age = 0 -- Handle as new entity
 133                 own_stack:set_count(total_count)
 134                 self:set_item(own_stack)
 135
 136                 entity.itemstring = ""
 137                 object:remove()
 138                 return true
 139         end,
 140
 141         enable_physics = function(self)
 142                 if not self.physical_state then
 143                         self.physical_state = true
 144                         self.object:set_properties({physical = true})
 145                         self.object:set_velocity({x=0, y=0, z=0})
 146                         self.object:set_acceleration({x=0, y=-gravity, z=0})
 147                 end
 148         end,
 149
 150         disable_physics = function(self)
 151                 if self.physical_state then
 152                         self.physical_state = false
 153                         self.object:set_properties({physical = false})
 154                         self.object:set_velocity({x=0, y=0, z=0})
 155                         self.object:set_acceleration({x=0, y=0, z=0})
 156                 end
 157         end,
 158
 159         on_step = function(self, dtime, moveresult)
 160                 self.age = self.age + dtime
 161                 if time_to_live > 0 and self.age > time_to_live then
 162                         self.itemstring = ""
 163                         self.object:remove()
 164                         return
 165                 end
 166
 167                 local pos = self.object:get_pos()
 168                 local node = core.get_node_or_nil({
 169                         x = pos.x,
 170                         y = pos.y + self.object:get_properties().collisionbox[2] - 0.05,
 171                         z = pos.z
 172                 })
 173                 -- Delete in 'ignore' nodes
 174                 if node and node.name == "ignore" then
 175                         self.itemstring = ""
 176                         self.object:remove()
 177                         return
 178                 end
 179
 180                 if self.force_out then
 181                         -- This code runs after the entity got a push from the is_stuck code.
 182                         -- It makes sure the entity is entirely outside the solid node
 183                         local c = self.object:get_properties().collisionbox
 184                         local s = self.force_out_start
 185                         local f = self.force_out
 186                         local ok = (f.x > 0 and pos.x + c[1] > s.x + 0.5) or
 187                                 (f.y > 0 and pos.y + c[2] > s.y + 0.5) or
 188                                 (f.z > 0 and pos.z + c[3] > s.z + 0.5) or
 189                                 (f.x < 0 and pos.x + c[4] < s.x - 0.5) or
 190                                 (f.z < 0 and pos.z + c[6] < s.z - 0.5)
 191                         if ok then
 192                                 -- Item was successfully forced out
 193                                 self.force_out = nil
 194                                 self:enable_physics()
 195                                 return
 196                         end
 197                 end
 198
 199                 if not self.physical_state then
 200                         return -- Don't do anything
 201                 end
 202
 203                 assert(moveresult)
 204                 if not moveresult.collides then
 205                         -- future TODO: items should probably decelerate in air
 206                         return
 207                 end
 208
 209                 -- Push item out when stuck inside solid node
 210                 local is_stuck = false
 211                 local snode = core.get_node_or_nil(pos)
 212                 if snode then
 213                         local sdef = core.registered_nodes[snode.name] or {}
 214                         is_stuck = (sdef.walkable == nil or sdef.walkable == true)
 215                                 and (sdef.collision_box == nil or sdef.collision_box.type == "regular")
 216                                 and (sdef.node_box == nil or sdef.node_box.type == "regular")
 217                 end
 218
 219                 if is_stuck then
 220                         local shootdir
 221                         local order = {
 222                                 {x=1, y=0, z=0}, {x=-1, y=0, z= 0},
 223                                 {x=0, y=0, z=1}, {x= 0, y=0, z=-1},
 224                         }
 225
 226                         -- Check which one of the 4 sides is free
 227                         for o = 1, #order do
 228                                 local cnode = core.get_node(vector.add(pos, order[o])).name
 229                                 local cdef = core.registered_nodes[cnode] or {}
 230                                 if cnode ~= "ignore" and cdef.walkable == false then
 231                                         shootdir = order[o]
 232                                         break
 233                                 end
 234                         end
 235                         -- If none of the 4 sides is free, check upwards
 236                         if not shootdir then
 237                                 shootdir = {x=0, y=1, z=0}
 238                                 local cnode = core.get_node(vector.add(pos, shootdir)).name
 239                                 if cnode == "ignore" then
 240                                         shootdir = nil -- Do not push into ignore
 241                                 end
 242                         end
 243
 244                         if shootdir then
 245                                 -- Set new item moving speed accordingly
 246                                 local newv = vector.multiply(shootdir, 3)
 247                                 self:disable_physics()
 248                                 self.object:set_velocity(newv)
 249
 250                                 self.force_out = newv
 251                                 self.force_out_start = vector.round(pos)
 252                                 return
 253                         end
 254                 end
 255
 256                 node = nil -- ground node we're colliding with
 257                 if moveresult.touching_ground then
 258                         for _, info in ipairs(moveresult.collisions) do
 259                                 if info.axis == "y" then
 260                                         node = core.get_node(info.node_pos)
 261                                         break
 262                                 end
 263                         end
 264                 end
 265
 266                 -- Slide on slippery nodes
 267                 local def = node and core.registered_nodes[node.name]
 268                 local keep_movement = false
 269
 270                 if def then
 271                         local slippery = core.get_item_group(node.name, "slippery")
 272                         local vel = self.object:get_velocity()
 273                         if slippery ~= 0 and (math.abs(vel.x) > 0.1 or math.abs(vel.z) > 0.1) then
 274                                 -- Horizontal deceleration
 275                                 local factor = math.min(4 / (slippery + 4) * dtime, 1)
 276                                 self.object:set_velocity({
 277                                         x = vel.x * (1 - factor),
 278                                         y = 0,
 279                                         z = vel.z * (1 - factor)
 280                                 })
 281                                 keep_movement = true
 282                         end
 283                 end
 284
 285                 if not keep_movement then
 286                         self.object:set_velocity({x=0, y=0, z=0})
 287                 end
 288
 289                 if self.moving_state == keep_movement then
 290                         -- Do not update anything until the moving state changes
 291                         return
 292                 end
 293                 self.moving_state = keep_movement
 294
 295                 -- Only collect items if not moving
 296                 if self.moving_state then
 297                         return
 298                 end
 299                 -- Collect the items around to merge with
 300                 local own_stack = ItemStack(self.itemstring)
 301                 if own_stack:get_free_space() == 0 then
 302                         return
 303                 end
 304                 local objects = core.get_objects_inside_radius(pos, 1.0)
 305                 for k, obj in pairs(objects) do
 306                         local entity = obj:get_luaentity()
 307                         if entity and entity.name == "__builtin:item" then
 308                                 if self:try_merge_with(own_stack, obj, entity) then
 309                                         own_stack = ItemStack(self.itemstring)
 310                                         if own_stack:get_free_space() == 0 then
 311                                                 return
 312                                         end
 313                                 end
 314                         end
 315                 end
 316         end,
 317
 318         on_punch = function(self, hitter)
 319                 local inv = hitter:get_inventory()
 320                 if inv and self.itemstring ~= "" then
 321                         local left = inv:add_item("main", self.itemstring)
 322                         if left and not left:is_empty() then
 323                                 self:set_item(left)
 324                                 return
 325                         end
 326                 end
 327                 self.itemstring = ""
 328                 self.object:remove()
 329         end,
 330 })