builtin/game/falling.lua

   1 -- Minetest: builtin/item.lua
   2
   3 local builtin_shared = ...
   4 local SCALE = 0.667
   5
   6 local facedir_to_euler = {
   7         {y = 0, x = 0, z = 0},
   8         {y = -math.pi/2, x = 0, z = 0},
   9         {y = math.pi, x = 0, z = 0},
  10         {y = math.pi/2, x = 0, z = 0},
  11         {y = math.pi/2, x = -math.pi/2, z = math.pi/2},
  12         {y = math.pi/2, x = math.pi, z = math.pi/2},
  13         {y = math.pi/2, x = math.pi/2, z = math.pi/2},
  14         {y = math.pi/2, x = 0, z = math.pi/2},
  15         {y = -math.pi/2, x = math.pi/2, z = math.pi/2},
  16         {y = -math.pi/2, x = 0, z = math.pi/2},
  17         {y = -math.pi/2, x = -math.pi/2, z = math.pi/2},
  18         {y = -math.pi/2, x = math.pi, z = math.pi/2},
  19         {y = 0, x = 0, z = math.pi/2},
  20         {y = 0, x = -math.pi/2, z = math.pi/2},
  21         {y = 0, x = math.pi, z = math.pi/2},
  22         {y = 0, x = math.pi/2, z = math.pi/2},
  23         {y = math.pi, x = math.pi, z = math.pi/2},
  24         {y = math.pi, x = math.pi/2, z = math.pi/2},
  25         {y = math.pi, x = 0, z = math.pi/2},
  26         {y = math.pi, x = -math.pi/2, z = math.pi/2},
  27         {y = math.pi, x = math.pi, z = 0},
  28         {y = -math.pi/2, x = math.pi, z = 0},
  29         {y = 0, x = math.pi, z = 0},
  30         {y = math.pi/2, x = math.pi, z = 0}
  31 }
  32
  33 local gravity = tonumber(core.settings:get("movement_gravity")) or 9.81
  34
  35 --
  36 -- Falling stuff
  37 --
  38
  39 core.register_entity(":__builtin:falling_node", {
  40         initial_properties = {
  41                 visual = "item",
  42                 visual_size = {x = SCALE, y = SCALE, z = SCALE},
  43                 textures = {},
  44                 physical = true,
  45                 is_visible = false,
  46                 collide_with_objects = false,
  47                 collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
  48         },
  49
  50         node = {},
  51         meta = {},
  52         floats = false,
  53
  54         set_node = function(self, node, meta)
  55                 self.node = node
  56                 meta = meta or {}
  57                 if type(meta.to_table) == "function" then
  58                         meta = meta:to_table()
  59                 end
  60                 for _, list in pairs(meta.inventory or {}) do
  61                         for i, stack in pairs(list) do
  62                                 if type(stack) == "userdata" then
  63                                         list[i] = stack:to_string()
  64                                 end
  65                         end
  66                 end
  67                 local def = core.registered_nodes[node.name]
  68                 if not def then
  69                         -- Don't allow unknown nodes to fall
  70                         core.log("info",
  71                                 "Unknown falling node removed at "..
  72                                 core.pos_to_string(self.object:get_pos()))
  73                         self.object:remove()
  74                         return
  75                 end
  76                 self.meta = meta
  77
  78                 -- Cache whether we're supposed to float on water
  79                 self.floats = core.get_item_group(node.name, "float") ~= 0
  80
  81                 -- Set entity visuals
  82                 if def.drawtype == "torchlike" or def.drawtype == "signlike" then
  83                         local textures
  84                         if def.tiles and def.tiles[1] then
  85                                 local tile = def.tiles[1]
  86                                 if type(tile) == "table" then
  87                                         tile = tile.name
  88                                 end
  89                                 if def.drawtype == "torchlike" then
  90                                         textures = { "("..tile..")^[transformFX", tile }
  91                                 else
  92                                         textures = { tile, "("..tile..")^[transformFX" }
  93                                 end
  94                         end
  95                         local vsize
  96                         if def.visual_scale then
  97                                 local s = def.visual_scale
  98                                 vsize = {x = s, y = s, z = s}
  99                         end
 100                         self.object:set_properties({
 101                                 is_visible = true,
 102                                 visual = "upright_sprite",
 103                                 visual_size = vsize,
 104                                 textures = textures,
 105                                 glow = def.light_source,
 106                         })
 107                 elseif def.drawtype ~= "airlike" then
 108                         local itemstring = node.name
 109                         if core.is_colored_paramtype(def.paramtype2) then
 110                                 itemstring = core.itemstring_with_palette(itemstring, node.param2)
 111                         end
 112                         local vsize
 113                         if def.visual_scale then
 114                                 local s = def.visual_scale * SCALE
 115                                 vsize = {x = s, y = s, z = s}
 116                         end
 117                         self.object:set_properties({
 118                                 is_visible = true,
 119                                 wield_item = itemstring,
 120                                 visual_size = vsize,
 121                                 glow = def.light_source,
 122                         })
 123                 end
 124
 125                 -- Rotate entity
 126                 if def.drawtype == "torchlike" then
 127                         self.object:set_yaw(math.pi*0.25)
 128                 elseif (node.param2 ~= 0 and (def.wield_image == ""
 129                                 or def.wield_image == nil))
 130                                 or def.drawtype == "signlike"
 131                                 or def.drawtype == "mesh"
 132                                 or def.drawtype == "normal"
 133                                 or def.drawtype == "nodebox" then
 134                         if (def.paramtype2 == "facedir" or def.paramtype2 == "colorfacedir") then
 135                                 local fdir = node.param2 % 32
 136                                 -- Get rotation from a precalculated lookup table
 137                                 local euler = facedir_to_euler[fdir + 1]
 138                                 if euler then
 139                                         self.object:set_rotation(euler)
 140                                 end
 141                         elseif (def.paramtype2 == "wallmounted" or def.paramtype2 == "colorwallmounted") then
 142                                 local rot = node.param2 % 8
 143                                 local pitch, yaw, roll = 0, 0, 0
 144                                 if rot == 1 then
 145                                         pitch, yaw = math.pi, math.pi
 146                                 elseif rot == 2 then
 147                                         pitch, yaw = math.pi/2, math.pi/2
 148                                 elseif rot == 3 then
 149                                         pitch, yaw = math.pi/2, -math.pi/2
 150                                 elseif rot == 4 then
 151                                         pitch, yaw = math.pi/2, math.pi
 152                                 elseif rot == 5 then
 153                                         pitch, yaw = math.pi/2, 0
 154                                 end
 155                                 if def.drawtype == "signlike" then
 156                                         pitch = pitch - math.pi/2
 157                                         if rot == 0 then
 158                                                 yaw = yaw + math.pi/2
 159                                         elseif rot == 1 then
 160                                                 yaw = yaw - math.pi/2
 161                                         end
 162                                 elseif def.drawtype == "mesh" or def.drawtype == "normal" then
 163                                         if rot >= 0 and rot <= 1 then
 164                                                 roll = roll + math.pi
 165                                         else
 166                                                 yaw = yaw + math.pi
 167                                         end
 168                                 end
 169                                 self.object:set_rotation({x=pitch, y=yaw, z=roll})
 170                         end
 171                 end
 172         end,
 173
 174         get_staticdata = function(self)
 175                 local ds = {
 176                         node = self.node,
 177                         meta = self.meta,
 178                 }
 179                 return core.serialize(ds)
 180         end,
 181
 182         on_activate = function(self, staticdata)
 183                 self.object:set_armor_groups({immortal = 1})
 184                 self.object:set_acceleration({x = 0, y = -gravity, z = 0})
 185
 186                 local ds = core.deserialize(staticdata)
 187                 if ds and ds.node then
 188                         self:set_node(ds.node, ds.meta)
 189                 elseif ds then
 190                         self:set_node(ds)
 191                 elseif staticdata ~= "" then
 192                         self:set_node({name = staticdata})
 193                 end
 194         end,
 195
 196         try_place = function(self, bcp, bcn)
 197                 local bcd = core.registered_nodes[bcn.name]
 198                 -- Add levels if dropped on same leveled node
 199                 if bcd and bcd.leveled and
 200                                 bcn.name == self.node.name then
 201                         local addlevel = self.node.level
 202                         if not addlevel or addlevel <= 0 then
 203                                 addlevel = bcd.leveled
 204                         end
 205                         if core.add_node_level(bcp, addlevel) == 0 then
 206                                 return true
 207                         end
 208                 end
 209
 210                 -- Decide if we're replacing the node or placing on top
 211                 local np = vector.new(bcp)
 212                 if bcd and bcd.buildable_to and
 213                                 (not self.floats or bcd.liquidtype == "none") then
 214                         core.remove_node(bcp)
 215                 else
 216                         np.y = np.y + 1
 217                 end
 218
 219                 -- Check what's here
 220                 local n2 = core.get_node(np)
 221                 local nd = core.registered_nodes[n2.name]
 222                 -- If it's not air or liquid, remove node and replace it with
 223                 -- it's drops
 224                 if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
 225                         if nd and nd.buildable_to == false then
 226                                 nd.on_dig(np, n2, nil)
 227                                 -- If it's still there, it might be protected
 228                                 if core.get_node(np).name == n2.name then
 229                                         return false
 230                                 end
 231                         else
 232                                 core.remove_node(np)
 233                         end
 234                 end
 235
 236                 -- Create node
 237                 local def = core.registered_nodes[self.node.name]
 238                 if def then
 239                         core.add_node(np, self.node)
 240                         if self.meta then
 241                                 core.get_meta(np):from_table(self.meta)
 242                         end
 243                         if def.sounds and def.sounds.place then
 244                                 core.sound_play(def.sounds.place, {pos = np}, true)
 245                         end
 246                 end
 247                 core.check_for_falling(np)
 248                 return true
 249         end,
 250
 251         on_step = function(self, dtime, moveresult)
 252                 -- Fallback code since collision detection can't tell us
 253                 -- about liquids (which do not collide)
 254                 if self.floats then
 255                         local pos = self.object:get_pos()
 256
 257                         local bcp = vector.round({x = pos.x, y = pos.y - 0.7, z = pos.z})
 258                         local bcn = core.get_node(bcp)
 259
 260                         local bcd = core.registered_nodes[bcn.name]
 261                         if bcd and bcd.liquidtype ~= "none" then
 262                                 if self:try_place(bcp, bcn) then
 263                                         self.object:remove()
 264                                         return
 265                                 end
 266                         end
 267                 end
 268
 269                 assert(moveresult)
 270                 if not moveresult.collides then
 271                         return -- Nothing to do :)
 272                 end
 273
 274                 local bcp, bcn
 275                 if moveresult.touching_ground then
 276                         for _, info in ipairs(moveresult.collisions) do
 277                                 if info.axis == "y" then
 278                                         bcp = info.node_pos
 279                                         bcn = core.get_node(bcp)
 280                                         break
 281                                 end
 282                         end
 283                 end
 284
 285                 if not bcp then
 286                         -- We're colliding with something, but not the ground. Irrelevant to us.
 287                         return
 288                 elseif bcn.name == "ignore" then
 289                         -- Delete on contact with ignore at world edges
 290                         self.object:remove()
 291                         return
 292                 end
 293
 294                 local failure = false
 295
 296                 local pos = self.object:get_pos()
 297                 local distance = vector.apply(vector.subtract(pos, bcp), math.abs)
 298                 if distance.x >= 1 or distance.z >= 1 then
 299                         -- We're colliding with some part of a node that's sticking out
 300                         -- Since we don't want to visually teleport, drop as item
 301                         failure = true
 302                 elseif distance.y >= 2 then
 303                         -- Doors consist of a hidden top node and a bottom node that is
 304                         -- the actual door. Despite the top node being solid, the moveresult
 305                         -- almost always indicates collision with the bottom node.
 306                         -- Compensate for this by checking the top node
 307                         bcp.y = bcp.y + 1
 308                         bcn = core.get_node(bcp)
 309                         local def = core.registered_nodes[bcn.name]
 310                         if not (def and def.walkable) then
 311                                 failure = true -- This is unexpected, fail
 312                         end
 313                 end
 314
 315                 -- Try to actually place ourselves
 316                 if not failure then
 317                         failure = not self:try_place(bcp, bcn)
 318                 end
 319
 320                 if failure then
 321                         local drops = core.get_node_drops(self.node, "")
 322                         for _, item in pairs(drops) do
 323                                 core.add_item(pos, item)
 324                         end
 325                 end
 326                 self.object:remove()
 327         end
 328 })
 329
 330 local function convert_to_falling_node(pos, node)
 331         local obj = core.add_entity(pos, "__builtin:falling_node")
 332         if not obj then
 333                 return false
 334         end
 335         node.level = core.get_node_level(pos)
 336         local meta = core.get_meta(pos)
 337         local metatable = meta and meta:to_table() or {}
 338
 339         local def = core.registered_nodes[node.name]
 340         if def and def.sounds and def.sounds.fall then
 341                 core.sound_play(def.sounds.fall, {pos = pos}, true)
 342         end
 343
 344         obj:get_luaentity():set_node(node, metatable)
 345         core.remove_node(pos)
 346         return true
 347 end
 348
 349 function core.spawn_falling_node(pos)
 350         local node = core.get_node(pos)
 351         if node.name == "air" or node.name == "ignore" then
 352                 return false
 353         end
 354         return convert_to_falling_node(pos, node)
 355 end
 356
 357 local function drop_attached_node(p)
 358         local n = core.get_node(p)
 359         local drops = core.get_node_drops(n, "")
 360         local def = core.registered_items[n.name]
 361         if def and def.preserve_metadata then
 362                 local oldmeta = core.get_meta(p):to_table().fields
 363                 -- Copy pos and node because the callback can modify them.
 364                 local pos_copy = {x=p.x, y=p.y, z=p.z}
 365                 local node_copy = {name=n.name, param1=n.param1, param2=n.param2}
 366                 local drop_stacks = {}
 367                 for k, v in pairs(drops) do
 368                         drop_stacks[k] = ItemStack(v)
 369                 end
 370                 drops = drop_stacks
 371                 def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
 372         end
 373         if def and def.sounds and def.sounds.fall then
 374                 core.sound_play(def.sounds.fall, {pos = p}, true)
 375         end
 376         core.remove_node(p)
 377         for _, item in pairs(drops) do
 378                 local pos = {
 379                         x = p.x + math.random()/2 - 0.25,
 380                         y = p.y + math.random()/2 - 0.25,
 381                         z = p.z + math.random()/2 - 0.25,
 382                 }
 383                 core.add_item(pos, item)
 384         end
 385 end
 386
 387 function builtin_shared.check_attached_node(p, n)
 388         local def = core.registered_nodes[n.name]
 389         local d = {x = 0, y = 0, z = 0}
 390         if def.paramtype2 == "wallmounted" or
 391                         def.paramtype2 == "colorwallmounted" then
 392                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 393                 -- to voxelmanip placing a wallmounted node without resetting a
 394                 -- pre-existing param2 value that is out-of-range for wallmounted.
 395                 -- The fallback vector corresponds to param2 = 0.
 396                 d = core.wallmounted_to_dir(n.param2) or {x = 0, y = 1, z = 0}
 397         else
 398                 d.y = -1
 399         end
 400         local p2 = vector.add(p, d)
 401         local nn = core.get_node(p2).name
 402         local def2 = core.registered_nodes[nn]
 403         if def2 and not def2.walkable then
 404                 return false
 405         end
 406         return true
 407 end
 408
 409 --
 410 -- Some common functions
 411 --
 412
 413 function core.check_single_for_falling(p)
 414         local n = core.get_node(p)
 415         if core.get_item_group(n.name, "falling_node") ~= 0 then
 416                 local p_bottom = {x = p.x, y = p.y - 1, z = p.z}
 417                 -- Only spawn falling node if node below is loaded
 418                 local n_bottom = core.get_node_or_nil(p_bottom)
 419                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 420                 if d_bottom and
 421
 422                                 (core.get_item_group(n.name, "float") == 0 or
 423                                 d_bottom.liquidtype == "none") and
 424
 425                                 (n.name ~= n_bottom.name or (d_bottom.leveled and
 426                                 core.get_node_level(p_bottom) <
 427                                 core.get_node_max_level(p_bottom))) and
 428
 429                                 (not d_bottom.walkable or d_bottom.buildable_to) then
 430                         convert_to_falling_node(p, n)
 431                         return true
 432                 end
 433         end
 434
 435         if core.get_item_group(n.name, "attached_node") ~= 0 then
 436                 if not builtin_shared.check_attached_node(p, n) then
 437                         drop_attached_node(p)
 438                         return true
 439                 end
 440         end
 441
 442         return false
 443 end
 444
 445 -- This table is specifically ordered.
 446 -- We don't walk diagonals, only our direct neighbors, and self.
 447 -- Down first as likely case, but always before self. The same with sides.
 448 -- Up must come last, so that things above self will also fall all at once.
 449 local check_for_falling_neighbors = {
 450         {x = -1, y = -1, z = 0},
 451         {x = 1, y = -1, z = 0},
 452         {x = 0, y = -1, z = -1},
 453         {x = 0, y = -1, z = 1},
 454         {x = 0, y = -1, z = 0},
 455         {x = -1, y = 0, z = 0},
 456         {x = 1, y = 0, z = 0},
 457         {x = 0, y = 0, z = 1},
 458         {x = 0, y = 0, z = -1},
 459         {x = 0, y = 0, z = 0},
 460         {x = 0, y = 1, z = 0},
 461 }
 462
 463 function core.check_for_falling(p)
 464         -- Round p to prevent falling entities to get stuck.
 465         p = vector.round(p)
 466
 467         -- We make a stack, and manually maintain size for performance.
 468         -- Stored in the stack, we will maintain tables with pos, and
 469         -- last neighbor visited. This way, when we get back to each
 470         -- node, we know which directions we have already walked, and
 471         -- which direction is the next to walk.
 472         local s = {}
 473         local n = 0
 474         -- The neighbor order we will visit from our table.
 475         local v = 1
 476
 477         while true do
 478                 -- Push current pos onto the stack.
 479                 n = n + 1
 480                 s[n] = {p = p, v = v}
 481                 -- Select next node from neighbor list.
 482                 p = vector.add(p, check_for_falling_neighbors[v])
 483                 -- Now we check out the node. If it is in need of an update,
 484                 -- it will let us know in the return value (true = updated).
 485                 if not core.check_single_for_falling(p) then
 486                         -- If we don't need to "recurse" (walk) to it then pop
 487                         -- our previous pos off the stack and continue from there,
 488                         -- with the v value we were at when we last were at that
 489                         -- node
 490                         repeat
 491                                 local pop = s[n]
 492                                 p = pop.p
 493                                 v = pop.v
 494                                 s[n] = nil
 495                                 n = n - 1
 496                                 -- If there's nothing left on the stack, and no
 497                                 -- more sides to walk to, we're done and can exit
 498                                 if n == 0 and v == 11 then
 499                                         return
 500                                 end
 501                         until v < 11
 502                         -- The next round walk the next neighbor in list.
 503                         v = v + 1
 504                 else
 505                         -- If we did need to walk the neighbor, then
 506                         -- start walking it from the walk order start (1),
 507                         -- and not the order we just pushed up the stack.
 508                         v = 1
 509                 end
 510         end
 511 end
 512
 513 --
 514 -- Global callbacks
 515 --
 516
 517 local function on_placenode(p, node)
 518         core.check_for_falling(p)
 519 end
 520 core.register_on_placenode(on_placenode)
 521
 522 local function on_dignode(p, node)
 523         core.check_for_falling(p)
 524 end
 525 core.register_on_dignode(on_dignode)
 526
 527 local function on_punchnode(p, node)
 528         core.check_for_falling(p)
 529 end
 530 core.register_on_punchnode(on_punchnode)