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 = true,
  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                 node.param2 = node.param2 or 0
  56                 self.node = node
  57                 meta = meta or {}
  58                 if type(meta.to_table) == "function" then
  59                         meta = meta:to_table()
  60                 end
  61                 for _, list in pairs(meta.inventory or {}) do
  62                         for i, stack in pairs(list) do
  63                                 if type(stack) == "userdata" then
  64                                         list[i] = stack:to_string()
  65                                 end
  66                         end
  67                 end
  68                 local def = core.registered_nodes[node.name]
  69                 if not def then
  70                         -- Don't allow unknown nodes to fall
  71                         core.log("info",
  72                                 "Unknown falling node removed at "..
  73                                 core.pos_to_string(self.object:get_pos()))
  74                         self.object:remove()
  75                         return
  76                 end
  77                 self.meta = meta
  78
  79                 -- Cache whether we're supposed to float on water
  80                 self.floats = core.get_item_group(node.name, "float") ~= 0
  81
  82                 -- Set entity visuals
  83                 if def.drawtype == "torchlike" or def.drawtype == "signlike" then
  84                         local textures
  85                         if def.tiles and def.tiles[1] then
  86                                 local tile = def.tiles[1]
  87                                 if def.drawtype == "torchlike" and def.paramtype2 ~= "wallmounted" then
  88                                         tile = def.tiles[2] or def.tiles[1]
  89                                 end
  90                                 if type(tile) == "table" then
  91                                         tile = tile.name
  92                                 end
  93                                 if def.drawtype == "torchlike" then
  94                                         textures = { "("..tile..")^[transformFX", tile }
  95                                 else
  96                                         textures = { tile, "("..tile..")^[transformFX" }
  97                                 end
  98                         end
  99                         local vsize
 100                         if def.visual_scale then
 101                                 local s = def.visual_scale
 102                                 vsize = {x = s, y = s, z = s}
 103                         end
 104                         self.object:set_properties({
 105                                 is_visible = true,
 106                                 visual = "upright_sprite",
 107                                 visual_size = vsize,
 108                                 textures = textures,
 109                                 glow = def.light_source,
 110                         })
 111                 elseif def.drawtype ~= "airlike" then
 112                         local itemstring = node.name
 113                         if core.is_colored_paramtype(def.paramtype2) then
 114                                 itemstring = core.itemstring_with_palette(itemstring, node.param2)
 115                         end
 116                         -- FIXME: solution needed for paramtype2 == "leveled"
 117                         local vsize
 118                         if def.visual_scale then
 119                                 local s = def.visual_scale * SCALE
 120                                 vsize = {x = s, y = s, z = s}
 121                         end
 122                         self.object:set_properties({
 123                                 is_visible = true,
 124                                 wield_item = itemstring,
 125                                 visual_size = vsize,
 126                                 glow = def.light_source,
 127                         })
 128                 end
 129
 130                 -- Set collision box (certain nodeboxes only for now)
 131                 local nb_types = {fixed=true, leveled=true, connected=true}
 132                 if def.drawtype == "nodebox" and def.node_box and
 133                         nb_types[def.node_box.type] and def.node_box.fixed then
 134                         local box = table.copy(def.node_box.fixed)
 135                         if type(box[1]) == "table" then
 136                                 box = #box == 1 and box[1] or nil -- We can only use a single box
 137                         end
 138                         if box then
 139                                 if def.paramtype2 == "leveled" and (self.node.level or 0) > 0 then
 140                                         box[5] = -0.5 + self.node.level / 64
 141                                 end
 142                                 self.object:set_properties({
 143                                         collisionbox = box
 144                                 })
 145                         end
 146                 end
 147
 148                 -- Rotate entity
 149                 if def.drawtype == "torchlike" then
 150                         if def.paramtype2 == "wallmounted" then
 151                                 self.object:set_yaw(math.pi*0.25)
 152                         else
 153                                 self.object:set_yaw(-math.pi*0.25)
 154                         end
 155                 elseif ((node.param2 ~= 0 or def.drawtype == "nodebox" or def.drawtype == "mesh")
 156                                 and (def.wield_image == "" or def.wield_image == nil))
 157                                 or def.drawtype == "signlike"
 158                                 or def.drawtype == "mesh"
 159                                 or def.drawtype == "normal"
 160                                 or def.drawtype == "nodebox" then
 161                         if (def.paramtype2 == "facedir" or def.paramtype2 == "colorfacedir") then
 162                                 local fdir = node.param2 % 32
 163                                 -- Get rotation from a precalculated lookup table
 164                                 local euler = facedir_to_euler[fdir + 1]
 165                                 if euler then
 166                                         self.object:set_rotation(euler)
 167                                 end
 168                         elseif (def.paramtype2 == "wallmounted" or def.paramtype2 == "colorwallmounted") then
 169                                 local rot = node.param2 % 8
 170                                 local pitch, yaw, roll = 0, 0, 0
 171                                 if def.drawtype == "nodebox" or def.drawtype == "mesh" then
 172                                         if rot == 0 then
 173                                                 pitch, yaw = math.pi/2, 0
 174                                         elseif rot == 1 then
 175                                                 pitch, yaw = -math.pi/2, math.pi
 176                                         elseif rot == 2 then
 177                                                 pitch, yaw = 0, math.pi/2
 178                                         elseif rot == 3 then
 179                                                 pitch, yaw = 0, -math.pi/2
 180                                         elseif rot == 4 then
 181                                                 pitch, yaw = 0, math.pi
 182                                         end
 183                                 else
 184                                         if rot == 1 then
 185                                                 pitch, yaw = math.pi, math.pi
 186                                         elseif rot == 2 then
 187                                                 pitch, yaw = math.pi/2, math.pi/2
 188                                         elseif rot == 3 then
 189                                                 pitch, yaw = math.pi/2, -math.pi/2
 190                                         elseif rot == 4 then
 191                                                 pitch, yaw = math.pi/2, math.pi
 192                                         elseif rot == 5 then
 193                                                 pitch, yaw = math.pi/2, 0
 194                                         end
 195                                 end
 196                                 if def.drawtype == "signlike" then
 197                                         pitch = pitch - math.pi/2
 198                                         if rot == 0 then
 199                                                 yaw = yaw + math.pi/2
 200                                         elseif rot == 1 then
 201                                                 yaw = yaw - math.pi/2
 202                                         end
 203                                 elseif def.drawtype == "mesh" or def.drawtype == "normal" or def.drawtype == "nodebox" then
 204                                         if rot >= 0 and rot <= 1 then
 205                                                 roll = roll + math.pi
 206                                         else
 207                                                 yaw = yaw + math.pi
 208                                         end
 209                                 end
 210                                 self.object:set_rotation({x=pitch, y=yaw, z=roll})
 211                         end
 212                 end
 213         end,
 214
 215         get_staticdata = function(self)
 216                 local ds = {
 217                         node = self.node,
 218                         meta = self.meta,
 219                 }
 220                 return core.serialize(ds)
 221         end,
 222
 223         on_activate = function(self, staticdata)
 224                 self.object:set_armor_groups({immortal = 1})
 225                 self.object:set_acceleration({x = 0, y = -gravity, z = 0})
 226
 227                 local ds = core.deserialize(staticdata)
 228                 if ds and ds.node then
 229                         self:set_node(ds.node, ds.meta)
 230                 elseif ds then
 231                         self:set_node(ds)
 232                 elseif staticdata ~= "" then
 233                         self:set_node({name = staticdata})
 234                 end
 235         end,
 236
 237         try_place = function(self, bcp, bcn)
 238                 local bcd = core.registered_nodes[bcn.name]
 239                 -- Add levels if dropped on same leveled node
 240                 if bcd and bcd.paramtype2 == "leveled" and
 241                                 bcn.name == self.node.name then
 242                         local addlevel = self.node.level
 243                         if (addlevel or 0) <= 0 then
 244                                 addlevel = bcd.leveled
 245                         end
 246                         if core.add_node_level(bcp, addlevel) < addlevel then
 247                                 return true
 248                         elseif bcd.buildable_to then
 249                                 -- Node level has already reached max, don't place anything
 250                                 return true
 251                         end
 252                 end
 253
 254                 -- Decide if we're replacing the node or placing on top
 255                 local np = vector.new(bcp)
 256                 if bcd and bcd.buildable_to and
 257                                 (not self.floats or bcd.liquidtype == "none") then
 258                         core.remove_node(bcp)
 259                 else
 260                         np.y = np.y + 1
 261                 end
 262
 263                 -- Check what's here
 264                 local n2 = core.get_node(np)
 265                 local nd = core.registered_nodes[n2.name]
 266                 -- If it's not air or liquid, remove node and replace it with
 267                 -- it's drops
 268                 if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
 269                         if nd and nd.buildable_to == false then
 270                                 nd.on_dig(np, n2, nil)
 271                                 -- If it's still there, it might be protected
 272                                 if core.get_node(np).name == n2.name then
 273                                         return false
 274                                 end
 275                         else
 276                                 core.remove_node(np)
 277                         end
 278                 end
 279
 280                 -- Create node
 281                 local def = core.registered_nodes[self.node.name]
 282                 if def then
 283                         core.add_node(np, self.node)
 284                         if self.meta then
 285                                 core.get_meta(np):from_table(self.meta)
 286                         end
 287                         if def.sounds and def.sounds.place then
 288                                 core.sound_play(def.sounds.place, {pos = np}, true)
 289                         end
 290                 end
 291                 core.check_for_falling(np)
 292                 return true
 293         end,
 294
 295         on_step = function(self, dtime, moveresult)
 296                 -- Fallback code since collision detection can't tell us
 297                 -- about liquids (which do not collide)
 298                 if self.floats then
 299                         local pos = self.object:get_pos()
 300
 301                         local bcp = vector.round({x = pos.x, y = pos.y - 0.7, z = pos.z})
 302                         local bcn = core.get_node(bcp)
 303
 304                         local bcd = core.registered_nodes[bcn.name]
 305                         if bcd and bcd.liquidtype ~= "none" then
 306                                 if self:try_place(bcp, bcn) then
 307                                         self.object:remove()
 308                                         return
 309                                 end
 310                         end
 311                 end
 312
 313                 assert(moveresult)
 314                 if not moveresult.collides then
 315                         return -- Nothing to do :)
 316                 end
 317
 318                 local bcp, bcn
 319                 local player_collision
 320                 if moveresult.touching_ground then
 321                         for _, info in ipairs(moveresult.collisions) do
 322                                 if info.type == "object" then
 323                                         if info.axis == "y" and info.object:is_player() then
 324                                                 player_collision = info
 325                                         end
 326                                 elseif info.axis == "y" then
 327                                         bcp = info.node_pos
 328                                         bcn = core.get_node(bcp)
 329                                         break
 330                                 end
 331                         end
 332                 end
 333
 334                 if not bcp then
 335                         -- We're colliding with something, but not the ground. Irrelevant to us.
 336                         if player_collision then
 337                                 -- Continue falling through players by moving a little into
 338                                 -- their collision box
 339                                 -- TODO: this hack could be avoided in the future if objects
 340                                 --       could choose who to collide with
 341                                 local vel = self.object:get_velocity()
 342                                 self.object:set_velocity({
 343                                         x = vel.x,
 344                                         y = player_collision.old_velocity.y,
 345                                         z = vel.z
 346                                 })
 347                                 self.object:set_pos(vector.add(self.object:get_pos(),
 348                                         {x = 0, y = -0.5, z = 0}))
 349                         end
 350                         return
 351                 elseif bcn.name == "ignore" then
 352                         -- Delete on contact with ignore at world edges
 353                         self.object:remove()
 354                         return
 355                 end
 356
 357                 local failure = false
 358
 359                 local pos = self.object:get_pos()
 360                 local distance = vector.apply(vector.subtract(pos, bcp), math.abs)
 361                 if distance.x >= 1 or distance.z >= 1 then
 362                         -- We're colliding with some part of a node that's sticking out
 363                         -- Since we don't want to visually teleport, drop as item
 364                         failure = true
 365                 elseif distance.y >= 2 then
 366                         -- Doors consist of a hidden top node and a bottom node that is
 367                         -- the actual door. Despite the top node being solid, the moveresult
 368                         -- almost always indicates collision with the bottom node.
 369                         -- Compensate for this by checking the top node
 370                         bcp.y = bcp.y + 1
 371                         bcn = core.get_node(bcp)
 372                         local def = core.registered_nodes[bcn.name]
 373                         if not (def and def.walkable) then
 374                                 failure = true -- This is unexpected, fail
 375                         end
 376                 end
 377
 378                 -- Try to actually place ourselves
 379                 if not failure then
 380                         failure = not self:try_place(bcp, bcn)
 381                 end
 382
 383                 if failure then
 384                         local drops = core.get_node_drops(self.node, "")
 385                         for _, item in pairs(drops) do
 386                                 core.add_item(pos, item)
 387                         end
 388                 end
 389                 self.object:remove()
 390         end
 391 })
 392
 393 local function convert_to_falling_node(pos, node)
 394         local obj = core.add_entity(pos, "__builtin:falling_node")
 395         if not obj then
 396                 return false
 397         end
 398         -- remember node level, the entities' set_node() uses this
 399         node.level = core.get_node_level(pos)
 400         local meta = core.get_meta(pos)
 401         local metatable = meta and meta:to_table() or {}
 402
 403         local def = core.registered_nodes[node.name]
 404         if def and def.sounds and def.sounds.fall then
 405                 core.sound_play(def.sounds.fall, {pos = pos}, true)
 406         end
 407
 408         obj:get_luaentity():set_node(node, metatable)
 409         core.remove_node(pos)
 410         return true
 411 end
 412
 413 function core.spawn_falling_node(pos)
 414         local node = core.get_node(pos)
 415         if node.name == "air" or node.name == "ignore" then
 416                 return false
 417         end
 418         return convert_to_falling_node(pos, node)
 419 end
 420
 421 local function drop_attached_node(p)
 422         local n = core.get_node(p)
 423         local drops = core.get_node_drops(n, "")
 424         local def = core.registered_items[n.name]
 425         if def and def.preserve_metadata then
 426                 local oldmeta = core.get_meta(p):to_table().fields
 427                 -- Copy pos and node because the callback can modify them.
 428                 local pos_copy = {x=p.x, y=p.y, z=p.z}
 429                 local node_copy = {name=n.name, param1=n.param1, param2=n.param2}
 430                 local drop_stacks = {}
 431                 for k, v in pairs(drops) do
 432                         drop_stacks[k] = ItemStack(v)
 433                 end
 434                 drops = drop_stacks
 435                 def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
 436         end
 437         if def and def.sounds and def.sounds.fall then
 438                 core.sound_play(def.sounds.fall, {pos = p}, true)
 439         end
 440         core.remove_node(p)
 441         for _, item in pairs(drops) do
 442                 local pos = {
 443                         x = p.x + math.random()/2 - 0.25,
 444                         y = p.y + math.random()/2 - 0.25,
 445                         z = p.z + math.random()/2 - 0.25,
 446                 }
 447                 core.add_item(pos, item)
 448         end
 449 end
 450
 451 function builtin_shared.check_attached_node(p, n)
 452         local def = core.registered_nodes[n.name]
 453         local d = {x = 0, y = 0, z = 0}
 454         if def.paramtype2 == "wallmounted" or
 455                         def.paramtype2 == "colorwallmounted" then
 456                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 457                 -- to voxelmanip placing a wallmounted node without resetting a
 458                 -- pre-existing param2 value that is out-of-range for wallmounted.
 459                 -- The fallback vector corresponds to param2 = 0.
 460                 d = core.wallmounted_to_dir(n.param2) or {x = 0, y = 1, z = 0}
 461         else
 462                 d.y = -1
 463         end
 464         local p2 = vector.add(p, d)
 465         local nn = core.get_node(p2).name
 466         local def2 = core.registered_nodes[nn]
 467         if def2 and not def2.walkable then
 468                 return false
 469         end
 470         return true
 471 end
 472
 473 --
 474 -- Some common functions
 475 --
 476
 477 function core.check_single_for_falling(p)
 478         local n = core.get_node(p)
 479         if core.get_item_group(n.name, "falling_node") ~= 0 then
 480                 local p_bottom = {x = p.x, y = p.y - 1, z = p.z}
 481                 -- Only spawn falling node if node below is loaded
 482                 local n_bottom = core.get_node_or_nil(p_bottom)
 483                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 484                 if d_bottom then
 485                         local same = n.name == n_bottom.name
 486                         -- Let leveled nodes fall if it can merge with the bottom node
 487                         if same and d_bottom.paramtype2 == "leveled" and
 488                                         core.get_node_level(p_bottom) <
 489                                         core.get_node_max_level(p_bottom) then
 490                                 convert_to_falling_node(p, n)
 491                                 return true
 492                         end
 493                         -- Otherwise only if the bottom node is considered "fall through"
 494                         if not same and
 495                                         (not d_bottom.walkable or d_bottom.buildable_to) and
 496                                         (core.get_item_group(n.name, "float") == 0 or
 497                                         d_bottom.liquidtype == "none") then
 498                                 convert_to_falling_node(p, n)
 499                                 return true
 500                         end
 501                 end
 502         end
 503
 504         if core.get_item_group(n.name, "attached_node") ~= 0 then
 505                 if not builtin_shared.check_attached_node(p, n) then
 506                         drop_attached_node(p)
 507                         return true
 508                 end
 509         end
 510
 511         return false
 512 end
 513
 514 -- This table is specifically ordered.
 515 -- We don't walk diagonals, only our direct neighbors, and self.
 516 -- Down first as likely case, but always before self. The same with sides.
 517 -- Up must come last, so that things above self will also fall all at once.
 518 local check_for_falling_neighbors = {
 519         {x = -1, y = -1, z = 0},
 520         {x = 1, y = -1, z = 0},
 521         {x = 0, y = -1, z = -1},
 522         {x = 0, y = -1, z = 1},
 523         {x = 0, y = -1, z = 0},
 524         {x = -1, y = 0, z = 0},
 525         {x = 1, y = 0, z = 0},
 526         {x = 0, y = 0, z = 1},
 527         {x = 0, y = 0, z = -1},
 528         {x = 0, y = 0, z = 0},
 529         {x = 0, y = 1, z = 0},
 530 }
 531
 532 function core.check_for_falling(p)
 533         -- Round p to prevent falling entities to get stuck.
 534         p = vector.round(p)
 535
 536         -- We make a stack, and manually maintain size for performance.
 537         -- Stored in the stack, we will maintain tables with pos, and
 538         -- last neighbor visited. This way, when we get back to each
 539         -- node, we know which directions we have already walked, and
 540         -- which direction is the next to walk.
 541         local s = {}
 542         local n = 0
 543         -- The neighbor order we will visit from our table.
 544         local v = 1
 545
 546         while true do
 547                 -- Push current pos onto the stack.
 548                 n = n + 1
 549                 s[n] = {p = p, v = v}
 550                 -- Select next node from neighbor list.
 551                 p = vector.add(p, check_for_falling_neighbors[v])
 552                 -- Now we check out the node. If it is in need of an update,
 553                 -- it will let us know in the return value (true = updated).
 554                 if not core.check_single_for_falling(p) then
 555                         -- If we don't need to "recurse" (walk) to it then pop
 556                         -- our previous pos off the stack and continue from there,
 557                         -- with the v value we were at when we last were at that
 558                         -- node
 559                         repeat
 560                                 local pop = s[n]
 561                                 p = pop.p
 562                                 v = pop.v
 563                                 s[n] = nil
 564                                 n = n - 1
 565                                 -- If there's nothing left on the stack, and no
 566                                 -- more sides to walk to, we're done and can exit
 567                                 if n == 0 and v == 11 then
 568                                         return
 569                                 end
 570                         until v < 11
 571                         -- The next round walk the next neighbor in list.
 572                         v = v + 1
 573                 else
 574                         -- If we did need to walk the neighbor, then
 575                         -- start walking it from the walk order start (1),
 576                         -- and not the order we just pushed up the stack.
 577                         v = 1
 578                 end
 579         end
 580 end
 581
 582 --
 583 -- Global callbacks
 584 --
 585
 586 local function on_placenode(p, node)
 587         core.check_for_falling(p)
 588 end
 589 core.register_on_placenode(on_placenode)
 590
 591 local function on_dignode(p, node)
 592         core.check_for_falling(p)
 593 end
 594 core.register_on_dignode(on_dignode)
 595
 596 local function on_punchnode(p, node)
 597         core.check_for_falling(p)
 598 end
 599 core.register_on_punchnode(on_punchnode)