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