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 = vector.new(SCALE, SCALE, 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 type(tile) == "table" then
  88                                         tile = tile.name
  89                                 end
  90                                 if def.drawtype == "torchlike" then
  91                                         textures = { "("..tile..")^[transformFX", tile }
  92                                 else
  93                                         textures = { tile, "("..tile..")^[transformFX" }
  94                                 end
  95                         end
  96                         local vsize
  97                         if def.visual_scale then
  98                                 local s = def.visual_scale
  99                                 vsize = vector.new(s, s, s)
 100                         end
 101                         self.object:set_properties({
 102                                 is_visible = true,
 103                                 visual = "upright_sprite",
 104                                 visual_size = vsize,
 105                                 textures = textures,
 106                                 glow = def.light_source,
 107                         })
 108                 elseif def.drawtype ~= "airlike" then
 109                         local itemstring = node.name
 110                         if core.is_colored_paramtype(def.paramtype2) then
 111                                 itemstring = core.itemstring_with_palette(itemstring, node.param2)
 112                         end
 113                         -- FIXME: solution needed for paramtype2 == "leveled"
 114                         local s = (def.visual_scale or 1) * SCALE
 115                         if def.drawtype == "mesh" then
 116                                 s = s * 0.5
 117                         end
 118                         self.object:set_properties({
 119                                 is_visible = true,
 120                                 wield_item = itemstring,
 121                                 visual_size = vector.new(s, s, s),
 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] and def.node_box.fixed 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 or def.drawtype == "nodebox" or def.drawtype == "mesh")
 148                                 and (def.wield_image == "" 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" or def.drawtype == "signlike") then
 161                                 local rot = node.param2 % 8
 162                                 if (def.drawtype == "signlike" and def.paramtype2 ~= "wallmounted" and def.paramtype2 ~= "colorwallmounted") then
 163                                         -- Change rotation to "floor" by default for non-wallmounted paramtype2
 164                                         rot = 1
 165                                 end
 166                                 local pitch, yaw, roll = 0, 0, 0
 167                                 if def.drawtype == "nodebox" or def.drawtype == "mesh" then
 168                                         if rot == 0 then
 169                                                 pitch, yaw = math.pi/2, 0
 170                                         elseif rot == 1 then
 171                                                 pitch, yaw = -math.pi/2, math.pi
 172                                         elseif rot == 2 then
 173                                                 pitch, yaw = 0, math.pi/2
 174                                         elseif rot == 3 then
 175                                                 pitch, yaw = 0, -math.pi/2
 176                                         elseif rot == 4 then
 177                                                 pitch, yaw = 0, math.pi
 178                                         end
 179                                 else
 180                                         if rot == 1 then
 181                                                 pitch, yaw = math.pi, math.pi
 182                                         elseif rot == 2 then
 183                                                 pitch, yaw = math.pi/2, math.pi/2
 184                                         elseif rot == 3 then
 185                                                 pitch, yaw = math.pi/2, -math.pi/2
 186                                         elseif rot == 4 then
 187                                                 pitch, yaw = math.pi/2, math.pi
 188                                         elseif rot == 5 then
 189                                                 pitch, yaw = math.pi/2, 0
 190                                         end
 191                                 end
 192                                 if def.drawtype == "signlike" then
 193                                         pitch = pitch - math.pi/2
 194                                         if rot == 0 then
 195                                                 yaw = yaw + math.pi/2
 196                                         elseif rot == 1 then
 197                                                 yaw = yaw - math.pi/2
 198                                         end
 199                                 elseif def.drawtype == "mesh" or def.drawtype == "normal" or def.drawtype == "nodebox" then
 200                                         if rot >= 0 and rot <= 1 then
 201                                                 roll = roll + math.pi
 202                                         else
 203                                                 yaw = yaw + math.pi
 204                                         end
 205                                 end
 206                                 self.object:set_rotation({x=pitch, y=yaw, z=roll})
 207                         elseif (def.drawtype == "mesh" and def.paramtype2 == "degrotate") then
 208                                 local p2 = (node.param2 - (def.place_param2 or 0)) % 240
 209                                 local yaw = (p2 / 240) * (math.pi * 2)
 210                                 self.object:set_yaw(yaw)
 211                         elseif (def.drawtype == "mesh" and def.paramtype2 == "colordegrotate") then
 212                                 local p2 = (node.param2 % 32 - (def.place_param2 or 0) % 32) % 24
 213                                 local yaw = (p2 / 24) * (math.pi * 2)
 214                                 self.object:set_yaw(yaw)
 215                         end
 216                 end
 217         end,
 218
 219         get_staticdata = function(self)
 220                 local ds = {
 221                         node = self.node,
 222                         meta = self.meta,
 223                 }
 224                 return core.serialize(ds)
 225         end,
 226
 227         on_activate = function(self, staticdata)
 228                 self.object:set_armor_groups({immortal = 1})
 229                 self.object:set_acceleration(vector.new(0, -gravity, 0))
 230
 231                 local ds = core.deserialize(staticdata)
 232                 if ds and ds.node then
 233                         self:set_node(ds.node, ds.meta)
 234                 elseif ds then
 235                         self:set_node(ds)
 236                 elseif staticdata ~= "" then
 237                         self:set_node({name = staticdata})
 238                 end
 239         end,
 240
 241         try_place = function(self, bcp, bcn)
 242                 local bcd = core.registered_nodes[bcn.name]
 243                 -- Add levels if dropped on same leveled node
 244                 if bcd and bcd.paramtype2 == "leveled" and
 245                                 bcn.name == self.node.name then
 246                         local addlevel = self.node.level
 247                         if (addlevel or 0) <= 0 then
 248                                 addlevel = bcd.leveled
 249                         end
 250                         if core.add_node_level(bcp, addlevel) < addlevel then
 251                                 return true
 252                         elseif bcd.buildable_to then
 253                                 -- Node level has already reached max, don't place anything
 254                                 return true
 255                         end
 256                 end
 257
 258                 -- Decide if we're replacing the node or placing on top
 259                 local np = vector.new(bcp)
 260                 if bcd and bcd.buildable_to and
 261                                 (not self.floats or bcd.liquidtype == "none") then
 262                         core.remove_node(bcp)
 263                 else
 264                         np.y = np.y + 1
 265                 end
 266
 267                 -- Check what's here
 268                 local n2 = core.get_node(np)
 269                 local nd = core.registered_nodes[n2.name]
 270                 -- If it's not air or liquid, remove node and replace it with
 271                 -- it's drops
 272                 if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
 273                         if nd and nd.buildable_to == false then
 274                                 nd.on_dig(np, n2, nil)
 275                                 -- If it's still there, it might be protected
 276                                 if core.get_node(np).name == n2.name then
 277                                         return false
 278                                 end
 279                         else
 280                                 core.remove_node(np)
 281                         end
 282                 end
 283
 284                 -- Create node
 285                 local def = core.registered_nodes[self.node.name]
 286                 if def then
 287                         core.add_node(np, self.node)
 288                         if self.meta then
 289                                 core.get_meta(np):from_table(self.meta)
 290                         end
 291                         if def.sounds and def.sounds.place then
 292                                 core.sound_play(def.sounds.place, {pos = np}, true)
 293                         end
 294                 end
 295                 core.check_for_falling(np)
 296                 return true
 297         end,
 298
 299         on_step = function(self, dtime, moveresult)
 300                 -- Fallback code since collision detection can't tell us
 301                 -- about liquids (which do not collide)
 302                 if self.floats then
 303                         local pos = self.object:get_pos()
 304
 305                         local bcp = pos:offset(0, -0.7, 0):round()
 306                         local bcn = core.get_node(bcp)
 307
 308                         local bcd = core.registered_nodes[bcn.name]
 309                         if bcd and bcd.liquidtype ~= "none" then
 310                                 if self:try_place(bcp, bcn) then
 311                                         self.object:remove()
 312                                         return
 313                                 end
 314                         end
 315                 end
 316
 317                 assert(moveresult)
 318                 if not moveresult.collides then
 319                         return -- Nothing to do :)
 320                 end
 321
 322                 local bcp, bcn
 323                 local player_collision
 324                 if moveresult.touching_ground then
 325                         for _, info in ipairs(moveresult.collisions) do
 326                                 if info.type == "object" then
 327                                         if info.axis == "y" and info.object:is_player() then
 328                                                 player_collision = info
 329                                         end
 330                                 elseif info.axis == "y" then
 331                                         bcp = info.node_pos
 332                                         bcn = core.get_node(bcp)
 333                                         break
 334                                 end
 335                         end
 336                 end
 337
 338                 if not bcp then
 339                         -- We're colliding with something, but not the ground. Irrelevant to us.
 340                         if player_collision then
 341                                 -- Continue falling through players by moving a little into
 342                                 -- their collision box
 343                                 -- TODO: this hack could be avoided in the future if objects
 344                                 --       could choose who to collide with
 345                                 local vel = self.object:get_velocity()
 346                                 self.object:set_velocity(vector.new(
 347                                         vel.x,
 348                                         player_collision.old_velocity.y,
 349                                         vel.z
 350                                 ))
 351                                 self.object:set_pos(self.object:get_pos():offset(0, -0.5, 0))
 352                         end
 353                         return
 354                 elseif bcn.name == "ignore" then
 355                         -- Delete on contact with ignore at world edges
 356                         self.object:remove()
 357                         return
 358                 end
 359
 360                 local failure = false
 361
 362                 local pos = self.object:get_pos()
 363                 local distance = vector.apply(vector.subtract(pos, bcp), math.abs)
 364                 if distance.x >= 1 or distance.z >= 1 then
 365                         -- We're colliding with some part of a node that's sticking out
 366                         -- Since we don't want to visually teleport, drop as item
 367                         failure = true
 368                 elseif distance.y >= 2 then
 369                         -- Doors consist of a hidden top node and a bottom node that is
 370                         -- the actual door. Despite the top node being solid, the moveresult
 371                         -- almost always indicates collision with the bottom node.
 372                         -- Compensate for this by checking the top node
 373                         bcp.y = bcp.y + 1
 374                         bcn = core.get_node(bcp)
 375                         local def = core.registered_nodes[bcn.name]
 376                         if not (def and def.walkable) then
 377                                 failure = true -- This is unexpected, fail
 378                         end
 379                 end
 380
 381                 -- Try to actually place ourselves
 382                 if not failure then
 383                         failure = not self:try_place(bcp, bcn)
 384                 end
 385
 386                 if failure then
 387                         local drops = core.get_node_drops(self.node, "")
 388                         for _, item in pairs(drops) do
 389                                 core.add_item(pos, item)
 390                         end
 391                 end
 392                 self.object:remove()
 393         end
 394 })
 395
 396 local function convert_to_falling_node(pos, node)
 397         local obj = core.add_entity(pos, "__builtin:falling_node")
 398         if not obj then
 399                 return false
 400         end
 401         -- remember node level, the entities' set_node() uses this
 402         node.level = core.get_node_level(pos)
 403         local meta = core.get_meta(pos)
 404         local metatable = meta and meta:to_table() or {}
 405
 406         local def = core.registered_nodes[node.name]
 407         if def and def.sounds and def.sounds.fall then
 408                 core.sound_play(def.sounds.fall, {pos = pos}, true)
 409         end
 410
 411         obj:get_luaentity():set_node(node, metatable)
 412         core.remove_node(pos)
 413         return true, obj
 414 end
 415
 416 function core.spawn_falling_node(pos)
 417         local node = core.get_node(pos)
 418         if node.name == "air" or node.name == "ignore" then
 419                 return false
 420         end
 421         return convert_to_falling_node(pos, node)
 422 end
 423
 424 local function drop_attached_node(p)
 425         local n = core.get_node(p)
 426         local drops = core.get_node_drops(n, "")
 427         local def = core.registered_items[n.name]
 428         if def and def.preserve_metadata then
 429                 local oldmeta = core.get_meta(p):to_table().fields
 430                 -- Copy pos and node because the callback can modify them.
 431                 local pos_copy = vector.new(p)
 432                 local node_copy = {name=n.name, param1=n.param1, param2=n.param2}
 433                 local drop_stacks = {}
 434                 for k, v in pairs(drops) do
 435                         drop_stacks[k] = ItemStack(v)
 436                 end
 437                 drops = drop_stacks
 438                 def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
 439         end
 440         if def and def.sounds and def.sounds.fall then
 441                 core.sound_play(def.sounds.fall, {pos = p}, true)
 442         end
 443         core.remove_node(p)
 444         for _, item in pairs(drops) do
 445                 local pos = {
 446                         x = p.x + math.random()/2 - 0.25,
 447                         y = p.y + math.random()/2 - 0.25,
 448                         z = p.z + math.random()/2 - 0.25,
 449                 }
 450                 core.add_item(pos, item)
 451         end
 452 end
 453
 454 function builtin_shared.check_attached_node(p, n)
 455         local def = core.registered_nodes[n.name]
 456         local d = vector.new()
 457         if def.paramtype2 == "wallmounted" or
 458                         def.paramtype2 == "colorwallmounted" then
 459                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 460                 -- to voxelmanip placing a wallmounted node without resetting a
 461                 -- pre-existing param2 value that is out-of-range for wallmounted.
 462                 -- The fallback vector corresponds to param2 = 0.
 463                 d = core.wallmounted_to_dir(n.param2) or vector.new(0, 1, 0)
 464         else
 465                 d.y = -1
 466         end
 467         local p2 = vector.add(p, d)
 468         local nn = core.get_node(p2).name
 469         local def2 = core.registered_nodes[nn]
 470         if def2 and not def2.walkable then
 471                 return false
 472         end
 473         return true
 474 end
 475
 476 --
 477 -- Some common functions
 478 --
 479
 480 function core.check_single_for_falling(p)
 481         local n = core.get_node(p)
 482         if core.get_item_group(n.name, "falling_node") ~= 0 then
 483                 local p_bottom = vector.offset(p, 0, -1, 0)
 484                 -- Only spawn falling node if node below is loaded
 485                 local n_bottom = core.get_node_or_nil(p_bottom)
 486                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 487                 if d_bottom then
 488                         local same = n.name == n_bottom.name
 489                         -- Let leveled nodes fall if it can merge with the bottom node
 490                         if same and d_bottom.paramtype2 == "leveled" and
 491                                         core.get_node_level(p_bottom) <
 492                                         core.get_node_max_level(p_bottom) then
 493                                 convert_to_falling_node(p, n)
 494                                 return true
 495                         end
 496                         -- Otherwise only if the bottom node is considered "fall through"
 497                         if not same and
 498                                         (not d_bottom.walkable or d_bottom.buildable_to) and
 499                                         (core.get_item_group(n.name, "float") == 0 or
 500                                         d_bottom.liquidtype == "none") then
 501                                 convert_to_falling_node(p, n)
 502                                 return true
 503                         end
 504                 end
 505         end
 506
 507         if core.get_item_group(n.name, "attached_node") ~= 0 then
 508                 if not builtin_shared.check_attached_node(p, n) then
 509                         drop_attached_node(p)
 510                         return true
 511                 end
 512         end
 513
 514         return false
 515 end
 516
 517 -- This table is specifically ordered.
 518 -- We don't walk diagonals, only our direct neighbors, and self.
 519 -- Down first as likely case, but always before self. The same with sides.
 520 -- Up must come last, so that things above self will also fall all at once.
 521 local check_for_falling_neighbors = {
 522         vector.new(-1, -1,  0),
 523         vector.new( 1, -1,  0),
 524         vector.new( 0, -1, -1),
 525         vector.new( 0, -1,  1),
 526         vector.new( 0, -1,  0),
 527         vector.new(-1,  0,  0),
 528         vector.new( 1,  0,  0),
 529         vector.new( 0,  0,  1),
 530         vector.new( 0,  0, -1),
 531         vector.new( 0,  0,  0),
 532         vector.new( 0,  1,  0),
 533 }
 534
 535 function core.check_for_falling(p)
 536         -- Round p to prevent falling entities to get stuck.
 537         p = vector.round(p)
 538
 539         -- We make a stack, and manually maintain size for performance.
 540         -- Stored in the stack, we will maintain tables with pos, and
 541         -- last neighbor visited. This way, when we get back to each
 542         -- node, we know which directions we have already walked, and
 543         -- which direction is the next to walk.
 544         local s = {}
 545         local n = 0
 546         -- The neighbor order we will visit from our table.
 547         local v = 1
 548
 549         while true do
 550                 -- Push current pos onto the stack.
 551                 n = n + 1
 552                 s[n] = {p = p, v = v}
 553                 -- Select next node from neighbor list.
 554                 p = vector.add(p, check_for_falling_neighbors[v])
 555                 -- Now we check out the node. If it is in need of an update,
 556                 -- it will let us know in the return value (true = updated).
 557                 if not core.check_single_for_falling(p) then
 558                         -- If we don't need to "recurse" (walk) to it then pop
 559                         -- our previous pos off the stack and continue from there,
 560                         -- with the v value we were at when we last were at that
 561                         -- node
 562                         repeat
 563                                 local pop = s[n]
 564                                 p = pop.p
 565                                 v = pop.v
 566                                 s[n] = nil
 567                                 n = n - 1
 568                                 -- If there's nothing left on the stack, and no
 569                                 -- more sides to walk to, we're done and can exit
 570                                 if n == 0 and v == 11 then
 571                                         return
 572                                 end
 573                         until v < 11
 574                         -- The next round walk the next neighbor in list.
 575                         v = v + 1
 576                 else
 577                         -- If we did need to walk the neighbor, then
 578                         -- start walking it from the walk order start (1),
 579                         -- and not the order we just pushed up the stack.
 580                         v = 1
 581                 end
 582         end
 583 end
 584
 585 --
 586 -- Global callbacks
 587 --
 588
 589 local function on_placenode(p, node)
 590         core.check_for_falling(p)
 591 end
 592 core.register_on_placenode(on_placenode)
 593
 594 local function on_dignode(p, node)
 595         core.check_for_falling(p)
 596 end
 597 core.register_on_dignode(on_dignode)
 598
 599 local function on_punchnode(p, node)
 600         core.check_for_falling(p)
 601 end
 602 core.register_on_punchnode(on_punchnode)