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                         -- Calculate size of falling node
 115                         local s = {}
 116                         s.x = (def.visual_scale or 1) * SCALE
 117                         s.y = s.x
 118                         s.z = s.x
 119                         -- Compensate for wield_scale
 120                         if def.wield_scale then
 121                                 s.x = s.x / def.wield_scale.x
 122                                 s.y = s.y / def.wield_scale.y
 123                                 s.z = s.z / def.wield_scale.z
 124                         end
 125                         self.object:set_properties({
 126                                 is_visible = true,
 127                                 wield_item = itemstring,
 128                                 visual_size = s,
 129                                 glow = def.light_source,
 130                         })
 131                 end
 132
 133                 -- Set collision box (certain nodeboxes only for now)
 134                 local nb_types = {fixed=true, leveled=true, connected=true}
 135                 if def.drawtype == "nodebox" and def.node_box and
 136                         nb_types[def.node_box.type] and def.node_box.fixed then
 137                         local box = table.copy(def.node_box.fixed)
 138                         if type(box[1]) == "table" then
 139                                 box = #box == 1 and box[1] or nil -- We can only use a single box
 140                         end
 141                         if box then
 142                                 if def.paramtype2 == "leveled" and (self.node.level or 0) > 0 then
 143                                         box[5] = -0.5 + self.node.level / 64
 144                                 end
 145                                 self.object:set_properties({
 146                                         collisionbox = box
 147                                 })
 148                         end
 149                 end
 150
 151                 -- Rotate entity
 152                 if def.drawtype == "torchlike" then
 153                         self.object:set_yaw(math.pi*0.25)
 154                 elseif ((node.param2 ~= 0 or def.drawtype == "nodebox" or def.drawtype == "mesh")
 155                                 and (def.wield_image == "" or def.wield_image == nil))
 156                                 or def.drawtype == "signlike"
 157                                 or def.drawtype == "mesh"
 158                                 or def.drawtype == "normal"
 159                                 or def.drawtype == "nodebox" then
 160                         if (def.paramtype2 == "facedir" or def.paramtype2 == "colorfacedir") then
 161                                 local fdir = node.param2 % 32
 162                                 -- Get rotation from a precalculated lookup table
 163                                 local euler = facedir_to_euler[fdir + 1]
 164                                 if euler then
 165                                         self.object:set_rotation(euler)
 166                                 end
 167                         elseif (def.drawtype ~= "plantlike" and def.drawtype ~= "plantlike_rooted" and
 168                                         (def.paramtype2 == "wallmounted" or def.paramtype2 == "colorwallmounted" or def.drawtype == "signlike")) then
 169                                 local rot = node.param2 % 8
 170                                 if (def.drawtype == "signlike" and def.paramtype2 ~= "wallmounted" and def.paramtype2 ~= "colorwallmounted") then
 171                                         -- Change rotation to "floor" by default for non-wallmounted paramtype2
 172                                         rot = 1
 173                                 end
 174                                 local pitch, yaw, roll = 0, 0, 0
 175                                 if def.drawtype == "nodebox" or def.drawtype == "mesh" then
 176                                         if rot == 0 then
 177                                                 pitch, yaw = math.pi/2, 0
 178                                         elseif rot == 1 then
 179                                                 pitch, yaw = -math.pi/2, math.pi
 180                                         elseif rot == 2 then
 181                                                 pitch, yaw = 0, math.pi/2
 182                                         elseif rot == 3 then
 183                                                 pitch, yaw = 0, -math.pi/2
 184                                         elseif rot == 4 then
 185                                                 pitch, yaw = 0, math.pi
 186                                         end
 187                                 else
 188                                         if rot == 1 then
 189                                                 pitch, yaw = math.pi, math.pi
 190                                         elseif rot == 2 then
 191                                                 pitch, yaw = math.pi/2, math.pi/2
 192                                         elseif rot == 3 then
 193                                                 pitch, yaw = math.pi/2, -math.pi/2
 194                                         elseif rot == 4 then
 195                                                 pitch, yaw = math.pi/2, math.pi
 196                                         elseif rot == 5 then
 197                                                 pitch, yaw = math.pi/2, 0
 198                                         end
 199                                 end
 200                                 if def.drawtype == "signlike" then
 201                                         pitch = pitch - math.pi/2
 202                                         if rot == 0 then
 203                                                 yaw = yaw + math.pi/2
 204                                         elseif rot == 1 then
 205                                                 yaw = yaw - math.pi/2
 206                                         end
 207                                 elseif def.drawtype == "mesh" or def.drawtype == "normal" or def.drawtype == "nodebox" then
 208                                         if rot >= 0 and rot <= 1 then
 209                                                 roll = roll + math.pi
 210                                         else
 211                                                 yaw = yaw + math.pi
 212                                         end
 213                                 end
 214                                 self.object:set_rotation({x=pitch, y=yaw, z=roll})
 215                         elseif (def.drawtype == "mesh" and def.paramtype2 == "degrotate") then
 216                                 local p2 = (node.param2 - (def.place_param2 or 0)) % 240
 217                                 local yaw = (p2 / 240) * (math.pi * 2)
 218                                 self.object:set_yaw(yaw)
 219                         elseif (def.drawtype == "mesh" and def.paramtype2 == "colordegrotate") then
 220                                 local p2 = (node.param2 % 32 - (def.place_param2 or 0) % 32) % 24
 221                                 local yaw = (p2 / 24) * (math.pi * 2)
 222                                 self.object:set_yaw(yaw)
 223                         end
 224                 end
 225         end,
 226
 227         get_staticdata = function(self)
 228                 local ds = {
 229                         node = self.node,
 230                         meta = self.meta,
 231                 }
 232                 return core.serialize(ds)
 233         end,
 234
 235         on_activate = function(self, staticdata)
 236                 self.object:set_armor_groups({immortal = 1})
 237                 self.object:set_acceleration(vector.new(0, -gravity, 0))
 238
 239                 local ds = core.deserialize(staticdata)
 240                 if ds and ds.node then
 241                         self:set_node(ds.node, ds.meta)
 242                 elseif ds then
 243                         self:set_node(ds)
 244                 elseif staticdata ~= "" then
 245                         self:set_node({name = staticdata})
 246                 end
 247         end,
 248
 249         try_place = function(self, bcp, bcn)
 250                 local bcd = core.registered_nodes[bcn.name]
 251                 -- Add levels if dropped on same leveled node
 252                 if bcd and bcd.paramtype2 == "leveled" and
 253                                 bcn.name == self.node.name then
 254                         local addlevel = self.node.level
 255                         if (addlevel or 0) <= 0 then
 256                                 addlevel = bcd.leveled
 257                         end
 258                         if core.add_node_level(bcp, addlevel) < addlevel then
 259                                 return true
 260                         elseif bcd.buildable_to then
 261                                 -- Node level has already reached max, don't place anything
 262                                 return true
 263                         end
 264                 end
 265
 266                 -- Decide if we're replacing the node or placing on top
 267                 local np = vector.new(bcp)
 268                 if bcd and bcd.buildable_to and
 269                                 (not self.floats or bcd.liquidtype == "none") then
 270                         core.remove_node(bcp)
 271                 else
 272                         np.y = np.y + 1
 273                 end
 274
 275                 -- Check what's here
 276                 local n2 = core.get_node(np)
 277                 local nd = core.registered_nodes[n2.name]
 278                 -- If it's not air or liquid, remove node and replace it with
 279                 -- it's drops
 280                 if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
 281                         if nd and nd.buildable_to == false then
 282                                 nd.on_dig(np, n2, nil)
 283                                 -- If it's still there, it might be protected
 284                                 if core.get_node(np).name == n2.name then
 285                                         return false
 286                                 end
 287                         else
 288                                 core.remove_node(np)
 289                         end
 290                 end
 291
 292                 -- Create node
 293                 local def = core.registered_nodes[self.node.name]
 294                 if def then
 295                         core.add_node(np, self.node)
 296                         if self.meta then
 297                                 core.get_meta(np):from_table(self.meta)
 298                         end
 299                         if def.sounds and def.sounds.place then
 300                                 core.sound_play(def.sounds.place, {pos = np}, true)
 301                         end
 302                 end
 303                 core.check_for_falling(np)
 304                 return true
 305         end,
 306
 307         on_step = function(self, dtime, moveresult)
 308                 -- Fallback code since collision detection can't tell us
 309                 -- about liquids (which do not collide)
 310                 if self.floats then
 311                         local pos = self.object:get_pos()
 312
 313                         local bcp = pos:offset(0, -0.7, 0):round()
 314                         local bcn = core.get_node(bcp)
 315
 316                         local bcd = core.registered_nodes[bcn.name]
 317                         if bcd and bcd.liquidtype ~= "none" then
 318                                 if self:try_place(bcp, bcn) then
 319                                         self.object:remove()
 320                                         return
 321                                 end
 322                         end
 323                 end
 324
 325                 assert(moveresult)
 326                 if not moveresult.collides then
 327                         return -- Nothing to do :)
 328                 end
 329
 330                 local bcp, bcn
 331                 local player_collision
 332                 if moveresult.touching_ground then
 333                         for _, info in ipairs(moveresult.collisions) do
 334                                 if info.type == "object" then
 335                                         if info.axis == "y" and info.object:is_player() then
 336                                                 player_collision = info
 337                                         end
 338                                 elseif info.axis == "y" then
 339                                         bcp = info.node_pos
 340                                         bcn = core.get_node(bcp)
 341                                         break
 342                                 end
 343                         end
 344                 end
 345
 346                 if not bcp then
 347                         -- We're colliding with something, but not the ground. Irrelevant to us.
 348                         if player_collision then
 349                                 -- Continue falling through players by moving a little into
 350                                 -- their collision box
 351                                 -- TODO: this hack could be avoided in the future if objects
 352                                 --       could choose who to collide with
 353                                 local vel = self.object:get_velocity()
 354                                 self.object:set_velocity(vector.new(
 355                                         vel.x,
 356                                         player_collision.old_velocity.y,
 357                                         vel.z
 358                                 ))
 359                                 self.object:set_pos(self.object:get_pos():offset(0, -0.5, 0))
 360                         end
 361                         return
 362                 elseif bcn.name == "ignore" then
 363                         -- Delete on contact with ignore at world edges
 364                         self.object:remove()
 365                         return
 366                 end
 367
 368                 local failure = false
 369
 370                 local pos = self.object:get_pos()
 371                 local distance = vector.apply(vector.subtract(pos, bcp), math.abs)
 372                 if distance.x >= 1 or distance.z >= 1 then
 373                         -- We're colliding with some part of a node that's sticking out
 374                         -- Since we don't want to visually teleport, drop as item
 375                         failure = true
 376                 elseif distance.y >= 2 then
 377                         -- Doors consist of a hidden top node and a bottom node that is
 378                         -- the actual door. Despite the top node being solid, the moveresult
 379                         -- almost always indicates collision with the bottom node.
 380                         -- Compensate for this by checking the top node
 381                         bcp.y = bcp.y + 1
 382                         bcn = core.get_node(bcp)
 383                         local def = core.registered_nodes[bcn.name]
 384                         if not (def and def.walkable) then
 385                                 failure = true -- This is unexpected, fail
 386                         end
 387                 end
 388
 389                 -- Try to actually place ourselves
 390                 if not failure then
 391                         failure = not self:try_place(bcp, bcn)
 392                 end
 393
 394                 if failure then
 395                         local drops = core.get_node_drops(self.node, "")
 396                         for _, item in pairs(drops) do
 397                                 core.add_item(pos, item)
 398                         end
 399                 end
 400                 self.object:remove()
 401         end
 402 })
 403
 404 local function convert_to_falling_node(pos, node)
 405         local obj = core.add_entity(pos, "__builtin:falling_node")
 406         if not obj then
 407                 return false
 408         end
 409         -- remember node level, the entities' set_node() uses this
 410         node.level = core.get_node_level(pos)
 411         local meta = core.get_meta(pos)
 412         local metatable = meta and meta:to_table() or {}
 413
 414         local def = core.registered_nodes[node.name]
 415         if def and def.sounds and def.sounds.fall then
 416                 core.sound_play(def.sounds.fall, {pos = pos}, true)
 417         end
 418
 419         obj:get_luaentity():set_node(node, metatable)
 420         core.remove_node(pos)
 421         return true, obj
 422 end
 423
 424 function core.spawn_falling_node(pos)
 425         local node = core.get_node(pos)
 426         if node.name == "air" or node.name == "ignore" then
 427                 return false
 428         end
 429         return convert_to_falling_node(pos, node)
 430 end
 431
 432 local function drop_attached_node(p)
 433         local n = core.get_node(p)
 434         local drops = core.get_node_drops(n, "")
 435         local def = core.registered_items[n.name]
 436         if def and def.preserve_metadata then
 437                 local oldmeta = core.get_meta(p):to_table().fields
 438                 -- Copy pos and node because the callback can modify them.
 439                 local pos_copy = vector.new(p)
 440                 local node_copy = {name=n.name, param1=n.param1, param2=n.param2}
 441                 local drop_stacks = {}
 442                 for k, v in pairs(drops) do
 443                         drop_stacks[k] = ItemStack(v)
 444                 end
 445                 drops = drop_stacks
 446                 def.preserve_metadata(pos_copy, node_copy, oldmeta, drops)
 447         end
 448         if def and def.sounds and def.sounds.fall then
 449                 core.sound_play(def.sounds.fall, {pos = p}, true)
 450         end
 451         core.remove_node(p)
 452         for _, item in pairs(drops) do
 453                 local pos = {
 454                         x = p.x + math.random()/2 - 0.25,
 455                         y = p.y + math.random()/2 - 0.25,
 456                         z = p.z + math.random()/2 - 0.25,
 457                 }
 458                 core.add_item(pos, item)
 459         end
 460 end
 461
 462 function builtin_shared.check_attached_node(p, n)
 463         local def = core.registered_nodes[n.name]
 464         local d = vector.new()
 465         if def.paramtype2 == "wallmounted" or
 466                         def.paramtype2 == "colorwallmounted" then
 467                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 468                 -- to voxelmanip placing a wallmounted node without resetting a
 469                 -- pre-existing param2 value that is out-of-range for wallmounted.
 470                 -- The fallback vector corresponds to param2 = 0.
 471                 d = core.wallmounted_to_dir(n.param2) or vector.new(0, 1, 0)
 472         else
 473                 d.y = -1
 474         end
 475         local p2 = vector.add(p, d)
 476         local nn = core.get_node(p2).name
 477         local def2 = core.registered_nodes[nn]
 478         if def2 and not def2.walkable then
 479                 return false
 480         end
 481         return true
 482 end
 483
 484 --
 485 -- Some common functions
 486 --
 487
 488 function core.check_single_for_falling(p)
 489         local n = core.get_node(p)
 490         if core.get_item_group(n.name, "falling_node") ~= 0 then
 491                 local p_bottom = vector.offset(p, 0, -1, 0)
 492                 -- Only spawn falling node if node below is loaded
 493                 local n_bottom = core.get_node_or_nil(p_bottom)
 494                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 495                 if d_bottom then
 496                         local same = n.name == n_bottom.name
 497                         -- Let leveled nodes fall if it can merge with the bottom node
 498                         if same and d_bottom.paramtype2 == "leveled" and
 499                                         core.get_node_level(p_bottom) <
 500                                         core.get_node_max_level(p_bottom) then
 501                                 convert_to_falling_node(p, n)
 502                                 return true
 503                         end
 504                         -- Otherwise only if the bottom node is considered "fall through"
 505                         if not same and
 506                                         (not d_bottom.walkable or d_bottom.buildable_to) and
 507                                         (core.get_item_group(n.name, "float") == 0 or
 508                                         d_bottom.liquidtype == "none") then
 509                                 convert_to_falling_node(p, n)
 510                                 return true
 511                         end
 512                 end
 513         end
 514
 515         if core.get_item_group(n.name, "attached_node") ~= 0 then
 516                 if not builtin_shared.check_attached_node(p, n) then
 517                         drop_attached_node(p)
 518                         return true
 519                 end
 520         end
 521
 522         return false
 523 end
 524
 525 -- This table is specifically ordered.
 526 -- We don't walk diagonals, only our direct neighbors, and self.
 527 -- Down first as likely case, but always before self. The same with sides.
 528 -- Up must come last, so that things above self will also fall all at once.
 529 local check_for_falling_neighbors = {
 530         vector.new(-1, -1,  0),
 531         vector.new( 1, -1,  0),
 532         vector.new( 0, -1, -1),
 533         vector.new( 0, -1,  1),
 534         vector.new( 0, -1,  0),
 535         vector.new(-1,  0,  0),
 536         vector.new( 1,  0,  0),
 537         vector.new( 0,  0,  1),
 538         vector.new( 0,  0, -1),
 539         vector.new( 0,  0,  0),
 540         vector.new( 0,  1,  0),
 541 }
 542
 543 function core.check_for_falling(p)
 544         -- Round p to prevent falling entities to get stuck.
 545         p = vector.round(p)
 546
 547         -- We make a stack, and manually maintain size for performance.
 548         -- Stored in the stack, we will maintain tables with pos, and
 549         -- last neighbor visited. This way, when we get back to each
 550         -- node, we know which directions we have already walked, and
 551         -- which direction is the next to walk.
 552         local s = {}
 553         local n = 0
 554         -- The neighbor order we will visit from our table.
 555         local v = 1
 556
 557         while true do
 558                 -- Push current pos onto the stack.
 559                 n = n + 1
 560                 s[n] = {p = p, v = v}
 561                 -- Select next node from neighbor list.
 562                 p = vector.add(p, check_for_falling_neighbors[v])
 563                 -- Now we check out the node. If it is in need of an update,
 564                 -- it will let us know in the return value (true = updated).
 565                 if not core.check_single_for_falling(p) then
 566                         -- If we don't need to "recurse" (walk) to it then pop
 567                         -- our previous pos off the stack and continue from there,
 568                         -- with the v value we were at when we last were at that
 569                         -- node
 570                         repeat
 571                                 local pop = s[n]
 572                                 p = pop.p
 573                                 v = pop.v
 574                                 s[n] = nil
 575                                 n = n - 1
 576                                 -- If there's nothing left on the stack, and no
 577                                 -- more sides to walk to, we're done and can exit
 578                                 if n == 0 and v == 11 then
 579                                         return
 580                                 end
 581                         until v < 11
 582                         -- The next round walk the next neighbor in list.
 583                         v = v + 1
 584                 else
 585                         -- If we did need to walk the neighbor, then
 586                         -- start walking it from the walk order start (1),
 587                         -- and not the order we just pushed up the stack.
 588                         v = 1
 589                 end
 590         end
 591 end
 592
 593 --
 594 -- Global callbacks
 595 --
 596
 597 local function on_placenode(p, node)
 598         core.check_for_falling(p)
 599 end
 600 core.register_on_placenode(on_placenode)
 601
 602 local function on_dignode(p, node)
 603         core.check_for_falling(p)
 604 end
 605 core.register_on_dignode(on_dignode)
 606
 607 local function on_punchnode(p, node)
 608         core.check_for_falling(p)
 609 end
 610 core.register_on_punchnode(on_punchnode)