builtin/game/falling.lua

   1 -- Minetest: builtin/item.lua
   2
   3 local builtin_shared = ...
   4
   5 --
   6 -- Falling stuff
   7 --
   8
   9 core.register_entity(":__builtin:falling_node", {
  10         initial_properties = {
  11                 visual = "wielditem",
  12                 visual_size = {x = 0.667, y = 0.667},
  13                 textures = {},
  14                 physical = true,
  15                 is_visible = false,
  16                 collide_with_objects = false,
  17                 collisionbox = {-0.5, -0.5, -0.5, 0.5, 0.5, 0.5},
  18         },
  19
  20         node = {},
  21
  22         set_node = function(self, node)
  23                 self.node = node
  24                 self.object:set_properties({
  25                         is_visible = true,
  26                         textures = {node.name},
  27                 })
  28         end,
  29
  30         get_staticdata = function(self)
  31                 return core.serialize(self.node)
  32         end,
  33
  34         on_activate = function(self, staticdata)
  35                 self.object:set_armor_groups({immortal = 1})
  36
  37                 local node = core.deserialize(staticdata)
  38                 if node then
  39                         self:set_node(node)
  40                 elseif staticdata ~= "" then
  41                         self:set_node({name = staticdata})
  42                 end
  43         end,
  44
  45         on_step = function(self, dtime)
  46                 -- Set gravity
  47                 local acceleration = self.object:getacceleration()
  48                 if not vector.equals(acceleration, {x = 0, y = -10, z = 0}) then
  49                         self.object:setacceleration({x = 0, y = -10, z = 0})
  50                 end
  51                 -- Turn to actual node when colliding with ground, or continue to move
  52                 local pos = self.object:getpos()
  53                 -- Position of bottom center point
  54                 local bcp = {x = pos.x, y = pos.y - 0.7, z = pos.z}
  55                 -- Avoid bugs caused by an unloaded node below
  56                 local bcn = core.get_node_or_nil(bcp)
  57                 local bcd = bcn and core.registered_nodes[bcn.name]
  58                 if bcn and
  59                                 (not bcd or bcd.walkable or
  60                                 (core.get_item_group(self.node.name, "float") ~= 0 and
  61                                 bcd.liquidtype ~= "none")) then
  62                         if bcd and bcd.leveled and
  63                                         bcn.name == self.node.name then
  64                                 local addlevel = self.node.level
  65                                 if not addlevel or addlevel <= 0 then
  66                                         addlevel = bcd.leveled
  67                                 end
  68                                 if core.add_node_level(bcp, addlevel) == 0 then
  69                                         self.object:remove()
  70                                         return
  71                                 end
  72                         elseif bcd and bcd.buildable_to and
  73                                         (core.get_item_group(self.node.name, "float") == 0 or
  74                                         bcd.liquidtype == "none") then
  75                                 core.remove_node(bcp)
  76                                 return
  77                         end
  78                         local np = {x = bcp.x, y = bcp.y + 1, z = bcp.z}
  79                         -- Check what's here
  80                         local n2 = core.get_node(np)
  81                         local nd = core.registered_nodes[n2.name]
  82                         -- If it's not air or liquid, remove node and replace it with
  83                         -- it's drops
  84                         if n2.name ~= "air" and (not nd or nd.liquidtype == "none") then
  85                                 core.remove_node(np)
  86                                 if nd and nd.buildable_to == false then
  87                                         -- Add dropped items
  88                                         local drops = core.get_node_drops(n2.name, "")
  89                                         for _, dropped_item in pairs(drops) do
  90                                                 core.add_item(np, dropped_item)
  91                                         end
  92                                 end
  93                                 -- Run script hook
  94                                 for _, callback in pairs(core.registered_on_dignodes) do
  95                                         callback(np, n2)
  96                                 end
  97                         end
  98                         -- Create node and remove entity
  99                         if core.registered_nodes[self.node.name] then
 100                                 core.add_node(np, self.node)
 101                         end
 102                         self.object:remove()
 103                         core.check_for_falling(np)
 104                         return
 105                 end
 106                 local vel = self.object:getvelocity()
 107                 if vector.equals(vel, {x = 0, y = 0, z = 0}) then
 108                         local npos = self.object:getpos()
 109                         self.object:setpos(vector.round(npos))
 110                 end
 111         end
 112 })
 113
 114 local function spawn_falling_node(p, node)
 115         local obj = core.add_entity(p, "__builtin:falling_node")
 116         if obj then
 117                 obj:get_luaentity():set_node(node)
 118         end
 119 end
 120
 121 function core.spawn_falling_node(pos)
 122         local node = core.get_node(pos)
 123         if node.name == "air" or node.name == "ignore" then
 124                 return false
 125         end
 126         local obj = core.add_entity(pos, "__builtin:falling_node")
 127         if obj then
 128                 obj:get_luaentity():set_node(node)
 129                 core.remove_node(pos)
 130                 return true
 131         end
 132         return false
 133 end
 134
 135 local function drop_attached_node(p)
 136         local nn = core.get_node(p).name
 137         core.remove_node(p)
 138         for _, item in pairs(core.get_node_drops(nn, "")) do
 139                 local pos = {
 140                         x = p.x + math.random()/2 - 0.25,
 141                         y = p.y + math.random()/2 - 0.25,
 142                         z = p.z + math.random()/2 - 0.25,
 143                 }
 144                 core.add_item(pos, item)
 145         end
 146 end
 147
 148 function builtin_shared.check_attached_node(p, n)
 149         local def = core.registered_nodes[n.name]
 150         local d = {x = 0, y = 0, z = 0}
 151         if def.paramtype2 == "wallmounted" or
 152                         def.paramtype2 == "colorwallmounted" then
 153                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 154                 -- to voxelmanip placing a wallmounted node without resetting a
 155                 -- pre-existing param2 value that is out-of-range for wallmounted.
 156                 -- The fallback vector corresponds to param2 = 0.
 157                 d = core.wallmounted_to_dir(n.param2) or {x = 0, y = 1, z = 0}
 158         else
 159                 d.y = -1
 160         end
 161         local p2 = vector.add(p, d)
 162         local nn = core.get_node(p2).name
 163         local def2 = core.registered_nodes[nn]
 164         if def2 and not def2.walkable then
 165                 return false
 166         end
 167         return true
 168 end
 169
 170 --
 171 -- Some common functions
 172 --
 173
 174 function core.check_single_for_falling(p)
 175         local n = core.get_node(p)
 176         if core.get_item_group(n.name, "falling_node") ~= 0 then
 177                 local p_bottom = {x = p.x, y = p.y - 1, z = p.z}
 178                 -- Only spawn falling node if node below is loaded
 179                 local n_bottom = core.get_node_or_nil(p_bottom)
 180                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 181                 if d_bottom and
 182
 183                                 (core.get_item_group(n.name, "float") == 0 or
 184                                 d_bottom.liquidtype == "none") and
 185
 186                                 (n.name ~= n_bottom.name or (d_bottom.leveled and
 187                                 core.get_node_level(p_bottom) <
 188                                 core.get_node_max_level(p_bottom))) and
 189
 190                                 (not d_bottom.walkable or d_bottom.buildable_to) then
 191                         n.level = core.get_node_level(p)
 192                         core.remove_node(p)
 193                         spawn_falling_node(p, n)
 194                         return true
 195                 end
 196         end
 197
 198         if core.get_item_group(n.name, "attached_node") ~= 0 then
 199                 if not builtin_shared.check_attached_node(p, n) then
 200                         drop_attached_node(p)
 201                         return true
 202                 end
 203         end
 204
 205         return false
 206 end
 207
 208 -- This table is specifically ordered.
 209 -- We don't walk diagonals, only our direct neighbors, and self.
 210 -- Down first as likely case, but always before self. The same with sides.
 211 -- Up must come last, so that things above self will also fall all at once.
 212 local check_for_falling_neighbors = {
 213         {x = -1, y = -1, z = 0},
 214         {x = 1, y = -1, z = 0},
 215         {x = 0, y = -1, z = -1},
 216         {x = 0, y = -1, z = 1},
 217         {x = 0, y = -1, z = 0},
 218         {x = -1, y = 0, z = 0},
 219         {x = 1, y = 0, z = 0},
 220         {x = 0, y = 0, z = 1},
 221         {x = 0, y = 0, z = -1},
 222         {x = 0, y = 0, z = 0},
 223         {x = 0, y = 1, z = 0},
 224 }
 225
 226 function core.check_for_falling(p)
 227         -- Round p to prevent falling entities to get stuck.
 228         p = vector.round(p)
 229
 230         -- We make a stack, and manually maintain size for performance.
 231         -- Stored in the stack, we will maintain tables with pos, and
 232         -- last neighbor visited. This way, when we get back to each
 233         -- node, we know which directions we have already walked, and
 234         -- which direction is the next to walk.
 235         local s = {}
 236         local n = 0
 237         -- The neighbor order we will visit from our table.
 238         local v = 1
 239
 240         while true do
 241                 -- Push current pos onto the stack.
 242                 n = n + 1
 243                 s[n] = {p = p, v = v}
 244                 -- Select next node from neighbor list.
 245                 p = vector.add(p, check_for_falling_neighbors[v])
 246                 -- Now we check out the node. If it is in need of an update,
 247                 -- it will let us know in the return value (true = updated).
 248                 if not core.check_single_for_falling(p) then
 249                         -- If we don't need to "recurse" (walk) to it then pop
 250                         -- our previous pos off the stack and continue from there,
 251                         -- with the v value we were at when we last were at that
 252                         -- node
 253                         repeat
 254                                 local pop = s[n]
 255                                 p = pop.p
 256                                 v = pop.v
 257                                 s[n] = nil
 258                                 n = n - 1
 259                                 -- If there's nothing left on the stack, and no
 260                                 -- more sides to walk to, we're done and can exit
 261                                 if n == 0 and v == 11 then
 262                                         return
 263                                 end
 264                         until v < 11
 265                         -- The next round walk the next neighbor in list.
 266                         v = v + 1
 267                 else
 268                         -- If we did need to walk the neighbor, then
 269                         -- start walking it from the walk order start (1),
 270                         -- and not the order we just pushed up the stack.
 271                         v = 1
 272                 end
 273         end
 274 end
 275
 276 --
 277 -- Global callbacks
 278 --
 279
 280 local function on_placenode(p, node)
 281         core.check_for_falling(p)
 282 end
 283 core.register_on_placenode(on_placenode)
 284
 285 local function on_dignode(p, node)
 286         core.check_for_falling(p)
 287 end
 288 core.register_on_dignode(on_dignode)
 289
 290 local function on_punchnode(p, node)
 291         core.check_for_falling(p)
 292 end
 293 core.register_on_punchnode(on_punchnode)
 294
 295 --
 296 -- Globally exported functions
 297 --
 298
 299 -- TODO remove this function after the 0.4.15 release
 300 function nodeupdate(p)
 301         core.log("deprecated", "nodeupdate: deprecated, please use core.check_for_falling instead")
 302         core.check_for_falling(p)
 303 end
 304
 305 -- TODO remove this function after the 0.4.15 release
 306 function nodeupdate_single(p)
 307         core.log("deprecated", "nodeupdate_single: deprecated, please use core.check_single_for_falling instead")
 308         core.check_single_for_falling(p)
 309 end