builtin/game/falling.lua

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