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 local function drop_attached_node(p)
 122         local nn = core.get_node(p).name
 123         core.remove_node(p)
 124         for _, item in pairs(core.get_node_drops(nn, "")) do
 125                 local pos = {
 126                         x = p.x + math.random()/2 - 0.25,
 127                         y = p.y + math.random()/2 - 0.25,
 128                         z = p.z + math.random()/2 - 0.25,
 129                 }
 130                 core.add_item(pos, item)
 131         end
 132 end
 133
 134 function builtin_shared.check_attached_node(p, n)
 135         local def = core.registered_nodes[n.name]
 136         local d = {x = 0, y = 0, z = 0}
 137         if def.paramtype2 == "wallmounted" then
 138                 -- The fallback vector here is in case 'wallmounted to dir' is nil due
 139                 -- to voxelmanip placing a wallmounted node without resetting a
 140                 -- pre-existing param2 value that is out-of-range for wallmounted.
 141                 -- The fallback vector corresponds to param2 = 0.
 142                 d = core.wallmounted_to_dir(n.param2) or {x = 0, y = 1, z = 0}
 143         else
 144                 d.y = -1
 145         end
 146         local p2 = vector.add(p, d)
 147         local nn = core.get_node(p2).name
 148         local def2 = core.registered_nodes[nn]
 149         if def2 and not def2.walkable then
 150                 return false
 151         end
 152         return true
 153 end
 154
 155 --
 156 -- Some common functions
 157 --
 158
 159 function core.check_single_for_falling(p)
 160         local n = core.get_node(p)
 161         if core.get_item_group(n.name, "falling_node") ~= 0 then
 162                 local p_bottom = {x = p.x, y = p.y - 1, z = p.z}
 163                 -- Only spawn falling node if node below is loaded
 164                 local n_bottom = core.get_node_or_nil(p_bottom)
 165                 local d_bottom = n_bottom and core.registered_nodes[n_bottom.name]
 166                 if d_bottom and
 167
 168                                 (core.get_item_group(n.name, "float") == 0 or
 169                                 d_bottom.liquidtype == "none") and
 170
 171                                 (n.name ~= n_bottom.name or (d_bottom.leveled and
 172                                 core.get_node_level(p_bottom) <
 173                                 core.get_node_max_level(p_bottom))) and
 174
 175                                 (not d_bottom.walkable or d_bottom.buildable_to) then
 176                         n.level = core.get_node_level(p)
 177                         core.remove_node(p)
 178                         spawn_falling_node(p, n)
 179                         return true
 180                 end
 181         end
 182
 183         if core.get_item_group(n.name, "attached_node") ~= 0 then
 184                 if not builtin_shared.check_attached_node(p, n) then
 185                         drop_attached_node(p)
 186                         return true
 187                 end
 188         end
 189
 190         return false
 191 end
 192
 193 -- This table is specifically ordered.
 194 -- We don't walk diagonals, only our direct neighbors, and self.
 195 -- Down first as likely case, but always before self. The same with sides.
 196 -- Up must come last, so that things above self will also fall all at once.
 197 local check_for_falling_neighbors = {
 198         {x = -1, y = -1, z = 0},
 199         {x = 1, y = -1, z = 0},
 200         {x = 0, y = -1, z = -1},
 201         {x = 0, y = -1, z = 1},
 202         {x = 0, y = -1, z = 0},
 203         {x = -1, y = 0, z = 0},
 204         {x = 1, y = 0, z = 0},
 205         {x = 0, y = 0, z = 1},
 206         {x = 0, y = 0, z = -1},
 207         {x = 0, y = 0, z = 0},
 208         {x = 0, y = 1, z = 0},
 209 }
 210
 211 function core.check_for_falling(p)
 212         -- Round p to prevent falling entities to get stuck.
 213         p = vector.round(p)
 214
 215         -- We make a stack, and manually maintain size for performance.
 216         -- Stored in the stack, we will maintain tables with pos, and
 217         -- last neighbor visited. This way, when we get back to each
 218         -- node, we know which directions we have already walked, and
 219         -- which direction is the next to walk.
 220         local s = {}
 221         local n = 0
 222         -- The neighbor order we will visit from our table.
 223         local v = 1
 224
 225         while true do
 226                 -- Push current pos onto the stack.
 227                 n = n + 1
 228                 s[n] = {p = p, v = v}
 229                 -- Select next node from neighbor list.
 230                 p = vector.add(p, check_for_falling_neighbors[v])
 231                 -- Now we check out the node. If it is in need of an update,
 232                 -- it will let us know in the return value (true = updated).
 233                 if not core.check_single_for_falling(p) then
 234                         -- If we don't need to "recurse" (walk) to it then pop
 235                         -- our previous pos off the stack and continue from there,
 236                         -- with the v value we were at when we last were at that
 237                         -- node
 238                         repeat
 239                                 local pop = s[n]
 240                                 p = pop.p
 241                                 v = pop.v
 242                                 s[n] = nil
 243                                 n = n - 1
 244                                 -- If there's nothing left on the stack, and no
 245                                 -- more sides to walk to, we're done and can exit
 246                                 if n == 0 and v == 11 then
 247                                         return
 248                                 end
 249                         until v < 11
 250                         -- The next round walk the next neighbor in list.
 251                         v = v + 1
 252                 else
 253                         -- If we did need to walk the neighbor, then
 254                         -- start walking it from the walk order start (1),
 255                         -- and not the order we just pushed up the stack.
 256                         v = 1
 257                 end
 258         end
 259 end
 260
 261 --
 262 -- Global callbacks
 263 --
 264
 265 local function on_placenode(p, node)
 266         core.check_for_falling(p)
 267 end
 268 core.register_on_placenode(on_placenode)
 269
 270 local function on_dignode(p, node)
 271         core.check_for_falling(p)
 272 end
 273 core.register_on_dignode(on_dignode)
 274
 275 local function on_punchnode(p, node)
 276         core.check_for_falling(p)
 277 end
 278 core.register_on_punchnode(on_punchnode)
 279
 280 --
 281 -- Globally exported functions
 282 --
 283
 284 -- TODO remove this function after the 0.4.15 release
 285 function nodeupdate(p)
 286         core.log("deprecated", "nodeupdate: deprecated, please use core.check_for_falling instead")
 287         core.check_for_falling(p)
 288 end
 289
 290 -- TODO remove this function after the 0.4.15 release
 291 function nodeupdate_single(p)
 292         core.log("deprecated", "nodeupdate_single: deprecated, please use core.check_single_for_falling instead")
 293         core.check_single_for_falling(p)
 294 end