mods/default/leafdecay.lua

   1 -- minetest/default/leafdecay.lua
   2
   3 -- To enable leaf decay for a node, add it to the "leafdecay" group.
   4 --
   5 -- The rating of the group determines how far from a node in the group "tree"
   6 -- the node can be without decaying.
   7 --
   8 -- If param2 of the node is ~= 0, the node will always be preserved. Thus, if
   9 -- the player places a node of that kind, you will want to set param2=1 or so.
  10
  11 default.leafdecay_trunk_cache = {}
  12 default.leafdecay_enable_cache = true
  13
  14 minetest.register_abm({
  15         nodenames = {"group:leafdecay"},
  16         neighbors = {"air", "group:liquid"},
  17         -- A low interval and a high inverse chance spreads the load
  18         interval = 2,
  19         chance = 5,
  20
  21         action = function(p0, node, _, _)
  22                 --print("leafdecay ABM at "..p0.x..", "..p0.y..", "..p0.z..")")
  23                 local do_preserve = false
  24                 local d = minetest.registered_nodes[node.name].groups.leafdecay
  25                 if not d or d == 0 then
  26                         --print("not groups.leafdecay")
  27                         return
  28                 end
  29                 local n0 = minetest.env:get_node(p0)
  30                 if n0.param2 ~= 0 then
  31                         --print("param2 ~= 0")
  32                         return
  33                 end
  34                 local p0_hash = nil
  35                 if default.leafdecay_enable_cache then
  36                         p0_hash = minetest.hash_node_position(p0)
  37                         local trunkp = default.leafdecay_trunk_cache[p0_hash]
  38                         if trunkp then
  39                                 local n = minetest.env:get_node(trunkp)
  40                                 local reg = minetest.registered_nodes[n.name]
  41                                 -- Assume ignore is a trunk, to make the thing work at the border of the active area
  42                                 if n.name == "ignore" or (reg.groups.tree and reg.groups.tree ~= 0) then
  43                                         --print("cached trunk still exists")
  44                                         return
  45                                 end
  46                                 --print("cached trunk is invalid")
  47                                 -- Cache is invalid
  48                                 table.remove(default.leafdecay_trunk_cache, p0_hash)
  49                         end
  50                 end
  51                 for dx = -d, d do if do_preserve then break end
  52                 for dy = -d, d do if do_preserve then break end
  53                 for dz = -d, d do if do_preserve then break end
  54                         local p = {
  55                                 x = p0.x + dx,
  56                                 y = p0.y + dy,
  57                                 z = p0.z + dz,
  58                         }
  59                         local n = minetest.env:get_node(p)
  60                         local reg = minetest.registered_nodes[n.name]
  61                         -- Assume ignore is a trunk, to make the thing work at the border of the active area
  62                         if n.name == "ignore" or (reg.groups.tree and reg.groups.tree ~= 0) then
  63                                 do_preserve = true
  64                                 if default.leafdecay_enable_cache then
  65                                         --print("caching trunk")
  66                                         -- Cache the trunk
  67                                         default.leafdecay_trunk_cache[p0_hash] = p
  68                                 end
  69                         end
  70                 end
  71                 end
  72                 end
  73                 if not do_preserve then
  74                         -- Drop stuff other than the node itself
  75                         itemstacks = minetest.get_node_drops(n0.name)
  76                         for _, itemname in ipairs(itemstacks) do
  77                                 if itemname ~= n0.name then
  78                                         local p_drop = {
  79                                                 x = p0.x - 0.5 + math.random(),
  80                                                 y = p0.y - 0.5 + math.random(),
  81                                                 z = p0.z - 0.5 + math.random(),
  82                                         }
  83                                         minetest.env:add_item(p_drop, itemname)
  84                                 end
  85                         end
  86                         -- Remove node
  87                         minetest.env:remove_node(p0)
  88                 end
  89         end
  90 })
  91