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 -- Spread the load of finding trunks
  14 default.leafdecay_trunk_find_allow_accumulator = 0
  15
  16 minetest.register_globalstep(function(dtime)
  17         local finds_per_second = 5000
  18         default.leafdecay_trunk_find_allow_accumulator =
  19                         math.floor(dtime * finds_per_second)
  20 end)
  21
  22 minetest.register_abm({
  23         nodenames = {"group:leafdecay"},
  24         neighbors = {"air", "group:liquid"},
  25         -- A low interval and a high inverse chance spreads the load
  26         interval = 2,
  27         chance = 5,
  28
  29         action = function(p0, node, _, _)
  30                 --print("leafdecay ABM at "..p0.x..", "..p0.y..", "..p0.z..")")
  31                 local do_preserve = false
  32                 local d = minetest.registered_nodes[node.name].groups.leafdecay
  33                 if not d or d == 0 then
  34                         --print("not groups.leafdecay")
  35                         return
  36                 end
  37                 local n0 = minetest.env:get_node(p0)
  38                 if n0.param2 ~= 0 then
  39                         --print("param2 ~= 0")
  40                         return
  41                 end
  42                 local p0_hash = nil
  43                 if default.leafdecay_enable_cache then
  44                         p0_hash = minetest.hash_node_position(p0)
  45                         local trunkp = default.leafdecay_trunk_cache[p0_hash]
  46                         if trunkp then
  47                                 local n = minetest.env:get_node(trunkp)
  48                                 local reg = minetest.registered_nodes[n.name]
  49                                 -- Assume ignore is a trunk, to make the thing work at the border of the active area
  50                                 if n.name == "ignore" or (reg.groups.tree and reg.groups.tree ~= 0) then
  51                                         --print("cached trunk still exists")
  52                                         return
  53                                 end
  54                                 --print("cached trunk is invalid")
  55                                 -- Cache is invalid
  56                                 table.remove(default.leafdecay_trunk_cache, p0_hash)
  57                         end
  58                 end
  59                 if default.leafdecay_trunk_find_allow_accumulator <= 0 then
  60                         return
  61                 end
  62                 default.leafdecay_trunk_find_allow_accumulator =
  63                                 default.leafdecay_trunk_find_allow_accumulator - 1
  64                 -- Assume ignore is a trunk, to make the thing work at the border of the active area
  65                 local p1 = minetest.env:find_node_near(p0, d, {"ignore", "group:tree"})
  66                 if p1 then
  67                         do_preserve = true
  68                         if default.leafdecay_enable_cache then
  69                                 --print("caching trunk")
  70                                 -- Cache the trunk
  71                                 default.leafdecay_trunk_cache[p0_hash] = p1
  72                         end
  73                 end
  74                 if not do_preserve then
  75                         -- Drop stuff other than the node itself
  76                         itemstacks = minetest.get_node_drops(n0.name)
  77                         for _, itemname in ipairs(itemstacks) do
  78                                 if itemname ~= n0.name then
  79                                         local p_drop = {
  80                                                 x = p0.x - 0.5 + math.random(),
  81                                                 y = p0.y - 0.5 + math.random(),
  82                                                 z = p0.z - 0.5 + math.random(),
  83                                         }
  84                                         minetest.env:add_item(p_drop, itemname)
  85                                 end
  86                         end
  87                         -- Remove node
  88                         minetest.env:remove_node(p0)
  89                 end
  90         end
  91 })
  92