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-- Prevent anyone else accessing those functions
local forceload_block = core.forceload_block
local forceload_free_block = core.forceload_free_block
core.forceload_block = nil
core.forceload_free_block = nil
local blocks_forceloaded
local blocks_temploaded = {}
local total_forceloaded = 0
-- true, if the forceloaded blocks got changed (flag for persistence on-disk)
local forceload_blocks_changed = false
local BLOCKSIZE = core.MAP_BLOCKSIZE
local function get_blockpos(pos)
return {
x = math.floor(pos.x/BLOCKSIZE),
y = math.floor(pos.y/BLOCKSIZE),
z = math.floor(pos.z/BLOCKSIZE)}
end
-- When we create/free a forceload, it's either transient or persistent. We want
-- to add to/remove from the table that corresponds to the type of forceload, but
-- we also need the other table because whether we forceload a block depends on
-- both tables.
-- This function returns the "primary" table we are adding to/removing from, and
-- the other table.
local function get_relevant_tables(transient)
if transient then
return blocks_temploaded, blocks_forceloaded
else
return blocks_forceloaded, blocks_temploaded
end
end
function core.forceload_block(pos, transient)
-- set changed flag
forceload_blocks_changed = true
local blockpos = get_blockpos(pos)
local hash = core.hash_node_position(blockpos)
local relevant_table, other_table = get_relevant_tables(transient)
if relevant_table[hash] ~= nil then
relevant_table[hash] = relevant_table[hash] + 1
return true
elseif other_table[hash] ~= nil then
relevant_table[hash] = 1
else
if total_forceloaded >= (tonumber(core.settings:get("max_forceloaded_blocks")) or 16) then
return false
end
total_forceloaded = total_forceloaded+1
relevant_table[hash] = 1
forceload_block(blockpos)
return true
end
end
function core.forceload_free_block(pos, transient)
-- set changed flag
forceload_blocks_changed = true
local blockpos = get_blockpos(pos)
local hash = core.hash_node_position(blockpos)
local relevant_table, other_table = get_relevant_tables(transient)
if relevant_table[hash] == nil then return end
if relevant_table[hash] > 1 then
relevant_table[hash] = relevant_table[hash] - 1
elseif other_table[hash] ~= nil then
relevant_table[hash] = nil
else
total_forceloaded = total_forceloaded-1
relevant_table[hash] = nil
forceload_free_block(blockpos)
end
end
-- Keep the forceloaded areas after restart
local wpath = core.get_worldpath()
local function read_file(filename)
local f = io.open(filename, "r")
if f==nil then return {} end
local t = f:read("*all")
f:close()
if t=="" or t==nil then return {} end
return core.deserialize(t) or {}
end
blocks_forceloaded = read_file(wpath.."/force_loaded.txt")
for _, __ in pairs(blocks_forceloaded) do
total_forceloaded = total_forceloaded + 1
end
core.after(5, function()
for hash, _ in pairs(blocks_forceloaded) do
local blockpos = core.get_position_from_hash(hash)
forceload_block(blockpos)
end
end)
-- persists the currently forceloaded blocks to disk
local function persist_forceloaded_blocks()
local data = core.serialize(blocks_forceloaded)
core.safe_file_write(wpath.."/force_loaded.txt", data)
end
-- periodical forceload persistence
local function periodically_persist_forceloaded_blocks()
-- only persist if the blocks actually changed
if forceload_blocks_changed then
persist_forceloaded_blocks()
-- reset changed flag
forceload_blocks_changed = false
end
-- recheck after some time
core.after(10, periodically_persist_forceloaded_blocks)
end
-- persist periodically
core.after(5, periodically_persist_forceloaded_blocks)
-- persist on shutdown
core.register_on_shutdown(persist_forceloaded_blocks)
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