allow re-check-log entries to time out gradually rather than

having to go all at once.  This purges the log sooner than before,
but without damaging the mapgen results.

init.lua

@@ -4,12 +4,28 @@
 -- Splizard's snow mod.
 --
 
+biome_lib = {}
+
+-- Boilerplate to support localized strings if intllib mod is installed.
+local S
+if minetest.global_exists("intllib") then
+	if intllib.make_gettext_pair then
+		S = intllib.make_gettext_pair()
+	else
+		S = intllib.Getter()
+	end
+else
+	S = function(s) return s end
+end
+biome_lib.intllib = S
+
 -- Various settings - most of these probably won't need to be changed
 
-biome_lib = {}
 biome_lib.air = {name = "air"}
 
 biome_lib.block_log = {}
+biome_lib.block_recheck_list = {}
+biome_lib.run_block_recheck_list = false
 
 biome_lib.actionslist_aircheck = {}
 biome_lib.actionslist_no_aircheck = {}
@@ -54,28 +70,25 @@ biome_lib.default_wet_surfaces = c3 and tableize(c3) or {"default:dirt", "defaul
 biome_lib.default_ground_nodes = c4 and tableize(c4) or {"default:dirt_with_grass"}
 biome_lib.default_grow_nodes =   c5 and tableize(c5) or {"default:dirt_with_grass"}
 
--- Boilerplate to support localized strings if intllib mod is installed.
+biome_lib.debug_log_level = tonumber(minetest.settings:get("biome_lib_debug_log_level")) or 0
-local S
-if minetest.global_exists("intllib") then
-	if intllib.make_gettext_pair then
-		S = intllib.make_gettext_pair()
-	else
-		S = intllib.Getter()
-	end
-else
-	S = function(s) return s end
-end
-biome_lib.intllib = S
 
-local DEBUG_LEVEL = tonumber(minetest.settings:get("biome_lib_debug")) or 0
+local rr = tonumber(minetest.settings:get("biome_lib_queue_run_ratio")) or -100
+biome_lib.queue_run_ratio = 100 - rr
+biome_lib.entries_per_step = math.max(-rr, 1)
 
-function biome_lib.dbg(msg, level)
+-- the timer that manages the block timeout is in microseconds, but the timer
-	local l = tonumber(level) or 0
+-- that manages the queue wakeup call has to be in seconds, and works best if
-	if DEBUG_LEVEL >= l then
+-- it takes a fraction of the block timeout interval.
-		print("[Biome Lib] "..msg)
+
-		minetest.log("verbose", "[Biome Lib] "..msg)
+local t = tonumber(minetest.settings:get("biome_lib_block_timeout")) or 300
-	end
+
-end
+biome_lib.block_timeout = t * 1000000
+
+-- we don't want the wakeup function to trigger TOO often,
+-- in case the user's block timeout setting is really low
+biome_lib.block_queue_wakeup_time = math.min(t/2, math.max(20, t/10))
+
+local time_speed = tonumber(minetest.settings:get("time_speed"))
 
 biome_lib.plantlife_seed_diff = 329 -- needs to be global so other mods can see it
 
@@ -94,7 +107,6 @@ local humidity_persistence = 0.5
 local humidity_scale = 250
 
 local time_scale = 1
-local time_speed = tonumber(minetest.settings:get("time_speed"))
 
 if time_speed and time_speed > 0 then
 	time_scale = 72 / time_speed
@@ -107,6 +119,14 @@ biome_lib.perlin_humidity = PerlinNoise(humidity_seeddiff, humidity_octaves, hum
 
 -- Local functions
 
+function biome_lib.dbg(msg, level)
+	local l = tonumber(level) or 0
+	if biome_lib.debug_log_level >= l then
+		print("[Biome Lib] "..msg)
+		minetest.log("verbose", "[Biome Lib] "..msg)
+	end
+end
+
 local function get_biome_data(pos, perlin_fertile)
 	local fertility = perlin_fertile:get_2d({x=pos.x, y=pos.z})
 
@@ -440,9 +460,6 @@ local function confirm_block_surroundings(p)
 	return true
 end
 
-biome_lib.block_recheck_list = {}
-biome_lib.run_block_recheck_list = false
-
 function biome_lib.generate_block(shutting_down)
 
 	if shutting_down then
@@ -472,10 +489,12 @@ function biome_lib.generate_block(shutting_down)
 	local pos_hash = 	minetest.hash_node_position(minp)
 
 	if not biome_lib.pos_hash then -- we need to read the maplock and get the surfaces list
+		local now = minetest.get_us_time()
 		biome_lib.pos_hash = {}
 		minetest.load_area(minp)
 		if not confirm_block_surroundings(minp)
-		  and not shutting_down then -- if any neighbors appear not to be loaded, skip this block for now
+		  and not shutting_down
+		  and (blocklog[1][4] + biome_lib.block_timeout) > now then -- if any neighbors appear not to be loaded and the block hasn't expired yet, defer it
 
 			if biome_lib.run_block_recheck_list then
 				biome_lib.block_log[#biome_lib.block_log + 1] = table.copy(biome_lib.block_recheck_list[1])
@@ -537,11 +556,6 @@ end
 
 -- "Play" them back, populating them with new stuff in the process
 
-local rr = tonumber(minetest.settings:get("biome_lib_queue_run_ratio")) or -100
-
-biome_lib.queue_run_ratio = 100 - rr
-biome_lib.entries_per_step = math.max(-rr, 1)
-
 minetest.register_globalstep(function(dtime)
 	if not biome_lib.block_log[1] then return end -- the block log is empty
 
@@ -551,26 +565,74 @@ minetest.register_globalstep(function(dtime)
 	end
 end)
 
+-- Periodically wake-up the queue to give old blocks a chance to time-out
+-- if the player isn't currently exploring (i.e. they're just playing in one area)
+
+function biome_lib.wake_up_queue()
+	if #biome_lib.block_recheck_list > 1
+	  and #biome_lib.block_log == 0 then
+		biome_lib.block_log[#biome_lib.block_log + 1] =
+			table.copy(biome_lib.block_recheck_list[#biome_lib.block_recheck_list])
+		biome_lib.block_recheck_list[#biome_lib.block_recheck_list] = nil
+		biome_lib.run_block_recheck_list = true
+		biome_lib.dbg("Woke-up the map queue to give old blocks a chance to time-out.", 3)
+	end
+	minetest.after(biome_lib.block_queue_wakeup_time, biome_lib.wake_up_queue)
+end
+
+biome_lib.wake_up_queue()
+
 -- Play out the entire log all at once on shutdown
 -- to prevent unpopulated map areas
 
+local function format_time(t)
+	if t > 59999999 then
+		return os.date("!%M minutes and %S seconds", math.ceil(t/1000000))
+	else
+		return os.date("!%S seconds", math.ceil(t/1000000))
+	end
+end
+
+function biome_lib.check_remaining_time()
+	if minetest.get_us_time() > (biome_lib.shutdown_last_timestamp + 10000000) then -- report progress every 10s
+		biome_lib.shutdown_last_timestamp = minetest.get_us_time()
+
+		local entries_remaining = #biome_lib.block_log + #biome_lib.block_recheck_list
+
+		local total_purged = biome_lib.starting_count - entries_remaining
+		local elapsed_time = biome_lib.shutdown_last_timestamp - biome_lib.shutdown_start_time
+		biome_lib.dbg(string.format("%i entries, approximately %s remaining.",
+			entries_remaining, format_time(elapsed_time/total_purged * entries_remaining)))
+	end
+end
+
 minetest.register_on_shutdown(function()
-	if #biome_lib.block_log + #biome_lib.block_recheck_list == 0 then
+	biome_lib.shutdown_start_time = minetest.get_us_time()
+	biome_lib.shutdown_last_timestamp = minetest.get_us_time()+1
+
+	biome_lib.starting_count = #biome_lib.block_log + #biome_lib.block_recheck_list
+
+	if biome_lib.starting_count == 0 then
 		return
 	end
 
-	biome_lib.dbg("[biome_lib] Stand by, playing out the rest of the mapblock log", 0)
+	biome_lib.dbg("Stand by, purging the mapblock log "..
-	biome_lib.dbg("(there are "..(#biome_lib.block_log + #biome_lib.block_recheck_list).." entries)...", 0)
+		"(there are "..(#biome_lib.block_log + #biome_lib.block_recheck_list).." entries) ...", 0)
+
 	while #biome_lib.block_log > 0 do
 		biome_lib.generate_block(true)
+		biome_lib.check_remaining_time()
 	end
 
 	if #biome_lib.block_recheck_list > 0 then
 		biome_lib.block_log = table.copy(biome_lib.block_recheck_list)
 		while #biome_lib.block_log > 0 do
 			biome_lib.generate_block(true)
+			biome_lib.check_remaining_time()
 		end
 	end
+	biome_lib.dbg("Log purge completed after "..
+		format_time(minetest.get_us_time() - biome_lib.shutdown_start_time)..".", 0)
 end)
 
 -- The spawning ABM
@@ -763,17 +825,23 @@ function biome_lib:get_nodedef_field(nodename, fieldname)
 	return minetest.registered_nodes[nodename][fieldname]
 end
 
-if DEBUG_LEVEL >= 3 then
+if biome_lib.debug_log_level >= 3 then
 	biome_lib.last_count = 0
 
 	function biome_lib.show_pending_block_count()
 		if biome_lib.last_count ~= #biome_lib.block_log then
-			biome_lib.dbg("Pending block count: "..(#biome_lib.block_log + #biome_lib.block_recheck_list), 3)
+			biome_lib.dbg(string.format("Pending block counts - ready to process: %-8icurrently deferred: %i",
+				#biome_lib.block_log, #biome_lib.block_recheck_list), 3)
 			biome_lib.last_count = #biome_lib.block_log
 			biome_lib.queue_idle_flag = false
 		elseif not biome_lib.queue_idle_flag then
+			if #biome_lib.block_recheck_list > 0 then
 				biome_lib.dbg("Mapblock queue only contains blocks that can't yet be processed.",  3)
-			biome_lib.dbg("Idling the queue until new mapblocks show up.",  3)
+				biome_lib.dbg("Idling the queue until new blocks arrive or the next wake-up call occurs.",  3)
+			else
+				biome_lib.dbg("Mapblock queue has run dry.",  3)
+				biome_lib.dbg("Idling the queue until new blocks arrive.",  3)
+			end
 			biome_lib.queue_idle_flag = true
 		end
 		minetest.after(1, biome_lib.show_pending_block_count)

search_functions.lua

@@ -56,6 +56,7 @@ end
 -- split into individual mapblocks to reduce lag
 
 minetest.register_on_generated(function(minp, maxp, blockseed)
+	local timestamp = minetest.get_us_time()
 	for x = 0, 4 do
 		local minx = minp.x + x*16
 		for y = 0, 4 do
@@ -65,8 +66,8 @@ minetest.register_on_generated(function(minp, maxp, blockseed)
 
 				local bmin = {x=minx, y=miny, z=minz}
 				local bmax = {x=minx + 15, y=miny + 15, z=minz + 15}
-				biome_lib.block_log[#biome_lib.block_log + 1] = { bmin, bmax, true }
+				biome_lib.block_log[#biome_lib.block_log + 1] = { bmin, bmax, true, timestamp }
-				biome_lib.block_log[#biome_lib.block_log + 1] = { bmin, bmax, false }
+				biome_lib.block_log[#biome_lib.block_log + 1] = { bmin, bmax, false, timestamp }
 			end
 		end
 	end