Use proper method for getting OS time. Use per-server-session time offset to vary precipitation timing each server session

README.txt

@@ -1,11 +1,11 @@
-snowdrift 0.5.2 by paramat
-For Minetest 0.4.15 and later
-Depends default
+snowdrift 0.6.4 by paramat.
+For Minetest 0.4.16 and later. Compatible with Minetest 5.0.0.
+Depends: default.
 
-Licenses:
-Source code:
-MIT by paramat
+Licenses
+--------
+Source code: MIT by paramat.
 Media:
-Textures CC BY-SA (3.0) by paramat
-Sounds CC BY (3.0) by inchadney
+Textures CC BY-SA (3.0) by paramat.
+Sounds CC BY (3.0) by inchadney.
 http://freesound.org/people/inchadney/sounds/58835/ 

init.lua

@@ -1,29 +1,39 @@
 -- Parameters
 
-local YLIMIT = 1 -- Set to world's water level
+local YWATER = 1 -- Normally set this to world's water level
 				-- Particles are timed to disappear at this y
-				-- Particles do not spawn when player's head is below this y
-local PRECSPR = 6 -- Time scale for precipitation variation in minutes
-local PRECOFF = -0.4 -- Precipitation offset, higher = rains more often
-local GSCYCLE = 0.5 -- Globalstep cycle (seconds)
-local FLAKES = 32 -- Snowflakes per cycle
-local DROPS = 128 -- Raindrops per cycle
+				-- Particles are not spawned for players below this y
+				-- Rain sound is not played for players below this y
+local YMIN = -48 -- Normally set this to deepest ocean
+local YMAX = 120 -- Normally set this to cloud level
+				-- Weather does not occur for players outside this y range
+local PRECTIM = 300 -- Precipitation noise 'spread'
+				-- Time scale for precipitation variation, in seconds
+local PRECTHR = 0.2 -- Precipitation noise threshold, -1 to 1:
+				-- -1 = precipitation all the time
+				-- 0 = precipitation half the time
+				-- 1 = no precipitation
+local FLAKLPOS = 32 -- Snowflake light-tested positions per 0.5s cycle
+				-- Maximum number of snowflakes spawned per 0.5s
+local DROPLPOS = 64 -- Raindrop light-tested positions per 0.5s cycle
+local DROPPPOS = 2 -- Number of raindrops spawned per light-tested position
 local RAINGAIN = 0.2 -- Rain sound volume
-local COLLIDE = false -- Whether particles collide with nodes
-local NISVAL = 39 -- Clouds RGB value at night
-local DASVAL = 175 -- Clouds RGB value in daytime
-local FRADIUS = 48 -- Radius in which flakes are created
-local DRADIUS = 24 -- Radius in which drops are created
+local NISVAL = 39 -- Overcast sky RGB value at night (brightness)
+local DASVAL = 159 -- Overcast sky RGB value in daytime (brightness)
+local FLAKRAD = 16 -- Radius in which flakes are created
+local DROPRAD = 16 -- Radius in which drops are created
+
+-- Precipitation noise
 
 local np_prec = {
 	offset = 0,
 	scale = 1,
-	spread = {x = PRECSPR, y = PRECSPR, z = PRECSPR},
+	spread = {x = PRECTIM, y = PRECTIM, z = PRECTIM},
 	seed = 813,
 	octaves = 1,
 	persist = 0,
 	lacunarity = 2.0,
-	--flags = ""
+	flags = "defaults"
 }
 
 -- These 2 must match biome heat and humidity noise parameters for a world
@@ -36,7 +46,7 @@ local np_temp = {
 	octaves = 3,
 	persist = 0.5,
 	lacunarity = 2.0,
-	--flags = ""
+	flags = "defaults"
 }
 
 local np_humid = {
@@ -47,11 +57,13 @@ local np_humid = {
 	octaves = 3,
 	persist = 0.5,
 	lacunarity = 2.0,
-	--flags = ""
+	flags = "defaults"
 }
 
+-- End parameters
 
--- Stuff
+
+-- Some stuff
 
 local difsval = DASVAL - NISVAL
 local grad = 14 / 95
@@ -65,14 +77,22 @@ local nobj_humid = nil
 local nobj_prec = nil
 
 
--- Globalstep function
+-- Player tables
 
 local handles = {}
+local skybox = {} -- true/false. To not turn off skyboxes of other mods
+
+
+-- Globalstep function
+
+local os_time_0 = os.time()
+local t_offset = math.random(0, 300000)
+
 local timer = 0
 
 minetest.register_globalstep(function(dtime)
 	timer = timer + dtime
-	if timer < GSCYCLE then
+	if timer < 0.5 then
 		return
 	end
 
@@ -80,136 +100,149 @@ minetest.register_globalstep(function(dtime)
 
 	for _, player in ipairs(minetest.get_connected_players()) do
 		local player_name = player:get_player_name()
-		-- Predict player position as slightly behind the CYCLE interval.
-		-- Assume scheduling gets behind slighly (the 1.5), this also tested well.
-		local ppos = vector.add(player:getpos(),
-			vector.multiply(player:get_player_velocity(), GSCYCLE * 1.5))
-		local pposy = math.floor(ppos.y) + 2 -- Precipitation when swimming
-		if pposy >= YLIMIT - 2 then
+		local ppos = player:getpos()
+		-- Point just above player head, to ensure precipitation when swimming
+		local pposy = math.floor(ppos.y) + 2
+		if pposy >= YMIN and pposy <= YMAX then
 			local pposx = math.floor(ppos.x)
 			local pposz = math.floor(ppos.z)
 			local ppos = {x = pposx, y = pposy, z = pposz}
 
+			-- Heat, humidity and precipitation noises
+
+			-- Time in seconds.
+			-- Add the per-server-session random time offset to avoid identical behaviour
+			-- each server session.
+			local time = os.difftime(os.time(), os_time_0) - t_offset
+
 			local nobj_temp = nobj_temp or minetest.get_perlin(np_temp)
 			local nobj_humid = nobj_humid or minetest.get_perlin(np_humid)
 			local nobj_prec = nobj_prec or minetest.get_perlin(np_prec)
 
 			local nval_temp = nobj_temp:get2d({x = pposx, y = pposz})
 			local nval_humid = nobj_humid:get2d({x = pposx, y = pposz})
-			local nval_prec = nobj_prec:get2d({x = os.clock() / 60, y = 0})
+			local nval_prec = nobj_prec:get2d({x = time, y = 0})
 
-			-- Biome system: Frozen biomes below heat 35,
+			-- Default Minetest Game biome system:
+			-- Frozen biomes below heat 35
 			-- deserts below line 14 * t - 95 * h = -1496
 			-- h = (14 * t + 1496) / 95
 			-- h = 14/95 * t + 1496/95
-			-- where 14/95 is gradient and 1496/95 is y intersection
-			-- h - 14/95 t = 1496/95 y intersection
+			-- where 14/95 is gradient and 1496/95 is 'y-intersection'
+			-- h - 14/95 * t = 1496/95
 			-- so area above line is
-			-- h - 14/95 t > 1496/95
+			-- h - 14/95 * t > 1496/95
+
 			local freeze = nval_temp < 35
-			local precip = nval_prec < (nval_humid - 50) / 50 + PRECOFF and
+			local precip = nval_prec > PRECTHR and
 				nval_humid - grad * nval_temp > yint
 
-			-- Check if player is outside
-			local outside = minetest.get_node_light(ppos, 0.5) == 15
-
-			-- Occasionally reset player sky
-			if math.random() < 0.1 then
-				if precip then
-					-- Set overcast sky
-					local sval
-					local time = minetest.get_timeofday()
-					if time >= 0.5 then
-						time = 1 - time
-					end
-					-- Sky brightness transitions:
-					-- First transition (24000 -) 4500, (1 -) 0.1875
-					-- Last transition (24000 -) 5750, (1 -) 0.2396
-					if time <= 0.1875 then
-						sval = NISVAL
-					elseif time >= 0.2396 then
-						sval = DASVAL
-					else
-						sval = math.floor(NISVAL +
-							((time - 0.1875) / 0.0521) * difsval)
-					end
-					-- Set sky to overcast bluish-grey
-					player:set_sky(
-						{r = sval, g = sval, b = sval + 16, a = 255},
-						"plain",
-						{}
-					)
-				else
-					-- Reset sky to normal
-					player:set_sky({}, "regular", {})
+			-- Set sky
+			if precip and not skybox[player_name] then
+				-- Set overcast sky only if normal
+				local sval
+				local time = minetest.get_timeofday()
+				if time >= 0.5 then
+					time = 1 - time
 				end
+				-- Sky brightness transitions:
+				-- First transition (24000 -) 4500, (1 -) 0.1875
+				-- Last transition (24000 -) 5750, (1 -) 0.2396
+				if time <= 0.1875 then
+					sval = NISVAL
+				elseif time >= 0.2396 then
+					sval = DASVAL
+				else
+					sval = math.floor(NISVAL +
+						((time - 0.1875) / 0.0521) * difsval)
+				end
+				player:set_sky({r = sval, g = sval, b = sval + 16, a = 255},
+					"plain", {}, false)
+				skybox[player_name] = true
+			elseif not precip and skybox[player_name] then
+				-- Set normal sky only if skybox
+				player:set_sky({}, "regular", {}, true)
+				skybox[player_name] = nil
 			end
 
-			if not precip or not outside or freeze then
+			-- Stop looping sound.
+			-- Stop sound if head below water level.
+			if not precip or freeze or pposy < YWATER then
 				if handles[player_name] then
-					-- Stop sound if playing
 					minetest.sound_stop(handles[player_name])
 					handles[player_name] = nil
 				end
 			end
 
-			if precip and outside then
-				-- Precipitation
+			-- Particles and sounds.
+			-- Only if head above water level.
+			if precip and pposy >= YWATER then
 				if freeze then
-					-- Snowfall
-					local extime = math.min((pposy + 12 - YLIMIT) / 2, 9)
-					for flake = 1, FLAKES do
-						minetest.add_particle({
-							pos = {
-								x = pposx - FRADIUS + math.random(0, FRADIUS * 2),
-								y = pposy + 12,
-								z = pposz - FRADIUS + math.random(0, FRADIUS * 2)
-							},
-							velocity = {
-								x = (-20 + math.random(0, 40)) / 100,
-								y = -2.0,
-								z = (-20 + math.random(0, 40)) / 100
-							},
-							acceleration = {x = 0, y = 0, z = 0},
-							expirationtime = extime,
-							size = 2.8,
-							collisiondetection = COLLIDE,
-							collision_removal = true,
-							vertical = false,
-							texture = "snowdrift_snowflake" ..
-								math.random(1, 12) .. ".png",
-							playername = player:get_player_name()
-						})
+					-- Snowfall particles
+					for lpos = 1, FLAKLPOS do
+						local lposx = pposx - FLAKRAD +
+							math.random(0, FLAKRAD * 2)
+						local lposz = pposz - FLAKRAD +
+							math.random(0, FLAKRAD * 2)
+						if minetest.get_node_light(
+								{x = lposx, y = pposy + 10, z = lposz},
+								0.5) == 15 then
+							-- Any position above light-tested position is also
+							-- light level 15.
+							-- Spawn Y randomised to avoid particles falling
+							-- in separated layers.
+							-- Random range = speed * cycle time
+							local spawny = pposy + 10 + math.random(0, 10) / 10
+							local extime = math.min((spawny - YWATER) / 2, 10)
+
+							minetest.add_particle({
+								pos = {x = lposx, y = spawny, z = lposz},
+								velocity = {x = 0, y = -2.0, z = 0},
+								acceleration = {x = 0, y = 0, z = 0},
+								expirationtime = extime,
+								size = 2.8,
+								collisiondetection = true,
+								collision_removal = true,
+								vertical = false,
+								texture = "snowdrift_snowflake" ..
+									math.random(1, 12) .. ".png",
+								playername = player:get_player_name()
+							})
+						end
 					end
 				else
-					-- Rainfall
-					for drop = 1, DROPS do
-						local spawny = pposy + 10 + math.random(0, 40) / 10
-						local extime = math.min((spawny - YLIMIT) / 10, 1.8)
-						minetest.add_particle({
-							pos = {
-								x = pposx - DRADIUS + math.random(0, DRADIUS * 2),
-								y = spawny,
-								z = pposz - DRADIUS + math.random(0, DRADIUS * 2)
-							},
-							velocity = {
-								x = 0.0,
-								y = -10.0,
-								z = 0.0
-							},
-							acceleration = {x = 0, y = 0, z = 0},
-							expirationtime = extime,
-							size = 2.8,
-							collisiondetection = COLLIDE,
-							collision_removal = true,
-							vertical = true,
-							texture = "snowdrift_raindrop.png",
-							playername = player:get_player_name()
-						})
-					end
+					-- Rainfall particles
+					for lpos = 1, DROPLPOS do
+						local lposx = pposx - DROPRAD +
+							math.random(0, DROPRAD * 2)
+						local lposz = pposz - DROPRAD +
+							math.random(0, DROPRAD * 2)
+						if minetest.get_node_light(
+								{x = lposx, y = pposy + 10, z = lposz},
+								0.5) == 15 then
+							for drop = 1, DROPPPOS do
+								local spawny = pposy + 10 + math.random(0, 60) / 10
+								local extime = math.min((spawny - YWATER) / 12, 2)
+								local spawnx = lposx - 0.4 + math.random(0, 8) / 10
+								local spawnz = lposz - 0.4 + math.random(0, 8) / 10
 
+								minetest.add_particle({
+									pos = {x = spawnx, y = spawny, z = spawnz},
+									velocity = {x = 0.0, y = -12.0, z = 0.0},
+									acceleration = {x = 0, y = 0, z = 0},
+									expirationtime = extime,
+									size = 2.8,
+									collisiondetection = true,
+									collision_removal = true,
+									vertical = true,
+									texture = "snowdrift_raindrop.png",
+									playername = player:get_player_name()
+								})
+							end
+						end
+					end
+					-- Start looping sound
 					if not handles[player_name] then
-						-- Start sound if not playing
 						local handle = minetest.sound_play(
 							"snowdrift_rain",
 							{
@@ -224,21 +257,34 @@ minetest.register_globalstep(function(dtime)
 					end
 				end
 			end
-		elseif handles[player_name] then
-			-- Stop sound when player goes under y limit
-			minetest.sound_stop(handles[player_name])
-			handles[player_name] = nil
+		else
+			-- Player outside y limits.
+			-- Stop sound if playing.
+			if handles[player_name] then
+				minetest.sound_stop(handles[player_name])
+				handles[player_name] = nil
+			end
+			-- Set normal sky if skybox
+			if skybox[player_name] then
+				player:set_sky({}, "regular", {}, true)
+				skybox[player_name] = nil
+			end
 		end
 	end
 end)
 
 
--- Stop sound and remove player handle on leaveplayer
+-- On leaveplayer function
 
 minetest.register_on_leaveplayer(function(player)
 	local player_name = player:get_player_name()
+	-- Stop sound if playing and remove handle
 	if handles[player_name] then
 		minetest.sound_stop(handles[player_name])
 		handles[player_name] = nil
 	end
+	-- Remove skybox bool if necessary
+	if skybox[player_name] then
+		skybox[player_name] = nil
+	end
 end)