add skycolor mod files

init.lua

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+local modpath = minetest.get_modpath("skycolor");
+dofile(modpath.."/skycolor.lua")
+

skycolor.lua

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+skycolor = {
+	-- Should be activated before do any effect.
+	active = false,
+	
+	-- Update interval.
+	update_interval = 15,
+
+	-- Main sky colors: starts from midnight to midnight.
+	colors = {},
+
+	-- Update sky color. If players not specified update sky for all players.
+	update_sky_color = function(players) 
+		timeofday = minetest.get_timeofday()
+		rounded_time = math.floor(timeofday * 1000)
+		color = skycolor.utils.convert_to_rgb(0, 1000, rounded_time, skycolor.colors)
+
+		if players == nil or #players == 0 then
+			players = minetest.get_connected_players()
+		end
+		for _, player in ipairs(players) do
+			player:set_sky(color, "plain", nil)
+		end
+
+	end,
+
+	-- Reset sky color to game default. If players not specified update sky for all players.
+	set_default_sky = function(players)
+		if players == nil or #players == 0 then
+			players = minetest.get_connected_players()
+		end
+		for _, player in ipairs(players) do
+			player:set_sky(nil, "regular", nil)
+		end
+	end,
+
+	utils = {
+		convert_to_rgb = function(minval, maxval, current_val, colors)
+			max_index = #colors - 1
+			val = (current_val-minval) / (maxval-minval) * max_index + 1.0
+			index1 = math.floor(val)
+			index2 = math.min(math.floor(val)+1, max_index + 1)
+			f = val - index1
+			c1 = colors[index1]
+			c2 = colors[index2]
+			return {r=math.floor(c1.r + f*(c2.r - c1.r)), g=math.floor(c1.g + f*(c2.g-c1.g)), b=math.floor(c1.b + f*(c2.b - c1.b))}
+		end
+	},
+
+}
+
+local timer = -1
+minetest.register_globalstep(function(dtime)	
+	if skycolor.active ~= true then
+		return
+	end
+
+	-- exceptional first time update
+	if timer <= 0 then
+		skycolor.update_sky_color()
+		timer = 0
+		return
+	end
+
+	-- regular updates based on iterval
+	timer = timer + dtime;
+	if timer >= skycolor.update_interval then
+		skycolor.update_sky_color()
+		timer = 0
+	end
+
+end)