adventure_core/spawning.lua

-- SPAWNING

--If default, and with biomes, spawn with biomes, otherwise randomly chosen.
--Here are the four combos:
--					|   High Heat   |   Low Heat   |
					--------------------------------
--High Humidity     |     Earth     |     Water    |
--Low Humidity		|     Fire      |      Air     |
--					--------------------------------

--Returns true on success, false on failure
local time_between = adv_core.setting("base_time_between_spawns", 80)
local spread	   = adv_core.setting("spawn_time_spread", 15)
local base_dist    = adv_core.setting("base_distance", 500)
local spawn_adjust = adv_core.setting("spawn_adjustment_time", 180)
local dist_adjust  = adv_core.setting("distance_adjustment_time", 2)
local min_time     = adv_core.setting("minimum_spawn_time", 30)
local spawn_point  = adv_core.setting("spawn_location",{x=0,y=0,z=0})
local biome_spawns = adv_core.setting("enable_spawn_biome", true)
local spawn_dist   = adv_core.setting("distance_from_player", 12)
local default_en   = (minetest.get_modpath("default")) ~= nil
local air_id       = minetest.get_content_id("air")
local ignore_id    = minetest.get_content_id("ignore")
--local init_time    = (time_between + spawn_adjust) * 1000000
local init_time = 1000000

--Used to randomly spawn element near a player
local function spawn_element(player, with_biomes)
	
	local function biome_spawn(environment, position)
		if environment.heat > 50 then
			if environment.humidity > 50 then --Earth
				adv_core.spawn_element("earth", position)
			else --Fire
				adv_core.spawn_element("fire", position)
			end
		else
			if environment.humidity > 50 then --Water
				adv_core.spawn_element("water", position)
			else --Air
				adv_core.spawn_element("air", position)
			end
		end
	end
	
	local function random_spawn(position)
		local rand = math.random(0,3)
		if rand == 0 then
			adv_core.spawn_element("fire", position)
		elseif rand == 1 then
			adv_core.spawn_element("water", position)
		elseif rand == 2 then
			adv_core.spawn_element("earth", position)
		else 
			adv_core.spawn_element("air", position)
		end
	end

	local position = player:get_pos()
	position.x = math.floor(position.x + math.random(-spawn_dist,spawn_dist))
	position.z = math.floor(position.z + math.random(-spawn_dist,spawn_dist))
	position.y = math.floor(position.y + math.random(0 , 10))
	
	if (minetest.get_node(position).name == "air") then
		minetest.chat_send_all("starting: ".. minetest.serialize(position))
		--find lowest node that's not air
		local vm         = minetest.get_voxel_manip()
		local position2 = position
		position2.y = position2.y - 2
		local emin, emax = vm:read_from_map(position, position2)
		local a = VoxelArea:new{
			MinEdge = emin,
			MaxEdge = emax, 
		}
		local data = vm:get_data()
		local stop = position.y-10
		for y = position.y, stop, -1 do
			local idx = a:index(position.x, y, position.z)
			if data[idx] ~= air_id or data[idx] == ignore_id then
				position.y = y+3
				if with_biomes then
					biome_spawn(minetest.get_biome_data(position), position)
					minetest.chat_send_all("ending: " .. minetest.serialize(position))
				else
					random_spawn(position)
				end
				return true
			end				
		end
		--Didn't find the ground, spawn at low position
		position.y = position.y - 7
		if with_biomes then
			biome_spawn(minetest.get_biome_data(position), position)
			minetest.chat_send_all("ending: " .. minetest.serialize(position))
		else
			random_spawn(position)
		end
		return true
	else
		return false
	end
end

local total_time = 0
minetest.register_globalstep(function(dtime)
	total_time = total_time + dtime
	if total_time > 1 then -- every second
		total_time = 0
		local new_time = minetest.get_us_time()
		for _,player in ipairs(minetest.get_connected_players()) do
			local name = player:get_player_name()
			local player_old_time = tonumber(adv_core.mod_storage:get_string(name .. "old_time")) 
			if player_old_time == nil then
				adv_core.mod_storage:set_string(name .. "old_time", new_time)
				player_old_time = new_time
			end
			local player_countdown = tonumber(adv_core.mod_storage:get_string(name .. "countdown")) or init_time
			minetest.chat_send_all("old_time: " .. player_old_time .. "countdown: " .. player_countdown)
			
			if player_old_time + player_countdown < new_time then
				minetest.chat_send_all("attempting spawn")
				local spawned = nil
				if biome_spawns and default_en then
					spawned = spawn_element(player, true)
				else
					spawned = spawn_element(player, false)
				end
				if spawned then
					minetest.chat_send_all("spawn_successful")
					local countdown = time_between + math.random(-spread,spread)
					local dist = vector.distance(player:get_pos(), spawn_point)
					if dist > base_dist then
						countdown = countdown - math.floor(base_dist / 1000) * dist_adjust
					else
						countdown = countdown + spawn_adjust
					end
					adv_core.mod_storage:set_string(name .. "countdown", 3000000)--math.max(countdown, min_time) * 1000000)
				else
					minetest.chat_send_all("spawn_unsuccessful")
					adv_core.mod_storage:set_string(name .. "countdown", 1000000) -- try again in 1 seconds...
				end
				adv_core.mod_storage:set_string(name .. "old_time", new_time)
			end
		end
	end
end)

-- --Do players respawn/spawn with a guidebook and pouch?
-- if adv_core.setting("enable_starting_items", true) then
	-- minetest.register_on_newplayer(function(playerRef)
		-- local inv = player:get_inventory()
		-- local main = inv:get_list("main")
		-- --for loop through main stacks
			-- --check if empty
				-- --add guidebook
				-- --break
		-- --for loop though main stacks
			-- --check if empty
				-- --add pouch
				-- --break
	-- end
	-- )
-- end