weather_pack/utils.lua

---------------------------------------
-- Happy Weather: Utilities / Helpers

-- License: MIT

-- Credits: xeranas
---------------------------------------

if hw_utils == nil then
	hw_utils = {}
end

-- outdoor check based on node light level
hw_utils.is_outdoor = function(pos, offset_y)
	if offset_y == nil then
		offset_y = 0
	end

	if minetest.get_node_light({x=pos.x, y=pos.y + offset_y, z=pos.z}, 0.5) == 15 then
		return true
	end
	return false
end

-- checks if player is undewater. This is needed in order to
-- turn off weather particles generation.
hw_utils.is_underwater = function(player)
    local ppos = player:getpos()
    local offset = player:get_eye_offset()
    local player_eye_pos = {x = ppos.x + offset.x, 
                            y = ppos.y + offset.y + 1.5, 
                            z = ppos.z + offset.z}
    local node_level = minetest.get_node_level(player_eye_pos)
    if node_level == 8 or node_level == 7 then
      return true
    end
    return false
end

-- trying to locate position for particles by player look direction for performance reason.
-- it is costly to generate many particles around player so goal is focus mainly on front view.  
hw_utils.get_random_pos = function(player, offset)
  local look_dir = player:get_look_dir()
  local player_pos = player:getpos()

  local random_pos_x = 0
  local random_pos_y = 0
  local random_pos_z = 0

  if look_dir.x > 0 then
    if look_dir.z > 0 then
      random_pos_x = math.random(player_pos.x - offset.back, player_pos.x + offset.front) + math.random()
      random_pos_z = math.random(player_pos.z - offset.back, player_pos.z + offset.front) + math.random() 
    else
      random_pos_x = math.random(player_pos.x - offset.back, player_pos.x + offset.front) + math.random()
      random_pos_z = math.random(player_pos.z - offset.front, player_pos.z + offset.back) + math.random()
    end
  else
    if look_dir.z > 0 then
      random_pos_x = math.random(player_pos.x - offset.front, player_pos.x + offset.back) + math.random()
      random_pos_z = math.random(player_pos.z - offset.back, player_pos.z + offset.front) + math.random()
    else
      random_pos_x = math.random(player_pos.x - offset.front, player_pos.x + offset.back) + math.random()
      random_pos_z = math.random(player_pos.z - offset.front, player_pos.z + offset.back) + math.random()
    end
  end

  if offset.bottom ~= nil then
  	random_pos_y = math.random(player_pos.y - offset.bottom, player_pos.y + offset.top)
  else
  	random_pos_y = player_pos.y + offset.top
  end

  
  return {x=random_pos_x, y=random_pos_y, z=random_pos_z}
end

local np_temp = {
  offset = 50,
  scale = 50,
  spread = {x = 1000, y = 1000, z = 1000},
  seed = 5349,
  octaves = 3,
  persist = 0.5,
  lacunarity = 2.0
}

local np_humid = {
  offset = 50,
  scale = 50,
  spread = {x = 1000, y = 1000, z = 1000},
  seed = 842,
  octaves = 3,
  persist = 0.5,
  lacunarity = 2.0
}

hw_utils.is_biome_frozen = function(position)
  local mg_name = minetest.get_mapgen_setting("mg_name")
  if mg_name == "v6" then
    return false -- v6 not supported yet.
  end
  return hw_utils.is_biome_frozen_v7(position)
end

hw_utils.is_biome_frozen_v7 = function(position)
  local posx = math.floor(position.x)
  local posz = math.floor(position.z)
  local noise_obj = minetest.get_perlin(np_temp)
  local noise_temp = noise_obj:get2d({x = posx, y = posz})

  -- below 35 heat biome considered to be frozen type
  return noise_temp < 35
end

hw_utils.is_biome_dry = function(position)
  local mg_name = minetest.get_mapgen_setting("mg_name")
  if mg_name == "v6" then
    return false -- v6 not supported yet.
  end
  return hw_utils.is_biome_dry_v7(position)
end

hw_utils.is_biome_dry_v7 = function(position)
  local posx = math.floor(position.x)
  local posz = math.floor(position.z)
  local noise_obj = minetest.get_perlin(np_humid)
  local noise_humid = noise_obj:get2d({x = posx, y = posz})

  -- below 50 humid biome considered to be dry type (at least by this mod)
  return noise_humid < 50
end

hw_utils.is_biome_tropic = function(position)
  local mg_name = minetest.get_mapgen_setting("mg_name")
  if mg_name == "v6" then
    return false -- v6 not supported yet.
  end
  return hw_utils.is_biome_tropic_v7(position)
end

hw_utils.is_biome_tropic_v7 = function(position)
  local posx = math.floor(position.x)
  local posz = math.floor(position.z)
  local noise_obj = minetest.get_perlin(np_humid)
  local noise_humid = noise_obj:get2d({x = posx, y = posz})
  noise_obj = minetest.get_perlin(np_temp)
  local noise_temp = noise_obj:get2d({x = posx, y = posz})

  -- humid and temp values are taked by testing flying around world (not sure actually)
  return noise_humid > 55 and noise_temp > 80
end