start using happy_weather_api, fix #8 sky reseting issue

utils.lua

@@ -0,0 +1,76 @@
+---------------------------------------
+-- 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