minetest-mm/mods/mob-engine/creatures/common.lua

--= Creatures MOB-Engine (cme) =--
-- Copyright (c) 2015-2016 BlockMen <blockmen2015@gmail.com>
--
-- common.lua
--
-- This software is provided 'as-is', without any express or implied warranty. In no
-- event will the authors be held liable for any damages arising from the use of
-- this software.
--
-- Permission is granted to anyone to use this software for any purpose, including
-- commercial applications, and to alter it and redistribute it freely, subject to the
-- following restrictions:
--
-- 1. The origin of this software must not be misrepresented; you must not
-- claim that you wrote the original software. If you use this software in a
-- product, an acknowledgment in the product documentation is required.
-- 2. Altered source versions must be plainly marked as such, and must not
-- be misrepresented as being the original software.
-- 3. This notice may not be removed or altered from any source distribution.
--


-- constants
nullVec = {x = 0, y = 0, z = 0}
DEGTORAD = math.pi / 180.0

-- common functions
function creatures.rnd(table, errval)
	if not errval then
		errval = false
	end

	local res = 1000000000
	local rn = math.random(0, res - 1)
  local retval = nil

	local psum = 0
	for s,w in pairs(table) do
		psum = psum + ((tonumber(w) or w.chance or 0) * res)
		if psum > rn then
			retval = s
  		break
		end
	end

	return retval
end

function throw_error(msg)
  core.log("error", "#Creatures: ERROR: " .. msg)
end

function creatures.compare_pos(pos1, pos2)
  if not pos1 or not pos2 then
    return
  end
	if pos1.x == pos2.x and pos1.y == pos2.y and pos1.z == pos2.z then
		return false
	end
	return true
end

function creatures.findTarget(search_obj, pos, radius, search_type, ignore_mob, xray, no_count)
	local player_near = false
	local mobs = {}
	for  _,obj in ipairs(core.get_objects_inside_radius(pos, radius)) do
    if obj ~= search_obj then
      if xray or core.line_of_sight(pos, obj:getpos()) == true then
				local is_player = obj:is_player()
				if is_player then
					player_near = true
					if no_count == true then
						return {}, true
					end
				end
        local entity = obj:get_luaentity()
        local isItem = (entity and entity.name == "__builtin:item") or false
        local ignore = (entity and entity.mob_name == ignore_mob and search_type ~= "mates") or false

        if search_type == "all" then
          if not isItem and not ignore then
            table.insert(mobs, obj)
          end
        elseif search_type == "hostile" then
          if not ignore and (entity and entity.hostile == true) or is_player then
          table.insert(mobs, obj)
          end
        elseif search_type == "nonhostile" then
          if entity and not entity.hostile and not isItem and not ignore then
            table.insert(mobs, obj)
          end
        elseif search_type == "player" then
          if is_player then
            table.insert(mobs, obj)
          end
        elseif search_type == "mate" then
          if not isItem and (entity and entity.mob_name == ignore_mob) then
            table.insert(mobs, obj)
          end
        end
      end
    end --for
	end

	return mobs,player_near
end

function creatures.dropItems(pos, drops)
  if not pos or not drops then
    return
  end

  -- convert drops table
  local tab = {}
  for _,elem in pairs(drops) do
    local name = tostring(elem[1])
    local v = elem[2]
    local chance = elem.chance
    local amount = ""
    -- check if drops depending on defined chance
    if name and chance then
      local ct = {}
      ct[name] = chance
      ct["_fake"] = 1 - chance
      local res = creatures.rnd(ct)
      if res == "_fake" then
        name = nil
      end
    end
    -- get amount
    if name and v then
      if type(v) == "table" then
        amount = math.random(v.min or 1, v.max or 1) or 1
      elseif type(v) == "number" then
        amount = v
      end
      if amount > 0 then
        amount = " " .. amount
      end
    end
    if name then
      local obj = core.add_item(pos, name .. amount)
      if not obj then
        throw_error("Could not drop item '" .. name .. amount .. "'")
      end
    end
  end
end