maidroid/modules/_aux.lua

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-- Copyright (c) 2016 tacigar
-- https://github.com/tacigar/maidroid
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maidroid.modules._aux = {}

local velocity = 3

-- change direction to destination and velocity vector
function maidroid.modules._aux.change_dir_to(self, dest)
    local pos = self.object:getpos()
    local dir = vector.subtract(dest, pos)
    local vel = vector.multiply(vector.normalize(dir), velocity)
    self.object:setvelocity(vel)
    self.object:setyaw(math.atan2(vel.z, vel.x) + math.pi / 2)
end

-- change direction and velocity vector
function maidroid.modules._aux.change_dir(self)
    local rnd = function() return math.random(0, 5) * 2 - 5 end
    local dir = {x = rnd(), y = 0, z = rnd()}
    local vel = vector.multiply(vector.normalize(dir), velocity)
    self.object:setvelocity(vel)
    self.object:setyaw(math.atan2(vel.z, vel.x) + math.pi / 2)
end

-- get direction vector by yaw
function maidroid.modules._aux.get_forward(yaw)
    return { x = math.sin(yaw), y = 0.0, z = -math.cos(yaw) }
end

-- round direction vector
function maidroid.modules._aux.get_round_forward(forward)
    local rforward = { x = 0, y = 0, z = 0}
    if math.abs((forward.x / (math.abs(forward.x) + math.abs(forward.z)))) > 0.5 then
        if forward.x > 0 then rforward.x = 1
        else rforward.x = -1 end
    end
    if math.abs((forward.z / (math.abs(forward.x) + math.abs(forward.z)))) > 0.5 then
        if forward.z > 0 then rforward.z = 1
        else rforward.z = -1 end
    end
    return rforward
end


function maidroid.modules._aux.get_under_pos(vec)
    return { x = vec.x, y = vec.y - 1, z = vec.z }
end


function maidroid.modules._aux.get_upper_pos(vec)
    return { x = vec.x, y = vec.y + 1, z = vec.z }
end

-- pickup droped items
function maidroid.modules._aux.pickup_item(self, radius, target_pred)
    local pos = self.object:getpos()
    local pred = target_pred or (function(itemstring) return true end)
    local all_objects = minetest.get_objects_inside_radius(pos, radius)
    for _, obj in ipairs(all_objects) do
        if not obj:is_player() and obj:get_luaentity() then
            local itemstring = obj:get_luaentity().itemstring
            if itemstring then
                if pred(itemstring) then
                    local inv = maidroid._aux.get_maidroid_inventory(self)
                    local stack = ItemStack(itemstring)
                    local leftover = inv:add_item("main", stack)
                    minetest.add_item(obj:getpos(), leftover)
                    obj:get_luaentity().itemstring = ""
                    obj:remove()
                end
            end
        end
    end
end

-- search surrounding nodes
function maidroid.modules._aux.search_surrounding(self, lenvec, pred)
    local pos = vector.round(self.object:getpos())
    for xi = -lenvec.x, lenvec.x do
        for yi = -lenvec.y, lenvec.y do
            for zi = -lenvec.z, lenvec.z do
                local p = {x = pos.x + xi, y = pos.y + yi, z = pos.z + zi}
                local node = minetest.get_node(p)
                if pred(self, p, node) then return true, p, node end
            end
        end
    end
    return false, nil, nil
end