Lua圆形随机点：半径内均匀撒点

local function spot(cx, cy, r)
    local a = math.random() * 6.283
    local d = math.random() * r    -- 半径线性取样，圆心扎堆
    return cx + d * math.cos(a), cy + d * math.sin(a)
end

local function spot(cx, cy, r)
    local a = math.random() * 6.283
    local d = math.sqrt(math.random()) * r   -- 平方根均匀化
    return math.floor(cx + d * math.cos(a)),
        math.floor(cy + d * math.sin(a))
end
sendmsg(actor, 1, "补给刷新点 "
    .. spot(200, 200, 30))