点击光圈：触点反馈的扩散光环

-- 错误：光圈不回收，连点堆积满屏
function onClick(x, y)
    spawnRing(x, y)
end

local LIFE = 0.3
local function spawnRing(x, y)
    local ring = poolGet()
    ring:setPosition(x, y)
    ring:setVisible(true)
    later(LIFE, function()
        ring:setVisible(false)
        poolPut(ring)
    end)
end