剪窗花：一剪一折藏着对称

fx-paper

local PaperCut = {}
local cuts = {}
local opened = false

function PC.Cut(x, y, len)
    if opened then return end
    cuts[#cuts + 1] = { x = x, y = y, len = len }
    SL:PlaySfx("scissor")
    SL:PlayBurst(x + len, y + len / 2, "paper_bit", 3)
end

function PC.Unfold()
    if #cuts == 0 or opened then return end
    opened = true
    -- 展开动画: 红纸从中心向四周放大
    SL:PlayFxAt("paper_unfold", 330, 160)
    SL:PlaySfx("unfold")
    SL:Schedule(function(dt)
        local k = SL:GetValue("unfoldK") or 0
        k = math.min(1, k + dt * 1.2)
        SL:SetValue("unfoldK", k)
        SL:SetFxScale("paper", 0.2 + 0.8 * k)
        if k >= 1 then
            SL:UnSchedule("unfoldRun")
            SL:PlaySfx("reveal")
        end
    end, 0.016, "unfoldRun")
end

-- 渲染: 镂空沿对称轴镜像复制
function PC.RenderCuts()
    for _, c in ipairs(cuts) do
        for m = -2, 2 do
            SL:PunchHole(
                330 + m * 88 + c.x - 40 + c.len / 2,
                c.y - 50,
                8 + c.len / 4
            )
        end
    end
end

return PC