Lua受击闪白：叠加渐隐的一层白

flowchart TD
A[命中发生] --> B[白层透明度加一档]
B --> C{超过封顶一了吗}
C -- 是 --> D[钉死在一]
C -- 否 --> E[逐拍渐隐]
D --> E
E --> F{透明度归零}
F -- 否 --> E
F -- 是 --> G[白层歇着 待下次命中]

 fx-flashwhite

-- @file FlashWhite.lua
-- 受击闪白 —— 叠加渐隐的一层白

local FlashWhite = {}

local CONST = {
    HIT_STEP      = 0.35,
    ALPHA_CAP     = 1.0,
    FADE_SPEED    = 1.5,

    AUTOINC_BASE  = 1156000,
}

local _alpha     = 0
local _whiteFx   = nil
local _hostNode  = nil
local _scheduler = nil
local _autoInc   = 0

local function GenID(prefix)
    _autoInc = _autoInc + 1
    return string.format("%s_%d", prefix or "FWS",
        CONST.AUTOINC_BASE + _autoInc)
end

local function ShowTip(msg)
    if msg and msg ~= "" then SL:ShowSystemTips(msg) end
end

function FlashWhite.Alpha()
    return _alpha
end

function FlashWhite.BindHost(node)
    _hostNode = node
end

local function EnsureLayer()
    if _whiteFx and not GUI:Widget_IsNull(_whiteFx) then
        return
    end
    if not _hostNode or GUI:Widget_IsNull(_hostNode) then
        return
    end
    _whiteFx = GUI:Layout_Create(_hostNode,
        GenID("White"), 0, 0, 0, 0, false)
    GUI:setLocalZOrder(_whiteFx, 200)
    GUI:setContentSize(_whiteFx,
        GUI:getContentSize(_hostNode))
end

-- 叠层结算：命中那一拍白层涨一档
SL:RegisterLUAEvent(LUA_EVENT_HURT_TAKEN, "FWS_Hit", function()
    EnsureLayer()
    if not _whiteFx then return 0 end
    _alpha = math.min(CONST.ALPHA_CAP, _alpha + CONST.HIT_STEP)
    return 0
end)

-- 渐隐推进：白层每一拍匀速往下褪
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        if _alpha <= 0 then return end
        _alpha = math.max(0, _alpha - CONST.FADE_SPEED * dt)
        if _whiteFx and not GUI:Widget_IsNull(_whiteFx) then
            GUI:setOpacity(_whiteFx,
                math.floor(_alpha * 255))
        end
        if _alpha <= 0 then
            SafeRemove(_whiteFx)
            _whiteFx = nil
        end
    end, 0.02)
end

local function SafeRemove(node)
    if node and not GUI:Widget_IsNull(node) then
        GUI:removeFromParent(node)
    end
end

SL:ScheduleOnce(function()
    SL:BindDebugButton("打一下", function()
        FlashWhite.Hit()
    end)
    ShowTip("技能已加载: 受击闪白 (调试按钮触发)")
end, 1.0)

function FlashWhite.Hit()
    SL:FireEvent(LUA_EVENT_HURT_TAKEN)
end

function FlashWhite.Unload()
    if _scheduler then SL:Unschedule(_scheduler) end
    SafeRemove(_whiteFx)
    _alpha = 0
end

return FlashWhite