扫堂光纹：光柱贴地横扫，扫到哪烧到哪

flowchart TD
A[点引光] --> B[光柱落在最左]
B --> C[匀速往右扫]
C --> D{光压着怪了吗}
D -- 压着 --> E[每零点二秒烧六]
D -- 没压着 --> C
E --> F{光扫尽了吗}
F -- 没有 --> C
F -- 扫尽 --> G[收光 十秒后再引]

-- @file CrestBeam.lua
-- 扫堂光纹 —— 光柱贴地横扫 扫到哪烧到哪

local CrestBeam = {}

local CONST = {
    SWEEP_SPEED   = 300,
    BEAM_HALF     = 32,
    BURN_TICK     = 0.2,
    BURN_DMG      = 6,
    BEAM_CD       = 10,

    AUTOINC_BASE  = 1204600,
}

local _x        = 60
local _on       = false
local _tick     = 0
local _cd       = 0
local _autoInc  = 0

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

local function GenID()
    _autoInc = _autoInc + 1
    return CONST.AUTOINC_BASE + _autoInc
end

function CrestBeam.Pos() return _x end

-- 引光: 光柱落在最左
function CrestBeam.Summon()
    if _cd > 0 then
        ShowTip("天光还没聚——再等" .. math.ceil(_cd) .. "秒")
        return
    end
    _cd = CONST.BEAM_CD
    _on = true
    _x = 60
    _tick = 0
    ShowTip("天光垂落——横扫开始")
end

-- 每拍推进: 压身即烧 扫尽即收
if not _ticker then
    _ticker = SL:Schedule(function(dt)
        if _cd > 0 then _cd = _cd - dt end
        if not _on then return end
        _x = _x + CONST.SWEEP_SPEED * dt
        _tick = _tick - dt
        if _tick <= 0
            and math.abs((SL:GetValue("mobX") or 0) - _x)
                < CONST.BEAM_HALF then
            _tick = CONST.BURN_TICK
            ShowTip("光压着了——烧" .. CONST.BURN_DMG)
        end
        if _x > 800 then
            _on = false
            ShowTip("光扫尽——十秒后再引")
        end
    end, 0.02)
end

SL:ScheduleOnce(function()
    SL:BindDebugButton("引光!", function()
        CrestBeam.Summon()
    end)
    ShowTip("技能已加载: 扫堂光纹")
end, 1.0)

function CrestBeam.Unload()
    if _ticker then SL:Unschedule(_ticker) end
    _on = false
end

return CrestBeam