雌雄双剑：一左一右一起收

fx-twinswords

local TwinSwords = {}
local KEY = { FLY = 0.55, MERGE_BONUS = 25 }
local swords = nil

local function Bezier(t, p0, c1, c2, p1)
    local u = 1 - t
    return u*u*u*p0 + 3*u*u*t*c1 + 3*u*t*t*c2 + t*t*t*p1
end

function TwinSwords.Cast(self_, target)
    if swords then return end
    SL:PlayActorAct(self_, "cast")
    local sx, sy = SL:GetValue("actorX", self_), SL:GetValue("actorY", self_)
    local tx, ty = SL:GetValue("actorX", target), SL:GetValue("actorY", target) - 58
    swords = {
        t = 0,
        top = { sx=sx+16, sy=sy-64, c1x=sx+110, c1y=sy-190, c2x=tx-120, c2y=sy-190, ex=tx, ey=ty },
        bot = { sx=sx+16, sy=sy-40, c1x=sx+130, c1y=sy+46,  c2x=tx-90,  c2y=sy+46,  ex=tx, ey=ty }
    }
    -- 雄剑晚 0.06 秒出发，抵消下弧路程短的时间差
    SL:ScheduleOnce(function() swords.bot.delayDone = true end, 0.06)
    SL:Schedule(function(dt)
        swords.t = swords.t + dt / KEY.FLY
        TwinSwords.Step(target)
    end, 0.016, "twinFly")
end

function TwinSwords.Step(target)
    local s = swords
    local tm = math.min(1, s.t)
    local tf = s.bot.delayDone and math.min(1, (s.t * KEY.FLY - 0.06) / KEY.FLY) or 0
    s.posTop = Bezier(tm, s.top.sy and 0 or 0, {x=s.top.c1x,y=s.top.c1y}, {x=s.top.c2x,y=s.top.c2y}, {x=s.top.ex,y=s.top.ey})
    if tf >= 1 and tm >= 1 and not s.merged then
        s.merged = true
        SL:UnSchedule("twinFly")
        local bonus = KEY.MERGE_BONUS
        SL:ScreenShake(0.26, 4)
        SL:ShowHitNum(target, 26 + bonus, "merge")
        SL:PlayActorAct(target, "stuck")
        SL:ShowSystemTips("同帧双命中! 合击+" .. bonus .. "%")
        SL:ScheduleOnce(function() swords = nil end, 0.5)
    end
end

return TwinSwords