踏前斩：穿身而过留一条刀痕

local SteelDash = {}
local CONST = { KEY = "SteelDash", SPEED = 1600, DURATION = 0.14, HIT_W = 40 }

function SteelDash.Cast(myID, dirSign)
    SteelDash._dash = { dir = dirSign, left = CONST.DURATION, hit = {} }
end

function SteelDash:Update(dt)
    local d = self._dash
    if not d then return end
    d.left = d.left - dt
    local nx = SL:GetValue("ACTOR_POSITION_X", self._myID) + d.dir * CONST.SPEED * dt
    SL:SetActorPosition(self._myID, nx)
    for _, id in ipairs(SL:GetValue("FIND_IN_VIEW_MONSTER_LIST") or {}) do
        if not d.hit[id] then
            local mx = SL:GetValue("ACTOR_POSITION_X", id)
            if mx > math.min(d.lastX, nx) and mx < math.max(d.lastX, nx) then
                d.hit[id] = true
                SL:SendLuaNetMsg(CONST.MSG_ID, id, 0, 0,
                    SL:JsonEncode({ key = CONST.KEY, op = 2, hit = id }))
            end
        end
    end
    d.lastX = nx
    if d.left <= 0 then self._dash = nil end
end

return SteelDash