穿心刺：一箭穿心，最大血量百分之六的穿透

 fx-heartshot

-- @file HeartShot.lua
-- 穿心刺 —— 一箭穿心 额外扣最大生命百分之六

local HeartShot = {}

local CONST = {
    ARROW_CD      = 3.0,
    ARROW_SPEED   = 320,
    HEART_PCT     = 0.06,

    COLOR_HEART   = "#e0524a",
    COLOR_DEEP    = "#6b1a2a",
    COLOR_GHOST   = "#ffb0a8",

    ZORDER_ARROW  = 133,
    ZORDER_FX     = 135,
    AUTOINC_BASE  = 981000,
}

local _arrows    = {}
local _cdLeft    = 0
local _scheduler = nil
local _autoInc   = 0

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

local function GetActorPos(id)
    if not id then return nil end
    local x = SL:GetValue("ACTOR_POSITION_X", id)
    local y = SL:GetValue("ACTOR_POSITION_Y", id)
    if not x or not y then return nil end
    return { x = x, y = y }
end

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

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

local function CreateArrowNode()
    local node = GUI:Layout_Create(GUI:Attach_SceneF(),
        GenID("Arr"), 0, 0, 0, 0, false)
    GUI:setLocalZOrder(node, CONST.ZORDER_ARROW)
    GUI:DrawLine_Create(node, "shaft", 0, 0, 2,
        -10, 0, 10, 0, CONST.COLOR_HEART, 240)
    GUI:DrawLine_Create(node, "head", 0, 0, 3,
        10, 0, 5, -3, CONST.COLOR_HEART, 240)
    GUI:DrawLine_Create(node, "head2", 0, 0, 3,
        10, 0, 5, 3, CONST.COLOR_HEART, 240)
    return node
end

-- 穿心入口
function HeartShot.Cast(myID, targetID)
    if _cdLeft > 0 then return end
    _cdLeft = CONST.ARROW_CD
    local mp = GetActorPos(myID)
    if not mp then return end
    local arrow = { x = mp.x + 16, y = mp.y - 58,
        vx = CONST.ARROW_SPEED, targetID = targetID,
        node = CreateArrowNode() }
    table.insert(_arrows, arrow)
end

-- 定时器：弹道推进与穿心判定
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        _cdLeft = math.max(0, _cdLeft - dt)
        for i = #_arrows, 1, -1 do
            local a = _arrows[i]
            a.x = a.x + a.vx * dt
            local tp = GetActorPos(a.targetID)
            if tp and math.abs(a.x - tp.x) < 18 then
                local maxHp = SL:GetValue("ACTOR_MAX_HP",
                    a.targetID)
                local dmg = math.floor(maxHp * CONST.HEART_PCT)
                SL:ActorHurt(a.targetID, dmg)
                SL:TipAbove(a.targetID, "-" .. dmg)
                SafeRemove(a.node)
                table.remove(_arrows, i)
            elseif a.x > 700 then
                SafeRemove(a.node)
                table.remove(_arrows, i)
            end
        end
    end, 0.02)
end

return HeartShot