Lua引力球：丢出去把怪吸过来

flowchart TD
A[丢球落地] --> B[球体激活 计时开始]
B --> C[逐拍扫周围的怪]
C --> D{怪在吸力范围内}
D -- 是 --> E[朝球方向推进]
D -- 否 --> F[不受力 原地不动]
E --> G{计时归零}
F --> G
G -- 是 --> H[球消散 怪停]

 fx-gravityball

-- @file GravityBall.lua
-- 引力球 —— 丢出去把怪吸过来

local GravityBall = {}

local 参数配置 = {
    BALL_LIFE     = 3.0,
    PULL_RANGE    = 200,
    PULL_SPEED    = 80,
    BALL_RADIUS   = 18,

    AUTOINC_BASE  = 1168000,
}

local _ballOn    = false
local _ballT     = 0
local _ballX     = 0
local _ballY     = 0
local _scheduler = nil
local _autoInc   = 0

local function GenID(prefix)
    _autoInc = _autoInc + 1
    return string.format("%s_%d", prefix or "GRB",
        参数配置.AUTOINC_BASE + _autoInc)
end

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

function GravityBall.Active()
    return _ballOn
end

-- 吸力推进：球活着的每一拍推周围的怪
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        if not _ballOn then return end
        _ballT = _ballT - dt
        local mobs = SL:EnumMobsInRange(_ballX, _ballY,
            参数配置.PULL_RANGE)
        for _, mob in ipairs(mobs) do
            local mp = SL:GetPosition(mob)
            if mp then
                local dx = _ballX - mp.x
                local dy = _ballY - mp.y
                local d = math.sqrt(dx * dx + dy * dy)
                if d > 25 then
                    SL:SetPosition(mob,
                        mp.x + dx / d * 参数配置.PULL_SPEED * dt,
                        mp.y + dy / d * 参数配置.PULL_SPEED * dt)
                end
            end
        end
        if _ballT <= 0 then
            _ballOn = false
            ShowTip("引力球散了——怪停在原地")
        end
    end, 0.02)
end

function GravityBall.Cast(x, y)
    if _ballOn then return end
    _ballOn = true
    _ballT = 参数配置.BALL_LIFE
    _ballX = x
    _ballY = y
    SL:PlayBallUpFx(x, y)
    ShowTip("引力球丢出去了——周围的怪被吸过来")
end

SL:ScheduleOnce(function()
    SL:BindDebugButton("丢球", function()
        GravityBall.Cast(330, 150)
    end)
    ShowTip("技能已加载: 引力球 (调试按钮触发)")
end, 1.0)

function GravityBall.卸载()
    if _scheduler then SL:Unschedule(_scheduler) end
    _ballOn = false
end

return GravityBall