Lua帧率无关：按秒算账的步长折算

flowchart TD
A[每拍累计真实耗时] --> B{攒够一帧的时长}
B -- 是 --> C[按帧走的走一步]
B -- 否 --> D[跳过]
C --> E[按秒走的走 耗时乘速度]
D --> E
E --> A

 fx-deltatime

-- @file DeltaTime.lua
-- 帧率无关 —— 按秒算账的步长折算

local DeltaTime = {}

local CONST = {
    SPEED         = 120,
    FRAME_FPS     = 60,
    FRAME_STEP    = 2,
    WORLD_MAX     = 620,

    COLOR_BYSEC   = "#58a6ff",
    COLOR_BYFRAME = "#f0883e",

    AUTOINC_BASE  = 1151000,
}

local _fps       = 60
local _acc       = 0
local _bySec     = 40
local _byFrame   = 40

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

function DeltaTime.SetFps(fps)
    _fps = fps
    ShowTip("帧率切成" .. fps .. "——看两球分家")
end

function DeltaTime.Reset()
    _bySec = 40
    _byFrame = 40
    _acc = 0
end

function DeltaTime.Pos()
    return _bySec, _byFrame
end

-- 帧长折算与双轨推进：每拍给两条账各记各的
if not _scheduler then
    _scheduler = SL:Schedule(function(dt)
        _acc = _acc + dt
        local frameLen = 1 / _fps
        while _acc >= frameLen do
            _acc = _acc - frameLen
            _byFrame = _byFrame + CONST.FRAME_STEP
            if _byFrame > CONST.WORLD_MAX then
                _byFrame = 40
                _bySec = 40
            end
        end
        _bySec = _bySec + CONST.SPEED * dt
        if _bySec > CONST.WORLD_MAX then
            _bySec = 40
            _byFrame = 40
        end
    end, 0.02)
end

SL:ScheduleOnce(function()
    SL:BindDebugButton("切十帧", function()
        DeltaTime.SetFps(10)
    end)
    ShowTip("技能已加载: 帧率无关 (调试按钮触发)")
end, 1.0)

function DeltaTime.Unload()
    if _scheduler then SL:Unschedule(_scheduler) end
    _scheduler = nil
end

return DeltaTime