【进阶实战】Lua线性插值：烈火剑法伤害800到1200的平滑爬升

local function buffUp(actor)
    setplayvar(actor, "FIRE_DMG", 1200)   -- 800直接跳1200，瞬变
end

local function stepDmg(actor, t, dt)
    t = math.min(t + dt / 3, 1)          -- 3秒走完，钳在1内
    local v = math.floor(800 + (1200 - 800) * t)
    setplayvar(actor, "FIRE_DMG", v)
    if t >= 1 then
        sendmsg(actor, 1, "烈火剑法伤害到位 " .. v)
    end
    return t
end