风云突变：天气轮换触发场景增益

-- 错误：天气只是贴图切换，不挂增益
function switchWeather(picId)
    setSky(picId)
end

local WEATHER = {"sunny", "rain", "wind", "fog"}
local EFFECT = {
    sunny = {atk = 0,    spd = 0},
    rain  = {atk = -0.1, spd = 0},
    wind  = {atk = 0,    spd = 0.15},
    fog   = {atk = -0.05, spd = -0.05},
}
local cur = "sunny"
local function rollWeather()
    local w = cur
    while w == cur do
        w = WEATHER[math.random(#WEATHER)]
    end
    cur = w
    broadcast("天气转为 " .. w)
    applyMapBuff("allmap", EFFECT[w])
end