风铃：风过五音错落

fx-windchime

local WindChime = {}
local KEY = { DECAY = 2 }

local chimes = {}

function WC.Init()
    for i = 1, 5 do
        chimes[i] = {
            swing = 0,
            sway = math.random() * 6.28,
            tubeLen = 34 + i * 6 % 18,      -- 长短错落
            tone = i
        }
        SL:HangChime(i, 130 + i * 100)
    end
end

function WC.Tick(dt)
    local wind = SL:GetValue("windPower") or 12
    for _, c in ipairs(chimes) do
        c.sway = c.sway + dt * (1.4 + wind / 30)
        -- 摆幅: 风力推动 + 指数衰减
        c.swing = c.swing * (1 - dt * 2)
                    + math.sin(c.sway * 1.6) * wind / 60
        SL:SetFxPos("chime" .. c.tone,
            SL:GetValue("hangX", c.tone) + c.swing * 26,
            SL:GetValue("hangY", c.tone))
        -- 摆幅过界: 相击发声
        if math.abs(c.swing) > 0.5 and not c.ringing then
            c.ringing = true
            c.ringT = 0.3
            SL:PlayFxAt("chime_ring", SL:GetValue("chimeX", c.tone),
                                    SL:GetValue("chimeY", c.tone))
            SL:PlaySfx("chime", c.tone)
        elseif c.ringing then
            c.ringT = c.ringT - dt
            if c.ringT <= 0 then c.ringing = false end
        end
    end
end

function WC.Gust()
    SL:SetValue("windPower", SL:GetValue("gustPower") or 60)
    SL:SetValue("gustT", 1.2)     -- 一阵风持续一点二秒
end

return WC