世界BOSS：屏幕顶上的多段大血条

boss-hp

local BOSS_SEG      = 5          -- 5 个阶段
local SEG_HP        = 100        -- 每段血量
local SEG_COLORS    = { blue, green, gold, orange, red }

function BossHudBar:getSeg()
    return math.max(1, math.ceil(self._hp / SEG_HP))
end

function BossHudBar:draw(bar)
    local totalW = bar:getContentSize().width
    local fillW  = totalW * math.max(0, self._displayHp) / (BOSS_SEG * SEG_HP)

    for s = 1, BOSS_SEG do                        -- 先铺五段底色
        bar.segs[s]:setColor(SEG_COLORS[s])
    end
    bar.fillMask:setContentSize(width = fillW)    -- 总宽度填充穿越到哪段哪段亮

    local seg = self:getSeg()
    if seg < self._lastSeg then                   -- 跨段: 白闪 + 震屏 + 换阶段技能
        bar:playSegFlash()
        global.Facade:sendNotification(global.NoticeTable.ScreenShake, {level = 1})
        self._boss:EnterPhase(seg)
    end
    self._lastSeg = seg
end

function BossHudBar:onTick(dt)                    -- 显示血量向逻辑血量收敛
    self._displayHp = self._displayHp + (self._hp - self._displayHp) * math.min(1, dt * 7)
end