火把视野：黑暗地图里的光圈世界

torch-light

local darkNodeManager = {}

local MAX_LIGHTS = 6                        -- 光源上限: 超出回收最早

function darkNodeManager:createNode(param)
    local node = { x = param.x, y = param.y, r = param.r, w = param.w }
    table.insert(self._lightNodes, node)
    if #self._lightNodes > MAX_LIGHTS then
        table.remove(self._lightNodes, 1)   -- 池化思想: 最老的先让位
    end
    self._dirty = true                      -- 遮罩需要重绘
    return #self._lightNodes                -- 返回下标用作 removeNode 的句柄
end

function darkNodeManager:removeNode(handle)
    table.remove(self._lightNodes, handle)
    self._dirty = true
end

function darkNodeManager:drawMask(maskCanvas)
    -- 先铺黑, 再逐光源 destination-out 挖洞
    maskCanvas:clear()
    maskCanvas:fillSolid(2, 4, 10, 0.94)
    for _, light in ipairs(self._lightNodes) do
        local breath = math.sin(os.clock() * 7 + light.y) * 6   -- 火光呼吸
        maskCanvas:punchRadial(light.x, light.y, light.r + breath)
    end
end