如何实现camera四周变红的效果

[GLDZPang (HandsomeBoy1690)]

玩家被击现在实现了camera震动，但不够明显，想多做一个四周变红的效果，如何实现呢

[317529039 (let MyWife = new DoubleWife() But I want more wife -Harem 3000 girls)]

美术出个镂空图

[836518683 (Harvey)]

拿个图片一蒙