Gamma校正

http://www.manew.com/forum.php?mod=viewthread&tid=105872

https://blog.csdn.net/game_fengxiaorui/article/details/79268558

https://www.colortell.com/2424.html

https://blog.csdn.net/candycat1992/article/details/46228771

Gamma模拟Linear的Shader

https://blog.csdn.net/t163361/article/details/80148449