Unity3D Projector的应用

参考网址：
http://blog.sina.com.cn/s/blog_471132920101hhsd.html
https://blog.csdn.net/winchyy/article/details/51564489
https://www.jianshu.com/p/1fade1e8c309
https://docs.unity3d.com/Manual/class-Projector.html
http://qiankanglai.me/2016/11/14/unity-projector/index.html //分析与shadowmap优劣比较
http://www.dreamfairy.cn/blog/2018/11/19/unity-projector-opmize/