20180219reference

reference from internet:

1.Aritra , 2014. Python/matplotlib : plotting a 3d cube, a sphere and a vector? Available  at: <https://stackoverflow.com/questions/11140163/python-matplotlib-plotting-a-3d-cube-a-sphere-and-a-vector> [Accessed 24  January 2018].
2. 当耐特,2013. 码农干货系列【10】--光线追踪进阶:javascript玩转3D纹理映射. at: <http://blog.csdn.net/qq_33274326/article/details/54607173> [Accessed 24  January 2018].
3.CSDN.net,2017. 图形学基础（1）——光线追踪. at: <http://blog.csdn.net/qq_33274326/article/details/54607173> [Accessed 24  January 2018].

book:
4. Lengyel, E., 2012. Mathematics for 3D game programming and computer graphics. Cengage Learning.