球谐函数的demo，将球谐函数可视化，加深对球谐函数的理解，对高级光照打下坚实数学基础。

我费了好大得劲，也是我在别人代码的基础上改的。-Spherical harmonics demo ball harmonic function visualization, understanding spherical harmonics, advanced lighting and lay a solid mathematical foundation. I take a great handy, I changed on the basis of someone else' s code.