NEXT s.Lim Computer Graphics OpenGL practice

References

1. OpenGL with C++ class
   http://stackoverflow.com/questions/3589422/using-opengl-glutdisplayfunc-within-class

2. OpenGL doesn't support solidsphere with texture mapping
   http://stackoverflow.com/questions/8251911/texturing-a-glutsolidsphere

3. OpenGL load .obj file
   http://www.opengl-tutorial.org/beginners-tutorials/tutorial-7-model-loading/