ShadedQuad-PerVertexLighting
http://en.wikibooks.org/wiki/GLSL_Programming/GLUT/Diffuse_Reflection
http://en.wikibooks.org/wiki/GLSL_Programming/GLUT/Specular_Highlights
![사용자 삽입 이미지](http://dis.dankook.ac.kr/lectures/cg13/attach/1/4743697385.png)
ShadedQuad-PerPixelLighting
http://en.wikibooks.org/wiki/GLSL_Programming/GLUT/Smooth_Specular_Highlights
![사용자 삽입 이미지](http://dis.dankook.ac.kr/lectures/cg13/attach/1/1282164251.png)