IBL 없이 광원만 고려할 시

https://youtu.be/xuvTx66uoxs?si=EjIPUK7ik8M-ng1a

IBL 반영

http://youtube.com/watch?v=BSy7VlGQJa8&feature=youtu.be

PBR Model

https://youtu.be/dldauGfPlHU?si=JZvoKmGMX2LdnJfF