In the time I worked on computer graphics (late 90s to early 2000s) I had lots of fun learnign to render basic lighting effects in OpenGL using shadow mapping which includes a clever application of the depth buffer. It was also enough to convince me that techniques short of ray casting would always be ugly hacks.
I am actually really impressed with the current state of the art for real time rasterization: cascaded shadow maps + global illumination or even just screen space ambient occlusion. I feel it comes close enough in most scenes. At least when the purpose is to look pretty and not stand out as obviously wrong while playing a game. The cases where it fails are mainly the pathological ones such as caustics.
That said, it is still amazing how big the actual gap is between this and ray tracing when carefully analysing a complex scene.
