In a lot of ways, all that old software rasterizing theory is even more relevant now, because shader languages really don't give you very much. They can convert

In a lot of ways, all that old software rasterizing theory is even more relevant now, because shader languages really don't give you very much. They can convert polygons into screen fragments, but it's up to you to figure out projection, mapping, lighting, and everything else. It makes advanced techniques infinitely easier. There is stuff you just couldn't do on the fixed function pipeline without a vendor-specific extension. But it makes for a huge learning curve for simple stuff. For that reason, I general suggest people start with a game engine like Unity or PlayCanvas, or if they are already experienced programmers, a scene graph like Three.js.