1) Asset managers - textures, geometry...
2) Scene graph for managing objects and hiearchy in the world
3) Render translation, taking scene graph objects... depth sorting, instancing etc... ready for the graphic API (OpenGL in my case)
4) Rendering, calling the API specific things to actually draw. This linear list of things to call would be figured out at the render translation stage?
Basically I'll probably need to read some books, if u have any must have suggestions let me know. Any links to useful information online is much appreciated. I'm looking for architecture level information atm, but any specifics are highly useful aswell.