Ogre3d

SceneManager

MovableObject 

 Entity

 Camera

 Light

SceneNode

Material

 

Resource Management

ResourceGroupManager

ResourceManager

Mesh

Texture

GpuProgram

ArchiveFactory

 

Rendering

Renderable

RenderWindow

HardwareBufferManager

RenderSystem

Scene Management

This is about the contents of your scene, how it's structured, 

how it's viewed from cameras, etc. Objects in this area are 

responsible for giving you a natural declarative interface to 

the world you're building; ie you don't tell OGRE "set these 

render states and then render 3 polygons", you tell it "I want 

an object here, here and here, with these materials on them, 

rendered from this view", and let it get on with it.

Resource Management

All rendering needs resources, whether it's geometry, textures, 

fonts, whatever. It's important to manage the loading, re-use and 

unloading of these things carefully, so that's what classes in this area do.

Rendering

Finally, there's getting the visuals on the screen - this is about 

the lower-level end of the rendering pipeline, the specific rendering 

system API objects like buffers, render states and the like and pushing 

it all down the pipeline. Classes in the Scene Management subsystem 

use this to get their higher-level scene information onto the screen.