Thomas, 2008-06-18, "Character version 2.0"

[Thomas]

In "normal" rendering called Forward Rendering you check what models a light intersects, render these, then check what models intersects with the next light render these and so on.

In deferred shading one renders all models to a special G-Buffer (which is bunch or textures storing normals, color, depth, etc). Now using this G-buffer one iterates the lights and draws them according to the information the G-buffer.

My main reasons for using deferred shading is because it makes it easier to maintain shader combinations, is faster when rendering many small (as in screen coverage) lights and makes it easier for the artist to optimize.