Normal Mapping

Normal maps provide an easy way to give the illusion of very complex geometry in the rendered scene without the memory and computational impact of actually having to represent that geometry using vertices.

The implementation was straightforward and I did not encounter any major issues, since the vector provided in the normal texture just replaces the shading normal computed by the intersection routine.

The two images given below illustrate the difference a normal map can make.

In my final render, this can be best observed on the bark:

The left image shows the render without any normal maps, for the right image the normal map was enabled.