Normal mapping is an application of bump mapping, and was introduced by Peercy et al. [2]. While bump mapping perturbs the existing surface normals of an object, normal mapping replaces the normals entirely. A normal map is a texture that stores normals. These normals are usually stored as unit-length vectors with three components: X, Y and Z. Normal mapping has significant performance benefits over bump mapping, in that far fewer operations are required to calculate the surface lighting.
MVARTS 