Blinn Bump Mapping = True Reflective Bump Mapping
GeForce2 as well as ATi's Radeon are already able to do some really nice dot3 bump mapping , which requires a special texture, the normal map. This normal map gives each pixel of the surface (triangle) a new surface vector (normal), creating a 'geometrically non-existent but real looking' bumpy surface on a smooth triangle. The pixel rendering unit of GeForce2, also called NSR = 'NVIDIA Shading Rasterizer' is however unable to do a look-up in a cubic environment map to add reflection to the bumped surface.
GeForce3's Pixel Shader is finally able to do true reflective bump mapping, also known as Blinn bump mapping. After the Vertex Shader has done the per-vertex dot3 setup and supplied the Pixel Shader with basis vectors for the transform of the bump map, the Pixel Shader generates a reflection vector out of the normal and the eye vector which looks into a cubic environment map to create the reflection.
'Blinn bump mapping' is almost as realistic as it gets.
