GLSL - Normal maps

http://www.ozone3d.net/tutorials/normal_map.php

- Normal-map, also called bump-map, is a texture in which each texel (texel = texture element) contains a normal XYZ vector. In an usual texture, still called color-map, diffuse-map or base-map, each texel contains a RGB color. Fundamentally, there is no difference between a normal-map and a color-map except the interpretation which is given to the texels.

- The normal vector contained in a texel of a normal-map represents the vector perpendicular to the surface of an object on the considered texel. In this quite particular case, the normal vector has the {0.0, 0.0, 1.0} triplet as XYZ components.



- The main use of a normal-map is the (per pixel) description of an object's surface. This very accurate description, as it is made at a pixel level, is used in the bump mapping and per pixel lighting algorithms.

- The Photoshop plugins provided by nVidia to create a normal-map may be downloaded from the following page: Adobe Photoshop Plug-ins.