Normalmap



Normal maps are images that store per-pixel surface normals directly in the RGB values of an image. Properly done normalmaps can dramatically increase object detalisation without adding more polygons.

Therefore, normalmaps have a bunch fo limits and quirks:


 * Tangentspace normalmap is based on vertex normals, if vertex normals is adjusted, normalmap is outdated.
 * There is DirectX and OpenGL normalmap format, should figure out what format tool is producing and fix normalmap if it doesnt fit.
 * UV seams and 'hard edges' produced by vertex normals is tricky.
 * Normalmappers have a couple of quirks (aliasing, noise).

Recommended articles on normalmaps:
 * Polycount Wiki
 * Normalmaps for the Technical Game Modeler

In Darkplaces engine, normalmaps are:
 * Tangent-space RGB
 * OpenGL-oriented (X stores horizontal, Y vertical)
 * Optionally can store alpha component which represents height that will be used for parallax mapping.
 * Compressed to DXT1 (if not alpha) or DXT5