About normal map, a stupid question, or is it?
Posted: 23.05.2003, 09:36
by Beginner
Hi all you Celestia-Gurus!
Could someone explain in short, what does normal map really do, and is it necessary for doing something?
Beginner
Posted: 23.05.2003, 11:27
by selden
A "normal map" tells the graphics hardware what directions pixels are facing.
"Surface normal vectors" is the mathematical name for those directions, which is where these maps get their names. "Vectors" specify directions, "Normal" is the mathematical term for "perpendicular" and "Surface" has the standard English meaning: they're the directions which are perpendicular to the surfaces.
When the surface normal associated with a pixel points away from a light source, the graphics hardware colors the pixel darker than the pixel's texture map. When it points toward a light source, the hardware makes it brighter. As a result, this makes the surface look like it's bumpy, even though it really isn't.
This fakery is much easier to implement than a 3D model with all of the necessary self-shadowing facets.