Normal map意思

"Normal map" is a term used in computer graphics, particularly in the context of 3D rendering and game development. It refers to a type of texture map that is used to add detail to a 3D model without increasing the model's polygon count.

A normal map contains information about the surface normal vectors of a 3D model. These vectors are used by the graphics engine to calculate the lighting and shading of the model. By using a normal map, artists and developers can create the illusion of detail and bumpiness on a model's surface, even if the model is relatively low in polygon detail.

Normal maps are often used in conjunction with other types of texture maps, such as diffuse maps and specular maps, to create a more realistic appearance for a 3D model. They are particularly useful for creating complex surfaces like metal, stone, and wood, where the subtle variations in surface normal direction can make a big difference in the model's appearance.