Flat Shading

Flat shading is a shading model where 3D polygons have no corrective algorithm for reflection of light. Therefore, all of the polygons reflect as a flat surface, giving a blocky look and feel to a model. Because no mathematical correction is needed for flat shading, it requires relatively little overhead when compared to more complex shading models such as Blinn-Phong or Lambert.

Consumer PC graphics accelerators quickly adopted hard-coded hardware shaders using algorithms such as Phong to make rendering these algorithms efficient; all but the earliest 3D-accelerated PC games have some sort of shader applied. However a number of earlier 3D arcade machines and consoles used flat shading, such as Virtua Fighter and the PlayStation (the latter of which also had Gourard shading available which is considered superior to flat shading but looks similar).