Computer graphics

:For the ACM SIGGRAPH journal, see Computer Graphics.

Shading

The process of shading (in the context of 3D computer graphics) involves the computer simulating (or more accurately; calculating) how the faces of a polygon will look when illuminated by a virtual light source. The exact calculation varies depending on not only what data is available about the face being shaded, but also the shading technique.

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• Flat shading: A technique that shades each polygon of an object based on the polygon's "normal" and the position and intensity of a light source.
• Gouraud shading: Invented by Henri Gouraud in 1971, a fast and resource-conscious technique used to simulate smoothly shaded surfaces by interpolating vertex colors across a polygon's surface.
• Texture mapping: A technique for simulating surface detail by mapping images (textures) onto polygons.
• Phong shading: Invented by Bui Tuong Phong, a smooth shading technique that approximates curved-surface lighting by interpolating the vertex normals of a polygon across the surface; the lighting model includes glossy reflection with a controllable level of gloss.
• Bump mapping: Invented by Jim Blinn, a normal-perturbation technique used to simulate bumpy or wrinkled surfaces.
• Ray Tracing: A method based on the physical principles of geometric optics that can simulate multiple reflections and transparency.
• Radiosity: a technique for global illumination that uses radiative transfer theory to simulate indirect (reflected) illumination in scenes with diffuse surfaces.
• Blobs: a technique for representing surfaces without specifying a hard boundary representation, usually implemented as a procedural surface like a Van der Waals equipotential (in chemistry).