Another, generally offline method interpolates the colors themselves rather than normal vectors; those two methods are named for (*) Gouraud and Phong, both of which are more advanced than the "flat" type which is constant for the whole polygon and therefore does not need to repeatedly use the illumination model.
In one language, objects that do this task take on one of several enum values including TESS_CONTROL and TESS_EVALUATION. This process is usually combined with a "diffuse" process that utilizes a cosine law relating intensity and angles named for Lambert. A popular language used for this task is RenderMan, and a reasonably fast method of doing this calculates vertex normals and then interpolates the vertex's value across adjacent faces. Another, generally offline method interpolates the colors themselves rather than normal vectors; those two methods are named for (*) Gouraud and Phong, both of which are more advanced than the "flat" type which is constant for the whole polygon and therefore does not need to repeatedly use the illumination model. For 10 points, name this process in computer graphics by which objects are assigned different levels of lighting.
In one language, objects that do this task take on one of several enum values including TESS_CONTROL and TESS_EVALUATION.
shading [accept word forms or descriptive answers; prompt on answers about “coloring objects”]