G

gamma correction

A function applied to colors stored in the frame buffer to correct for the nonlinear response of the eye (and sometimes of the monitor) to linear changes in color-intensity values.

geometric model

The object-coordinate vertices and parameters that describe an object. Note that OpenGL doesn't define a syntax for geometric models, but rather a syntax and semantics for the rendering of geometric models.

geometric object

A geometric model.

geometric primitive

A point, line, or polygon.

Gouraud shading

Smooth interpolation of colors across a polygon or line segment. Colors are assigned at vertices and linearly interpolated across the primitive to produce a relatively smooth variation in color. Also called smooth shading.

group

A group of one, two, three, or four elements that represents each pixel of an image in client memory. Thus, in the context of a client memory image, a group and a pixel are the same thing.