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.