Choosing Between RGBA and Color-Index Mode

In general, use the RGBA mode for your OpenGL applications; it provides more flexibility than the color-index mode for effects such as shading, lighting, color mapping, fog, antialiasing, and blending.

Consider using the color-index mode in the following cases:

• If you have a limited number of bitplanes available; the color-index mode can produce less-coarse shading than the RGBA mode.
• If you are not concerned about using "real" colors; for example, using several colors in a topographic map to designate relative elevations.
• When you're porting an existing application that uses color-index mode extensively.
• When you want to use color-map animation and effects in your application. (This is not possible on true-color devices.)