OpenGL Programming Guide

Chapter 5Color

Specifying a Color and a Shading Model

OpenGL maintains a current color (in RGBA mode) and a current color index (in color-index mode). Unless you're using a more complicated coloring model such as lighting or texture mapping, each object is drawn using the current color (or color index). Look at the following pseudocode sequence:

set_color(RED);
draw_item(A);
draw_item(B);
set_color(GREEN);
set_color(BLUE);
draw_item(C);

Items A and B are drawn in red, and item C is drawn in blue. The fourth line, which sets the current color to green, has no effect (except to waste a bit of time). With no lighting or texturing, when the current color is set, all items drawn afterward are drawn in that color until the current color is changed to something else.

Specifying a Color in RGBA Mode
Specifying a Color in Color-Index Mode
Specifying a Shading Model

OpenGL Programming Guide