The OpenGL function glClearColor establishes, in essence, the background color in our rendered image. The method is called with four float values with the the first three corresponding to the red, green and blue components of the color. The fourth parameter is the alpha component of the color. Until we study transparency and the purpose of the alpha value, we use any value such as 1.0 for this component. The background color is set to dark blue in this example. If we did not make a call to glClearColor within our program, then the default background color is used, which is black.