WINDOW MECHANICS

[Angel, p.96]

One must always begin by clearing the window:

glClearColor(0.0, 0.0, 0.0, 0.0); glClear(GL_COLOR_BUFFER_BIT);

-- The first sets the color for clearing (here it is black).
-- The second clears the frame buffer. If you want to also clear the depth buffer, do instead:

glClear(GL_COLOR_BUFFER_BIT \| GL_DEPTH_BUFFER_BIT);

You may need to force the primitives to be written by calling

glFlush();

If you need to synchronize with the flushing (E.g., you do not want to accept user inputs until all the drawing has appearing on the screen), issue the stronger command

glFinish();

To make sure that hidden surfaces are removed, call

glEnable(GL_DEPTH_TEST);

-- Also make sure taht the depth buffer is cleared in the beginning (see above).

You may want to begin by specifying the drawing colors, using glColor3f(r,g,b).