Draw a point with a mouse click

Using GLUT, I want to be able to draw a point with a left-click of the mouse, but I’m not sure how to do it. The x and y coordinates in glutMouseFunc are window coordinates, not vertex coordinates, so how do I translate them so that a point will be drawn exactly where I click the mouse?

Never mind, I figured it out. I found the answer on page 286 of the OpenGL redbook(newest edition).