Plotting your revenge
Okay, so you're not really plotting your revenge. But you are plotting everything in your game as if you were putting it all down on a piece of graph paper. Remember high-school geometry? You got out your graph paper, drew a couple of lines for the X and Y axis, and the plotted points on the graph. OpenGL works in pretty much the same way.
The OpenGL coordinate system
The OpenGL coordinate system is a standard X and Y axis system that you have most likely learned all your life. You can conceptualize (0, 0) as being the center of the screen.
Let's say that we want to display a moving car on the screen. We could start by plotting our car at position (5, 5) in the coordinate plane. If we then moved the car from (5, 5) to (6, 5), then (7, 5), and so forth, the car would move to the right (and eventually leave the screen), as illustrated in the following figure:
We haven't been completely honest with you. Since OpenGL is a 3D rendering engine, there is actually...
