CMSC 425 : Lecture 4 More about OpenGL and GLUT

Idealized Drawing Window: Because we generally do not have complete control over the window size, it is a good idea to think in terms of drawing on a rectangular idealized drawing region, whose size and shape are completely under our control. Then we will scale this region to fit within the actual graphics window on the display. There are many reasons for doing this. For example, if you design your program to work specifically for 400 × 400 window, but then the user resizes the window, what do you do? It is a much better idea to assume a window of arbitrary size. For example, you could define two variables w and h, that indicate the width and height of the window, respectively. The values w and h could be measured in whatever units are most natural to your application: pixels, inches, light years, microns, furlongs or fathoms.