Trigonometry for Animation

Summary

This chapter covered nearly all the trigonometry you will need for animating in ActionScript. There is one principle, called The Law of Cosines, that I left out for now, as it is a lot more complex and deals with triangles that are not right triangles (they have no angle measuring 90 degrees). If you are now addicted to trig and just can’t get enough, you can jump ahead to Chapter 14, which covers inverse kinematics, where trig really comes in handy.

But, for now, you know about sine, cosine, and tangent and their opposites: arcsine, arccosine, and arctangent, as well as the ActionScript methods to calculate each one.

Best of all, you got some hands-on experience using most of them in ActionScript, with some of the most common real-life uses of them. As you move through the book, you’ll see many more ways in which these techniques become useful. But you now have a solid footing with the concepts, and when you come across those examples, you should have no problem understanding them or how they work.

The next chapter covers some of the more common rendering techniques for getting graphics on the screen, including the all-important drawing API. As you go through that chapter, see if you can find ways to use the rendering methods to visualize some of the trig functions you’ve learned here. I’m sure you’ll have no trouble creating some beautiful pictures or animations with trigonometry.