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So, where is all this leading? In this opening chapter, I’ve gone over some of the basics of animation. But what do you actually do with this? Well, that’s up to you.

In the following chapters, I’m going to put some tools in your hands and give you a quick lesson in how to use each one. What you build with these tools is entirely your decision. The most obvious use for much of what’s in this book would be for game creation. Games are essentially interactive animations with some goals for players to achieve. But I really want to avoid this becoming simply a games book. I have used almost all of the techniques here in some kind of professional work other than games—from horrendous 3D menus and other not-so-bad navigation systems, to advertisements and educational applications.

A word of warning: Pick up any web design book, and you’ll find a chapter telling you all about how too much animation is bad. I won’t disagree, but I’m not going to say another word about it. If you want to hang yourself with animation, I’m going to spend the next few hundred pages giving you all the rope you need!

This chapter covered just about all the basics of ActionScript needed for animation. You now know about frame loops, events, listeners, handlers, and movie clips. I’ve touched on classes, objects, and basic user interaction. That’s a lot of material! Don’t worry if some of these areas are still a little vague. I’ll be covering most of them in much more detail as I get into specific techniques, and you can always come back here to brush up on any concepts. At the very least, now you are familiar with the terms and concepts, and you’re ready to move forward.

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.

This chapter didn’t cover too much about making anything move, but it did show you a number of ways to create visual content, which you’ll learn how to animate in future chapters. Specifically, the chapter covered the following topics:

These subjects will give you the tools you need to make dynamic, expressive content for your animation, and since everything covered here is based on ActionScript, you can animate directly using all of these methods. Just use some code to create content, change the variables used in the code, and render it again.

You’ll be using many of the techniques introduced in this chapter throughout the book, so it will be useful for you to know and understand them well now. In fact, you’ll get your first hands-on experience using several of these techniques in the next chapter, which covers velocity and acceleration.

This chapter covered basic velocity and acceleration, the two factors that will make up the vast majority of your scripted animations. You’ve learned about vectors and vector addition. You’ve seen how to accomplish velocity on a single axis, two axes, and on an angle by converting it to its x and y components. And you’ve learned about acceleration—how it relates to velocity and how to apply it to a single axis, two axes, or an angle.

The biggest thing to take from this chapter is a basic understanding of the application of acceleration and velocity, as described in the following steps:

In the next chapter, you’ll build on these concepts, adding some environmental interaction with bouncing and friction.

This chapter covered an object’s interaction with its own environment. Specifically, an object’s interaction with the edges of its universe and the universe itself. You learned the possible ways to deal with an object that has gone off the edge of the world, including removing, regenerating, wrapping, and bouncing. And, you now know more about friction than you probably ever wanted to know. But with these simple techniques, you can make the objects in your movies move with a great deal of realism. In the next chapter, you’ll delve into allowing the user to interact with the objects.

While this was not a long chapter, it covered some extremely valuable ground, and made some great headway in interactivity. By now, you should be able to drag any object, drop it, and throw it.

Most important, you’ve worked with a lot of the small details that go into doing a really professional job with interactivity. In future chapters, you’ll be looking at many other ways of allowing the user to interact with objects in your movies. The complexity is going to start building up fast, but if you have these basics down, you’ll do great.

This chapter covered the two basic techniques of proportional motion: easing and springing. You’ve learned that easing is proportional motion and springing is proportional velocity, and you should have a very good understanding of how to apply both of these techniques.

I hope that you now understand why I get so excited about springs, and that you have begun to play with them and create some really fun and interesting effects yourself.

Now that you’ve learned all sorts of ways of moving things around, let’s move on to the next chapter, where you’ll find out what to do when they start hitting each other!

This chapter covered just about everything you need to know about collision detection, including the built-in hitTest function in all its variations, distance-based collision checking, and how to efficiently track collisions among many objects. You should know the pluses and minuses of each method, and situations where each works well or does not perform satisfactorily. You’ll be using all of this material as you move forward in the book, and no doubt, you’ll be using it extensively in your own projects.

In the next chapter, you’ll find out what to do to create a realistic reaction to the collisions you have now detected.

As you’ve seen in this chapter, coordinate rotation can give you some very complex behavior, but it all boils down to a couple of formulas that never change. Once you’re comfortable with the formulas, you can use them anywhere. I hope you’re starting to see how you can create very complicated and richly realistic motion just by adding in more and more simple techniques.

You’ll be using the coordinate rotation formula quite a bit in the next chapter, where you’ll learn how to handle the results of collisions of objects with different velocities and masses.