Book Image

Box2D for Flash Games

Book Image

Box2D for Flash Games

Overview of this book

Physics games are getting more and more popular, and Box2D is the best choice if you are looking for a free, stable and robust library to handle physics. With Box2D you can create every kind of 2D physics game, only coding is not the fun part, but the game itself. "Box2D for Flash Games" will guide you through the process of making a Flash physics game starting from the bare bones and taking you by hand through complex features such as forces, joints and motors. As you are learning, your game will have more and more features, like the physics games you are used to playing. The book analyzes two of the most played physics games, and breaks them down to allow readers to build them from scratch in a step-by-step approach. By the end of the book, you will learn how to create basic primitive bodies as well as complex, compound bodies. Motors will give life to cars, catapults and siege machines firing bullets, while a complete collision management will make your game look even more realistic. If you want to make full Flash games with physics, then Box2D for Flash Games will guide you through the entire process of making a Flash physics game.
Table of Contents (15 chapters)
Box2D for Flash Games
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Looping through bodies and getting their properties


The next example will build some kind of information display that monitors the idol. At every frame, we'll read the idol position, rotation, and speed. This way, you can assign events according to idol properties, such as giving a bonus if the idol did not fall down, or if it never reached a certain y-speed, or if it moved too far on the left, and so on. Knowing body properties is also very useful when you want to skin your game, as you can synchronize custom graphic assets to what happens in the Box2D World.

One step at time, let's start with our idol monitor. We are going to display idol data in a dynamic text field, so we need to make some basic changes to our class. I won't explain such changes as they are simple AS3 routines you should already know.

  1. First, we import the required classes to dynamically generate a text field and give it some style:

    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import...