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

Creating a fixture


A fixture is used to bind the shape on a body, and to define its material setting density, friction, and restitution. Don't worry about materials at the moment, and let's focus on the fixture.

  1. The first step is to create the fixture:

    var fixtureDef:b2FixtureDef = new b2FixtureDef();
    fixtureDef.shape=circleShape;

    Once we have created the fixture with the constructor, we assign the previously created shape using the shape property.

  2. Finally we are ready to add the ball to the world:

    var theBall:b2Body=world.CreateBody(bodyDef);
    theBall.CreateFixture(fixtureDef);

    b2Body is the body itself: the physical, concrete body that has been created using the bodyDef attribute.

  3. To recap, use the following steps when you want to place a body in the world:

    i. Create a body definition, which will hold body information such as its position.

    ii. Create a shape, which is how the body will look.

    iii. Create a fixture to attach the shape to the body definition.

    iv. Create the body itself in the world...