Chapter 1, Let's Dive Right in…, takes you through a complete tutorial for creating a simple game complete with an introduction screen, game over screen, a score, mouse input, and sound. This tutorial serves the purpose of introducing you to Greenfoot basics, Java basics, and good programming practices.

Chapter 2, Animation, discusses how to perform animation in Greenfoot. Animation requires appropriate and well-timed image swapping as well as realistic movement around the screen. After reading the given topic and seeing an example, you will apply learned animation techniques to the game you created in Chapter 1, Let's Dive Right in….

Chapter 3, Collision Detection, discusses why collision detection is necessary for most simulations and games. You will learn how to use Greenfoot's built-in collision detection mechanisms and then learn more accurate methods to do collision detection. You will use both border-based and hidden-sprite methods of collision detection to create a zombie invasion simulation.

Chapter 4, Projectiles, talks about how actors in creative Greenfoot often have movement that can best be described as being launched. A soccer ball, bullet, laser, light ray, baseball, and firework are examples of this type of object. You will learn how to implement this type of propelled movement. You will also learn how gravity, if present, affects it by working through the implementation of a comprehensive platform game.

Chapter 5, Interactive Application Design and Theory, discusses creating engaging and immersive experiences in Greenfoot, which is far more involved than compiling a collection of programming effects into one application. In this chapter, you will learn how to engage your user by understanding the relationship between user choice and outcome, conditioning the user, and including the right level of complexity into your work. You will be shown a proven iterative development process that helps you put the theory into practice.

Chapter 6, Scrolling and Mapped Worlds, discusses how to create worlds that are much more extensive than the ones that can fit into the confines of a single screen. At the beginning of the chapter, you will code a scrolling exploration game and by the end of the chapter you will expand it into a large mapped game.

Chapter 7, Artificial Intelligence, talks about how AI, despite being a deep and complex topic, has some simple techniques you can learn to give the illusion of having intelligent, autonomous actors in your worlds. First, you will learn how to effectively use random behaviors. Next, you will implement simple heuristics to simulate intelligent behavior. Last, you will learn the A* search algorithm to allow game actors to intelligently bypass obstacles when moving between two locations on the screen.

Chapter 8, User Interfaces, discusses adding an interface to your Greenfoot scenarios. In this chapter, you will learn how to communicate with your user through buttons, labels, menus, and a heads-up display.

Chapter 9, Gamepads in Greenfoot, discusses the capabilities of a gamepad device and then teaches you how to set up Greenfoot to work with it. You will then add gamepad support to the game we created in Chapter 1, Let's Dive Right in…, and Chapter 2, Animation.

Chapter 10, What to Dive into Next…, gives you an opportunity to reflect on the skills you learned during the course of this book. I then go on to suggest projects you should attempt in order to continue your journey as a programmer and interactive application author.

For this book, you will need to download Greenfoot from http://www.greenfoot.org/door and install it on your computer. Greenfoot is free and works on Windows, Mac, and Linux. The Greenfoot website provides easy-to-follow installation instructions. After installation, you should work through the six simple tutorials found on http://www.greenfoot.org/doc. These tutorials can be completed in less than two hours and will give you all you need to know to get the most from this book.

If you are ready to explore the world of creative programming, then you will appreciate the methods, tips, and processes described in this book. Appropriate for Java programmers of all levels (novice to expert), it methodically guides you through topics crucial to building engaging interactive applications. You will learn how to build games, simulations, and animations through guided programming exercises.

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "As you can see, we made some really simple changes to the Enemy class."

A block of code is set as follows:

private void increaseLevel() {
  int score = scoreBoard.getValue();

  if( score > nextLevel ) {
    enemySpawnRate += 2;
    enemySpeed++;
    nextLevel += 100;
  }
}

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

  public void act() {
    if( Greenfoot.mouseClicked(this) ) {
      AvoiderWorld world = new AvoiderWorld(pad);
      Greenfoot.setWorld(world);
    }
  }

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Hit the Ok button in the New class pop-up window, and then, in the main scenario window, hit the Compile button."

Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or may have disliked. Reader feedback is important for us to develop titles that you really get the most out of.

To send us general feedback, simply send an e-mail to <[email protected]>, and mention the book title via the subject of your message.

If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide on www.packtpub.com/authors.

Now that you are the proud owner of a Packt book, we have a number of things to help you to get the most from your purchase.