[JAVA][Beginning Java 8 Games Development]

Chapter 13 ■ Animating Your Action Figure States: Setting the Image States Based on KeyEvent Processing
Summary
In this thirteenth chapter, we implemented sprite animation across the InvinciBagel application using highly
optimized code. We combined seven basic sprite shapes with the key movement that we developed in Chapter 11 and
the boundary detection that we developed in Chapter 12 to create a fully animated InvinciBagel character that really
comes alive, and does so based on the use of six basic game play control keys (up, down, left, right, W, and S).
We learned how to use the JavaFX ImageView class ScaleX property with its special -1 use case setting to flip or
mirror the Image asset that is inside of the ImageView “Image container” around the Y axis. This allows us to create
36 sprite image states using only 9 basic sprite states, which we have imported as Image assets, into a List
ArrayList object. This is a form of optimization, as it allows us to use less than 84KB of image assets instead of 336KB
of Image assets for our primary game superhero, the InvinciBagel character.
Next, we learned how to implement a Boolean animator variable, which we used to animate between two
different sprite cel run states, imageStates(1) and imageStates(2) in our List. The resulting run cycle was too rapid for
professional use, so next, we then added a framecounter variable, to slow the movement down, and a runningspeed
variable, allowing us to implement a fine-tuned control over the sprite’s running speed, which we will be able to take
advantage of in later on in our game play logic.
Next we optimized our code so that the variables and processing code used for the run cycle were not used if the
run cycle was not showing, that is, if the InvinciBagel is flying or landing. We also made sure to set the isFlipH property
in our Actor superclass (and therefore in our Bagel object) using the this.setIsFlipH() method call.
Next we added four new game play control keys in our event handling code in the InvinciBagel.java class, and
added four new private Boolean variables aKey, sKey, dKey, and wKey, and had NetBeans create Getter and Setter
methods for them automatically. After we made that enhancement, we added the sprite evade action image to the S
key and the sprite jump over action image to the W key to make our game a two-hand game and to get ready to make
the game prepared to use professional game controller hardware.
Finally, we tested this new sprite animation code with the rest of the event handling, Actor and Hero class,
CastingDirector class, GamePlayLoop class, and Bagel class sprite movement and boundary code that we have written
over the previous six chapters (Chapters 7 through 12). Our sprite movement and animation work together seamlessly
to provide a professional result when navigating our InvinciBagel character around the game play Stage.
In the next chapter, we are going take a look at how to add fixed game sprite (Prop Actor) objects into the game,
so that we have something to work with when we get into collision detection, and so we can start to really use our
recent CastingDirector class.
298
www.it-ebooks.info