[JAVA][Beginning Java 8 Games Development]

Chapter 17 ■ Enhancing Game Play: Creating a Scoring Engine, Adding Treasure and an Enemy Auto-Attack Engine
Figure 17-26. Install the skyCloud background Image (left), and use a .toBack() method call to set proper
z-index (right)
Since we want to have our background image at the lowest (zero) z-index so it will be behind all of our game play
assets, but also have all the splashscreen assets at the highest z-index, so that those image plates will cover (be in front
of) all of our game play assets, we normally would have to implement yet another ImageView compositing plate, to
be able to do this. However, there is a handy set of z-index related Node class methods that will allow us to use the
SplashScreenBackplate ImageView object to hold both the game splashscreen and a game background image plate at
the same time! This is one of the ImageView Node optimizations that I wanted to implement to keep our game Nodes
at a minimum, to reduce memory and processing overhead. The code to place the ImageView behind our game assets
will call the .toBack() method off of the SplashScreenBackplate ImageView Node object, which relocates that Node
to the Back (Bottom layer) of the JavaFX Scene Graph Node Stack. This is the equivalent of setting this Node’s z-index
to zero. The Java statement can be seen highlighted in light blue at the top of Figure 17-26, and the completed Java
code for your gameButton.setOnAction((ActionEvent)->{} event handling structure should look like the following:
gameButton.setOnAction((ActionEvent) -> {
splashScreenBackplate.setImage(skyCloud);
splashScreenBackplate.setVisible(true);
splashScreenBackplate.toBack();
splashScreenTextArea.setVisible(false);
});
As you probably realize by now, we’ll need to “counter” this move in the other three Button event handling
structures. We will use the opposite of the .toBack() method call, which is of course the .toFront() method call. As you
can see, we need to not only call the .toFront() method off of the splashScreenBackplate ImageView Node object, but
also off of the splashScreenTextArea ImageView object, and the buttonContainer HBox object that is holding our UI
Button controls. We will need to call this method off of all of these Splashscreen and UI objects so that all of these are
brought back to the front of the JavaFX Scene Graph Node Stack. The Java code, shown in Figure 17-27, looks like this:
helpButton.setOnAction((ActionEvent) -> {
splashScreenBackplate.setImage(splashScreen);
splashScreenBackplate.toFront();
splashScreenBackplate.setVisible(true);
splashScreenTextArea.setVisible(true);
splashScreenTextArea.setImage(instructionLayer);
splashScreenTextArea.toFront();
buttonContainer.toFront();
});
www.it-ebooks.info
415