[JAVA][Beginning Java 8 Games Development]

Chapter 12 ■ Setting Boundaries for Your Action Figure in 2D: Using the Node Class LocalToParent Attribute
Organizing the .update( ) Method: .moveInvinciBagel( )
Since we are going to be adding more and more Java programming logic into the .update() method of the Bagel class
during the remainder of the book, I want to put into place some “method modularization” that will be quite similar to
what we did for the InvinciBagel class in Chapter 11 when we added the six new logical method structures. Since we
will be performing a number of complex operations inside of the .update() method as the game becomes more and
more complex, it is logical that the .update() method should contain calls to other methods that logically organize
the tasks that we will need to do on each frame, such as determining keys pressed (or not pressed), moving the
InvinciBagel character, looking to see if he has gone off the screen (setting boundaries), and eventually controlling
his visual states, detecting collision, and applying physics effects. The first thing that I want to do is to “extract” the
movement of the sprite into a .moveInvinciBagel() method that will perform any translation transforms that need to
be implemented using a moveInvinciBagel(iX, iY); method call. This means that we will have to create the private
void moveInvinciBagel(double x, double y){...} method structure and place the .setTranslate() method calls
inside of it, replacing them in the .update() method with the .moveInvinciBagel() method call. The basic Java code to
perform these changes to the Bagel.java class are shown in Figure 12-13, and will look like this Java code:
@Override
public void update() {
if(invinciBagel.isRight()) { iX += vX }
if(invinciBagel.isLeft()) { iX -= vX }
if(invinciBagel.isDown()) { iY += vY }
if(invinciBagel.isUp()) { iY -= vY }
moveInvinciBagel(iX, iY);
}
private void moveInvinciBagel(double x, double y) {
spriteFrame.setTranslateX(x);
spriteFrame.setTranslateY(y);
}
Figure 12-13. Create a .moveInvinciBagel() method for .setTranslate() method calls, and call if from .update() method
Next, let’s move an iBagel on the screen using the ImageView .setTranslateX() and .setTranslateY() methods.
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