[JAVA][Beginning Java 8 Games Development]

Chapter 16 ■ Collision Detection: Creating SVG Polygons for the Game Actors and Writing Code to Detect Collision
When you test your collision code, you will find that you cannot get to some of these tiles! Let’s fix this next.
Go into the Bagel.java class and modify the screen boundary constants at the top of the class so that the left and
the top boundaries use the 0,0 origin values, since the Group class uses the upper-left corner of your screen as its
point of reference, rather than the center of the screen, as the StackPane does. To calculate the rightBoundary value,
you would take the WIDTH of the screen and subtract the width of the sprite using the SPRITE_PIXELS_X constant.
A similar approach would be used for the bottomBoundary value, which will take the HEIGHT of the screen and
subtract the height of the sprite using the SPRITE_PIXELS_Y constant. As you can see in Figure 16-45, we don’t have
to change the .setBoundaries() method at all, thanks to the modular, logical and organized way that we have set up
our code.
Figure 16-45. Update the Bagel.java class with new Boundary values for the right, left, bottom and top Boundary value
Before we finish up with the chapter, let’s add a scoring engine framework to our game, so that this collision
detection routine calls a scoringEngine method, in addition to playing a sound and removing the Actor from the game.
Creating a Scoring Engine Method: .scoringEngine( )
Before we finish up with this chapter, let’s put a framework in place for the scoring engine, so we can focus the entire
next chapter on game play. Create a private void scoringEngine(Actor object){} empty method right after the
checkCollision() method, and add a scoringEngine(object); method call at the end of the if(collide(object))
conditional if() structure, inside of the checkCollision() method. As you can see in Figure 16-46, you will get one wavy
gray warning highlight under the Actor object reference inside of the .scoringEngine() method declaration. This is
because the object reference has not been implemented inside of the method body.
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