[JAVA][Beginning Java 8 Games Development]

Chapter 17 ■ Enhancing Game Play: Creating a Scoring Engine, Adding Treasure and an Enemy Auto-Attack Engine
Use a Run ➤ Project work process, and play and test the game, which is seen in Figure 17-55. The first thing that
you will notice is that all of our z-index character layer ordering is correct. You will also see that your Enemy and
Projectiles are not visible at game start-up, which is another step toward a professional end-user experience.
Figure 17-55. Use a Run ➤ Project work process to test the game and the enemy attack, bullet types, and scoring engine
You will notice that it is much more difficult to get the InvinciBagel into position, as you do not know where,
when, or what direction the enemy attack is going to come from! Well, that is not entirely true, as we would need to
randomize the attackFrequency variable to get the “when he appears” part to not be triggered at even time intervals.
Since our objective is to make this game progressively more and more challenging and professional, let’s do this next!
For the remainder of the chapter we will add some features that make the game play more challenging and
realistic. We will add some of the important game design elements such as randomization, artificial intelligence, and
physics simulation, all of which will make your Java 8 games more professional and popular. You need to have some
exposure to these concepts before we finish this first (beginner) round of our core Java 8 games development cycle.
Add the Element of Surprise: Randomizing the Attack Frequency
Now that we have made the point of entry on the screen as well as the side of the screen that is used for the attack to
be completely random, let’s go into the fourth dimension (time) and make when the attack will occur also random.
This is done by randomizing the attackFrequency variable, which before this we had set to 4.167 seconds (250/60FPS).
We will set this random value in the else structure in the .initiateAttack() method where we set your boolean flag
settings and call the .load() methods that we created to make sure the auto-attack engine always has Enemy and
Projectile objects to work with. We will put a Java statement that inserts a random value into the attackFrequency
variable at the end of this else portion of the if(onScreen && launchIt) conditional structure, so that a new random
time is in place when the .update() method starts using this variable for its attack delay counter programming logic.
Since the .nextInt(int bounds) method call structure gives us a random integer between zero and the upper bounds, in
order to get a range of attack delay between one second (60) and nine seconds (60+480), we will need to add 60 to the
value generated by the randomNum.nextInt(480) part of the statement, and then set the attackFrequency variable
equal to that value. The Java code for this attackFrequency randomization statement can be seen in Figure 17-56 and
should look like the following:
attackFrequency = 60 + randomNum.nextInt(480);
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