Java Video Tutorial 60

import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.Polygon;
import java.awt.Rectangle; 
import java.util.ArrayList;

import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.Clip;

// Extending the Polygon class because I'm drawing Polygons

class Rock extends Polygon{
	// Upper left hand corner of the Polygon
	int uLeftXPos, uLeftYPos;
	// Used to change the direction of the asteroid when 
	// it hits something and determines how fast it moves
	int xDirection = 1;
	int yDirection = 1;
	// Define rock height and width
	int rockWidth = 26;
	int rockHeight = 31;
	// Copy of the Rock ArrayList
	// Holds every Rock I create
	static ArrayList<Rock> rocks = new ArrayList<Rock>();
	// For JApplet
	// int width = ExampleBoard.WIDTH;
	// int height = ExampleBoard.HEIGHT;
	// Get the board width and height
	int width = GameBoard.boardWidth;
	int height = GameBoard.boardHeight;
	// Will hold the x & y coordinates for the Polygons
	int[] polyXArray, polyYArray;
	// x & y positions available for other methods
	// There will be more Polygon points available later
	public static int[] sPolyXArray = {10,17,26,34,27,36,26,14,8,1,5,1,10};
	public static int[] sPolyYArray = {0,5,1,8,13,20,31,28,31,22,16,7,0};
	// NEW Keep track of whether Rock is on screen
	public boolean onScreen = true;
	// NEW Sound file names
	// The JavaSound api allows wavs, au, aiff files
	String explodeFile = "file:./src/explode.wav";
	// Creates a new asteroid 
	public Rock(int[] polyXArray, int[] polyYArray, int pointsInPoly, int randomStartXPos, int randomStartYPos){
		// Creates a Polygon by calling the super or parent class of Rock Polygon
		super(polyXArray, polyYArray, pointsInPoly);
		// Randomly generate a speed for the Polygon
		this.xDirection = (int) (Math.random() * 4 + 1);
		this.yDirection = (int) (Math.random() * 4 + 1);
		// Holds the starting x & y position for the Rock
		this.uLeftXPos = randomStartXPos;
		this.uLeftYPos = randomStartYPos;
	// Creates a bounding rectangle for collision checking
	public Rectangle getBounds() {
        return new Rectangle(super.xpoints[0], super.ypoints[0], rockWidth, rockHeight);

	// NEW move receives SpaceShip and Torpedos now
	public void move(SpaceShip theShip, ArrayList<PhotonTorpedo> torpedos){
		// This rectangle surrounds the rock I'll check against
		// all of the other rocks below
		Rectangle rockToCheck = this.getBounds();
		// Cycle through all the other rocks and check if they
		// cross over the rectangle I created above
		for(Rock rock : rocks){
			// NEW Is rock viewable
			// Creates a bounding rectangle that is used temporarily
			// for each other rock on the board
			Rectangle otherRock = rock.getBounds();
			// Check to make sure I'm not comparing one rock to itself
			// Check if one rock crosses over another rock
			if(rock != this && otherRock.intersects(rockToCheck)){

				// Switch the direction the rocks are moving on impact
				int tempXDirection = this.xDirection;
				int tempYDirection = this.yDirection;
				this.xDirection = rock.xDirection;
				this.yDirection = rock.yDirection;
				rock.xDirection = tempXDirection;
				rock.yDirection = tempYDirection;
				// NEW Check if theShip hits a Rock
				Rectangle shipBox = theShip.getBounds();
					// NEW play explosion if ship is hit
				for(PhotonTorpedo torpedo : torpedos){
					// Make sure the Torpedo is on the screen
						// NEW Check if a torpedo hits a Rock
							rock.onScreen = false;
							torpedo.onScreen = false;
							// NEW play explosion sound if rock is destroyed
		// Get the upper left and top most point for the Polygon
		// This will be dynamic later on
		int uLeftXPos = super.xpoints[0]; 
		int uLeftYPos = super.ypoints[0];
		// If the Rock hits a wall it will go in the opposite direction
		if (uLeftXPos < 0 || (uLeftXPos + 25) > width) xDirection = -xDirection; 
		if (uLeftYPos < 0 || (uLeftYPos + 50) > height) yDirection = -yDirection;
		// Change the values of the points for the Polygon
		for (int i = 0; i < super.xpoints.length; i++){
			super.xpoints[i] += xDirection;
			super.ypoints[i] += yDirection;
	// public method available for creating Polygon x point arrays
	public static int[] getpolyXArray(int randomStartXPos){
		// Clones the array so that the original shape isn't changed for the asteroid
		int[] tempPolyXArray = (int[])sPolyXArray.clone();
		for (int i = 0; i < tempPolyXArray.length; i++){
			tempPolyXArray[i] += randomStartXPos;
		return tempPolyXArray;
	// public method available for creating Polygon y point arrays
	public static int[] getpolyYArray(int randomStartYPos){
		// Clones the array so that the original shape isn't changed for the asteroid
		int[] tempPolyYArray = (int[])sPolyYArray.clone();
		for (int i = 0; i < tempPolyYArray.length; i++){
			tempPolyYArray[i] += randomStartYPos;
		return tempPolyYArray;

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26 Responses to “Java Video Tutorial 60”

  1. mr.roshik says:

    Hi do u have any plan to make tutorial on magento or drupal for developing ecommerce site ? i think advanced step of this type tutorials are not available. so please …..

    • admin says:

      Not at this time because I made a free wordpress ecommerce tutorial that has worked perfectly for me for almost a year with a single problem. I don’t know of an iron clad free ecommerce solution other than what I covered in Create an Online Store. I don’t know if you’ve seen that tutorial or not?

  2. mr.roshik says:

    display none and visibility hidden , whts the difference of this two css property ? help me to know.

    • admin says:

      visibility:hidden hides an element, but it will still take up the same space as before and still affect the layout.

      display:none hides an element, it will not take up any space and the page will be displayed as if the element is not there

  3. mr.roshik says:

    Thanks a lot.

  4. Bilou says:

    Look man you did a great job ^^ I am glad because there is people like you alive :p I’ll be happier if you make more Java tutorials

    • admin says:

      More pure Java tutorials are right around the bend. My last tutorials on design patterns and UML are technically Java tutorials. You have to learn a bunch of things to be a great programmer. Refactoring using java is coming next. Thanks for stopping by 🙂

  5. MADLY says:

    Is there a .zip archive for the noises…

  6. bob says:

    I also do games long time ago using Java and J2ME. I just do simple box collission detection. I think circles are much easier because you just compute the distance between the 2 centers.

  7. Samuel Pius says:

    Hey Derek 🙂

  8. Umair says:

    Hi Derek,

    I liked this series of video game. I just wanted to ask is this include MVC(Model View Controller) pattern. My question is what is MVC and how did you achieved in this video game.

  9. Umair says:


    Is it true that C,C++ supports more graphics option than Java. This is what you told in one of the game video series.

  10. Umair says:

    Thank you in advance…

  11. Prakash says:

    Hi.. I am your great fan. I learnt java from your tutorial.. You are really awesome.. Keep going.

  12. Alex says:

    Woooooooooo!!!!!! first video game down!

    Just wanted to say thank you. I have learned so much through your tutorials. They may have also played a part in me getting a job, so congratulations you are feeding me now too.

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