A Little Help

[raverocker]

Hey guys! I'm new here. And I need your help.

IMPROVE TargetPractice.java to allow the user to do the following:
1. add any number of targets he/she wishes to "shoot-at" by inputting
the top-left coordinate of target and its scale
2. specify the flight of the projectile by inputting its velocity and
angle of elevation

PROGRAMMING HINTS:
Your program should declare an ArrayList of "targets", since the
target is a Polygon, the declaration of the list should be something
like this...
ArrayList<Polygon> myList;

To create a target, use the createTarget method in the program...
Polygon target = createTarget(200, 300, 4);
// creates a target at coordinates 200, 300 in the applet, the
// third argument specifies that scale which is 4-times larger
// that the original size of the target


and to add this target to list myList, do this...
myList.add(target);

To access each target in myList, do this...

for (int i=0; i<myList.size(); i++) {
// process "target" after this statement
Polygon target = myList.get(i);

// process "target" here...
}

THE CODE IS HERE

FEEL FREE TO EDIT IT OR ADD TO IT

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*; // imports "Graphics2D" class
import javax.swing.*; // imports "JApplet"
import javax.swing.border.*;

// Java treat TargetPractice as a JApplet class
public class TargetPractice extends JApplet implements ActionListener
{
final int WIDTH = 800; // PIXELS
final int HEIGHT = 600;
boolean initialized, firstTime;

Polygon target;

/***
* Just a constructor...
*/
public TargetPractice() {
super(); // invokes the JApplet constructor
initialized = false;
firstTime = true;
}

public void init() {
initializeFrame();
}

public void initializeFrame() {
JFrame mainFrame;
JPanel firingRangePanel, menuPanel, mainPanel;
JApplet firingRangeApplet;
JButton fireButton;
Font bigFont = new Font("Lucida Console", Font.BOLD, 18);

fireButton = new JButton("Fire!!!");
fireButton.setFont(bigFont);
fireButton.addActionListener(this);
fireButton.setMnemonic(KeyEvent.VK_F); // VK: "Virtual Key"
// Shortcut key: "ALT-F"

firingRangeApplet = this;
firingRangeApplet.setPreferredSize(new Dimension(WIDTH, HEIGHT));

firingRangePanel = new JPanel();
firingRangePanel.setLayout(new BorderLayout());
firingRangePanel.setBorder(new EtchedBorder(EtchedBorder.RAISED));
firingRangePanel.add(firingRangeApplet);

menuPanel = new JPanel();
menuPanel.setBorder(new EtchedBorder(EtchedBorder.RAISED));
menuPanel.add(fireButton);

mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));
mainPanel.add(menuPanel);
mainPanel.add(firingRangePanel);

mainFrame = new JFrame("Target Practice");
mainFrame.setContentPane(mainPanel);
mainFrame.pack();
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainFrame.setResizable(false);
mainFrame.setLocationRelativeTo(null);
mainFrame.setAlwaysOnTop(true);
mainFrame.setVisible(true);

initialized = true;
firstTime = true;

repaint(); // invokes the "paint" method
}

/***
* Decorate the applet...
*/
public void paint(Graphics g) {
if (initialized==false) {
return;
}

Graphics2D canvas = (Graphics2D)g;
/*
//left(x), top(y), width,height
canvas.draw(new Rectangle2D.Double(100, 200, 100, 50));

canvas.setColor(Color.RED);
//left(x), top(y), width,height
canvas.fill(new Ellipse2D.Double(200, 100, 200, 150));
*/

if (firstTime==true) {
// draw the TARGET the FIRST TIME the paint method was invoked
(with "repaint()")

target = createTarget(200, 200, 5); // arguments are: left
coordinate, top coordinate, scale

canvas.setColor(Color.GREEN); // draw the target
canvas.fill(target);

canvas.setColor(Color.BLACK); // draw the "outline" of the
target
canvas.draw(target);
} else {
// draw the PROJECTILE the "NEXT TIME" the paint method was
invoked (by clicking the FIRE BUTTON)
double velocity = 100; // meters per second
double elevation = 70; // (degrees) angle of elevation
final double G = 9.8; // meters per second^2
double x=0, y=0;

elevation = Math.toRadians(elevation);

double time = 0;
double offsetX = 0;
Rectangle2D.Double eraser = new Rectangle2D.Double(0, 0, 7, 7);
Rectangle2D.Double projectile = new Rectangle2D.Double(0, 0, 5,
5);

do {
eraser.x = projectile.x-1;
eraser.y = projectile.y-1;

x = velocity*time*Math.cos(elevation);
y = velocity*time*Math.sin(elevation)-G*time*time/2;

projectile.x = offsetX + x;
projectile.y = HEIGHT - y;

// a better alternative than:
// if (target.contains(projectile.x, projectile.y))
if (target!=null && target.intersects(projectile)) {

canvas.setColor(Color.WHITE); // "remove" the target on
the ...
canvas.fill(target); // ... "canvas" by drawing it
white
canvas.setColor(Color.WHITE);
canvas.draw(target);

target=null; // physically remove the target
}

canvas.setColor(Color.WHITE);
canvas.fill(eraser);

canvas.setColor(Color.BLUE);
canvas.fill(projectile);

time += 0.01;
try {
Thread.sleep(1); // milliseconds
} catch(Exception e) {
// do nothing
}

/*
if (y<0) {
offsetX+=x;
time=0;
x=0;
}
*/
} while (y>=0);

canvas.setColor(Color.WHITE);
canvas.fill(eraser);

} // end of IF-FIRSTTIME
}

public Polygon createTarget(int left, int top, double scale) {
int[] xpoints={4,6,8,12,8,12,8,6,4,0,4,0};
int[] ypoints={0,4,0,4,6,8,12,8,12,8,6,4};

for (int i=0; i<xpoints.length; i++) {
xpoints=(int)(xpoints*scale); // set the scale
ypoints=(int)(ypoints*scale);

xpoints+=left; // set the position
ypoints+=top;
}

return new Polygon(xpoints, ypoints, xpoints.length);
}

/***
* invoked by the fireButton
*/
public void actionPerformed(ActionEvent ae) {
firstTime = false;
repaint();
}

public static void main(String[] args) {
new TargetPractice().init();
}
}

ANY HELP WOULD BE REALLY APPRECIATED

 

[Hunter Gratzner]

Hey guys! I'm new here. And I need your help.

IMPROVE TargetPractice.java to allow the user to do the following:
1. add any number of targets he/she wishes to "shoot-at" by inputting
the top-left coordinate of target and its scale
2. specify the flight of the projectile by inputting its velocity and
angle of elevation

Try this for a start http://tinyurl.com/3dh2bx

 

[Lothar Kimmeringer]

Hey guys! I'm new here. And I need your help.

[homework-description

ANY HELP WOULD BE REALLY APPRECIATED

So what exactly is your problem? I haven't seen any question
of yours.


Regards, Lothar
--
Lothar Kimmeringer E-Mail: (e-mail address removed)
PGP-encrypted mails preferred (Key-ID: 0x8BC3CD81)

Always remember: The answer is forty-two, there can only be wrong
questions!

 

[Roedy Green]

ANY HELP WOULD BE REALLY APPRECIATED

see http://mindprod.com/jgloss/homework.html