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Uniformly Varied Rectilinear Motion (UVRM) (Animation)

I'm making an UVRM calculator and also looking to make an animation of an image. I use the Timer class, for the animation, but it happens that I have problems in making the image stop when the seconds have passed or it has reached the entered distance, and of course it is done correctly.
Timer, it receives the milliseconds, and it occurred to me to pass the seconds * 1000, but I do not know if it is correct. Also, I need the image not to span the width of the window (JFrame)
I don't know much about animations and I don't know what to do really.
Car class
public class Car {
private final ImageIcon imagen;
private double posx;
private int width;
public Car() {
imagen = new ImageIcon(getClass().getResource("/images/carred.png"));
posx = 10;
width = 400;
}
public double getPosx() {
return posx;
}
public int getWidth() {
return width;
}
public void setPosx(double posx) {
this.posx = posx;
}
public void draw(Graphics g){
g.drawImage(imagen.getImage(), (int) posx , 50, width, 300, null);
}
public void move(double x){
posx+=x;
}
}
JPanel
private void btnCalcActionPerformed(java.awt.event.ActionEvent evt) {
String text_vf = txfvf.getText();
String text_v0 = txfv0.getText();
String text_a = txfa.getText();
String text_d = txfd.getText();
String text_t = txft.getText();
String res = "message.. res";
// Calculations...
//text_d = distance
moveCarImage(t, Integer.parseInt(text_v0), a, Integer.parseInt(text_d));
}
private void moveCarImage(double timeMilis, double v0, double acceleration, int fDistance) {
timer = new Timer(timeMilis, (e) -> {
car.move(acceleration);
repaint();
if (car.getPosx() >= fDistance+car.getWidth() ) {
timer.stop();
}
});
timer.start();
if (!timer.isRunning()) {
System.out.println("Car Stopped.........");
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
car.draw(g);
//g.drawRect(10, 50, 300, 300);
}
Can you help me please.. thanks so much.
EDIT:
I changed the milliseconds a timeMilis

how to show balls on screen in java swing

this is my board class and i try to call ball object in GameBoard class but i didn't and my problem is didn't show ball on screen.
Used to execute code after a given delay
The attribute is corePoolSize - the number of threads to keep in
the pool, even if they are idle
package test2;
public class Board extends JFrame{
public static int boardWidth = 800;
public static int boardHeight = 800;
public static void main(String[] args){
new Board();
}
public Board() {
this.setSize(boardWidth, boardHeight);
this.setTitle("Ball");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GameBoard gb = new GameBoard();
this.add(gb, BorderLayout.CENTER);
ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(5);
executor.scheduleAtFixedRate(new RepaintTheBoard(this), 0L, 20L, TimeUnit.MILLISECONDS);
this.setVisible(true);
}
}
class RepaintTheBoard implements Runnable{
Board theBoard;
public RepaintTheBoard(Board theBoard){
this.theBoard = theBoard;
}
#Override
public void run() {
// Redraws the game board
theBoard.repaint();
}
}
#SuppressWarnings("serial")
//GameDrawingPanel is what we are drawing on
class GameBoard extends JComponent {
Random rnd=new Random();
public ArrayList<Ball> balls = new ArrayList<Ball>();
int width = Board.boardWidth;
int height = Board.boardHeight;
public GameBoard(){
for(int i=0; i<50; i++){
int randomStartXPos = (int) (Math.random() * (Board.boardWidth - 40) + 1);
int randomStartYPos = (int) (Math.random() * (Board.boardHeight - 40) + 1);
balls.add(new Ball(randomStartXPos,randomStartYPos,30));
}
}
public void paint(Graphics g) {
// Allows me to make many settings changes in regards to graphics
Graphics2D g2d = (Graphics2D)g;
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setPaint(new Color(rnd.nextInt(255),rnd.nextInt(255),rnd.nextInt(255)));
for(Ball ball : balls){
ball.move();
g2d.draw(ball);
}
}
}
this ball class and i think , i have problem in move() class
package test2;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
public class Ball extends Ellipse2D{
int uLeftXPos, uLeftYPos;
int xDirection = 1;
int yDirection = 1;
int diameter;
int width = Board.boardWidth;
int height = Board.boardHeight;
public Ball(int randomStartXPos, int randomStartYPos, int Diam) {
super();
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;
this.diameter = Diam;
}
public void move(){
if (uLeftXPos + xDirection < 0)
xDirection = 1;
if (uLeftXPos + xDirection > width - diameter)
xDirection = -1;
if (uLeftYPos + yDirection < 0)
yDirection = 1;
if (uLeftYPos + yDirection > height - diameter)
yDirection = -1;
uLeftXPos = uLeftXPos + xDirection;
uLeftYPos = uLeftYPos + yDirection;
}
#Override
public Rectangle2D getBounds2D() {
// TODO Auto-generated method stub
return null;
}
#Override
public double getX() {
// TODO Auto-generated method stub
return 0;
}
#Override
public double getY() {
// TODO Auto-generated method stub
return 0;
}
#Override
public double getWidth() {
// TODO Auto-generated method stub
return 0;
}
#Override
public double getHeight() {
// TODO Auto-generated method stub
return 0;
}
#Override
public boolean isEmpty() {
// TODO Auto-generated method stub
return false;
}
#Override
public void setFrame(double x, double y, double w, double h) {
// TODO Auto-generated method stub
}
}

Your main problem is that your Ball class extends a Shape object, Ellipse2D and does so incompletely, preventing full Ellipse2D/Shape behavior. I think that you'd be far better off not using inheritance but rather using composition -- have Ball contain a valid and complete Ellipse2D object, one that it uses to help it draw itself.
Other issues:
Your JComponent should have paintComponent overridden, not paint
You should always call the super's painting method within your override
It's not a good idea to have program logic within a painting method, as you can never fully control this method, nor do you want to. Better to have your move method separate and have the painting method do one thing -- paint the state of the component, and that's it.
Your code is skirting danger with Swing threading. Consider using a Swing Timer and not a scheduled executor service.
Start your GUI on the Swing thread using SwingUtilities.invokeLater(...)
Since your Ball object uses default overrides for most of the Ellipse2D methods, no movement will occur since its these method returns that determine the location of the Shape.
But again, you don't want to really override this object, but instead use composition.
Something like:
class Ball {
private static final double ELLIPSE_W = 20;
private static final double ELLIPSE_H = ELLIPSE_W;
private int x = 0;
private int y = 0;
private Ellipse2D ellipse = new Ellipse2D.Double(x, y, ELLIPSE_W, ELLIPSE_H);
int uLeftXPos, uLeftYPos;
int xDirection = 1;
int yDirection = 1;
int diameter;
int width = Board.boardWidth;
int height = Board.boardHeight;
public Ball(int randomStartXPos, int randomStartYPos, int Diam) {
super();
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;
this.diameter = Diam;
x = uLeftXPos;
y = uLeftYPos;
ellipse = new Ellipse2D.Double(x, y, ELLIPSE_W, ELLIPSE_H);
}
public Ellipse2D getEllipse() {
return ellipse;
}
public void move() {
if (uLeftXPos + xDirection < 0)
xDirection = 1;
if (uLeftXPos + xDirection > width - diameter)
xDirection = -1;
if (uLeftYPos + yDirection < 0)
yDirection = 1;
if (uLeftYPos + yDirection > height - diameter)
yDirection = -1;
uLeftXPos = uLeftXPos + xDirection;
uLeftYPos = uLeftYPos + yDirection;
x = uLeftXPos;
y = uLeftYPos;
ellipse = new Ellipse2D.Double(x, y, ELLIPSE_W, ELLIPSE_H);
}
}
And in the game board:
class GameBoard extends JComponent {
Random rnd = new Random();
public ArrayList<Ball> balls = new ArrayList<Ball>();
int width = Board.boardWidth;
int height = Board.boardHeight;
public GameBoard() {
for (int i = 0; i < 50; i++) {
int randomStartXPos = (int) (Math.random() * (Board.boardWidth - 40) + 1);
int randomStartYPos = (int) (Math.random() * (Board.boardHeight - 40) + 1);
balls.add(new Ball(randomStartXPos, randomStartYPos, 30));
}
}
public void move() {
for (Ball ball : balls) {
ball.move();
}
}
#Override
protected void paintComponent(java.awt.Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setColor(Color.BLACK);
g2d.fillRect(0, 0, getWidth(), getHeight());
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setPaint(new Color(rnd.nextInt(255), rnd.nextInt(255), rnd.nextInt(255)));
for (Ball ball : balls) {
// ball.move();
g2d.draw(ball.getEllipse());
}
}
}

Game in java: rotating selected object

I'm developing a Java game just for study purposes.
I want the player to select the object. The selected object can move, but the others (non-selected objects) must not move.
Game.java:
import javax.swing.JFrame;
public class Game {
public static void main(String[] args) {
JFrame frame = new JFrame("Kibe");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(new GamePanel());
frame.pack();
frame.setVisible(true);
}
}
GamePanel.java:
import javax.swing.JPanel;
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.util.*;
public class GamePanel extends JPanel implements Runnable, KeyListener {
// fields
public static final int WIDTH = 640, HEIGHT = 480;
private Thread thread;
private boolean running;
private int FPS = 30;
private double averageFPS;
private BufferedImage image;
private Graphics2D g;
public ArrayList<Circle> circles;
private int selectedCircle;
// constructor
public GamePanel(){
super();
setPreferredSize(new Dimension(WIDTH, HEIGHT));
setFocusable(true);
requestFocus();
}
// functions
public void addNotify(){
super.addNotify();
if(thread == null){
thread = new Thread(this);
thread.start();
}
addKeyListener(this);
}
public void run(){
running = true;
image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
g = (Graphics2D) image.getGraphics();
circles = new ArrayList<Circle>();
long startTime;
gameUpdate();
gameRender();
gameDraw();
long URDTimeMillis;
long waitTime;
long totalTime = 0;
int frameCount = 0;
int maxFrameCount = 30;
long targetTime = 1000 / FPS;
while(running){ // the game loop
startTime = System.nanoTime();
gameUpdate();
gameRender();
gameDraw();
URDTimeMillis = (System.nanoTime() - startTime) / 1000000;
waitTime = targetTime - URDTimeMillis;
try{
Thread.sleep(waitTime);
}catch(Exception e){
e.printStackTrace();
}
frameCount++;
if(frameCount == maxFrameCount){
averageFPS = 1000.0 / ((totalTime / frameCount) / 1000000);
frameCount = 0;
totalTime = 0;
}
}
}
private void gameUpdate(){
circles.get(selectedCircle).update();
}
private void gameRender(){
g.setColor(Color.BLACK);
g.fillRect(0, 0, WIDTH, HEIGHT);
for(int i = 0; i < circles.size(); i++){
circles.get(i).draw(g);
}
}
private void gameDraw(){
Graphics g2 = this.getGraphics();
g2.drawImage(image, 0, 0, null);
g2.dispose();
}
// key functions
public void keyTyped(KeyEvent e){
int keyCode = e.getKeyCode();
}
public void keyPressed(KeyEvent e){
int keyCode = e.getKeyCode();
if(keyCode == KeyEvent.VK_SPACE){
circles.add(new Circle());
}
else if(keyCode == KeyEvent.VK_Z){
selectedCircle = (selectedCircle + 1) % circles.size();
}
}
public void keyReleased(KeyEvent e){
int keyCode = e.getKeyCode();
}
}
Circle.java:
import java.awt.*;
public class Circle {
// fields
private double x;
private double y;
private int speed;
private int dx;
private int dy;
private int r;
private boolean up;
private boolean down;
private boolean left;
private boolean right;
private Color color;
// constructor
public Circle(){
x = Math.random() * GamePanel.WIDTH / 2 + GamePanel.HEIGHT / 4;
y = -r;
speed = 5;
dx = 0;
dy = 0;
r = 5;
color = Color.WHITE;
}
// functions
public void setUp(boolean b) { up = b; }
public void setDown(boolean b) { down = b; }
public void setLeft(boolean b) { left = b; }
public void setRight(boolean b ) { right = b; }
public void update(){
if(up)
dy = -speed;
else
dy = 0;
if(down)
dy = speed;
if(left)
dx = -speed;
else
dx = 0;
if(right)
dx = speed;
color = Color.RED;
}
public void draw(Graphics2D g){
g.setColor(Color.WHITE);
g.fillOval((int) x - r, (int) y - r, 2 * r, 2 * r);
}
}
The error when I try to run:
Exception in thread "Thread-2" java.lang.IndexOutOfBoundsException: Index: 0, Si
ze: 0
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at GamePanel.gameUpdate(GamePanel.java:102)
at GamePanel.run(GamePanel.java:51)
at java.lang.Thread.run(Unknown Source)

The error message is clear:
IndexOutOfBoundsException: Index: 0, Size: 0
You're trying to get the 0th item out of an ArrayList whose size is 0, meaning there is no 0th item (first item).
This line:
private void gameUpdate(){
circles.get(selectedCircle).update(); // here ****
}
This is happening at game start before the circles ArrayList holds any Circle objects.
One solution is to do a validity check before trying to extract something that doesn't exist, e.g.,
private void gameUpdate() {
if (selectedCircle < circles.size()) {
circles.get(selectedCircle).update();
}
}
Of course this won't prevent the other problems that you will soon encounter with this code including
negative Thread.sleep times
Drawing with a Graphics object obtained by calling getGraphics() on a Swing component
Making Swing calls directly from a background thread

Firing a projectile in mouse direction in java

I'm trying to fire a projectile in the mouse direction but i am having trouble.
The angles are wrong, and by that I mean it will only go up left or in the top-left corner.
This is my Gun class for which I fire the Bullet.
package assets;
import Reaper.Game;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
public class Gun
{
public ArrayList<Bullet> bullets;
protected double angle;
Mouse mouse = new Mouse();
private BufferedImage image;
private int centerX = Game.WIDTH / 2;
private int centerY = Game.HEIGHT;
public Gun()
{
bullets = new ArrayList<Bullet>();
image = null;
try
{
image = ImageIO.read(new File("assets/gun.png"));
}
catch (IOException e)
{
e.printStackTrace();
}
}
public BufferedImage loadImage()
{
return image;
}
public int getImageWidth()
{
return image.getWidth(null);
}
public int getImageHeight()
{
return image.getHeight(null);
}
public void rotate(Graphics g)
{
angle = Math.atan2(centerY - mouse.getMouseY(), centerX - mouse.getMouseX()) - Math.PI / 2;
((Graphics2D) g).rotate(angle, centerX, centerY);
g.drawImage(image, Game.WIDTH / 2 - image.getWidth() / 2,
900 - image.getHeight(), image.getWidth(), image.getHeight(),
null);
}
public Image getImage()
{
return image;
}
public void update()
{
shoot();
for (int i = 0; i < bullets.size(); i++)
{
Bullet b = bullets.get(i);
b.update();
}
}
public void shoot()
{
if (mouse.mouseB == 1)
{
double dx = mouse.getMouseX() - Game.WIDTH / 2;
double dy = mouse.getMouseY() - Game.HEIGHT / 2;
double dir = Math.atan2(dy, dx);
bullets.add(new Bullet(Game.WIDTH / 2, Game.HEIGHT / 2, dir));
mouse.mouseB = -1;
}
}
public void render(Graphics g)
{
for (int i = 0; i < bullets.size(); i++)
{
bullets.get(i).render(g);
}
rotate(g);
}
}
This is my Bullet class:
package assets;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
public class Bullet
{
private double dx, dy;
private int x, y;
private double dir;
private BufferedImage image;
public Bullet(int x, int y, double angle)
{
this.x = x;
this.y = y;
this.dir = angle;
image = null;
try
{
image = ImageIO.read(new File("assets/bolt.png"));
}
catch (IOException e)
{
e.printStackTrace();
}
dx = Math.cos(dir);
dy = Math.sin(dir);
}
public void update()
{
x += dx;
y += dy;
System.out.println("dx : " + dx + " " + dy);
}
public void render(Graphics g)
{
g.drawImage(image, x, y, image.getWidth(), image.getHeight(), null);
}
public BufferedImage getImage()
{
return image;
}
}
And this is the main Game class:
package Reaper;
import Reaper.graphics.Screen;
import assets.Gun;
import assets.Mouse;
import gameState.MenuState;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferStrategy;
public class Game extends Canvas implements Runnable
{
private static final long serialVersionUID = 1L;
public static int WIDTH = 900;
public static int HEIGHT = 900;
public static int scale = 3;
public int frames = 0;
public int updates = 0;
private boolean running = false;
private Thread thread;
private JFrame frame;
#SuppressWarnings("unused")
private Screen screen;
private Gun gun;
private MenuState mns;
private Mouse mouse;
public Game()
{
Dimension size = new Dimension(WIDTH, HEIGHT);
setPreferredSize(size);
screen = new Screen(WIDTH, HEIGHT);
frame = new JFrame();
gun = new Gun();
mns = new MenuState();
mouse = new Mouse();
addMouseListener(mouse);
addMouseMotionListener(mouse);
}
public static void main(String[] args)
{
Game game = new Game();
game.frame.setResizable(false);
game.frame.add(game);
game.frame.pack();
game.frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
game.frame.setVisible(true);
game.frame.setLocationRelativeTo(null);
game.strat();
}
public void strat()
{
running = true;
thread = new Thread(this, "Reaper");
thread.start();
}
public void stop()
{
running = false;
try
{
thread.join();
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
public void run()
{
long timer = System.currentTimeMillis();
long lastTime = System.nanoTime();
double ns = 1000000000.0 / 60;
double delta = 0;
while (running)
{
long now = System.nanoTime();
delta += (now - lastTime) / ns;
lastTime = now;
while (delta >= 1)
{
update();
updates++;
delta--;
}
render();
frames++;
if (System.currentTimeMillis() - timer > 1000)
{
timer = System.currentTimeMillis();
frame.setTitle("Reaper! " + " | " + updates + " ups , " + frames + " fps");
updates = 0;
frames = 0;
}
}
stop();
}
public void update()
{
if (mns.play)
{
gun.update();
}
}
public void render()
{
BufferStrategy bs = getBufferStrategy();
if (bs == null)
{
createBufferStrategy(3);
return;
}
Graphics g = bs.getDrawGraphics();
g.fillRect(0, 0, WIDTH, HEIGHT);
if (mns.menu)
{
mns.draw(g);
}
if (mns.play)
{
g.clearRect(0, 0, WIDTH, HEIGHT);
g.drawImage(mns.getImage(), 0, 0, mns.getImageWidth(), mns.getImageHeight(), this);
gun.render(g);
}
if (mns.rules)
{
g.clearRect(0, 0, WIDTH, HEIGHT);
}
bs.show();
}
}
I know it's very badly coded, and I will try to fix it as much as I can, but I am really stuck on this. Searched around the web, tried some of the solutions but it wont work. I guess I'm doing it wrong by putting methods in wrong places and calling them, I guess.

I know it's very badly coded, and I will try to fix it as much as I can, ...
Next time, consider first cleaning up the mess and then asking the question.
(Are the variables storing the values returned by getMouseX() and getMouseY() really static?)
However, the main reason for the actual problem are the x and y values in the Bullet class:
class Bullet
{
private double dx, dy;
private int x, y;
....
public void update()
{
x += dx;
y += dy;
System.out.println("dx : " + dx + " " + dy);
}
...
}
They are declared as int values. Imagine what happens in the update method, for example, when x=0 and dx = 0.75: It will compute 0+0.75 = 0.75, truncate this to be an int value, and the result will be 0.
Thus, the x and y values will never change, unless the dx and dy values are >= 1.0, respectively.
Just changing the type of x and y to double will solve this. You'll have to add casts in the render method accordingly:
g.drawImage(image, (int)x, (int)y, ...);
But you should really clean this up.

How to detect a collision?

I'm having a two image(a cat and a dog) inside the world which is in my Board class. The cat moves in a random direction while the dog move only when I press the arrow keys. My problem now is that how can I make the cat disappear whenever there is a collision between the two images? Any answer or idea would be much appreciated.
Here's what I've tried...
public class Cat extends Sprite implements ImageObserver
{
private java.awt.Image catImage;
private final Board board;
private double x;
private double y;
private double speed;
private double angle;
private boolean visible;
public Cat(Board board, double x, double y, double speed)
{
this.board = board;
this.x = x;
this.y = y;
this.speed = convertToMeterPerSecond(speed);
visible = true;
URL iU = this.getClass().getResource("cat.gif");
ImageIcon icon = new ImageIcon(iU);
catImage = icon.getImage();
}
public Image getImage()
{
return catImage;
}
public void move(long dt)
{
double dt_s = dt / 1e9;
double dx_m = speed * dt_s * Math.sin(angle);
double dy_m = speed * dt_s * Math.cos(angle);
final double right_wall = board.x1_world;
final double up_wall = board.y1_world;
final double down_wall = 0.0;
final double left_wall = 0.0;
x += dx_m;
y += dy_m;
if (x >= right_wall)
{
x = right_wall;
setRandomDirection();
}
if (y > up_wall)
{
y = up_wall;
setRandomDirection();
}
if (x <= left_wall)
{
x = left_wall;
setRandomDirection();
}
if (y < down_wall)
{
y = down_wall;
setRandomDirection();
}
}
public void setRandomDirection()
{
Cat myObject = this;
myObject.setAngle(Math.PI * 2 * Math.random());
}
#Override
public void render(Graphics2D g2d)
{
AffineTransform t = g2d.getTransform();
double height = 0.3; //meter
double width = 0.3; //meter
double cat_footy = height;
double cat_footx = width / 2;
int xx = board.convertToPixelX(x - cat_footx);
int yy = board.convertToPixelY(y + cat_footy);
g2d.translate(xx, yy);
double x_expected_pixels = width * board.meter;
double y_expected_pixels = height * board.meter;
double x_s = x_expected_pixels / ((ToolkitImage) catImage).getWidth();
double y_s = y_expected_pixels / ((ToolkitImage) catImage).getHeight();
double w = ((ToolkitImage) catImage).getWidth();
double h = ((ToolkitImage) catImage).getHeight();
g2d.scale(x_s, y_s);
g2d.drawImage(getImage(), 0, 0, this); // upper left corner
g2d.setColor(Color.BLACK);
g2d.drawRect(0, 0, (int) w, (int) h);
g2d.setTransform(t);
}
public void moveAt(double distance_x, double distance_y)
{
this.x = (int) distance_x;
this.y = (int) distance_y;
}
#Override
public Rectangle getBounds()
{
double w = ((ToolkitImage) catImage).getWidth();
double h = ((ToolkitImage) catImage).getHeight();
return new Rectangle((int) x, (int) y, (int) w, (int) h);
}
public void setAngle(double angle)
{
this.angle = angle;
}
public boolean isVisible()
{
return visible;
}
public void setVisible(Boolean visible)
{
this.visible = visible;
}
#Override
public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height)
{
return true;
}
}
for my Cat class
public class Dog extends Sprite implements ImageObserver
{
private java.awt.Image humanImage;
private final Board board;
private double x;
private double y;
private double speed;
private boolean visible;
private double angle;
private double dx_m;
private double dy_m;
public Dog(Board board, double x, double y, double speed)
{
this.board = board;
this.x = x;
this.y = y;
this.speed = convertToMeterPerSecond(speed);
visible = true;
URL iU = this.getClass().getResource("dog.jpg");
ImageIcon icon = new ImageIcon(iU);
dogImage = icon.getImage();
}
public Image getImage()
{
return dogImage;
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT)
{
dx_m = -0.3;
}
if (key == KeyEvent.VK_RIGHT)
{
dx_m = 0.3;
}
if (key == KeyEvent.VK_UP)
{
dy_m = 0.3;
}
if (key == KeyEvent.VK_DOWN)
{
dy_m = -0.3;
}
}
public void keyReleased(KeyEvent e)
{
int key = e.getKeyCode();
if (key == KeyEvent.VK_LEFT)
{
dx_m = 0;
}
if (key == KeyEvent.VK_RIGHT)
{
dx_m = 0;
}
if (key == KeyEvent.VK_UP)
{
dy_m = 0;
}
if (key == KeyEvent.VK_DOWN)
{
dy_m = 0;
}
}
#Override
public void move(long dt)
{
double dt_s = dt / 1e9;
final double right_wall = board.x1_world;
final double up_wall = board.y1_world;
final double down_wall = 0.0;
final double left_wall = 0.0;
x += dx_m;
y += dy_m;
if (x <= left_wall)
{
x = left_wall;
}
if (x >= right_wall)
{
x = right_wall;
}
if (y <= down_wall)
{
y = down_wall;
}
if (y >= up_wall)
{
y=up_wall;
}
}
public void setRandomDirection()
{
Dog myObject = this;
myObject.setAngle(Math.PI * 2 * Math.random());
}
#Override
public void render(Graphics2D g2d)
{
AffineTransform t = g2d.getTransform();
final double dogHeight = 1.6;// meter
final double dogWidth = 1.8; //meter
final double foot_position_y = dogHeight;
final double foot_position_x = dogWidth / 2;
int xx = board.convertToPixelX(x - foot_position_x); // to find the upper-left corner
int yy = board.convertToPixelY(y + foot_position_y); // to find the upper-left corner
g2d.translate(xx, yy);
// ratio for actual Image size
double x_expected_pixels = dogHeight * board.meter;
double y_expected_pixels = dogWidth * board.meter;
double w = ((ToolkitImage) dogImage).getWidth();
double h = ((ToolkitImage) dogImage).getHeight();
double x_s = x_expected_pixels / w;
double y_s = y_expected_pixels / h;
g2d.scale(x_s, y_s);
g2d.drawImage(getImage(), 0, 0, this); // upper left corner
g2d.setColor(Color.BLACK);
g2d.drawRect(0, 0, (int) w, (int) h);
g2d.setTransform(t);
}
#Override
public void moveAt(double distance_x, double distance_y)
{
this.x = distance_x;
this.y = distance_y;
}
public void setAngle(double angle)
{
this.angle = angle;
}
#Override
public Rectangle getBounds()
{
double width = ((ToolkitImage) dogImage).getWidth();
double height = ((ToolkitImage) dogImage).getHeight();
return new Rectangle((int) x, (int) y, (int) width, (int) height);
}
public boolean isVisible()
{
return visible;
}
public void setVisible(Boolean visible)
{
this.visible = visible;
}
#Override
public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height)
{
return true;
}
}
for my Dog class
public class Board extends Canvas
{
private Cat cat;
public static final long SECOND = 1000 * 1000 * 1000;
public double meter;//PIXEL
private HumanBeing humanBeing;
/**
* ascending from 0 to N
* 0 : most far way...
* N : is the closest (painted the last)
*/
private final java.util.List<Sprite> z_sorted_sprites = new ArrayList<Sprite>();
private BufferStrategy strategy;
int x0_pixel;
int y0_pixel;
int x1_pixel;
int y1_pixel;
double x1_world;
double y1_world;
private final Frame frame;
public Board(Frame frame, double meter)
{
addKeyListener(new TAdapter());
this.frame = frame;
this.setIgnoreRepaint(true);
this.meter = meter;
setFocusable(true);
dog = new Dog(this, 5, 5, 40);
init();
addComponentListener(new ComponentAdapter()
{
#Override
public void componentResized(ComponentEvent e)
{
render();
}
});
}
public void init()
{
z_sorted_sprites.add(new Cat(this, 0, 0, 30));
z_sorted_sprites.add(new Cat(this, 1, 1, 10));
z_sorted_sprites.add(new Cat(this, 2, 2, 20));
z_sorted_sprites.add(new Cat(this, 3, 3, 100));
}
public void render()
{
setupStrategy();
x0_pixel = 0;
y0_pixel = 0;
x1_pixel = getWidth();
y1_pixel = getHeight();
x1_world = x1_pixel / meter;
y1_world = y1_pixel / meter;
Graphics2D g2d = (Graphics2D) strategy.getDrawGraphics();
g2d.setBackground(Color.lightGray);
g2d.clearRect(0, 0, x1_pixel, y1_pixel);
g2d.setColor(Color.BLACK);
for (double x = 0; x < x1_world; x++)
{
for (double y = 0; y < y1_world; y++)
{
int xx = convertToPixelX(x);
int yy = convertToPixelY(y);
g2d.drawOval(xx, yy, 2, 2);
}
}
for (Sprite z_sorted_sprite : z_sorted_sprites)
{
z_sorted_sprite.render(g2d);
}
dog.render(g2d);
g2d.dispose();
strategy.show();
Toolkit.getDefaultToolkit().sync();
}
public int convertToPixelX(double distance)
{
return (int) (distance * meter);
}
public int convertToPixelY(double y_world)
{
return (int) (y1_pixel - (y_world * meter));
}
public void onZoomUpdated(int value)
{
meter = value;
render();
}
private void setupStrategy()
{
if (strategy == null)
{
this.createBufferStrategy(2);
strategy = this.getBufferStrategy();
}
}
public void start() throws InterruptedException
{
long prevLoopStart = System.nanoTime();
Avg avg = new Avg();
while (true)
{
final long loopStart = System.nanoTime();
final long dt = loopStart - prevLoopStart;
for (Sprite sprite : z_sorted_sprites)
{
sprite.move(dt);
}
dog.move(dt);
render();
frame.onFpsUpdated(1.0 / dt * SECOND, avg.add(loopStart));
final long elapsed_ns = System.nanoTime() - loopStart;
long expected_elapsed_ms = 1000 / 60;
long elapsed_ms = (long) (elapsed_ns / (1000.0 * 1000.0));
long sleep_ms = expected_elapsed_ms - elapsed_ms;
if (sleep_ms > 0)
{
Thread.sleep(sleep_ms /* ms */);
}
prevLoopStart = loopStart;
}
}
private void checkCollision()
{
Rectangle r2 = cat.getBounds();
Rectangle r3 = dog.getBounds();
if (r3.intersects(r2))
{
dog.setVisible(false);
cat.setVisible(false);
}
}
static class Avg
{
java.util.List<Long> ticks = new ArrayList<Long>();
/**
* #return the rate for the last second
*/
int add(long tick)
{
ticks.add(0, tick);
if (ticks.size() < 2)
{
return -1;
}
int last = -1;
for (int pos = ticks.size() - 1; pos >= 0; pos--)
{
if (tick - ticks.get(pos) <= SECOND)
{
last = pos;
break;
}
}
while (ticks.size() - 1 > last)
{
ticks.remove(ticks.size() - 1);
}
return ticks.size();
}
}
private class TAdapter extends KeyAdapter
{
public void keyReleased(KeyEvent e)
{
dog.keyReleased(e);
}
public void keyPressed(KeyEvent e)
{
dog.keyPressed(e);
}
}
}
For my Board class
public abstract class Sprite
{
public Sprite()
{
}
public Rectangle getBounds()
{
return new Rectangle();
}
public static double convertToMeterPerSecond(double speed)
{
// 25 km / hour
// 25000 m / 3600 s
return speed / 3.6;
}
public abstract void move(long dt);
public abstract void moveAt(double distance_x, double distance_y);
public abstract void render(Graphics2D g2d);
public abstract void setVisible(Boolean visible);
}
For my sprite class
public boolean checkCollisions(java.util.List<Sprite> sprites)
{
Dog dog = this;
Rectangle r1 = dog.getBounds();
for (int i = 0; i < sprites.size(); i++)
{
Rectangle r2 = sprites.get(i).getBounds();
if (r1.intersects(r2))
{
sprites.remove(i);
}
}
return true;
}

You have given a lot of code, but as Sibbo said, I don't see your checkCollisions method being called anywhere. It should be called every loop of your game.
Check out this tutorial, specifically look at the gameLoop method in the Game class. When I made a sprite based game that required a lot of collision detection this tutorial helped me out a lot.

I'd implement method that detects that positions of cat and dog overlap in the board class since board is the only instance that "knows" both dog and cat. The implementation is pretty simple: compare coordinates (something like dog.x + dog.width < cat.x || dog.x > cat.x + cat.width etc, etc.
If future you can implement more generic method, so if you will wish to add mouse you will be able to reuse the code.

The dog class doesn't overwrite the getBounds() method. So everytime you check if the rectangle (0, 0, 0, 0) intersects for example (3, 4, 50, 50) (if the cat is at (3, 4)).
Where do you call the checkCollision() method?
EDIT:
Create a method like your checkCollision() in your Dog class:
public boolean checkCollision(Sprite s) {...}
It should return true, when a collision is detected. Call this method from the Board.start() method for every Sprite in z_sorted_sprites. IF it returns true, remove the Sprite from the list.