trouble running smooth animation in thread only when using key listener

Question

first time using a forum for coding help so sorry if i post this all wrong. i have more than a few classes i don't think screenManger or core holds the problem but i included them just incase. i got most of this code working through a set of tutorials. but a certain point started trying to do more on my own.

i want to play the animation only when i'm moving my sprite.

in my KeyTest class i am using threads to run the animation it used to work (poorly) but now not at all pluss it really gunks up my computer. i think it's because of the thread. im new to threads so i'm not to sure if i should even be using one in this situation or if its dangerous for my computer.

the animation worked smoothly when i had the sprite bouce around the screen forever. the animation loop played with out stopping.

i think the main problem is between the animationThread, Sprite, and keyTest classes, but itcould be more indepth.

if someone could point me in the right direction for making the animation run smoothly when i push down a key and stop runing when i let off it would be greatly apriciated.

i already looked at this Java a moving animation (sprite) obviously we were doing the same tutorial. but i feel my problem is slightly different.

p.s. sorry for the typos.

import java.awt.*;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.ImageIcon;

public class KeyTest extends Core implements KeyListener {

public static void main(String[] args){
    new KeyTest().run();
}

Sprite player1;
Image hobo;
Image background;
animation hoboRun;
animationThread t1;



//init also calls init form superclass
public void init(){
    super.init();
    loadImages();
    Window w = s.getFullScreenWindow();
    w.setFocusTraversalKeysEnabled(false);
    w.addKeyListener(this);
}

//load method will go here.
//load all pics need for animation and sprite
public void loadImages(){
    background = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\yellow square.jpg").getImage();
    Image face1 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\circle.png").getImage();
    Image face2 = new ImageIcon("\\\\STUART-PC\\Users\\Stuart\\workspace\\Gaming\\one eye.png").getImage();
    hoboRun = new animation();
    hoboRun.addScene(face1, 250);
    hoboRun.addScene(face2, 250);
    player1 = new Sprite(hoboRun);
    t1 = new animationThread();
    t1.setAnimation(player1);
}


//key pressed
public void keyPressed(KeyEvent e){
    int keyCode = e.getKeyCode();
    if(keyCode == KeyEvent.VK_ESCAPE){
        stop();
    }
    if(keyCode == KeyEvent.VK_RIGHT){
        player1.setVelocityX(0.3f);
        try{
            t1.setRunning(true);
            Thread th1 = new Thread(t1);
            th1.start();
        }catch(Exception ex){System.out.println("noooo");}
    }
    if(keyCode == KeyEvent.VK_LEFT){
        player1.setVelocityX(-0.3f);
        try{
            t1.setRunning(true);
            Thread th1 = new Thread(t1);
            th1.start();
        }catch(Exception ex){System.out.println("noooo");}
    }
    if(keyCode == KeyEvent.VK_DOWN){
        player1.setVelocityY(0.3f);
        try{
            t1.setRunning(true);
            Thread th1 = new Thread(t1);
            th1.start();
        }catch(Exception ex){System.out.println("noooo");}
    }
    if(keyCode == KeyEvent.VK_UP){
        player1.setVelocityY(-0.3f);
        try{
            t1.setRunning(true);
            Thread th1 = new Thread(t1);;
            th1.start();
        }catch(Exception ex){System.out.println("noooo");}
    }else{
        e.consume();
    }
}

//keyReleased
@SuppressWarnings("static-access")
public void keyReleased(KeyEvent e){
    int keyCode = e.getKeyCode();
    if(keyCode == KeyEvent.VK_RIGHT || keyCode == KeyEvent.VK_LEFT){
        player1.setVelocityX(0);
        try{
            this.t1.setRunning(false);
        }catch(Exception ex){}
    }
    if(keyCode == KeyEvent.VK_UP || keyCode == KeyEvent.VK_DOWN){
        player1.setVelocityY(0);
        try{
            this.t1.setRunning(false);
        }catch(Exception ex){}
    }else{
        e.consume();
    }
}

//last method from interface
public void keyTyped(KeyEvent e){
    e.consume();
}

//draw
public void draw(Graphics2D g){
    Window w = s.getFullScreenWindow();
    g.setColor(w.getBackground());
    g.fillRect(0, 0, s.getWidth(), s.getHieght());
    g.setColor(w.getForeground());
    g.drawImage(player1.getImage(), Math.round(player1.getX()), Math.round(player1.getY()), null);
}

public void update(long timePassed){
    player1.update(timePassed);
}
}


abstract class Core {

    private static DisplayMode modes[] = {
        new DisplayMode(1600, 900, 64, 0),
        new DisplayMode(800, 600, 32, 0),
        new DisplayMode(800, 600, 24, 0),
        new DisplayMode(800, 600, 16, 0),
        new DisplayMode(800, 480, 32, 0),
        new DisplayMode(800, 480, 24, 0),
        new DisplayMode(800, 480, 16, 0),};
    private boolean running;
    protected ScreenManager s;

    //stop method
    public void stop() {
        running = false;
    }

    public void run() {
        try {
            init();
            gameLoop();
        } finally {
            s.restoreScreen();
        }
    }

    //set to full screen
    //set current background here
    public void init() {
        s = new ScreenManager();
        DisplayMode dm = s.findFirstCompatibleMode(modes);
        s.setFullScreen(dm);

        Window w = s.getFullScreenWindow();
        w.setFont(new Font("Arial", Font.PLAIN, 20));
        w.setBackground(Color.GREEN);
        w.setForeground(Color.WHITE);
        running = true;
    }

    //main gameLoop
    public void gameLoop() {
        long startTime = System.currentTimeMillis();
        long cumTime = startTime;

        while (running) {
            long timePassed = System.currentTimeMillis() - cumTime;
            cumTime += timePassed;

            update(timePassed);

            Graphics2D g = s.getGraphics();
            draw(g);
            g.dispose();
            s.update();

            try {
                Thread.sleep(20);
            } catch (Exception ex) {
            }
        }
    }

    //update animation
    public void update(long timePassed) {
    }

    //draws to screen
    abstract void draw(Graphics2D g);
}


public class animationThread implements Runnable{

String name;
volatile boolean playing;
Sprite a;

//constructor takes input from keyboard
public animationThread(){
}

//The run method for animation
public void run() {
    long startTime = System.currentTimeMillis();
    long cumTime = startTime; 

    while(getRunning()){
        long timePassed = System.currentTimeMillis() - cumTime;
        cumTime += timePassed;
        a.startAnimation(timePassed);
    }
}

public String getName(){
    return name;
}

public void setAnimation(Sprite a){
    this.a=a;
}

public void setName(String name){
    this.name=name;
}

public synchronized void setRunning(boolean running){
    this.playing = running;
}

public synchronized boolean getRunning(){
    return playing;
}
}


class animation {

    private ArrayList scenes;
    private int sceneIndex;
    private long movieTime;
    private long totalTime;

    //constructor
    public animation() {
        scenes = new ArrayList();
        totalTime = 0;
        start();
    }

    //add scene to ArrayLisy and set time for each scene
    public synchronized void addScene(Image i, long t) {
        totalTime += t;
        scenes.add(new OneScene(i, totalTime));
    }

    public synchronized void start() {
        movieTime = 0;
        sceneIndex = 0;
    }

    //change scenes
    public synchronized void update(long timePassed) {
        if (scenes.size() > 1) {
            movieTime += timePassed;
            if (movieTime >= totalTime) {
                movieTime = 0;
                sceneIndex = 0;
            }
            while (movieTime > getScene(sceneIndex).endTime) {
                sceneIndex++;
            }
        }
    }

    //get animations current scene(aka image)
    public synchronized Image getImage() {
        if (scenes.size() == 0) {
            return null;
        } else {
            return getScene(sceneIndex).pic;
        }
    }

    //get scene
    private OneScene getScene(int x) {
        return (OneScene) scenes.get(x);
    }

    //Private Inner CLASS//////////////
    private class OneScene {

        Image pic;
        long endTime;

        public OneScene(Image pic, long endTime) {
            this.pic = pic;
            this.endTime = endTime;
        }
    }
}

class Sprite {

    private animation a;
    private float x;
    private float y;
    private float vx;
    private float vy;

    //Constructor
    public Sprite(animation a) {
        this.a = a;
    }

    //change position
    public void update(long timePassed) {
        x += vx * timePassed;
        y += vy * timePassed;
    }

    public void startAnimation(long timePassed) {
        a.update(timePassed);
    }

    //get x position
    public float getX() {
        return x;
    }

    //get y position
    public float getY() {
        return y;
    }

    //set x
    public void setX(float x) {
        this.x = x;
    }

    //set y
    public void setY(float y) {
        this.y = y;
    }

    //get sprite width
    public int getWidth() {
        return a.getImage().getWidth(null);
    }

    //get sprite height
    public int getHeight() {
        return a.getImage().getHeight(null);
    }

    //get horizontal velocity
    public float getVelocityX() {
        return vx;
    }

    //get vertical velocity
    public float getVelocityY() {
        return vx;
    }

    //set horizontal velocity
    public void setVelocityX(float vx) {
        this.vx = vx;
    }

    //set vertical velocity
    public void setVelocityY(float vy) {
        this.vy = vy;
    }

    //get sprite / image
    public Image getImage() {
        return a.getImage();
    }
}

class ScreenManager {

    private GraphicsDevice vc;

    public ScreenManager() {
        GraphicsEnvironment e = GraphicsEnvironment.getLocalGraphicsEnvironment();
        vc = e.getDefaultScreenDevice();
    }

    //get all compatible DM
    public DisplayMode[] getCompatibleDisplayModes() {
        return vc.getDisplayModes();
    }

    //compares DM passed into vc DM and see if they match
    public DisplayMode findFirstCompatibleMode(DisplayMode modes[]) {
        DisplayMode goodModes[] = vc.getDisplayModes();
        for (int x = 0; x < modes.length; x++) {
            for (int y = 0; y < goodModes.length; y++) {
                if (displayModesMatch(modes[x], goodModes[y])) {
                    return modes[x];
                }
            }
        }
        return null;
    }

    //get current DM
    public DisplayMode getCurrentDisplayMode() {
        return vc.getDisplayMode();
    }

    //checks if two modes match each other
    public boolean displayModesMatch(DisplayMode m1, DisplayMode m2) {
        if (m1.getWidth() != m2.getWidth() || m1.getHeight() != m2.getHeight()) {
            return false;
        }
        if (m1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && m1.getBitDepth() != m2.getBitDepth()) {
            return false;
        }
        if (m1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && m1.getRefreshRate() != m2.getRefreshRate()) {
            return false;
        }
        return true;
    }

    //make frame full screen
    public void setFullScreen(DisplayMode dm) {
        JFrame f = new JFrame();
        f.setUndecorated(true);
        f.setIgnoreRepaint(true);
        f.setResizable(false);
        vc.setFullScreenWindow(f);

        if (dm != null && vc.isDisplayChangeSupported()) {
            try {
                vc.setDisplayMode(dm);
            } catch (Exception ex) {
            }
        }
        f.createBufferStrategy(2);
    }

    //sets graphics object = this return
    public Graphics2D getGraphics() {
        Window w = vc.getFullScreenWindow();
        if (w != null) {
            BufferStrategy s = w.getBufferStrategy();
            return (Graphics2D) s.getDrawGraphics();
        } else {
            return null;
        }
    }

    //updates display
    public void update() {
        Window w = vc.getFullScreenWindow();
        if (w != null) {
            BufferStrategy s = w.getBufferStrategy();
            if (!s.contentsLost()) {
                s.show();
            }
        }
    }

    //returns full screen window
    public Window getFullScreenWindow() {
        return vc.getFullScreenWindow();
    }

    //get width of window
    public int getWidth() {
        Window w = vc.getFullScreenWindow();
        if (w != null) {
            return w.getWidth();
        } else {
            return 0;
        }
    }

    //get height of window
    public int getHieght() {
        Window w = vc.getFullScreenWindow();
        if (w != null) {
            return w.getHeight();
        } else {
            return 0;
        }
    }

    //get out of full screen
    public void restoreScreen() {
        Window w = vc.getFullScreenWindow();
        if (w != null) {
            w.dispose();
        }
        vc.setFullScreenWindow(null);
    }

    //create image compatible with monitor
    public BufferedImage createCopatibleImage(int w, int h, int t) {
        Window win = vc.getFullScreenWindow();
        if (win != null) {
            GraphicsConfiguration gc = win.getGraphicsConfiguration();
            return gc.createCompatibleImage(w, h, t);
        }
        return null;
    }
}

Answer 1

In your animationThread class you are accessing the field "playing". This should be done using synchronized blocks. As one option put the "synchronized" keyword before "playing". As one option put the "volatile" keyword before "playing".

Without "synchronized" one thread may not see a change of "playing" done in another thread. So the threads may run forever. (short answer only, because I am on one of those fancy mobile devices now)

EDIT:

With the "volatile" keyword the "playing" field, the field is accessed each time its value is read or written. Without it, a Thread may use a copy of it and doesn't see when the original field has changed.

You can make blocks "synchronized":

boolean setRunning(boolean running) {
    synchronized (this) {
        this.playing = running;
    }
}

You can make methods "synchronized":

synchronized boolean setRunning(boolean running) {
    this.playing = running;
}

"synchronized" ensures, that no two threads execute this code at the same time and it makes sure that a thread sees an "up to date" object. For instance if one thread changes the "playing" field and when another thread enters a synchronized block, then that other thread will see the changed value of the field.

Answer 2

i just figured out something new that may be important to note: when holding down the the right key to move the sprite and update the animation the code is being re executed i found out by doing this

public void keyPressed(KeyEvent e){
    int keyCode = e.getKeyCode();
    if(keyCode == KeyEvent.VK_ESCAPE){
        stop();
    }
    if(keyCode == KeyEvent.VK_RIGHT){
        player1.setVelocityX(0.3f);
        try{
            t1.setRunning(true);
            Thread th1 = new Thread(t1);
            th1.start();
        }catch(Exception ex){System.out.println("noooo");}
        player1.setVelocityX(0);
    }

at first the spite doesn't move because the velocity is set to zero at the end but if i hold the butten long enough the sprite jumps across the screen.

this has to be the problem but idk how to fix it

Answer 3

hey thanks for all the help i just solved it though.

public void keyPressed(KeyEvent e){
    if(godDamn){
        godDamn=false;
        int keyCode = e.getKeyCode();
        if(keyCode == KeyEvent.VK_ESCAPE){
            stop();
        }
        if(keyCode == KeyEvent.VK_RIGHT){
            player1.setVelocityX(0.3f);
            try{
                t1.setRunning(true);
                Thread th1 = new Thread(t1);
                th1.start();
            }catch(Exception ex){System.out.println("noooo");}
        }
        if(keyCode == KeyEvent.VK_LEFT){
            player1.setVelocityX(-0.3f);
            try{
                t1.setRunning(true);
                Thread th1 = new Thread(t1);
                th1.start();
            }catch(Exception ex){System.out.println("noooo");}
        }
        if(keyCode == KeyEvent.VK_DOWN){
            player1.setVelocityY(0.3f);
            try{
                t1.setRunning(true);
                Thread th1 = new Thread(t1);
                th1.start();
            }catch(Exception ex){System.out.println("noooo");}
        }
        if(keyCode == KeyEvent.VK_UP){
            player1.setVelocityY(-0.3f);
            try{
                t1.setRunning(true);
                Thread th1 = new Thread(t1);;
                th1.start();
            }catch(Exception ex){System.out.println("noooo");}
        }else{
            e.consume();
        }

    }
}

//keyReleased
@SuppressWarnings("static-access")
public void keyReleased(KeyEvent e){
    int keyCode = e.getKeyCode();
    if(keyCode == KeyEvent.VK_RIGHT || keyCode == KeyEvent.VK_LEFT){
        player1.setVelocityX(0);
        try{
            this.t1.setRunning(false);
        }catch(Exception ex){}
        godDamn=true;
    }
    if(keyCode == KeyEvent.VK_UP || keyCode == KeyEvent.VK_DOWN){
        player1.setVelocityY(0);
        try{
            this.t1.setRunning(false);
        }catch(Exception ex){}
    }else{
        e.consume();
    }
}

the new boolean stops the multiple key events from executing. i have to fine tune it but other wise i'm good.