[java]background image

[galaxyAbstractor]

I want to make a background image in my game I do in class. Can anyone tell me how? Here is the code:

package dk.koderko.games.pong; // vilket package det tillhör

import java.io.IOException; // importerar några klasser för att kunna göra miljön i spelet
import javax.microedition.lcdui.game.GameCanvas;
import javax.microedition.lcdui.game.Sprite;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
import java.util.Random;

public class PongCanvas extends GameCanvas implements Runnable { // gör så att man kan starta spelet

    public PongCanvas() {
        super(false);
    }
    
    public void run() {
        
        while(true) {
            
            updateScreen(getGraphics());
            
            try {
                Thread.sleep(sleepTime);
            } catch (Exception e) {
                
            }
        }
        
    }
    
    public void start() { // vad man ska göra när spelet startat

        try {
            ballImg = Image.createImage("/ball.png"); // bilder
            padImg = Image.createImage("/pad.png");
        } catch (IOException ioex) {
            System.out.println(ioex);
        }

        ballSprite = new Sprite(ballImg, 20, 21); // gör spriten
        ballSprite.defineReferencePixel(2, 2);
        ballSprite.setRefPixelPosition(ballX, ballY);

        padSprite = new Sprite(padImg, 3, 20);
        padSprite.defineReferencePixel(1, 10);
        padSprite.setRefPixelPosition(padX, padY);        

        AISprite = new Sprite(padImg, 3, 20);
        AISprite.defineReferencePixel(3, 10);
        AISprite.setRefPixelPosition(AIX, AIY);

        Thread runner = new Thread(this);
        runner.start();
    }
    
    private void createBackground(Graphics g) { // gör bakgrunden
        g.setColor(0x000000); //sätter färgen på bakgrunden
        g.fillRect(0, 0, getWidth(), getHeight());
    }

    private void updateScreen(Graphics g) {
        
        createBackground(g);
        createScoreboard(g);
        creatWidth(g); // jag vet, felstavning på båda
        
        moveBall(); 
        movePad();
        moveAI();
        
        ballSprite.setRefPixelPosition(ballX, ballY);
        ballSprite.paint(g);        

        padSprite.setRefPixelPosition(padX, padY);
        padSprite.paint(g);

        AISprite.setRefPixelPosition(AIX, AIY);
        AISprite.paint(g);
        
        flushGraphics();
        
    }
    
    private void moveBall() { // flyttar bollen
        if (ballDirection == 0) {
            ballX -= ballXVel;
            ballY -= ballYVel;
        } else if (ballDirection == 1) {
            ballX += ballXVel;
            ballY -= ballYVel;
        } else if (ballDirection == 2) {
            ballX += ballXVel;
            ballY += ballYVel;
        } else if (ballDirection == 3) {
            ballX -= ballXVel;
            ballY += ballYVel;
        }

        if (ballDirection == 0 && ballX < 0) {
            ballDirection = 1;
            AIScore++;                                        // Added
        } else if (ballDirection == 0 && ballY < 0) {
            ballDirection = 3;
        } else if (ballDirection == 1 && ballY < 0) {
            ballDirection = 2;
        } else if (ballDirection == 1 && ballX > getWidth()) {
            ballDirection = 0;
            padScore++;                                        // Added
            if (sleepTime > 5) sleepTime--;
        } else if (ballDirection == 2 && ballY > getHeight()) {
            ballDirection = 1;
        } else if (ballDirection == 2 && ballX > getWidth()) {
            ballDirection = 3;
            padScore++;                                        // Added
            if (sleepTime > 5) sleepTime--;
        } else if (ballDirection == 3 && ballY > getHeight()) {
            ballDirection = 0;
        } else if (ballDirection == 3 && ballX < 0) {
            ballDirection = 2;
            AIScore++;                                        // Added
        }

        if (ballDirection == 0 && ballSprite.collidesWith(padSprite, false)) {
            ballDirection = 1;
        } else if (ballDirection == 3 && ballSprite.collidesWith(padSprite, false)) {
            ballDirection = 2;
        } else if (ballDirection == 1 && ballSprite.collidesWith(AISprite, false)) {
            ballDirection = 0;
        } else if (ballDirection == 2 && ballSprite.collidesWith(AISprite, false)) {
            ballDirection = 3;
        }
        
        sleepTime += AIScore - padScore;                                // Added
        if (sleepTime < 15) sleepTime = 10;                                 // Added
    
    }

    private void movePad() { // fixar så att man kanm kontrollera paden
        int keyState = getKeyStates();
        
        if ((keyState & UP_PRESSED) != 0 && padY > padSprite.getHeight() / 2) {
            padY -= padYVel;
        } else if ((keyState & DOWN_PRESSED) != 0 && padY <= getHeight() - padSprite.getHeight() / 2) {
            padY += padYVel;
        } 
    }
    
    private void moveAI() {
        Random random = new Random();
        actX = getWidth() / 3 + Math.abs(random.nextInt() % (getWidth() / 8));
        
        if (ballY < AIY && ballX > actX && AIY > AISprite.getHeight() / 2) AIY -= AIYVel;
        if (ballY > AIY && ballX > actX && AIY < getHeight() - AISprite.getHeight() / 2) AIY += AIYVel;
    }

    private void createScoreboard(Graphics g) {                                // Added entirely new method
        g.setColor(0xffffff);
        g.drawString(padScore + "  -  " + AIScore, getWidth() / 2, 20, Graphics.HCENTER | Graphics.TOP);        
    }
    
    private void creatWidth(Graphics g) {                                // Added entirely new method
        g.setColor(0xffffff);
        g.drawString(getWidth() + "  -  " + getHeight(), getWidth() / 2, 30, Graphics.HCENTER | Graphics.TOP);        
    }
    
    private int sleepTime = 10;
    
    private Image ballImg;
    private Sprite ballSprite;
    private int ballX = getWidth() / 2;
    private int ballY = getHeight() / 2;
    private final static int ballXVel = 3;
    private final static int ballYVel = 1;
    private int ballDirection = 1;

    
    private Image padImg;
    private Sprite padSprite;
    private int padX = 10;
    private int padY = getHeight() / 2;
    private final static int padYVel = 2;
    
    private Sprite AISprite;
    private int AIX = getWidth() - 10;
    private int AIY = getHeight() / 2;
    private final static int AIYVel = 2;
    private int actX;
    
    
    private int padScore = 0;                                        // Added
    private int AIScore = 0;                                        // Added
    
}

Ignore the swedish comments. The background image I made is 240 x 291 and it's name is back.png. If you could tell me how in a easy way I would be thankful.

[worldwise001]

In your createBackground function:

    private void createBackground(Graphics g) { // gör bakgrunden
        //g.setColor(0x000000); //sätter färgen på bakgrunden
       g.drawImage(bgImg, 0, 0, getWidth(), getHeight(), null);
        //g.fillRect(0, 0, getWidth(), getHeight());
    }

In your global var list at the end:

    private int sleepTime = 10;
    
    private Image bgImg;

    private Image ballImg;
    private Sprite ballSprite;

In your start function:

    public void start() { // vad man ska göra när spelet startat

        try {
            ballImg = Image.createImage("/ball.png"); // bilder
            padImg = Image.createImage("/pad.png");
            bgImg = Image.createImage("/bgimg.png");
        } catch (IOException ioex) {
            System.out.println(ioex);
        }

I'm not sure if this will create extra overhead in your application, but give it a shot anyway.

[galaxyAbstractor]

it returns:

Uncaught exception java/lang/Error: Unresolved compilation problem:
The method drawImage(Image, int, int, int) in the type Graphics is not applicable for the arguments (Image, int, int, int, int, null)
.

[galaxyAbstractor]

hey would be really good if this got fixed to my java lesson tomorrow.

[nyanko]

remove the extra arguments on the function call at the line specified and see what happen xD

Also you could review the java API to know which arguments that function accepts, I don't remember that function D:

[galaxyAbstractor]

remove the extra arguments on the function call at the line specified and see what happen xD

Also you could review the java API to know which arguments that function accepts, I don't remember that function D:

which arguments do you mean?

[galaxyAbstractor]

in:

    private void createBackground(Graphics g) { // gör bakgrunden
      //  g.setColor(0x000000); //sätter färgen på bakgrunden
      g.drawImage(bgImg, 0, 0, getWidth(), getHeight(), null);
       // g.fillRect(0, 0, getWidth(), getHeight());
    }

it want me to change it to

   private void createBackground(Graphics g) { // gör bakgrunden
      //  g.setColor(0x000000); //sätter färgen på bakgrunden
      g.drawImage(bgImg);
       // g.fillRect(0, 0, getWidth(), getHeight());
    }

When I do, it want's me to add them again...

It says: "The method drawImage(Image, int, int, int) in the type Graphics isn't applicable for the arguments (Image, int, int, int, int)"

[worldwise001]

Problem resolved.

the method was actually g.drawImage(Image img, int x, int y, int anchor);

anchor is used for relative placement of text. Weird thing how java decided to implement this in the microedition version as opposed to in the full version.

so it should have been g.drawImage(img, 0, 0, 0);

Also you could review the java API to know which arguments that function accepts, I don't remember that function D:

Well he was using Java ME (microedition) which is apparently drastically different from Java SE (standard edition). APIs for ME are at http://java.sun.com/javame/reference/apis/jsr118/

[galaxyAbstractor]

Thank you :P. *closed*