How to interact with system in mobile games

[want2win]

hi all,

I am new to J2ME mobile gaming,
I am doing fighting game, can any one help me how to make my user character to interact with the system character.
please send me any sample code......



thanking u in advance.........

-------------
WANT2WIN

[petrib]

What "system character"? Aren't you writing the whole game yourself? In other words, you control all the characters in your own game yourself with your own code.

[raj_J2ME]

hi all,

I am new to J2ME mobile gaming,
I am doing fighting game, can any one help me how to make my user character to interact with the system character.
please send me any sample code......



thanking u in advance.........

-------------
WANT2WIN

Hi,
Have you design the system character?Hope you develop the logic?
search the same on Google, and you will find the few projects concept and might be code too.

[want2win]

hi petrib,

thanks for ur reply......
i am writing the whole game myself...

"system character" in the sense opponent character...

as i am doing fight game i hav 2 characters
1) hero
2) villain(opponent).

i wrote code for hero movements(able to animate).
when i am pressing the keys only the hero is acting according to the keys events.
now parallel to hero movements the villan should also animate.

but i dont know how to make both characters animate at a time in on the single layer.

so please help me regarding this issue....

thanking you in advance........

[grahamhughes]

OK... Java games 101.

You need to animate BOTH of your characters, in the run() method of a thread. Don't update anything in your paint() method, just paint. Don't update your character position in the keyPressed() method.

Here's some sample code... this isn't complete!! It is for example only, to see how a typical Java game is structured.

public class MyGame extends Canvas implements Runnable {
    private static final int MILLIS_PER_FRAME = 100;  // 10 frames per second
    private static final int MINIMUM_SLEEP = 10;  // always sleep() for at least this

    private static final int LEFT_KEY = -3;  // this is right for Nokias, different on others

    private boolean exitGame;
    private boolean leftKeyPressed;
    private boolean leftKeyReleased;
    private int playerX;

    public MyGame() {
        exitGame = false;
        (new Thread(this)).start();
    }

    public void run() {
        // set exitGame to true to exit the game-thread
        while (!exitGame) {
            long startTime = System.currentTimeMillis();

            // update the game state

            // first, process input
            if (leftKeyPressed) {
                playerX--;
                if (leftKeyReleased) {
                    leftKeyPressed = false;
                    leftKeyReleased = false;
                }
            }

            // and other updates for the player, like:
            // playerAnimationFrame++;

            // next, update the "computer" character
            updateComputerCharacter();

            // paint the screen
            repaint();
            serviceRepaints();

            // this keeps the frame rate regular
            int timeTaken = (int)(System.currentTimeMillis() - startTime);
            int sleepTime = MILLIS_PER_FRAME - timeTaken;
            if (sleepTime < MINIMUM_SLEEP) {
                // if the game doesn't sleep on every frame, it is possible that
                // no time will be given to the event thread, and keyPressed() events
                // won't be delivered promptly
                sleepTime = MINIMUM_SLEEP;
            }
            if (sleepTime > 0) {
                try {
                    Thread.sleep(sleepTime);
                } catch (Exception e) {
                    // ignore
                }
            }
        }
    }

    public void paint(Graphics g) {
        // don't do anything here, except paint
        drawBackground(g);
        drawPlayer(g);
        drawEnemy(g);
    }

    public void keyPressed(int key) {
        // do nothing here, except record the event
        switch (key) {
        case LEFT_KEY:
            leftKeyPressed = true;
            break;
        }
    }

    public void keyReleased(int key) {
        // do nothing here, except record the event
        switch (key) {
        case LEFT_KEY:
            leftKeyReleased = true;
            break;
        }
    }
} 

Why are there two booleans for one key? Why not?

// don't do this!!
boolean leftKeyPressed;

public void keyPressed(int key) {
    if (key == LEFT_KEY) {
        leftKeyPressed = true;
    }
}

public void keyReleased(int key) {
    if (key == LEFT_KEY) {
        leftKeyPressed = false;
    }
}

Don't do this, because it is possible to receive a pressed and released event during the same frame. With this code, the update code will never see that key pressed, because data will be lost.

Setting MINIMUM_SLEEP to zero will make the game faster. But on some devices, it will make it less responsive to user input. Slowing the game down like this actually makes it feel faster.

Hope this helps.

Cheers,
Graham.

[balagopalks]

Also to add : have a look at Java Games Articles

Regards
Gopal

[junfeng14]

Hi Graham.,

Meaning I will be using game builder on netbeans ?

Thank you,

Jun Feng

[grahamhughes]

I've never used netbeans, I have no idea.

Graham.