android game-dev problem.

iQue · July 5th, 2012, 02:22 PM

Hi!
Im making a game with a sprite that moves thru a virtual joystick, only my joystick is taken from a code example and Ive played with it for a while but the problem is that when I change the location of the joystick on the screen, it stops working correctly, and I cant figure out why. Below follows the code that I use for controlling the sprite with the joystick and how I draw it.

Code:

//variables:
    public float initx = 425;
    public float inity = 267;
    public Point _touchingPoint = new Point(425, 267);
    public Point _pointerPosition = new Point(220, 150);
    private Boolean _dragging = false;
    private MotionEvent lastEvent;




    @Override
    public boolean onTouchEvent(MotionEvent event) {

        if (event == null && lastEvent == null) {
            return _dragging;
        } else if (event == null && lastEvent != null) {
            event = lastEvent;
        } else {
            lastEvent = event;
        }
        // drag drop
        if (event.getAction() == MotionEvent.ACTION_DOWN) {
            _dragging = true;

        } else if (event.getAction() == MotionEvent.ACTION_UP) {
            _dragging = false;
        }

        if (_dragging) {
            // get the pos
            _touchingPoint.x = (int) event.getX();
            _touchingPoint.y = (int) event.getY();

            // bound to a box
            if (_touchingPoint.x < 400) {
                _touchingPoint.x = 400;
            }
            if (_touchingPoint.x > 450) {
                _touchingPoint.x = 450;
            }
            if (_touchingPoint.y < 240) {
                _touchingPoint.y = 240;
            }
            if (_touchingPoint.y > 290) {
                _touchingPoint.y = 290;
            }

            // get the angle
            double angle = Math.atan2(_touchingPoint.y - inity,
                    _touchingPoint.x - initx) / (Math.PI / 180);

            // Move the beetle in proportion to how far
            // the joystick is dragged from its center
            _pointerPosition.y += Math.sin(angle * (Math.PI / 180))
                    * (_touchingPoint.x / 70);
            _pointerPosition.x += Math.cos(angle * (Math.PI / 180))
                    * (_touchingPoint.x / 70);

            // stop the sprite from goin thru
            if (_pointerPosition.x + happy.getWidth() >= getWidth()) {
                _pointerPosition.x = getWidth() - happy.getWidth();
            }

            if (_pointerPosition.x < 0) {
                _pointerPosition.x = 0;
            }

            if (_pointerPosition.y + happy.getHeight() >= getHeight()) {
                _pointerPosition.y = getHeight() - happy.getHeight();
            }

            if (_pointerPosition.y < 0) {
                _pointerPosition.y = 0;
            }
        }

        else if (!_dragging) {
            // Snap back to center when the joystick is released
            _touchingPoint.x = (int) initx;
            _touchingPoint.y = (int) inity;
            // shaft.alpha = 0;
        }
        return true;
    }

    public void render(Canvas canvas) {
        canvas.drawColor(Color.BLUE);
        canvas.drawBitmap(joystick.get_joystickBg(), 380, 220, null);
        canvas.drawBitmap(happy, _pointerPosition.x, _pointerPosition.y, null);
        canvas.drawBitmap(joystick.get_joystick(), _touchingPoint.x - 26,
                _touchingPoint.y - 26, null);
    }

initx and inity is where the bg for the joystick is, and if I change these variables + the pointer, the joystick stops working the way it should. But I need to change them since I want to move it :P
So if any1 can help, please do!

also, if you cant help me with that I have the problem that this app crashes when I try starting it in landscape-mode, and since I want to force it into landscape this is a problem, do NOT want portrait for my game. (changing it in manifest to "landscape" makes it crash)

Thank you!

jonbonazza · July 6th, 2012, 06:45 AM

If you change initx and inity, you would also need to change the x and y of both _touching Point and _pointerPosition to compensate from the differnce in location.

Allpowerfool · July 31st, 2012, 07:51 PM

the problem is your bounding box, you hard coded the numbers, you should adjust it to include your initx/inity and just subtract/add width/height. Would be easier if you just used a rectangle class.