Question

I am new to andengine and even android game development. i have created sprite as a box. this box is now draggable by using this coding. it works fine.

but i want multitouch on this which i want to rotate a sprite with 2 finger in that box and even it should be draggable. …. plz help someone…

i am trying this many days but no idea.

   final float centerX = (CAMERA_WIDTH - this.mBox.getWidth()) / 2;

   final float centerY = (CAMERA_HEIGHT - this.mBox.getHeight()) / 2;
     Box= new Sprite(centerX, centerY, this.mBox,
            this.getVertexBufferObjectManager()) {

     public boolean onAreaTouched(TouchEvent pSceneTouchEvent,
                float pTouchAreaLocalX, float pTouchAreaLocalY) {
           this.setPosition(pSceneTouchEvent.getX() - this.getWidth()/ 2,
                           pSceneTouchEvent.getY() - this.getHeight() / 2);

             float pValueX = pSceneTouchEvent.getX();
            float pValueY = CAMERA_HEIGHT-pSceneTouchEvent.getY();

            float  dx = pValueX -  gun.getX();
            float  dy = pValueY -  gun.getY();

             double  Radius = Math.atan2(dy,dx);
             double Angle = Radius * 360 ;

                Box.setRotation((float)Math.toDegrees(Angle));
                 return true;
        }

Answer 1

Make sure you enabled multi touch in your game. You can use the same code used in the MultiTouchExample in the onLoadEngine method.

The algorithm is quite simple, similar to what you’ve posted here.

1. Keep track of up to 2 pointer IDs you get in onAreaTouched method. (You can get the pointer ID by calling pSceneTouchEvent.getPointerID()).
2. Keep track of the pointers’ state (Currently touching/not touching) and location (pTouchAreaLocalX and pTouchAreaLocalY).
3. Whenever 2 pointers are touching (You received ACTION_DOWN for both), save the initial angle. (Math.tan2(pointer1Y - pointer2Y, pointer1X - pointer2X)).
4. As long as ACTION_UP is not called for the pointers, update the new angle in every ACTION_MOVE event of the pointers, and get the angle delta (delta = currentAngle - initialAngle). Then call setRotation(Math.toDegrees(delta)).

To make the sprite dragable with 2 pointers, you need to move your sprite the lesser of the distance each pointer has moved. For example, if:

pointer1.dX = 50;
pointer1.dY = -20;
pointer2.dX = 40;
pointer2.dY = -10;

the sprite should move +40 units in the X axis, and -10 units in the Y axis.