mouse zoom

OpenGL Development JOGL Development
#1

Hi,

I hope this isn’t too far OT, but just looking for a pointer. I’m using a MouseInputAdapter to catch mouse buttons and now I’m trying to zoom my model with the mouse. I’d like to zoom in when the mouse rolls forwards, and zoom out when the mouse is moved backwards, but only the motions forwards and backwards.

Anyone know how to detect this?

#2

I extend the MouseInputAdapter and use a mousePressed() event to call a method in my Renderer called ‘startZoom()’ where it stores a global point signifying the first point of the starting of the zoom:


    public void mousePressed( MouseEvent e ) {
        if (SwingUtilities.isMiddleMouseButton(e)) {
            renderer.startZoom(e.getPoint());
        } 
    }

    public void startZoom( Point MousePt ) {
        mousePoint.x = MousePt.x;
        mousePoint.y = MousePt.y;
    }

Next I have a mouseDragged() method in my mouse handler that calls the zoom() method of my renderer to calculate the deltas between the first point and the current point being dragged so that I can use this delta value for calculating the zoom


    public void mouseDragged( MouseEvent e ) {
        if (SwingUtilities.isMiddleMouseButton(e)) {
            renderer.zoom(e.getPoint() );
        }
    }


    public void zoom( Point MousePt ) {
        // calculate the delta point
        Point delta = new Point();
        delta.x = MousePt.x - mousePoint.x;
        delta.y = MousePt.y - mousePoint.y;

        // set the new mouse point to the old mouse point
        mousePoint.x = MousePt.x;
        mousePoint.y = MousePt.y; 
    }

and in my display() method I use the delta point to apply it either to a rotation or a zoom or whatever…this part is up to you on how to implement it.