/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *
 *    (C) 2007-2008, Open Source Geospatial Foundation (OSGeo)
 *
 *    This library is free software; you can redistribute it and/or
 *    modify it under the terms of the GNU Lesser General Public
 *    License as published by the Free Software Foundation;
 *    version 2.1 of the License.
 *
 *    This library is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *    Lesser General Public License for more details.
 */
package org.geotools.renderer3d.navigationgestures;

import com.jme.math.Vector3f;
import com.jme.renderer.Camera;

import java.awt.event.InputEvent;
import java.awt.event.MouseEvent;

/**
 * Implements a panning gesture for the 3D renderer.
 * <p/>
 * Pan / move across map with left mouse button drag (will actually move camera along the left/right,
 * up/down axes of the camera). (A single left mouse button click will select / click on an item on map).
 * The drag has some inertia, so a quick drag will move the camera faster than a slow one.
 * The camera is kept above the ground level at all times though.
 * <p/>
 * Also scale pan amount by altitude.
 *
 * @author Hans H�ggstr�m
 */
public final class PanGesture
        extends AbstractDragGesture
{

    //======================================================================
    // Private Constants

    private static final float DEFAULT_PAN_SENSITIVITY = 0.1f;

    //======================================================================
    // Public Methods

    //----------------------------------------------------------------------
    // Constructors

    public PanGesture()
    {
        super( DEFAULT_PAN_SENSITIVITY, MouseEvent.BUTTON3, InputEvent.BUTTON3_DOWN_MASK );
    }

    //======================================================================
    // Protected Methods

    protected void applyDragGesture( final Camera camera, final float deltaX, final float deltaY )
    {
        final float altitudeFactor = getAltitudeFactor();

        // TODO: Add inertia and acceleration
        // TODO: Add ground collision detection and keep the camera above ground.

        final Vector3f newLocation = new Vector3f( camera.getLocation() );

        newLocation.scaleAdd( -deltaX * altitudeFactor, camera.getLeft(), newLocation );
        newLocation.scaleAdd( -deltaY * altitudeFactor, camera.getUp(), newLocation );

        camera.setLocation( newLocation );
    }

}