shapeutils.java

world wind java sdk 源码

/* Copyright (C) 2001, 2008 United States Government as represented by
the Administrator of the National Aeronautics and Space Administration.
All Rights Reserved.
*/
package gov.nasa.worldwind.examples.util;

import gov.nasa.worldwind.WorldWindow;
import gov.nasa.worldwind.geom.*;
import gov.nasa.worldwind.globes.Globe;
import gov.nasa.worldwind.view.OrbitView;

import java.util.*;

/**
 * @author dcollins
 * @version $Id: ShapeUtils.java 9168 2009-03-05 00:40:03Z dcollins $
 */
public class ShapeUtils
{
    public static double getViewportScaleFactor(WorldWindow wwd)
    {
        return ((OrbitView) wwd.getView()).getZoom() / 8.0;
    }

    public static Position getNewShapePosition(WorldWindow wwd)
    {
        Line ray = new Line(wwd.getView().getEyePoint(), wwd.getView().getForwardVector());
        Intersection[] intersection = wwd.getSceneController().getTerrain().intersect(ray);

        if (intersection != null && intersection.length != 0)
        {
            return wwd.getModel().getGlobe().computePositionFromPoint(intersection[0].getIntersectionPoint());
        }
        else if (wwd.getView() instanceof OrbitView)
        {
            return ((OrbitView) wwd.getView()).getCenterPosition();
        }

        return Position.ZERO;
    }

    public static Angle getNewShapeHeading(WorldWindow wwd, boolean matchViewHeading)
    {
        if (matchViewHeading)
        {
            if (wwd.getView() instanceof OrbitView)
            {
                return ((OrbitView) wwd.getView()).getHeading();
            }
        }

        return Angle.ZERO;
    }

    public static List<LatLon> createSquareInViewport(WorldWindow wwd, Position position, Angle heading,
        double sizeInMeters)
    {
        Globe globe = wwd.getModel().getGlobe();
        Matrix transform = Matrix.IDENTITY;
        transform = transform.multiply(globe.computeTransformToPosition(position));
        transform = transform.multiply(Matrix.fromRotationZ(heading.multiply(-1)));

        double widthOver2 = sizeInMeters / 2.0;
        double heightOver2 = sizeInMeters / 2.0;
        Vec4[] points = new Vec4[]
        {
            new Vec4(-widthOver2, -heightOver2, 0.0).transformBy4(transform), // lower left
            new Vec4(widthOver2,  -heightOver2, 0.0).transformBy4(transform), // lower right
            new Vec4(widthOver2,   heightOver2, 0.0).transformBy4(transform), // upper right
            new Vec4(-widthOver2,  heightOver2, 0.0).transformBy4(transform)  // upper left
        };


        LatLon[] locations = new LatLon[points.length];
        for (int i = 0; i < locations.length; i++)
        {
            locations[i] = new LatLon(globe.computePositionFromPoint(points[i]));
        }

        return Arrays.asList(locations);
    }
}