com.nitrous.gwt.earth.client.demo.TiltCameraDemo.java Source code

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Here is the source code for com.nitrous.gwt.earth.client.demo.TiltCameraDemo.java

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/*
 * Copyright 2012 Nick Kerr
 *
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.nitrous.gwt.earth.client.demo;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.ui.RootLayoutPanel;
import com.nitrous.gwt.earth.client.api.GELayerId;
import com.nitrous.gwt.earth.client.api.GEPlugin;
import com.nitrous.gwt.earth.client.api.GEPluginReadyListener;
import com.nitrous.gwt.earth.client.api.GEVisibility;
import com.nitrous.gwt.earth.client.api.GoogleEarth;
import com.nitrous.gwt.earth.client.api.GoogleEarthWidget;
import com.nitrous.gwt.earth.client.api.KmlAltitudeMode;
import com.nitrous.gwt.earth.client.api.KmlLookAt;

/**
 * A GWT implementation of the demo found <a href="http://code.google.com/apis/ajax/playground/#tilt_camera">here</a>.
 * 
 * @author nick
 */
public class TiltCameraDemo implements EntryPoint {

    private GoogleEarthWidget earth;

    public void onModuleLoad() {
        // Load the Earth API
        GoogleEarth.loadApi(new Runnable() {
            @Override
            public void run() {
                // start the application
                onApiLoaded();
            }
        });
    }

    /**
     * The Google earth API has loaded, start the application
     */
    private void onApiLoaded() {
        // construct the UI widget
        earth = new GoogleEarthWidget();

        // register a listener to be notified when the earth plug-in has loaded
        earth.addPluginReadyListener(new GEPluginReadyListener() {
            public void pluginReady(GEPlugin ge) {
                // show map content once the plugin has loaded
                loadMapContent();
            }

            public void pluginInitFailure() {
                // failure!
                Window.alert("Failed to initialize Google Earth Plug-in");
            }
        });

        RootLayoutPanel.get().add(earth);

        // begin loading the Google Earth Plug-in
        earth.init();
    }

    /**
     * Display content on the map
     */
    private void loadMapContent() {
        // The GEPlugin is the core class and is a great place to start browsing
        // the API
        GEPlugin ge = earth.getGEPlugin();
        ge.getWindow().setVisibility(true);

        // add a navigation control
        ge.getNavigationControl().setVisibility(GEVisibility.VISIBILITY_AUTO);

        // add some layers
        ge.enableLayer(GELayerId.LAYER_BORDERS, true);
        ge.enableLayer(GELayerId.LAYER_ROADS, true);

        // begin tilting the camera
        tiltCamera(0);
    }

    private void tiltCamera(final int count) {
        GEPlugin ge = earth.getGEPlugin();

        double idealTilt = 80; // all angles in the API are in degrees.
        double c0 = 0.90;
        KmlLookAt la = ge.getView().copyAsLookAt(KmlAltitudeMode.ALTITUDE_RELATIVE_TO_GROUND);

        double tilt = la.getTilt();
        tilt = c0 * tilt + (1 - c0) * idealTilt;
        la.setTilt(tilt);
        ge.getView().setAbstractView(la);

        // tilt 60 times, pausing 33ms between updates
        if (count < 60) {
            Timer t = new Timer() {
                @Override
                public void run() {
                    tiltCamera(count + 1);
                }
            };
            t.schedule(33);
        }
    }
}