osgearth2.10 实现卫星轨道的绘制代码

以下是使用OSGEarth 2.10实现卫星轨道的绘制代码示例：

#include <osgEarth/MapNode>
#include <osgEarthUtil/Sky>
#include <osgEarthUtil/Controls>
#include <osgEarthUtil/ExampleResources>
#include <osgEarthUtil/Orbit>
#include <osgEarthUtil/Controls>
#include <osgEarthUtil/EarthManipulator>
#include <osgEarthAnnotation/AnnotationRegistry>
#include <osgEarthAnnotation/AnnotationNode>
#include <osgViewer/Viewer>

using namespace osgEarth;
using namespace osgEarth::Util;
using namespace osgEarth::Annotation;
using namespace osgEarth::Util::Controls;

//创建一个标记节点
AnnotationNode* createLabel(osg::Vec3d position, const std::string& text)
{
    LabelNode* label = new LabelNode(text);
    label->setStyle(
        new TextStyle(
            Color::White,
            Color::Black,
            2.0f));
    AnnotationNode* node = new AnnotationNode(
        label,
        GeoPoint(
            MapNode::getMapSRS(),
            position,
            ALTMODE_RELATIVE),
        AltitudeSymbol::CLAMP_TO_TERRAIN);
    return node;
}

int main(int argc, char** argv)
{
    osgViewer::Viewer viewer;

    //创建地球模型
    osgEarth::Map* map = new osgEarth::Map();
    osgEarth::TerrainOptions options;
    options.enableMercatorFastPath() = true;
    map->setTerrainOptions(options);
    osgEarth::ImageLayer* layer = new osgEarth::ImageLayer(osgEarth::TileSourceOptions::create("world"), osgEarth::ProfileOptions::create("global-geodetic"));
    map->addLayer(layer);
    osgEarth::ModelLayer* modelLayer = new osgEarth::ModelLayer(osgEarth::ModelLayerOptions("Earth"));
    osgEarth::ModelSourceOptions modelOptions;
    modelOptions.setURL(osgEarth::URI(osgEarth::URI::ZERO, EXAMPLES_DIR) + "osgearth/globe.earth");
    modelLayer->addModel(modelOptions);
    map->addLayer(modelLayer);
    osg::ref_ptr<osgEarth::MapNode> mapNode = new osgEarth::MapNode(map);

    //创建相机
    osg::ref_ptr<osg::Camera> camera = viewer.getCamera();
    camera->setViewport(0, 0, 800, 600);
    camera->setProjectionMatrixAsPerspective(
        30.0,
        static_cast<double>(800) / static_cast<double>(600),
        1.0,
        1000.0);

    //创建卫星轨道
    osg::ref_ptr<Orbit> orbit = new Orbit();
    orbit->setCenter(osg::Vec3d(0.0, 0.0, 0.0));
    orbit->setRadius(6371000.0 + 1000000.0);
    orbit->setInclination(osg::DegreesToRadians(45.0));
    orbit->setNumSegments(100);
    orbit->setRenderBinNumber(1);
    orbit->setAutoScaleToScreen(true);
    orbit->setColor(osg::Vec4(1.0, 1.0, 0.0, 1.0));
    mapNode->addChild(orbit.get());

    //创建标记节点
    osg::Vec3d position = orbit->getPosition(osg::Timer::instance()->time_s());
    osg::ref_ptr<AnnotationNode> label = createLabel(position, "Satellite");
    mapNode->addChild(label.get());

    //设置相机的初始位置和目标
    osgEarth::Util::EarthManipulator* manipulator = new osgEarth::Util::EarthManipulator();
    manipulator->setViewpoint(osgEarth::Viewpoint(
        osgEarth::SpatialReference::get("wgs84"),
        -122.4167, 37.7833, 5000.0,
        0.0, -90.0, 500000.0));
    viewer.setCameraManipulator(manipulator);

    //添加天空盒
    osg::ref_ptr<SkyNode> sky = SkyNode::create(map);
    mapNode->addChild(sky.get());

    //设置相机的初始位置和目标
    osgEarth::Viewpoint vp(
        osgEarth::SpatialReference::get("wgs84"),
        -122.4167, 37.7833, 5000.0,
        0.0, -90.0, 500000.0);
    manipulator->setViewpoint(vp);

    viewer.setSceneData(mapNode.get());
    return viewer.run();
}

在这个示例中，我们首先创建了一个地球模型，并将其添加到地图中。接着，我们创建了一个相机，并设置了其视口和投影矩阵。然后，我们创建了一个卫星轨道，将其添加到地球模型中，并创建了一个标记节点，将其添加到地球模型中。最后，我们添加了一个天空盒，并设置了相机的初始位置和目标。