Added osgterrain example

examples/osgterrain/osgterrain.cpp

@@ -0,0 +1,132 @@
+#include <osgViewer/Viewer>
+
+#include <osg/Group>
+#include <osg/Geode>
+#include <osg/ShapeDrawable>
+#include <osg/Texture2D>
+#include <osg/PositionAttitudeTransform>
+#include <osg/MatrixTransform>
+#include <osg/CoordinateSystemNode>
+#include <osg/ClusterCullingCallback>
+
+#include <osgDB/FileUtils>
+#include <osgDB/ReadFile>
+
+#include <osgText/FadeText>
+
+#include <osgSim/OverlayNode>
+#include <osgSim/SphereSegment>
+
+#include <osgGA/TerrainManipulator>
+
+#include <iostream>
+
+osg::Node* createEarth()
+{
+    osg::TessellationHints* hints = new osg::TessellationHints;
+    hints->setDetailRatio(5.0f);
+
+    
+    osg::ShapeDrawable* sd = new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0,0.0,0.0), osg::WGS_84_RADIUS_POLAR), hints);
+    
+    osg::Geode* geode = new osg::Geode;
+    geode->addDrawable(sd);
+    
+    std::string filename = osgDB::findDataFile("Images/land_shallow_topo_2048.jpg");
+    geode->getOrCreateStateSet()->setTextureAttributeAndModes(0, new osg::Texture2D(osgDB::readImageFile(filename)));
+    
+    osg::CoordinateSystemNode* csn = new osg::CoordinateSystemNode;
+    csn->setEllipsoidModel(new osg::EllipsoidModel());
+    csn->addChild(geode);
+    
+    return csn;
+    
+}
+
+osgText::Text* createText(osg::EllipsoidModel* ellipsoid, double latitude, double longitude, double height, const std::string& str)
+{
+    double X,Y,Z;
+    ellipsoid->convertLatLongHeightToXYZ( osg::DegreesToRadians(latitude), osg::DegreesToRadians(longitude), height, X, Y, Z);
+
+
+    osgText::Text* text = new osgText::FadeText;
+
+    osg::Vec3 normal = ellipsoid->computeLocalUpVector( X, Y, Z);
+    text->setCullCallback(new osg::ClusterCullingCallback(osg::Vec3(X,Y,Z), normal, 0.0));
+
+    text->setText(str);
+    text->setFont("fonts/arial.ttf");
+    text->setPosition(osg::Vec3(X,Y,Z));
+    text->setCharacterSize(300000.0f);
+    text->setCharacterSizeMode(osgText::Text::OBJECT_COORDS_WITH_MAXIMUM_SCREEN_SIZE_CAPPED_BY_FONT_HEIGHT);
+    text->setAutoRotateToScreen(true);
+    
+    return text;
+}
+
+osg::Node* createFadeText(osg::EllipsoidModel* ellipsoid)
+{
+    osg::Group* group = new osg::Group;
+
+    group->getOrCreateStateSet()->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
+    
+    osg::Geode* geode = new osg::Geode;
+    group->addChild(geode);
+    
+    std::vector<std::string> textList;
+    textList.push_back("Town");
+    textList.push_back("City");
+    textList.push_back("Village");
+    textList.push_back("River");
+    textList.push_back("Mountain");
+    textList.push_back("Road");
+    textList.push_back("Lake");
+    
+    unsigned int numLat = 15;
+    unsigned int numLong = 20;
+    double latitude = 0.0;
+    double longitude = -100.0;
+    double deltaLatitude = 1.0f;
+    double deltaLongitude = 1.0f;
+
+    unsigned int t = 0;
+    for(unsigned int i = 0; i < numLat; ++i, latitude += deltaLatitude)
+    {
+        double lgnt = longitude;
+        for(unsigned int j = 0; j < numLong; ++j, ++t, lgnt += deltaLongitude)
+        {
+            geode->addDrawable( createText( ellipsoid, latitude, lgnt, 0, textList[t % textList.size()]) );
+        }
+    }
+
+    return group;
+} 
+
+
+int main(int, char**)
+{
+    // construct the viewer.
+    osgViewer::Viewer viewer;
+
+    viewer.getCamera()->setComputeNearFarMode(osg::CullSettings::COMPUTE_NEAR_FAR_USING_PRIMITIVES);
+    viewer.getCamera()->setNearFarRatio(0.00001f);
+    
+    // read the scene from the list of file specified commandline args.
+    osg::ref_ptr<osg::Node> root = createEarth();
+    
+    if (!root) return 0;
+
+    // add a viewport to the viewer and attach the scene graph.
+    viewer.setSceneData(root.get());
+
+    osg::CoordinateSystemNode* csn = dynamic_cast<osg::CoordinateSystemNode*>(root.get());
+    if (csn)
+    {
+        // add fade text around the globe
+        csn->addChild(createFadeText(csn->getEllipsoidModel()));
+    }    
+
+    viewer.setCameraManipulator(new osgGA::TerrainManipulator);
+
+    return viewer.run();
+}