如何使用osg api在osgearth上绘制三角形

#include <osg/Geode>
#include <osg/Geometry>

osg::ref_ptr<osg::Geode> geode = new osg::Geode();

osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry();

osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
vertices->push_back(osg::Vec3(0.0f, 0.0f, 0.0f)); // 第一个顶点
vertices->push_back(osg::Vec3(1.0f, 0.0f, 0.0f)); // 第二个顶点
vertices->push_back(osg::Vec3(0.0f, 1.0f, 0.0f)); // 第三个顶点
geometry->setVertexArray(vertices.get());

osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array;
colors->push_back(osg::Vec4(1.0f, 0.0f, 0.0f, 1.0f)); // 第一个顶点的颜色
colors->push_back(osg::Vec4(0.0f, 1.0f, 0.0f, 1.0f)); // 第二个顶点的颜色
colors->push_back(osg::Vec4(0.0f, 0.0f, 1.0f, 1.0f)); // 第三个顶点的颜色
geometry->setColorArray(colors.get());
geometry->setColorBinding(osg::Geometry::BIND_PER_VERTEX);

geometry->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::TRIANGLES, 0, 3));

geode->addDrawable(geometry.get());

osg::ref_ptr<osg::Group> root = new osg::Group();
root->addChild(geode.get());

osgViewer::Viewer viewer;
viewer.setSceneData(root.get());

viewer.run();