osg画线_在osgearth里头画线

在OSGEarth中画线有多种方法，以下是其中一种基本方法：

1. 创建线段的几何体

osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
vertices->push_back(osg::Vec3d(0.0, 0.0, 0.0));
vertices->push_back(osg::Vec3d(0.0, 0.0, 1.0));

osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
geom->setVertexArray(vertices.get());

osg::ref_ptr<osg::DrawArrays> drawArrays = new osg::DrawArrays(osg::PrimitiveSet::LINES, 0, 2);
geom->addPrimitiveSet(drawArrays.get());

2. 创建线段的颜色

osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array;
colors->push_back(osg::Vec4(1.0f, 0.0f, 0.0f, 1.0f));

geom->setColorArray(colors.get());
geom->setColorBinding(osg::Geometry::BIND_OVERALL);

3. 创建线段的外观

osg::ref_ptr<osg::LineWidth> lineWidth = new osg::LineWidth(3.0f);

osg::ref_ptr<osg::StateSet> stateSet = geom->getOrCreateStateSet();
stateSet->setAttributeAndModes(lineWidth.get(), osg::StateAttribute::ON);

4. 创建节点并添加几何体

osg::ref_ptr<osg::Geode> geode = new osg::Geode;
geode->addDrawable(geom.get());

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

5. 将节点加入场景图

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

以上代码将会在场景中画一条从 (0,0,0) 到 (0,0,1) 的红色线段。