OSG学习：使用OSG中预定义的几何体

常用的内嵌几何体包括：

osg::Box                    //正方体
osg::Capsule                //太空舱
osg::Cone                   //椎体
osg::Cylinder               //柱体
osg::HeightField            //高度图
osg::InfinitePlane          //无限平面
osg::Sphere                 //球体
osg::TriangleMesh           //三角片

以下是代码示例：

/**********************************************************
*Write by FlySky
*[e-mail]  http://www.OsgChina.org
**********************************************************/

#include <osgViewer/Viewer>

#include <osg/Node>
#include <osg/Geode>
#include <osg/Group>
#include <osg/ShapeDrawable>

#include <osgDB/ReadFile>
#include <osgDB/WriteFile>

#include <osgUtil/Optimizer>

//绘制多个预定义的几何体
osg::ref_ptr<osg::Geode> createShape()
{
    //创建一个叶节点
    osg::ref_ptr<osg::Geode> geode = new osg::Geode();

    //设置半径和高度
    float radius = 0.8f;
    float height = 1.0f;

    //创建精细度对象，精细度越高，细分就越多
    osg::ref_ptr<osg::TessellationHints> hints = new osg::TessellationHints;
    //设置精细度为0.5f
    hints->setDetailRatio(0.5f);

    //添加一个球体，第一个参数是预定义几何体对象，第二个是精细度，默认为0
    geode->addDrawable(new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0f,0.0f,0.0f),radius),hints.get()));
    //添加一个正方体
    geode->addDrawable(new osg::ShapeDrawable(new osg::Box(osg::Vec3(2.0f,0.0f,0.0f),2*radius),hints.get()));
    //添加一个圆锥
    geode->addDrawable(new osg::ShapeDrawable(new osg::Cone(osg::Vec3(4.0f,0.0f,0.0f),radius,height),hints.get()));
    //添加一个圆柱体
    geode->addDrawable(new osg::ShapeDrawable(new osg::Cylinder(osg::Vec3(6.0f,0.0f,0.0f),radius,height),hints.get()));
    //添加一个太空舱
    geode->addDrawable(new osg::ShapeDrawable(new osg::Capsule(osg::Vec3(8.0f,0.0f,0.0f),radius,height),hints.get()));

    return geode.get() ;
}

int main()
{
    //创建Viewer对象，场景浏览器
    osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();

    osg::ref_ptr<osg::Group> root = new osg::Group();

    //添加到场景
    root->addChild(createShape());

    //优化场景数据
    osgUtil::Optimizer optimizer ;
    optimizer.optimize(root.get()) ;

    viewer->setSceneData(root.get());

    viewer->realize();

    viewer->run();

    return 0 ;
}

结果图：