建立独立的OSG程序

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1 /* OpenSceneGraph example, osgpick.*/
      2 
      3 /* osgpick sample
      4 * demonstrate use of osgUtil/PickVisitor for picking in a HUD or
      5 * in a 3d scene,
      6 */
      7 
      8 #include <osgUtil/Optimizer>
      9 #include <osgDB/ReadFile>
     10 #include <osgViewer/Viewer>
     11 #include <osgViewer/CompositeViewer>
     12 
     13 #include <osgGA/TerrainManipulator>
     14 #include <osgGA/StateSetManipulator>
     15 #include <osgGA/AnimationPathManipulator>
     16 #include <osgGA/TrackballManipulator>
     17 #include <osgGA/FlightManipulator>
     18 #include <osgGA/DriveManipulator>
     19 #include <osgGA/KeySwitchMatrixManipulator>
     20 #include <osgGA/StateSetManipulator>
     21 #include <osgGA/AnimationPathManipulator>
     22 #include <osgGA/TerrainManipulator>
     23 
     24 #include <osg/Material>
     25 #include <osg/Geode>
     26 #include <osg/BlendFunc>
     27 #include <osg/Depth>
     28 #include <osg/Projection>
     29 #include <osg/MatrixTransform>
     30 #include <osg/Camera>
     31 #include <osg/io_utils>
     32 #include <osg/ShapeDrawable>
     33 
     34 #include <osgText/Text>
     35 
     36 #include <sstream>
     37 
     38 // 处理拾取事件的类，继承自osgGA::GUIEventhandler 界面事件处理
     39 class PickHandler : public osgGA::GUIEventHandler {
     40 public: 
     41     //构造函数
     42     PickHandler(osgText::Text* updateText):
     43         _updateText(updateText) {}
     44     //析构函数    
     45     ~PickHandler() {}
     46     //处理（事件接口、动作接口）
     47     bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& aa);
     48     //拾取（视图、事件接口）
     49     virtual void pick(osgViewer::View* view, const osgGA::GUIEventAdapter& ea);
     50     //设置显示内容
     51     void setLabel(const std::string& name)
     52     {
     53         if (_updateText.get()) 
     54             _updateText->setText(name);
     55     }
     56     
     57 protected:
     58     //传递一个文字对象
     59     osg::ref_ptr<osgText::Text>  _updateText;
     60 };
     61 //事件处理（事件接口、动作接口）
     62 bool PickHandler::handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& aa)
     63 {
     64     switch(ea.getEventType())
     65     {
     66         case(osgGA::GUIEventAdapter::PUSH):
     67         {
     68             //dynamic_cast运算符的作用是将&aa转换成osgViewer::View*类型的对象
     69             osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
     70             if (view) pick(view,ea);
     71             return false;
     72         }    
     73         case(osgGA::GUIEventAdapter::KEYDOWN):
     74         {
     75             if (ea.getKey()=='c')
     76             {        
     77                 osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
     78                 //event也是一个指针，类型是osgGA::GUIEventAdapter
     79                 osg::ref_ptr<osgGA::GUIEventAdapter> event = new osgGA::GUIEventAdapter(ea);
     80                 event->setX((ea.getXmin()+ea.getXmax())*0.5);
     81                 event->setY((ea.getYmin()+ea.getYmax())*0.5);
     82                 if (view) pick(view,*event);
     83             }
     84             return false;
     85         }    
     86         default:
     87             return false;
     88     }
     89 }
     90 
     91 //拾取（视图、事件接口）通过view计算交点 ，从事件接口ea中获得 x和y
     92 void PickHandler::pick(osgViewer::View* view, const osgGA::GUIEventAdapter& ea)
     93 {
     94     //创建一个线段交集检测对象
     95     osgUtil::LineSegmentIntersector::Intersections intersections;
     96 
     97     std::string gdlist="";
     98     //得到鼠标的位置 x和y
     99     float x = ea.getX();
    100     float y = ea.getY();
    101     
    102     //如果发生交集运算 （即鼠标点中了物体）
    103     if (view->computeIntersections(x,y,intersections))
    104     {
    105         //得到相交交集的交点， hitr是一个迭代器
    106         for(osgUtil::LineSegmentIntersector::Intersections::iterator hitr = intersections.begin();
    107             hitr != intersections.end();
    108             ++hitr)
    109         {
    110             std::ostringstream os;//申请一个流
    111             if (!hitr->nodePath.empty() && !(hitr->nodePath.back()->getName().empty()))
    112             {
    113                 // the geodes are identified by name.
    114                 os<<"Object \""<<hitr->nodePath.back()->getName()<<"\""<<std::endl;
    115             }
    116             else if (hitr->drawable.valid())
    117             {
    118                 os<<"Object \""<<hitr->drawable->className()<<"\""<<std::endl;
    119             }
    120             //将局部坐标顶点和法线输入到os这个流里面。
    121             os<<"        local coords vertex("<< hitr->getLocalIntersectPoint()<<")"<<"  normal("<<hitr->getLocalIntersectNormal()<<")"<<std::endl;
    122             os<<"        world coords vertex("<< hitr->getWorldIntersectPoint()<<")"<<"  normal("<<hitr->getWorldIntersectNormal()<<")"<<std::endl;
    123             //交点索引列表vil，交点存在hitr里面
    124             const osgUtil::LineSegmentIntersector::Intersection::IndexList& vil = hitr->indexList;
    125             for(unsigned int i=0;i<vil.size();++i)
    126             {
    127                 os<<"        vertex indices ["<<i<<"] = "<<vil[i]<<std::endl;
    128             }
    129             //gdlist是一个字符串，用来存os中要显示的文字
    130             gdlist += os.str();
    131         }
    132     }
    133     //设置显示内容
    134     setLabel(gdlist);
    135 }
    136 //创建HUD 参数是osgText。HUD也是作为场景中的一个节点存在
    137 osg::Node* createHUD(osgText::Text* updateText)
    138 {
    139 
    140     // create the hud. derived from osgHud.cpp  （derived：来源于）
    141     // adds a set of quads, each in a separate Geode - which can be picked individually
    142     // eg to be used as a menuing/help system!
    143     // Can pick texts too!
    144 
    145     osg::Camera* hudCamera = new osg::Camera;//创建一个相机
    146     hudCamera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);//设置绝对帧引用
    147     hudCamera->setProjectionMatrixAsOrtho2D(0,1280,0,1024);//设置正投影矩阵
    148     hudCamera->setViewMatrix(osg::Matrix::identity());//设置视图矩阵
    149     hudCamera->setRenderOrder(osg::Camera::POST_RENDER);//设置渲染顺序为POST
    150     hudCamera->setClearMask(GL_DEPTH_BUFFER_BIT);//清除深度缓存
    151     
    152     //设置字体，声明一个timesFont，初始化为times.ttf
    153     std::string timesFont("fonts/times.ttf");
    154     
    155     //关掉字体的光照、禁用深度缓存  来保证字体一直在最上面
    156     
    157     osg::Vec3 position(150.0f,800.0f,0.0f);//设置位置
    158     osg::Vec3 delta(0.0f,-60.0f,0.0f);
    159     
    160     {
    161         osg::Geode* geode = new osg::Geode();//也可以写成osg::ref_ptr<osg::Geode> geode  = new osg::Geode();-------geode就是一个指针
    162         osg::StateSet* stateset = geode->getOrCreateStateSet();//状态设置
    163         stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);//关闭光照
    164         stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);//关闭深度缓存
    165         geode->setName("simple");//设置这个geode的名字，geode是场景中的叶子节点
    166         hudCamera->addChild(geode);
    167         
    168         osgText::Text* text = new  osgText::Text;
    169         geode->addDrawable( text );//geode是osg场景中的叶子节点，然后就是让所有drawable的东西成组
    170         
    171         text->setFont(timesFont);//设置字体
    172         text->setText("Picking in Head Up Displays is simple!\nHow to do it?\nAm I on the first quard?");//设置内容
    173         text->setPosition(position);//设置字体位置，用到上面申明的position
    174         
    175         position += delta;
    176     }    
    177     
    178     
    179     for (int i=0; i<6; i++) {
    180         osg::Vec3 dy(0.0f,-30.0f,0.0f);
    181         osg::Vec3 dx(120.0f,0.0f,0.0f);
    182         osg::Geode* geode = new osg::Geode();
    183         osg::StateSet* stateset = geode->getOrCreateStateSet();
    184         const char *opts[]={
      "One", "Two", "Three", "January", "Feb", "2003"};
    185         osg::Geometry *quad=new osg::Geometry;//申明一个指向几何体的指针
    186         stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
    187         stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
    188         std::string name="subOption";
    189         name += " ";
    190         name += std::string(opts[i]);
    191         geode->setName(name);//设置节点的名字
    192         osg::Vec3Array* vertices = new osg::Vec3Array(4); // 1 quad，弄个3元数组指针，数组有4个元素，分别保存矩形的4个顶点
    193         osg::Vec4Array* colors = new osg::Vec4Array;//4元数组指针 ，保存颜色
    194         colors = new osg::Vec4Array;
    195         colors->push_back(osg::Vec4(0.8-0.1*i, 0.1*i, 0.2*i, 1.0));//通过i的变化来实现块的渐变颜色
    196         quad->setColorArray(colors);
    197         quad->setColorBinding(osg::Geometry::BIND_PER_PRIMITIVE);//绑定颜色到方块上
    198         (*vertices)[0]=position;
    199         (*vertices)[1]=position+dx;
    200         (*vertices)[2]=position+dx+dy;
    201         (*vertices)[3]=position+dy;
    202         quad->setVertexArray(vertices);//设置顶点数组
    203         quad->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));
    204         geode->addDrawable(quad);
    205         hudCamera->addChild(geode);
    206         
    207         position += delta;
    208     }    
    209     
    210     
    211     
    212     { 
    213         //这里显示什么被选中
    214         osg::Geode* geode = new osg::Geode();
    215         osg::StateSet* stateset = geode->getOrCreateStateSet();
    216         stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
    217         stateset->setMode(GL_DEPTH_TEST,osg::StateAttribute::OFF);
    218         geode->setName("The text label");
    219         geode->addDrawable( updateText );//这里的updateText是createHUD函数的传入参数
    220         hudCamera->addChild(geode);
    221         
    222         updateText->setCharacterSize(20.0f);
    223         updateText->setFont(timesFont);
    224         updateText->setColor(osg::Vec4(1.0f,1.0f,0.0f,1.0f));
    225         updateText->setText("");
    226         updateText->setPosition(position);
    227         updateText->setDataVariance(osg::Object::DYNAMIC);
    228         
    229         position += delta;
    230     }    
    231     
    232     return hudCamera;
    233 
    234 }
    235 
    236 
    237 //主函数
    238 int main( int argc, char **argv )
    239 {
    240     //使用一个参数解析器对象来管理程序的参数
    241     osg::ArgumentParser arguments(&argc,argv);
    242 
    243     //从命令行参数指定的文件列表中读取场景
    244     osg::ref_ptr<osg::Node> scene = osgDB::readNodeFiles(arguments);
    245     //如果场景没有创建成功
    246     if (!scene && arguments.read("--relative-camera-scene"))
    247     {
    248            //创建一个带有相关引用帧的相机的测试场景
    249         osg::Group* group = new osg::Group();
    250 
    251         osg::Geode* sphere = new osg::Geode();//创建一个球
    252         sphere->setName("Sphere");
    253         sphere->addDrawable(new osg::ShapeDrawable(new osg::Sphere()));
    254 
    255         osg::Geode* cube = new osg::Geode();//创建一个盒子
    256         cube->setName("Cube");
    257         cube->addDrawable(new osg::ShapeDrawable(new osg::Box()));
    258 
    259         osg::Camera* camera = new osg::Camera();//创建一个相机
    260         camera->setRenderOrder(osg::Camera::POST_RENDER);//设置渲染顺序为POST
    261         camera->setClearMask(GL_DEPTH_BUFFER_BIT);//清除深度缓存
    262         camera->setReferenceFrame(osg::Transform::RELATIVE_RF);//设置相对帧引用
    263         camera->setViewMatrix(osg::Matrix::translate(-2, 0, 0));//设置视图矩阵
    264 
    265         osg::MatrixTransform* xform = new osg::MatrixTransform(osg::Matrix::translate(1, 1, 1));
    266         xform->addChild(camera);
    267 
    268         group->addChild(sphere);
    269         group->addChild(xform);
    270         camera->addChild(cube);
    271 
    272         scene = group;
    273     }
    274 
    275     //如果没有载入假设的场景，没有参数传进来。试着使用默认的模型代替。
    276     if (!scene) scene = osgDB::readNodeFile("fountain.osgt");
    277 
    278     osg::ref_ptr<osg::Group> group = dynamic_cast<osg::Group*>(scene.get());
    279     if (!group)
    280     {
    281         group = new osg::Group;
    282         group->addChild(scene.get());
    283     }
    284 
    285     osg::ref_ptr<osgText::Text> updateText = new osgText::Text;
    286 
    287     // add the HUD subgraph.    
    288     group->addChild(createHUD(updateText.get()));
    289 
    290     if (arguments.read("--CompositeViewer"))
    291     {
    292         osg::ref_ptr<osgViewer::View> view = new osgViewer::View;
    293         // 添加处理拾取事件的handler到视图中
    294         view->addEventHandler(new PickHandler(updateText.get()));
    295 
    296         // set the scene to render，设置场景到渲染中
    297         view->setSceneData(group.get());
    298 
    299         view->setUpViewAcrossAllScreens();
    300 
    301         osgViewer::CompositeViewer viewer;
    302         viewer.addView(view.get());
    303 
    304         return viewer.run();
    305 
    306     }
    307     else
    308     {
    309         osgViewer::Viewer viewer;
    310 
    311 
    312         // add all the camera manipulators
    313         {
    314             osg::ref_ptr<osgGA::KeySwitchMatrixManipulator> keyswitchManipulator = new osgGA::KeySwitchMatrixManipulator;
    315 
    316             keyswitchManipulator->addMatrixManipulator( '1', "Trackball", new osgGA::TrackballManipulator() );
    317             keyswitchManipulator->addMatrixManipulator( '2', "Flight", new osgGA::FlightManipulator() );
    318             keyswitchManipulator->addMatrixManipulator( '3', "Drive", new osgGA::DriveManipulator() );
    319 
    320             unsigned int num = keyswitchManipulator->getNumMatrixManipulators();
    321             keyswitchManipulator->addMatrixManipulator( '4', "Terrain", new osgGA::TerrainManipulator() );
    322 
    323             std::string pathfile;
    324             char keyForAnimationPath = '5';
    325             while (arguments.read("-p",pathfile))
    326             {
    327                 osgGA::AnimationPathManipulator* apm = new osgGA::AnimationPathManipulator(pathfile);
    328                 if (apm || !apm->valid()) 
    329                 {
    330                     num = keyswitchManipulator->getNumMatrixManipulators();
    331                     keyswitchManipulator->addMatrixManipulator( keyForAnimationPath, "Path", apm );
    332                     ++keyForAnimationPath;
    333                 }
    334             }
    335 
    336             keyswitchManipulator->selectMatrixManipulator(num);
    337 
    338             viewer.setCameraManipulator( keyswitchManipulator.get() );
    339         }
    340 
    341         // add the handler for doing the picking
    342         viewer.addEventHandler(new PickHandler(updateText.get()));
    343 
    344         // set the scene to render
    345         viewer.setSceneData(group.get());
    346     
    347         return viewer.run();
    348     }
    349 
    350 }