后视图与从相机问题~求助~

回复花花

看到书上讲从相机那块，我就照着书上做了一下。发现用从相机的时候，viewer->addSlave(leftcam.get(),osg::Matrix(),osg::Matrix::rotate(osg:egreesToRadians(180.0),0.0,1.0,0.0),true);这句话的结果本来是，显示主相机的后视图，结果运行之后发现，后视图没有显示，也就是从相机。忘懂的人能给我解惑一下，谢谢~

1. #include <osgDB/ReadFile>
   
2. #include <osgViewer/Viewer>
   
3. #include <osgGA/TrackballManipulator>
   
4. #include <iostream>
   
5. 
   
6. void CreateCamera(osgViewer::Viewer *viewer)
   
7. {
   
8. 
   
9.         if(!viewer)
   
10.         {
    
11.                 return;
    
12.         }
    
13. 
    
14.         //创建窗口系统接口
    
15.         osg::GraphicsContext::WindowingSystemInterface *wsi = osg::GraphicsContext::getWindowingSystemInterface();
    
16.         if(!wsi)
    
17.         {
    
18.                 return;
    
19.         }
    
20. 
    
21.         //得到窗口分辨率
    
22.         unsigned int width,height;
    
23.         wsi->getScreenResolution(osg::GraphicsContext::ScreenIdentifier(0),width,height);
    
24. 
    
25.         //设置图形环境特性
    
26.         osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
    
27.         traits->x = 0;
    
28.         traits->y = 0;
    
29.         traits->width = width;
    
30.         traits->height = height;
    
31.         traits->windowDecoration = false; //是否支持窗口扩展的功能，win32中的style
    
32.         traits->doubleBuffer =true;
    
33.         traits->sharedContext = 0;
    
34. 
    
35.         //创建图形环境
    
36.         osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits);
    
37.         if(!gc.valid())
    
38.         {
    
39.                 return;
    
40.         }
    
41. 
    
42.         //创建相机
    
43.         osg::ref_ptr<osg::Camera> master = new osg::Camera;
    
44.         master->setGraphicsContext(gc);
    
45.         master->setViewport(width/2,height/2,width/2,height/2);
    
46.         viewer->addSlave(master.get());
    
47. 
    
48.         osg::ref_ptr<osg::Camera> leftcam = new osg::Camera;
    
49.         leftcam->setGraphicsContext(gc);
    
50.         leftcam->setViewport(0,0,width/2,height/2);
    
51.         GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;
    
52.          //设置绘制缓冲，它在每帧绘制之前使用。注意：如果参数书GL_NONE，
    
53.          //则在每帧绘制后自动加载合适的参数
    
54.     leftcam->setDrawBuffer(buffer);
    
55.          //为拷贝操作设置读缓冲
    
56.     leftcam->setReadBuffer(buffer);
    
57.         //leftcam->setRenderOrder(osg::Camera::POST_RENDER);
    
58.         viewer->addSlave(leftcam.get(),osg::Matrix(),osg::Matrix::rotate(osg::DegreesToRadians(180.0),0.0,1.0,0.0),true);
    
59.         osg::ref_ptr<osg::Node> scene =osgDB::readNodeFile("cow.osg");
    
60.         viewer->setSceneData(scene);
    
61.         return;
    
62.        
    
63. }
    
64. 
    
65. int main()
    
66. {
    
67.         osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer;
    
68.         CreateCamera(viewer);
    
69.         viewer->run();
    
70.         return 0;
    
71. 
    
72. }
    
73. 
    
74. 
    
75. 
    

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