osg RTT 渲染到纹理

#include <osg/Camera>#include <osg/Group>#include <osg/Geometry>#include <osgDB/ReadFile>#include <osgViewer/Viewer>#include <osg/Texture2D>#include <osgViewer/ViewerEventHandlers>#include <osg/GraphicsContext>#include <iostream>using namespace std;void CreateTexture(osgViewer::Viewer *viewer){  if(!viewer)    return;  osg::GraphicsContext::WindowingSystemInterface *wsi= osg::GraphicsContext::getWindowingSystemInterface();  if(!wsi){    cout<<"wsi is NULL"<<endl;    return;  }  unsigned int width,height;  wsi->getScreenResolution(osg::GraphicsContext::ScreenIdentifier(0), width, height);  osg::ref_ptr<osg::GraphicsContext::Traits>traits=new osg::GraphicsContext::Traits;  traits->x=0;  traits->y=0;  traits->width=width;  traits->height=height;  traits->windowDecoration=false;  traits->doubleBuffer=true;  traits->sharedContext=0;  osg::ref_ptr<osg::GraphicsContext>gc=osg::GraphicsContext::createGraphicsContext(traits);  if(!gc.valid()){    cout<<"gc is NULL" <<endl;    return;  }  osg::ref_ptr<osg::Camera>master=new osg::Camera;  master->setGraphicsContext(gc);  master->setViewport(0, 0, width, height);  viewer->addSlave(master.get());  cout<<height<<"  ,  "<<width<<endl;  osg::ref_ptr<osg::Camera>rttCamera=new osg::Camera;  rttCamera->setRenderOrder(osg::Camera::PRE_RENDER);//最先渲染  rttCamera->setGraphicsContext(gc);  rttCamera->setViewport(0, 0, width, height);  rttCamera->addChild(osgDB::readNodeFile("ceep.ive"));  viewer->addSlave(rttCamera,false);  osg::ref_ptr<osg::Group>root=new osg::Group;  osg::ref_ptr<osg::Geode>geode=new osg::Geode;  root->addChild(geode);  osg::ref_ptr<osg::Geometry>gm=new osg::Geometry;  geode->addDrawable(gm);  osg::ref_ptr<osg::Vec3Array>vertex=new osg::Vec3Array;  vertex->push_back(osg::Vec3(-400,200,-300));  vertex->push_back(osg::Vec3(400,200,-300));  vertex->push_back(osg::Vec3(400,200,300));  vertex->push_back(osg::Vec3(-400,200,300));  gm->setVertexArray(vertex);  osg::ref_ptr<osg::Vec3Array>norm=new osg::Vec3Array;  norm->push_back(osg::Vec3(0,-1,0));  gm->setNormalArray(norm);  gm->setNormalBinding(osg::Geometry::BIND_OVERALL);  osg::ref_ptr<osg::Vec2Array>coord=new osg::Vec2Array;  coord->push_back(osg::Vec2(0,0));  coord->push_back(osg::Vec2(1,0));  coord->push_back(osg::Vec2(1,1));  coord->push_back(osg::Vec2(0,1));  gm->setTexCoordArray(0, coord);  gm->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,4));  gm->getOrCreateStateSet()->setMode(GL_LIGHTING,osg::StateAttribute::OFF);  osg::ref_ptr<osg::Texture2D>t2d=new osg::Texture2D;/*  osg::ref_ptr<osg::Image>image=osgDB::readImageFile("Images/blueFlowers.png");  if(!image){    cout<<"image is NULL"<<endl;    return;  }  t2d->setImage(0,image);*/  t2d->setInternalFormat(GL_RGBA);//  viewer->getCamera()->attach(osg::Camera::COLOR_BUFFER, t2d);  rttCamera->attach(osg::Camera::COLOR_BUFFER,t2d);  gm->getOrCreateStateSet()->setTextureAttributeAndModes(0, t2d,osg::StateAttribute::ON);  root->addChild(osgDB::readNodeFile("ceep.ive"));  viewer->setSceneData(root);  return;}int main(int argc, char *argv[]){  osg::ref_ptr<osgViewer::Viewer>viewer=new osgViewer::Viewer;  CreateTexture(viewer);  viewer->addEventHandler(new osgViewer::WindowSizeHandler);  viewer->addEventHandler(new osgViewer::ScreenCaptureHandler);  return viewer->run();  return 0;}