OSG（OpenSceneGraph）多视图多窗⼝渲染

osg系列文章目录

文章目录

前言

OSG（OpenSceneGraph）多视图多窗⼝渲染，在不同的窗口渲染不同的场景，实现不知道有什么用的多窗口渲染有两种情况：
1.多个不同的窗口渲染完全不同，相互独立的场景
2.多个窗口渲染一个场景的不同部分

二、使用步骤

1.第一种情况代码

多个不同的窗口渲染完全不同，相互独立的场景

#include "osg/Node"
#include "osg/Geode"
#include "osg/Geometry"
#include "osg/Group"
#include "osg/MatrixTransform" //移动节点的矩阵类，最常⽤的移动节点的类。可随动、旋转控制节点
#include "osg/PositionAttitudeTransform" //位置变换节点类，提供模型的位置变换、⼤⼩缩放、原点位置的设置、坐标系的变换
#include "osg/Camera"  //相机节点，管理OSG中的模型——视图矩阵，相机的管理主要是通过各种变换实现的
#include "osgDB/ReadFile"
#include "osgDB/WriteFile"
#include "osgUtil/Optimizer"
#include "osgViewer/Viewer"
#include "osgViewer/CompositeViewer" //多视图的管理，负责多个视图的管理及同步


#include<osgUtil/Optimizer>
#include<osg/StateSet>
#include<osg/TexGen>

#include <osgViewer/ViewerEventHandlers> //事件监听
#include <osgGA/StateSetManipulator> //事件响应类，对渲染状态进行控制
#include <osgUtil/Simplifier> //简化几何体
#include <osgUtil/DelaunayTriangulator>



osg::ref_ptr<osgViewer::Viewer> MultipleView(osg::ref_ptr<osg::Node> node, int i)
{
  int xoffset = 50;
  int yoffset = 200;
  //设置图形环境特性
  osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits();
  //两个视图窗⼝的横坐标位置不同，否则会重叠
  if (i == 1)
  {
    traits->x = xoffset + 0;
  }
  else
  {
    traits->x = xoffset + 600;
  }
  traits->y = yoffset + 0;
  traits->width = 600;
  traits->height = 480;
  traits->windowDecoration = true;
  traits->doubleBuffer = true;
  traits->sharedContext = 0;

  //创建视图
  osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
  //创建相机
  osg::ref_ptr<osg::Camera> camera = viewer->getCamera();
  //创建图形环境特性
  osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());
  //设置图形环境
  camera->setGraphicsContext(gc.get());
  //设置视⼝
  camera->setViewport(new osg::Viewport(0, 0, traits->width, traits->height));
  //设置缓冲
  GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;
  //设置缓冲区（设置每帧开始绘制时，绘制哪个缓存）
  camera->setDrawBuffer(buffer);
  camera->setReadBuffer(buffer);
  //设置场景数据
  viewer->setSceneData(node.get());
  return viewer.get();
}
int main()
{
  //读取模型，分别作为两个视图的节点
  osg::ref_ptr<osg::Node> cow = osgDB::readNodeFile("cessnafire.osg");
  osg::ref_ptr<osg::Node> cessna = osgDB::readNodeFile("skydome.osgt");

  //关联纹理
  osg::ref_ptr<osg::Image> image = osgDB::readImageFile("texture.jpg");
  if (image.get())
  {
    osg::ref_ptr<osg::Texture2D> texture = new osg::Texture2D();
    texture->setImage(image.get());

    //设置自动生成纹理坐标
    osg::ref_ptr<osg::TexGen> texgen = new osg::TexGen();
    texgen->setMode(osg::TexGen::SPHERE_MAP);

    //设置纹理环境，模式为BLEND
    osg::ref_ptr<osg::TexEnv> texenv = new osg::TexEnv;
    texenv->setMode(osg::TexEnv::Mode::BLEND);// ADD
    texenv->setColor(osg::Vec4(0.6, 0.6, 0.6, 0.0));

    //启动单元一自动生成纹理坐标，并使用纹理
    osg::ref_ptr<osg::StateSet> state = new osg::StateSet;
    state->setTextureAttributeAndModes(1, texture.get(), osg::StateAttribute::ON);
    state->setTextureAttributeAndModes(1, texgen.get(), osg::StateAttribute::ON);
    state->setTextureAttribute(0, texenv.get());

    cow->setStateSet(state.get());
  }
  else
  {
    std::cout << "Unable to load data file Exiting." << std::endl;
  }

  /*cow.release();*/


  //优化场景数据
  osgUtil::Optimizer optimizer;
  optimizer.optimize(cow.get());
  optimizer.optimize(cessna.get());
  //创建两个视图
  osg::ref_ptr<osgViewer::Viewer> viewer1 = MultipleView(cow, 1);
  osg::ref_ptr<osgViewer::Viewer> viewer2 = MultipleView(cessna, 2);
  //创建⼀个CompositeViewer对象
  osg::ref_ptr<osgViewer::CompositeViewer> viewer = new osgViewer::CompositeViewer();
  //添加视图
  viewer->addView(viewer1.get());
  viewer->addView(viewer2.get());
  viewer->realize();

  return viewer->run();
}

第二种情况代码

#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgViewer/Viewer>
#include <osgGA/TrackballManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/AnimationPathManipulator>
#include <iostream>

//实现多窗口渲染 
void multipleWindowMultipleCameras(osgViewer::Viewer& viewer, bool multipleScreens) 
{
  osg::GraphicsContext::WindowingSystemInterface* wsi = osg::GraphicsContext::getWindowingSystemInterface(); 
  unsigned int width, height; wsi->getScreenResolution(osg::GraphicsContext::ScreenIdentifier(0), width, height);
  
  //窗口数量 
  unsigned int numCameras = 6; 
  //缩放比率 
  double aspectRatioScale = (double)numCameras; 
  double translate_x = double(numCameras)-1; 
  //创建六个图形上下文 
  for(unsigned int i=0; i<numCameras;++i, translate_x -= 2.0) 
  { 
    osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits; 
    traits->screenNum = multipleScreens ? i / 3 : 0; 
    traits->x = (i*width)/numCameras; 
    traits->y = 0;
    traits->width = width / numCameras - 1; 
    traits->height = height; 

    //这个设置窗口要有边框修饰，否则不设置边框 
    traits->windowDecoration = true; 
    traits->doubleBuffer = true;
    traits->sharedContext = 0; 
    osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());

    //每一个对应一个窗口 
    osg::ref_ptr<osg::Camera> camera = new osg::Camera;
    camera->setGraphicsContext(gc.get()); 
    camera->setViewport(new osg::Viewport(0,0, width/numCameras, height)); 
    GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT; 
    camera->setDrawBuffer(buffer); camera->setReadBuffer(buffer);
    viewer.addSlave(camera.get(), osg::Matrix::scale(aspectRatioScale, 1.0, 1.0)*osg::Matrix::translate(translate_x, 0.0, 0.0), osg::Matrix() );

  } 
} 

int main( int argc, char **argv ) 
{ 
  osgViewer::Viewer viewer ;
  multipleWindowMultipleCameras(viewer, false); 
  viewer.setSceneData(osgDB::readNodeFile("glider.osg")); 
  viewer.realize();
  viewer.run();
  return 0; 
}

运行效果

第一种情况，2个窗口完全独立，相互不影响

第二种情况，多个窗口渲染同一个场景的不同部分

源码下载

​​源码下载地址​​