以下内容来自:
1、《OpenSceneGraph三维渲染引擎编程指南》肖鹏 刘更代 徐明亮 清华大学出版社
2、《OpenSceneGraph三维渲染引擎设计与实践》王锐 钱学雷 清华大学出版社
3、自己的总结
创建C++项目后,首先需要配置OSG环境,具体步骤看OSG学习:WIN10系统下OSG+VS2017编译及运行第六步:新建OSG项目测试。
// stdafx.h
#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 <osgGA/TrackballManipulator>
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
#include <osgUtil/Optimizer>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers> //事件监听
#include <osgViewer/CompositeViewer>
//.cpp
/*
*多视图相机渲染
*
*在OSG中,多视图的管理是通过osgViewer::CompositeViewer来实现的,它负责多个视图的管理及同步工作,继承自osgViewer::ViewerBase类
*
*视图的创建:
*设置图形环境特性
*创建图形环境特性
*创建视图
*设置视图场景数据
*(根据分辨率确定合适的投影来保证显示的图形不变形)
*设置相机视口及图形环境
*设置操作器
*(添加事件处理)
*/
osg::ref_ptr<osg::GraphicsContext> CreateGraphicsContext(osg::ref_ptr<osg::GraphicsContext::Traits> traits)
{
//设置图形环境特性
//osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits();
traits->x = 100;
traits->y = 100;
traits->width = 900;
traits->height = 700;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = 0;
//创建图形环境特性
osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());
if (gc->valid())
{
osg::notify(osg::INFO) << "GraphicsWindow has been created successfully." << std::endl;
//清除窗口颜色及颜色和深度缓冲
gc->setClearColor(osg::Vec4f(0.2f, 0.2f, 1.6f, 1.0f));
gc->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}
else
{
osg::notify(osg::NOTICE) << "GraphicsWindow has not been created successfully." << std::endl;
}
return gc.get();
}
//视图一
void View1(osg::ref_ptr<osgViewer::CompositeViewer> viewer, osg::ref_ptr<osg::Node> node, osg::ref_ptr<osg::GraphicsContext::Traits> traits, osg::ref_ptr<osg::GraphicsContext> gc)
{
//创建视图一
osg::ref_ptr<osgViewer::View> view = new osgViewer::View();
viewer->addView(view.get());
//设置视图场景数据
view->setSceneData(node.get());
//设置相机视口及图形环境
view->getCamera()->setViewport(new osg::Viewport(0, 0, traits->width / 2, traits->height / 2));
view->getCamera()->setGraphicsContext(gc.get());
//设置操作器
view->setCameraManipulator(new osgGA::TrackballManipulator);
//添加事件处理
view->addEventHandler(new osgViewer::StatsHandler);
view->addEventHandler(new osgViewer::WindowSizeHandler);
view->addEventHandler(new osgViewer::ThreadingHandler);
view->addEventHandler(new osgViewer::RecordCameraPathHandler);
}
//视图二
void View2(osg::ref_ptr<osgViewer::CompositeViewer> viewer, osg::ref_ptr<osg::Node> node, osg::ref_ptr<osg::GraphicsContext::Traits> traits, osg::ref_ptr<osg::GraphicsContext> gc)
{
//创建视图二
osg::ref_ptr<osgViewer::View> view = new osgViewer::View();
viewer->addView(view.get());
//设置视图场景数据
view->setSceneData(node.get());
//设置相机视口及图形环境
view->getCamera()->setViewport(new osg::Viewport(traits->width / 2, 0, traits->width / 2, traits->height / 2));
view->getCamera()->setGraphicsContext(gc.get());
//设置操作器
view->setCameraManipulator(new osgGA::TrackballManipulator);
}
//视图三
void View3(osg::ref_ptr<osgViewer::CompositeViewer> viewer, osg::ref_ptr<osg::Node> node, osg::ref_ptr<osg::GraphicsContext::Traits> traits, osg::ref_ptr<osg::GraphicsContext> gc)
{
//创建视图三
osg::ref_ptr<osgViewer::View> view = new osgViewer::View();
viewer->addView(view.get());
//设置视图场景数据
view->setSceneData(node.get());
//根据分辨率确定合适的投影来保证显示的图形不变形
double fovy, aspectRatio, zNear, zFar;
view->getCamera()->getProjectionMatrixAsPerspective(fovy, aspectRatio, zNear, zFar);
double newAspectRatio = double(traits->width) / double(traits->height / 2);
double aspectRatioChange = newAspectRatio / aspectRatio;
if (aspectRatioChange != 1.0)
{
view->getCamera()->getProjectionMatrix() *= osg::Matrix::scale(1.0 / aspectRatioChange, 1.0, 1.0);
}
//设置相机视口及图形环境
view->getCamera()->setViewport(new osg::Viewport(0, traits->height / 2, traits->width / 2, traits->height / 2));
view->getCamera()->setGraphicsContext(gc.get());
//设置操作器
view->setCameraManipulator(new osgGA::TrackballManipulator);
}
int main()
{
//读取模型
osg::ref_ptr<osg::Node> cow = osgDB::readNodeFile("cow.osg");
osg::ref_ptr<osg::Node> cessna = osgDB::readNodeFile("cessna.osg");
//优化场景数据
osgUtil::Optimizer optimizer;
optimizer.optimize(cow.get());
optimizer.optimize(cessna.get());
//设置并创建图形环境
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits();
osg::ref_ptr<osg::GraphicsContext> gc = CreateGraphicsContext(traits);
//创建CompositeViewer对象
osg::ref_ptr<osgViewer::CompositeViewer> viewer = new osgViewer::CompositeViewer();
View1(viewer, cow.get(), traits.get(), gc.get());
View2(viewer, cessna.get(), traits.get(), gc.get());
View3(viewer, cessna.get(), traits.get(), gc.get());
viewer->realize();
return viewer->run();
}