1、效果

  在osg的实际应用场景中，有时候需要同时创建多个场景视图，并保证各个场景视图中有不一样的显示和操作：例如：漫游器、照相机、粒子效果、多个模型组合等。此时就要用到OSG提供的osgViewer::CompositeViewer类来实现这个需求了。

2、源码

#include <iostream>

#include <osgUtil/Optimizer>
#include <osgDB/ReadFile>

#include <osg/Material>
#include <osg/Geode>
#include <osg/BlendFunc>
#include <osg/Depth>
#include <osg/Projection>
#include <osg/PolygonOffset>
#include <osg/MatrixTransform>
#include <osg/Camera>
#include <osg/FrontFace>

#include <osgText/Text>

#include <osgGA/TerrainManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/StateSetManipulator>
#include <osgViewer/ViewerEventHandlers>

#include <osgViewer/CompositeViewer>

#include <osg/io_utils>

#pragma comment(lib, "OpenThreadsd.lib")
#pragma comment(lib, "osgd.lib")
#pragma comment(lib, "osgDBd.lib")
#pragma comment(lib, "osgUtild.lib")
#pragma comment(lib, "osgGAd.lib")
#pragma comment(lib, "osgViewerd.lib")
#pragma comment(lib, "osgTextd.lib")
#pragma comment(lib, "osgSimd.lib")

int main(int argc, char** argv)
{
	//创建CompositeViewer
	osgViewer::CompositeViewer viewer;

	if (viewer.getNumViews() == 0)
	{

		osg::GraphicsContext::WindowingSystemInterface* wsi = osg::GraphicsContext::getWindowingSystemInterface();
		if (!wsi)
		{
			osg::notify(osg::NOTICE) << "Error, no WindowSystemInterface available, cannot create windows." << std::endl;
			return 1;
		}

		unsigned int width, height;
		osg::GraphicsContext::ScreenIdentifier main_screen_id;

		main_screen_id.readDISPLAY();
		main_screen_id.setUndefinedScreenDetailsToDefaultScreen();
		wsi->getScreenResolution(main_screen_id, width, height);

		osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;
		traits->x = 600;
		traits->y = 400;
		traits->width = 1000;
		traits->height = 800;
		traits->windowDecoration = true;
		traits->doubleBuffer = true;
		traits->sharedContext = 0;
		traits->readDISPLAY();
		traits->setUndefinedScreenDetailsToDefaultScreen();

		osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits.get());

		// 第一个视图
		{
			osgViewer::View* view = new osgViewer::View;

			osg::ref_ptr<osg::Node> scene = osgDB::readNodeFile("D:\\osg3.6.5_oe3.1\\OpenSceneGraph_Data\\dumptruck.osg");

			view->setName("View one");
			viewer.addView(view);

			view->setSceneData(scene);

			view->getCamera()->setName("Cam three");
			view->getCamera()->setProjectionMatrixAsPerspective(30.0, double(traits->width) / double(traits->height / 2), 1.0, 1000.0);
			view->getCamera()->setViewport(new osg::Viewport(0, traits->height / 2, traits->width / 2, traits->height / 2));
			view->getCamera()->setGraphicsContext(gc.get());
			view->setCameraManipulator(new osgGA::TerrainManipulator);
		}

		// 第二个视图
		{
			osgViewer::View* view = new osgViewer::View;
			view->setName("View two");

			osg::ref_ptr<osg::Node> scene = osgDB::readNodeFile("D:\\osg3.6.5_oe3.1\\OpenSceneGraph_Data\\cow.osgt");
			viewer.addView(view);

			view->setSceneData(scene);
			view->getCamera()->setName("Cam two");
			view->getCamera()->setViewport(new osg::Viewport(traits->width / 2, traits->height / 2, traits->width / 2, traits->height / 2));
			view->getCamera()->setGraphicsContext(gc.get());
			view->setCameraManipulator(new osgGA::TerrainManipulator);

		}

		// 第三个视图
		{
			osgViewer::View* view = new osgViewer::View;
			view->setName("View three");

			osg::ref_ptr<osg::Node> scene = osgDB::readNodeFile("D:\\osg3.6.5_oe3.1\\OpenSceneGraph_Data\\cessnafire.osgt");
			viewer.addView(view);

			view->setSceneData(scene);
			view->getCamera()->setName("Cam one");
			view->getCamera()->setViewport(new osg::Viewport(0, 0, traits->width / 2, traits->height / 2));
			view->getCamera()->setGraphicsContext(gc.get());

			osg::ref_ptr<osgGA::StateSetManipulator> statesetManipulator = new osgGA::StateSetManipulator;
			statesetManipulator->setStateSet(view->getCamera()->getOrCreateStateSet());

			view->setCameraManipulator(new osgGA::TerrainManipulator);
			view->addEventHandler(statesetManipulator.get());

			view->addEventHandler(new osgViewer::StatsHandler);
			view->addEventHandler(new osgViewer::HelpHandler);
			view->addEventHandler(new osgViewer::WindowSizeHandler);
			view->addEventHandler(new osgViewer::ThreadingHandler);
			view->addEventHandler(new osgViewer::RecordCameraPathHandler);
		}


		// 第四个视图
		{
			osgViewer::View* view = new osgViewer::View;
			view->setName("View four");

			osg::ref_ptr<osg::Node> scene = osgDB::readNodeFile("D:\\osg3.6.5_oe3.1\\OpenSceneGraph_Data\\robot.osg");
			viewer.addView(view);

			view->setSceneData(scene);
			view->getCamera()->setName("Cam one");
			view->getCamera()->setViewport(new osg::Viewport(traits->width / 2, 0, traits->width / 2, traits->height / 2));
			view->getCamera()->setGraphicsContext(gc.get());

			// add the state manipulator
			osg::ref_ptr<osgGA::StateSetManipulator> statesetManipulator = new osgGA::StateSetManipulator;
			statesetManipulator->setStateSet(view->getCamera()->getOrCreateStateSet());

			view->setCameraManipulator(new osgGA::TerrainManipulator);
			view->addEventHandler(statesetManipulator.get());

			view->addEventHandler(new osgViewer::StatsHandler);
			view->addEventHandler(new osgViewer::HelpHandler);
			view->addEventHandler(new osgViewer::WindowSizeHandler);
			view->addEventHandler(new osgViewer::ThreadingHandler);
			view->addEventHandler(new osgViewer::RecordCameraPathHandler);
		}

	}

	return viewer.run();
}