getProjectionMatrixAsOrtho

liyang2014

int main()
{
        osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
        osg::Vec3 eye;
        osg::Vec3 center;
        osg::Vec3 up;
        viewer->getCamera()->getViewMatrixAsLookAt(eye,center,up);
        osg::ref_ptr<osg::Camera> cameraMaster = viewer->getCamera();
        osg::Matrix _inverseMV;
        _inverseMV.invert( cameraMaster->getViewMatrix());//getviewMatrix视图矩阵
        //getProjectMatrix获取投影矩阵
        osg::Vec3 ptEye= osg::Vec3(  0, 0, 0) * _inverseMV;
        double left=0.0f;
        double right=0.0f;
        double bottom=0.0f;
        double top=0.0f;
        double znear=0.0f;
        double zfar=0.0f;
        cameraMaster->getProjectionMatrixAsOrtho(left, right, bottom, top, znear, zfar);
        osg::ref_ptr<osg::Group> root = new osg::Group();
        //加入渐变文字
        root->addChild(createFadeText());
        //读取地形模型
        osg::ref_ptr<osg::Node> node = osgDB::readNodeFile("lz.osg");
        root->addChild(node.get());
        //优化场景数据
        osgUtil::Optimizer optimizer ;
        optimizer.optimize(root.get()) ;
        viewer->setSceneData(root.get());
        viewer->realize();
        viewer->run();
        return 0 ;
}

这个投影矩阵，left, right, bottom, top, znear, zfar都设置为0，为什么执行完cameraMaster->getProjectionMatrixAsOrtho(left, right, bottom, top, znear, zfar); 这些参数信息还是0