c++ - 如何在 openscenegraph 中旋转相机(在模型中穿行)？

Question

我已经在我的场景中加载了 3D 模型，我想在世界中穿行。我实现了向前、向后、向左、向右、向上和向下，但我需要在该摄像头位置围绕 x、y、z 旋转我的摄像头，但我无法获得请帮助我？？

#include <osgViewer/ViewerEventHandlers>
#include <osgDB/ReadFile>
#include <osgViewer/Viewer>

#include <osg/Camera>



#include <math.h>



osg::Matrixd md ;
osg::Matrixd originalmd ;
osg::Quat qua;
float angle=0;

   osgViewer::Viewer viewer;
   osg::Vec3f eye=osg::Vec3f(1.0,-200.0,2.0);
   osg::Vec3f centre=osg::Vec3f(0.0,0.0,0.0);
   osg::Vec3f up=osg::Vec3f(0.0,0.0,1.0);

   osg::Vec3f originaleye=osg::Vec3f(0.0,-200.0,0.0);
   osg::Vec3f originalcentre=osg::Vec3f(0.0,0.0,0.0);
   osg::Vec3f originalup=osg::Vec3f(0.0,0.0,1.0);

   int ConstantVariation=5;


class PickHandler : public osgGA::GUIEventHandler 
{
public: 

PickHandler() {}

~PickHandler() {}

bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& aa);


protected:

};

bool PickHandler::handle(const osgGA::GUIEventAdapter&          ea,osgGA::GUIActionAdapter& aa)
{
switch(ea.getEventType())
{
    case(osgGA::GUIEventAdapter::PUSH):
    {
        osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
        //if (view) pick(view,ea);
        return false;
    }    
    case(osgGA::GUIEventAdapter::KEYDOWN):
    {
        if (ea.getKey()=='c')
        {    
            osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
            osg::ref_ptr<osgGA::GUIEventAdapter> event = new osgGA::GUIEventAdapter(ea);
            event->setX((ea.getXmin()+ea.getXmax())*0.5);
            event->setY((ea.getYmin()+ea.getYmax())*0.5);
           // if (view) pick(view,*event);
        }
        if (ea.getKey()== osgGA::GUIEventAdapter::KEY_Up)
        {   
            std::cout<<"Forward"<<std::endl;

            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans=md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            md.getLookAt(eye,centre,up);

            trans.z()=trans.z()+5;

            md.setTrans(trans);
        }
    if (ea.getKey()==osgGA::GUIEventAdapter::KEY_Down)
        { 
            std::cout<<"BackWard"<<std::endl;  


            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans=md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            md.getLookAt(eye,centre,up);
            trans.z()=trans.z()-5;

            md.setTrans(trans);

        }
        if (ea.getKey()==osgGA::GUIEventAdapter::KEY_Left)
        {        

            std::cout<<"LEFT Side"<<std::endl;

            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans=md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            md.getLookAt(eye,centre,up);

            trans.x()=trans.x()+5;

            md.setTrans(trans);
        }

        if (ea.getKey()==osgGA::GUIEventAdapter::KEY_Right)
        {        

            std::cout<<"Right Side"<<std::endl;

            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans = md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            trans.x()=trans.x()-5;
            md.setTrans(trans);


        }
        if(ea.getKey()==osgGA::GUIEventAdapter::KEY_Page_Up)
        {
            std::cout<<"UP"<<std::endl;

            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans = md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            trans.y()=trans.y()-5;
            md.setTrans(trans);


        }

        if(ea.getKey()==osgGA::GUIEventAdapter::KEY_Page_Down)
        {
            std::cout<<"Down"<<std::endl;

            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans = md.getTrans();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            trans.y()=trans.y()+5;
            md.setTrans(trans);


        }

        if(ea.getKey()==osgGA::GUIEventAdapter::KEY_8)
        {
            std::cout<<"Rotation"<<std::endl;
            md=viewer.getCamera()->getViewMatrix();
            osg::Vec3d trans=md.getTrans();
            double a=trans.x();
            double b=trans.y();
            double c=trans.z();
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;
            md.setTrans(osg::Vec3d(0,0,0));
            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;

            angle=0.077;
            //osg::Quat qa(angle,osg::Vec3d(0.0,0.0,1.0));

            md.getLookAt(eye,centre,up);
            osg::Quat qa(angle,up);
            md.setRotate(qa);
            up=md.getRotate()*trans;

            md.setRotate(qa);
            trans.x()=a;
            trans.y()=b;
            trans.z()=c;
            md.setTrans(trans);

            std::cout<<"translation="<<trans.x()<<","<<trans.y()<<","<<trans.z()<<std::endl;
            std::cout<<" End Rotation"<<std::endl;
        }           


        if(ea.getKey()==osgGA::GUIEventAdapter::KEY_Space)
        {
            md=originalmd;

        }
        return false;
    }    
    default:
        return false;
 }
}



int main( int argc, char **argv )
{



osg::ref_ptr<osg::Group> scene = new  osg::Group;

scene->addChild(osgDB::readNodeFile("cessna.osg"));

viewer.addEventHandler(new osgViewer::WindowSizeHandler);
viewer.addEventHandler(new PickHandler());

viewer.setSceneData(scene.get());

const osg::BoundingSphere& bs = scene->getBound();


viewer.getCamera()->setViewMatrixAsLookAt(bs.center()+osg::Vec3(0.0f, -(3*bs.radius()),0.0f), bs.center(), osg::Z_AXIS) ;

md=viewer.getCamera()->getViewMatrix();
originalmd=md;



viewer.realize();

while(!viewer.done())
{
    viewer.getCamera()->setViewMatrix(md);
    viewer.frame();
 }


}

编辑:-我怀疑我是否以正确的方式执行任务，即我需要移动相机但上面的代码翻译和旋转对象以感觉相机旋转......许多网站说在 opengl 中没有相机链接(https://www.opengl.org/archives/resources/faq/technical/viewing.htm) .

Answer 1

就像翻译一样，您使用 getTrans() 获取现有翻译并向其添加增量或减量，类似地对于旋转也使用 getRotate() 获得现有旋转然后给它加一个小的增量或减量，不要每次都直接设置相同的值。