widowss 发表于 2015-7-11 15:23:58

getViewMatrixAsLookAt的问题

各位好。新人遇到一个困惑的问题

//将参数设置给相机,并立即获取相机参数
viewer.setCameraManipulator(NULL);
viewer.getCamera()->setViewMatrixAsLookAt(eye,center,up);
viewer.getCamera()->getViewMatrixAsLookAt(eye,center,up);

//将各参数打印出来
    printf("eye: %f,%f,%f new\n",eye._v,eye._v,eye._v);
    printf("center: %f,%f,%f new\n",center._v,center._v,center._v);
    printf("up: %f,%f,%f new\n",up._v,up._v,up._v);

问题是,getViewMatrixAsLookAt修改了我eye,center,up参数值,我f5调试跟,发现是在这个方法里面
void Matrix_implementation::getLookAt(Vec3d& eye,Vec3d& center,Vec3d& up,value_type lookDistance) const
{
    Matrix_implementation inv;
    inv.invert(*this);

    // note: e and c variables must be used inside this method instead of eye and center
    // because eye and center are references and they may point to the same variable.
    Vec3d e = osg::Vec3d(0.0,0.0,0.0)*inv;
    up = transform3x3(*this,osg::Vec3d(0.0,1.0,0.0));
    Vec3d c = transform3x3(*this,osg::Vec3d(0.0,0.0,-1));
    c.normalize();
    c = e + c*lookDistance;

    // assign the results
    eye = e;
    center = c;
}

不是很懂原理,请大侠指点。
页: [1]
查看完整版本: getViewMatrixAsLookAt的问题