osg学习（七十）如何根据视口对象自动调整视点位置距离

Posted 2022-03-16 hankern

 

osgGA/CameraManipulator.cpp
void CameraManipulator::computeHomePosition(const osg::Camera *camera, bool useBoundingBox)

    double dist = 3.5f * boundingSphere.radius();
    if (camera)
        

            // try to compute dist from frustum
            double left,right,bottom,top,zNear,zFar;
            if (camera->getProjectionMatrixAsFrustum(left,right,bottom,top,zNear,zFar))
            
                double vertical2 = fabs(right - left) / zNear / 2.;
                double horizontal2 = fabs(top - bottom) / zNear / 2.;
                double dim = horizontal2 < vertical2 ? horizontal2 : vertical2;
                double viewAngle = atan2(dim,1.);
                dist = boundingSphere.radius() / sin(viewAngle);
            
    
    // set home position
        setHomePosition(boundingSphere.center() + osg::Vec3d(0.0,-dist,0.0f),
                        boundingSphere.center(),
                        osg::Vec3d(0.0f,0.0f,1.0f),
                        _autoComputeHomePosition);