void
CameraManipulator::setViewpoint(const Viewpoint& vp, double duration_seconds)
{// If the manip is not set up, save the viewpoint for later.if ( !established() ){_pendingViewpoint = vp;_pendingViewpointDuration.set(duration_seconds, Units::SECONDS);}else{// Save any existing tether node so we can properly invoke the callback.osg::ref_ptr<osg::Node> oldEndNode;if ( isTethering() && _tetherCallback.valid() )_setVP1->getNode(oldEndNode);// starting viewpoint; all fields will be set:_setVP0 = getViewpoint();// ending viewpoint_setVP1 = vp;// Reset the tethering offset quat._tetherRotationVP0 = _tetherRotation;_tetherRotationVP1 = osg::Quat();// Fill in any missing end-point data with defaults matching the current camera setup.// Then all fields are guaranteed to contain usable data during transition.double defPitch, defAzim;getEulerAngles( _rotation, &defAzim, &defPitch );if ( !_setVP1->heading().isSet() )_setVP1->heading() = Angle(defAzim, Units::RADIANS);if ( !_setVP1->pitch().isSet() )_setVP1->pitch() = Angle(defPitch, Units::RADIANS);if ( !_setVP1->range().isSet() )_setVP1->range() = Distance(_distance, Units::METERS);if ( !_setVP1->nodeIsSet() && !_setVP1->focalPoint().isSet() ){osg::ref_ptr<osg::Node> safeNode;if ( _setVP0->getNode( safeNode ) )_setVP1->setNode( safeNode.get() );else_setVP1->focalPoint() = _setVP0->focalPoint().get();}_setVPDuration.set( std::max(duration_seconds, 0.0), Units::SECONDS );OE_DEBUG << LC << "setViewpoint:\n"<< "    from " << _setVP0->toString() << "\n"<< "    to   " << _setVP1->toString() << "\n";// access the new tether node if it exists:osg::ref_ptr<osg::Node> endNode;_setVP1->getNode(endNode);// Timed transition, we need to calculate some things:if ( duration_seconds > 0.0 ){// Start point is the current manipulator center:
            osg::Vec3d startWorld;osg::ref_ptr<osg::Node> startNode;startWorld = _setVP0->getNode(startNode) ? computeWorld(startNode.get()) : _center;_setVPStartTime.unset();// End point is the world coordinates of the target viewpoint:
            osg::Vec3d endWorld;if ( endNode.valid() )endWorld = computeWorld(endNode.get());else_setVP1->focalPoint()->transform( _srs.get() ).toWorld(endWorld);// calculate an acceleration factor based on the Z differential._setVPArcHeight = 0.0;double range0 = _setVP0->range()->as(Units::METERS);double range1 = _setVP1->range()->as(Units::METERS);double pitch0 = _setVP0->pitch()->as(Units::RADIANS);double pitch1 = _setVP1->pitch()->as(Units::RADIANS);double h0 = range0 * sin( -pitch0 );double h1 = range1 * sin( -pitch1 );double dh = (h1 - h0);// calculate the total distance the focal point will travel and derive an arc height:double de = (endWorld - startWorld).length();// maximum height during viewpoint transitionif ( _settings->getArcViewpointTransitions() ){_setVPArcHeight = osg::maximum( de - fabs(dh), 0.0 );}// calculate acceleration coefficientsif ( _setVPArcHeight > 0.0 ){// if we're arcing, we need seperate coefficients for the up and down stagesdouble h_apex = 2.0*(h0+h1) + _setVPArcHeight;double dh2_up = fabs(h_apex - h0)/100000.0;_setVPAccel = log10( dh2_up );double dh2_down = fabs(h_apex - h1)/100000.0;_setVPAccel2 = -log10( dh2_down );}else{// on arc => simple unidirectional acceleration:double dh2 = (h1 - h0)/100000.0;_setVPAccel = fabs(dh2) <= 1.0? 0.0 : dh2 > 0.0? log10( dh2 ) : -log10( -dh2 );if ( fabs( _setVPAccel ) < 1.0 ) _setVPAccel = 0.0;}// Adjust the duration if necessary.if ( _settings->getAutoViewpointDurationEnabled() ){double maxDistance = _srs->getEllipsoid()->getRadiusEquator();double ratio = osg::clampBetween( de/maxDistance, 0.0, 1.0 );ratio = accelerationInterp( ratio, -4.5 );double minDur, maxDur;_settings->getAutoViewpointDurationLimits( minDur, maxDur );_setVPDuration.set( minDur + ratio*(maxDur-minDur), Units::SECONDS );}}else{// Immediate transition? Just do it now._setVPStartTime->set( _time_s_now, Units::SECONDS );setViewpointFrame( _time_s_now );}// Fire a tether callback if required.if ( _tetherCallback.valid() ){// starting a tether to a NEW node:if ( isTethering() && oldEndNode.get() != endNode.get() )(*_tetherCallback)( endNode.get() );// breaking a tether:else if ( !isTethering() && oldEndNode.valid() )(*_tetherCallback)( 0L );}}// reset other global state flags._thrown      = false;_task->_type = TASK_NONE;
}