OpenSceneGraph 3D编程切换鼠标灵敏度

Question

我需要输入代码来切换鼠标的灵敏度 - 增加或减少相机在场景中的行走速度。目前，我有一个事件处理程序连接到拦截键盘命令，并相应地处理它们。缺少的是使用选定数量减慢/提高速度的正确代码。 我在下面的枚举中描述了可接受的增加/减少值。

enum CameraSpeed {_WALK = 10, _BRISK_WALK = 17, _JOG = 23, _RUN = 31, _RUN_FAST = 34, _FLY=60};
 CameraSpeed _current_camera_speed;

我尝试覆盖CameraManipulator的基类的bool performMovement（）方法，但经过仔细检查，这似乎不是我需要覆盖或用于此目的的代码。我会感谢一些帮助，不仅要找到正确的方法，还要修改它，这样我就能更好地控制灵敏度。

bool WalkingCameraManipulator::performMovement()
{
    // return if less then two events have been added
    if( _ga_t0.get() == NULL || _ga_t1.get() == NULL )
        return false;

    // get delta time
    double eventTimeDelta = _ga_t0->getTime() - _ga_t1->getTime();
    if( eventTimeDelta < 0. )
    {
        OSG_WARN << "Manipulator warning: eventTimeDelta = " << eventTimeDelta << std::endl;
        eventTimeDelta = 0.;
    }

    // get deltaX and deltaY
    float dx = (_ga_t0->getXnormalized() - _ga_t1->getXnormalized()/_current_camera_speed);
    float dy = (_ga_t0->getYnormalized() - _ga_t1->getYnormalized())/_current_camera_speed;

    // return if there is no movement.
    if( dx == 0. && dy == 0. )
        return false;


    // call appropriate methods
    unsigned int buttonMask = _ga_t1->getButtonMask();
    if( buttonMask == GUIEventAdapter::LEFT_MOUSE_BUTTON )
    {
        return performMovementLeftMouseButton( eventTimeDelta, dx, dy );
    }
    else if( buttonMask == GUIEventAdapter::MIDDLE_MOUSE_BUTTON ||
            buttonMask == (GUIEventAdapter::LEFT_MOUSE_BUTTON | GUIEventAdapter::RIGHT_MOUSE_BUTTON) )
    {
        return performMovementMiddleMouseButton( eventTimeDelta, dx, dy );
    }
    else if( buttonMask == GUIEventAdapter::RIGHT_MOUSE_BUTTON )
    {
        return performMovementRightMouseButton( eventTimeDelta, dx, dy );
    }

    return false;
}