FPS摄像机自行旋转.QT 4.8 OpenGL C

我正在尝试移植从sfml到qt上编写的高度图可视化程序，因此可以在窗口上显示并由GUI元素控制。

问题是，当我启动应用程序时，相机开始非常快地在其中心周围滚动（实际上，它看起来像是地形网绕着相机飞行，就像太阳周围的地球一样，没有任何动作我的身边（例如移动鼠标，按按钮）。

当我按下W，A，S，D时，相机应向前移动，向后，向左，右，并在移动鼠标时环顾四周（只是典型的FPS摄像机行为）。

我认为这个问题在程序的主要循环中，因为它不是QT中的标准while(true){ //do something// }方法，而且有点令人困惑。

这是我的代码：

oglwidget class （在这里我在绘画。

class OGLWidget :
    public QGLWidget
{
    Q_OBJECT
public:
    OGLWidget(QWidget *parent = 0);
    ~OGLWidget(void);
public:
    void paintGL();
    void initializeGL();
    void resizeGL();
public:
    void updateCamera();
public slots:
    void mainLoop();
protected:
    void keyPressEvent(QKeyEvent *e);
    void keyReleaseEvent(QKeyEvent *e);
private:
    Terrain _terrain;
    Camera  _camera;
private:
    int           _keyPressed;
    QTimer        _timer;
    QElapsedTimer _elapsedTimer;
    float         _simulationTime;
    float         _fps;
};

OGLWidget::OGLWidget(QWidget *parent)  : QGLWidget(parent)
{
    _terrain.loadHeightMap("normalHeightMap256_2.png");
    _camera.setScreenDimension(this->width(), this->height());
    //setting vertical sync
    QGLFormat frmt;
    frmt.setSwapInterval(1);
    setFormat(frmt);
    setMouseTracking(true);
    setFocus();
    _simulationTime = 0;
    _fps = 1.f / 60.f;
    connect(&_timer, SIGNAL(timeout()), this, SLOT(mainLoop()));
    _timer.start();
    _elapsedTimer.start();
}

OGLWidget::~OGLWidget(void)
{
}
void OGLWidget::mainLoop()
{
    _simulationTime += _elapsedTimer.elapsed();
    _elapsedTimer.restart();
    while(_simulationTime > _fps)
    {
        _simulationTime -= _fps;
        updateCamera();
    }
    updateGL();
}
void OGLWidget::updateCamera()
{
    QPoint p = mapFromGlobal(QCursor::pos());
    _camera.computeMatrices(p.x(), p.y(), _fps, _keyPressed);
    glm::mat4 ViewMatrix = _camera.getViewMatrix();
    glm::mat4 ProjectionMatrix = _camera.getProjectionMatrix();
    glm::mat4 ModelMatrix = glm::mat4(1.0);
    _terrain.setMvp(ProjectionMatrix * ViewMatrix * ModelMatrix);
    QPoint center = mapToGlobal(QPoint(this->width() / 2, this->height() / 2));
    QCursor::setPos(center);
}
void OGLWidget::initializeGL()
{
    glewExperimental = GL_TRUE;
    if (glewInit() != GLEW_OK) 
    {
        return;
    }
    glViewport(0, 0, this->width(), this->height());
   _terrain.init();
}
void OGLWidget::paintGL()
{
    _terrain.draw();
}
void OGLWidget::resizeGL()
{
    glViewport(0, 0, this->width(), this->height());
}
void OGLWidget::keyPressEvent(QKeyEvent *e)
{
    switch(e->key())
    {
    case Qt::Key::Key_Escape:
        exit(0);
        break;
    case Qt::Key::Key_W:
        _keyPressed = Key::KEY_PRESSED_UP;
        break;
    case Qt::Key::Key_S:
        _keyPressed = Key::KEY_PRESSED_DOWN;
        break;
    case Qt::Key::Key_A:
        _keyPressed = Key::KEY_PRESSED_LEFT;
        break;
    case Qt::Key::Key_D:
        _keyPressed = Key::KEY_PRESSED_RIGHT;
        break;
    }
}
void OGLWidget::keyReleaseEvent(QKeyEvent *e)
{
    if(e->key() == Qt::Key::Key_W ||
       e->key() == Qt::Key::Key_S ||
       e->key() == Qt::Key::Key_A ||
       e->key() == Qt::Key::Key_D)
       _keyPressed = KEY_RELEASED;
}

我绝对确定地形和相机课程正确，因为自SFML项目以来我没有更改代码（除了使用Qimage而不是SF :: Image，但它也可以正确使用）

*相机主算法： *

void Camera::computeMatrices(int mouseXpos, int mouseYpos, float deltaTime, int keyPressed)
{
    _horizontalAngle += _mouseSpeed * deltaTime * float(_screenWidth / 2 - mouseXpos);
    _verticalAngle += _mouseSpeed * deltaTime * float(_screenHeight / 2 - mouseYpos);
    _direction = glm::vec3
    (
        cos(_verticalAngle) * sin(_horizontalAngle),
        sin(_verticalAngle),
        cos(_verticalAngle) * cos(_horizontalAngle)
    );
    glm::vec3 right = glm::vec3
    (
        sin(_horizontalAngle - 3.14f/2.0f), 
        0,
        cos(_horizontalAngle - 3.14f/2.0f)
    );
    glm::vec3 up = glm::cross( right, _direction );
    switch(keyPressed)
    {
    case Key::KEY_PRESSED_UP:
        _position += _direction * deltaTime * _speed;
        break;
    case Key::KEY_PRESSED_DOWN:
        _position -= _direction * deltaTime * _speed;
        break;
    case Key::KEY_PRESSED_LEFT:
        _position -= right * deltaTime * _speed;
        break;
    case Key::KEY_PRESSED_RIGHT:
        _position += right * deltaTime * _speed;
        break;
    case Key::KEY_RELEASED:
        break;
    }
    _projectionMatrix = glm::perspective(_initialFoV, 4.0f / 3.0f, 0.1f, 1000.0f);
    _viewMatrix = glm::lookAt
    (
        _position,            // Camera is here
        _position+_direction, // and looks here : at the same position, plus "direction"
        up                    // Head is up (set to 0,-1,0 to look upside-down)
    );
}