Qt中的GLWidget仅在mousemove上更新

我目前正在玩Qt,试图建立一个小粒子系统。在这里,我对GLWidget进行了子类化并对其进行了黑客攻击。一切都进行得很顺利,直到我做了一些未知的更改,现在小部件只在我移动鼠标时重新绘制(由于我触发了QTimer,它应该一直在这样做)。相关代码:

class OpenGLWidget :  public QGLWidget  {

   Q_OBJECT

public:
   OpenGLWidget(QWidget * parent = 0);
   ~OpenGLWidget();

public slots:
   void toggleEmitter();

protected:
   void initializeGL();
   void paintGL();
   void resizeGL(int width, int height);
   QSize minimumSizeHint() const;
   QSize sizeHint() const;
   void mousePressEvent(QMouseEvent *event);
   void mouseMoveEvent(QMouseEvent *event);

protected slots:
   void timeOut();

private:

   void testFunc(Particle & p, unsigned int t);

   QTime time;
   QTimer timer;

   Emitter emitter;

来自.cpp的相关代码

// in the constructor
time.start();
connect(&timer, SIGNAL(timeout()), this, SLOT(timeOut()));
timer.start(0);

void OpenGLWidget::initializeGL()  {
   GLuint tex = 0;

   qglClearColor(bgColor);
   glEnable(GL_DEPTH_TEST);   
   glClearDepth(1.0f);
    glDepthFunc(GL_LEQUAL);
   glShadeModel(GL_SMOOTH); 

   glDisable(GL_CULL_FACE);
   glEnable(GL_TEXTURE_2D); 
   glEnable( GL_BLEND );
   glBlendFunc( GL_SRC_ALPHA, GL_ONE); // _MINUS_SRC_ALPHA );

   glPointSize(3.0f);

   tex = bindTexture(QPixmap(QString("testparticle2.png")), GL_TEXTURE_2D);
   emitter = Emitter(Vector(0, 0, 0.0f), tex, 50, fastdelegate::FastDelegate2<Particle &, unsigned int>(this, &OpenGLWidget::testFunc));
}

void OpenGLWidget::paintGL()  {
   makeCurrent();
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

   mainCam.SetView();

   glRotatef(xRot, 1, 0, 0);
   glRotatef(yRot, 0, 1, 0);

   emitter.Process(time.elapsed());

   totalTime += time.elapsed();
   time.restart();

}

void OpenGLWidget::resizeGL(int width, int height)  {
   contextWidth = width;
   contextHeight = height;

   glViewport(0, 0, width, height);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluPerspective(55.0f, width / (float) height, 0.01f, 100.0f);

   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

}

void OpenGLWidget::timeOut()  {
   updateGL();
}

void OpenGLWidget::mousePressEvent(QMouseEvent *event)  {
    lastX = event->pos().x();
    lastY = event->pos().y();
}

void OpenGLWidget::mouseMoveEvent(QMouseEvent *event)  {
    int dx = event->x() - lastX;
    int dy = event->y() - lastY;

    if (event->buttons() & Qt::LeftButton) {
        xRot += 3 * dy;
        yRot += 3 * dx;
    } else if (event->buttons() & Qt::RightButton) {
        xRot += 3 * dy;
        yRot += 3 * dx;
    }

    lastX = event->pos().x();
    lastY = event->pos().y();

}