Qt gets matrix data

[Qt_crazyer]

I am drawing some 3D graphics on QOpenGLWidget. I want to use glGetFloatv(GL_MODELVIEW_MATRIX, m) to get the model-view matrix. But a problem occurs. When I use this function in my paintGL loop. I can get the right results. When I put this function in the mousePressEvent, the matrix m always an unit matrix.
Is it related to the Thread? Thanks in advance.
Qt Creator 5.9.1 on windows10

float m[16];

void Coordinary::paintGL()
{
    const qreal retinaScale = devicePixelRatio();
    glViewport(0, 0, width() * retinaScale, height() * retinaScale);

    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);

    glBegin(GL_TRIANGLES);

    glColor3f(1.0f,0.2f,0.3f);
    glVertex3f(1.0f,0.0f,0.0f);
    glColor3f(0.4f,1.0f,0.8f);
    glVertex3f(0.0f,1.0f,0.0f);
    glColor3f(0.1f,0.7f,1.0f);
    glVertex3f(0.0f,0.0f,1.0f);

    glEnd();

    update();

    glGetFloatv(GL_MODELVIEW_MATRIX, m);
}

void Coordinary::mousePressEvent(QMouseEvent *event)
{
    if(event->button() == Qt::RightButton)
    {
        glGetFloatv(GL_MODELVIEW_MATRIX, m);
    }
}

[beecksche]

Hi @Qt_crazyer

i'm really not into OpenGL but try the QOpenGLFunctions:

QOpenGLFunctions *glFuncs = QOpenGLContext::currentContext()->functions();
glFuncs-> glGetFloatv(GL_MODELVIEW_MATRIX, m);