[openGL with Qt] updating of screen when paintGL is updated

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Hello all,

I have a problem with the display in OpenGL. Currently I have a program that plot little by little some things in an openGL window.

=> i want to update screen each time that i go in the method "plotGL" but i don't know how i can do that

=> I noticed that openGL screen is updated if I increase the size of the openGL window but this update of the display is not automatically

So, How can I update my screen each time that i go in the paintGL function?

thank you in advance for your help

ps: I tried repaint () and updateGL () but it does not work then call these methods paintGL, it makes me so all block

this is my code:

void myGLWidget::paintGL()
{
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glClearColor(1.0f,1.0f,1.0f,1.0f);
        glMatrixMode( GL_MODELVIEW );
        glLoadIdentity( );
        gluLookAt( 1.2, 1.7, 1.0, 0, 0, 0, 0, 0, 1);
        glBegin(GL_LINES);
        //plot
        glEnd();
//        updateSCREEN();
}

void myGLWidget::paintGL()
{
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
        glClearColor(1.0f,1.0f,1.0f,1.0f);
        glMatrixMode( GL_MODELVIEW );
        glLoadIdentity( );
        gluLookAt( 1.2, 1.7, 1.0, 0, 0, 0, 0, 0, 1);
        glBegin(GL_LINES);
        //plot
        glEnd();
//        updateSCREEN();
}

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i have tried to decomment the line "updateSCREEN();" and put this method

void myGLWidget::updateSCREEN()
{
    updateGL();
//repaint(); //i have tried this too
}

void myGLWidget::updateSCREEN()
{
    updateGL();
//repaint(); //i have tried this too
}

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but it don't works, it creates a general blocage of alls my windows

Can you help me please? thanks a lot