Dynamic texture with QOpenGLWidget gives black texture

[LudoJ49]

I want to draw an opengl quad with a dynamic texture. For now, I want the texture to be updated each time I render the scene. In the futur, I want to update it in a separate thread.

I tried to use QOpenGLFramebufferObject and paint to it, but all I got is a black texture...

Here is what I do :

void QMyOpenGL::initializeGL()
{
	// in header: QOpenGLFramebufferObject* fbo;
	fbo = new QOpenGLFramebufferObject(800, 800);
}

void QMyOpenGL::paintGL()
{
	glClearColor(255, 255, 255, 255);
	glMatrixMode( GL_MODELVIEW );
	glEnable(GL_TEXTURE_2D);
	
	
	fbo->bind();
		//Here, I want to paint my tecture Just try a red cross on a yellow background
		QOpenGLPaintDevice device(fbo->size());
		QPainter painter;
		painter.begin(&device);
			painter.fillRect(0, 0, fbo->width(), fbo->height(), QBrush(Qt::yellow));
			painter.setPen(QPen(QBrush(Qt::red), 5));
			painter.drawLine(0, 0, 800, 800);
		painter.end();
	fbo->release();

	
	glBindTexture(GL_TEXTURE_2D, fbo->texture());
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); // Linear Filtering
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); // Linear Filterin

	
	//this is the quad I want the texture to
	glBegin(GL_QUADS);
		glTexCoord2i(0,0);       glVertex3d(1,1,1);
		glTexCoord2i(1,0);       glVertex3d(1,1,-1);
		glTexCoord2i(1,1);       glVertex3d(-1,1,-1);
		glTexCoord2i(0,1);       glVertex3d(-1,1,1);
	glEnd();
	
	glFlush();
}

Can anybody tell my what I am doing wront ?