Opengl/Qt Design Problem!

Hello!

I have a problem concerning the design of a opengl/qt programm.

I create a subclass from QGLWidget and overwrite the paintGl-method to do my renderstuff.
My subclass should have a vector with drawables. Drawables is a abstract class with a renderfunction. In this function every subclass from drawable should do their opengl stuff.
Something like this:

Code:

---

class Drawable {
virtual void render()=0;
}
 
class MyFirstObject : public Drawable {
 
void render() {
   glBegin(GL_QUAD)
   ...
  glEnd()
}
}
 
class GLWidget: public QGLWidget {
 
void paintGl() {
for(int i=0; i< drawables.size();i++) {
          drawables.render();
}
}

---

The problem is, that i don't have an active opengl context in my drawables and so the opengl functions don't work. How can i solve this problem?