title: how to make updateGL() realtime in QT
body: <p>I wonder if calling updateGL() in fixed timer intervals may slow down the rendering process. So, I want to try making the render real time. I do not the function to make it execute automatically. Anyone knows that? </p>
  
  <p>secondly, I commented updateGL() in my program, CPU usage reduced to 1% and 0%. Now, when I click on the display widget it jumps to 14%, why? isn't GPU doing all the rendering job? if yes why CPU jumps to 14? how can I resolve this?</p>