I have a display function that clears the screen and draws the user interface on the left side of the screen. The right side of the screen is an empty canvas and allows user to draw things on it. However, the drawn objects are not 'saved' and will be cleared when glutPostRedisplay() is called. But the display function would automatically be called whenever it is resized, is there a way to stop this? Or do I have to save all the shapes that is drawn and draw it all in the display function instead? Thank you.